HP vs STU vs B-Spec vs T1 pace at Buttonwillow Raceway Park
Quickest here:HP 2:03.082 Lee Fleming, Cal Club 2025 race · STU 1:50.913 Tony Rivera, Cal Club 2026 qualifying · B-Spec 2:09.353 Trenton Kramer, Cal Club 2026 qualifying · T1 1:46.465 Ian Barberi, Cal Club 2025 qualifying
HPSTUB-SpecT1solid race · dashed qualifying · slower is lower
HPSTUB-SpecT1solid race · dashed qualifying · each class's best lap as a share of HP's at the same event (the reference class, changeable above); 100% is level, higher is quicker
Event
HP
STU
B-Spec
T1
Qual best
Race best
Trap
Qual best
Race best
Trap
vs HP
% of HP
Qual best
Race best
Trap
vs HP
% of HP
Qual best
Race best
Trap
vs HP
% of HP
Cal Club 2026 CALCL262026-02-21
2:04.965Brian Linn · fastest of 3 · top 3 within 4.8s-1.805s (-1.42%)
2:03.324Lee Fleming · fastest of 3 · top 3 within 0.9s+0.242s (+0.20%)
126.2Lee Fleming+25.8 mph (+25.7%)
1:50.913Tony Rivera · fastest of 6 · top 5 within 14.1s-4.488s (-3.89%)
1:52.737Tony Rivera · fastest of 7 · top 5 within 7.7s-0.903s (-0.79%)
135.2Tony Rivera+21.8 mph (+19.3%)
-10.587squal -14.052s
91.4%qual 88.8%
2:09.353Trenton Kramer · fastest of 5 · top 5 within 6.1s-1.160s (-0.89%)
2:09.916Trenton Kramer · fastest of 5 · top 5 within 2.7s-0.138s (-0.11%)
121.5Trenton Kramer+23.3 mph (+23.8%)
+6.592squal +4.388s
105.3%qual 103.5%
1:59.760Ed Gless · only car+13.295s (+12.49%)
1:59.123Ed Gless · only car+11.689s (+10.88%)
120.7Ed Gless-18.6 mph (-13.3%)
-4.201squal -5.205s
96.6%qual 95.8%
83 rule changes (HP: 29, STU: 17, B-Spec: 24, T1: 13)24 weight · 9 cars added · 8 induction · 6 engine · 5 tyres & wheels · 2 suspension & brakes · 1 removed · 27 wording · 1 other · C-Spec rear sway bars approved for Chevrolet Cruze, Dodge Dart, Ford Focus, Honda Civic, Mazda3i, Toyota Corolla with specified part numbers. · HP Triumph Spitfire 1296cc compression ratio increases from 11.0 to 12.0:1. · T1 Corvette C6 LS1/LS6 Spec Line reinstated: 3200 lbs minimum weight, 70mm restrictor required. · B-Spec Chevrolet Sonic and Ford Fiesta, Honda Fit notes reorganized from individual allowances to approved parts lists; wording cleanup. · B-Spec: Sonic restrictors removed, Fit MT +25 lbs to 2550, Fit CVT restrictor removed, Mini Coopers restrictors increased 2-4 mm, Versa sedans -25 lbs to 2425, Versa/IA restrictors removed. · B-Spec Mazda2 10-14 cat-delete header swap removes 50 lb weight adder option, now Mazda Motorsports PN only. · HP Toyota MR-2 1.6L (85-89) compression ratio set to 11.0:1. · BMW 2002 newly classified to H Production at 2350 lbs with 1990cc iron block, 40 DCNF carburetor, 11.0:1 compression. · STU Mazda MZR (LF, L3, L5) Turbo classified; Jack Spania Racing 70 mm intake manifold and Fab9 Tuning bottom-mount turbo kit approved. · T1 Spec Line restrictor changes from 70mm flat plate to unspecified new specification. · Datsun SPL-311 newly classified to HP at 2050 lbs with 1595cc OHV iron engine and specified carburetors. · EP Triumph TR2-TR4A allows 5-speed gearbox without overdrive; removes Weber carb and weight specification. · EP BMW Z3 2.5L restrictor reduced 52mm to 50mm, weight increased to 2550 lbs base; five other BMW models get smaller restrictors. · HP Honda Civic and CRX models get wider 13-inch wheels: 6 to 7 inches. · STU 36mm restrictor allows 2830 lbs (up 10 lbs from 2820); 37mm allows 2980 lbs (down 5 lbs from 2985). · STU cars over 3150 lbs lose 275-tire option with 2% weight adder. · STU Honda K20 and K24 engines lose 2% minimum weight penalty. · Unable to summarize: letter states intent but provides no actual rule changes to S2000 specification. · T1 non-GT4 cars: multiple restrictors enlarged (70mm to 73mm, 75mm to 78mm, 55mm to 60mm, 61mm to 70mm); one weight increased to 3600. · T1 BMW M3 E92 (08-13) Spec Line 1090 removed entirely. · B-Spec Honda Fit MT 07-08 allows Torque Solution Shifter Cable Bushing kit TS-SCB-506. · B-Spec Ford Fiesta Hatchback and Sedan gain 55 lbs to 2525; restrictors increase 1 mm. · B-Spec Hyundai Accent and Kia Rio remove Bilstein B8 shock 33-187112 rear suspension approval. · B-Spec Honda Fit MT (07-08) becomes Runoffs-eligible; previous three-weekend Super Tour requirement removed. · EP Nissan 280Z minimum weight reduced from 2560 to 2400 lbs. · EP Mazda MX-5 1.8L 90-97 weight reduced to 2125 lbs from 2150 lbs. · HP Austin-Healey Sprite/Midget 1098cc minimum weight drops 80 lbs to 1550. · HP Volvo 142/142E gains compression ratio limit 12.0:1 and valve lift limit .425". · HP Mini Cooper 07-15 valve lift reduced to .390", from .450". · FP and HP Volkswagen Rabbit descriptions updated: Convertible changed to Cabriolet in FP; Cabriolet added to three HP engine variants. · EP, FP, HP: rear drum brake to disc conversion clarified; rotors solid, diameter limited to largest front rotor permitted. · EP Ford Mustang (94-98) fuel injected throttle body inside diameter specified at 60. · STU Honda K24 engine swap weight increases by 2% effective November 1, 2025. · HP Plymouth Arrow transmission max speeds clarified to 4 or 5. · EP, FP, HP wheel diameter added to Appendix G as absolute maximum specification. · EP, FP, HP throttle body inside dimensions must remain stock with +/-.25mm tolerance; butterfly dimensions stock in FP, HP only. · B-Spec and C-Spec: asterisk removed from public road usage note in rule 9.1.10.D.9. · STU Lotus Elise SC and Exige SC weight reduced from 2450 to 2250 lbs. · B-Spec Honda Fit MT 09-14 two pedal shutdown may be disabled by cutting/de-pinning pin 42 BKSW at main ECU connector. · B-Spec Honda Fit MT 07-08 intake restricted to Injen SP1511 only, from any Cold Air Intake Package. · STU-TCR tire width increases to 275 with weight adder raised from 100 to 150 pounds. · STL/STU Lotus weight reduced: Evora GT4 to 2700 lbs, Elise Cup R to 2250 lbs, Elise/Exige SC to 2450-2550 lbs. · EP BMW Z4 03-05 restricted to 52mm flat plate intake restrictor. · EP Fiat 124 Spider 1600 & 2000 weight drops 50 lbs to 2000; carburetors gain 2mm chokes to 36mm. · STU 2.8-3.2L N/A engines now allow 245 max tire width; over 3150 lbs may run 275 with 2% weight penalty. · STU Mazda MZR may use Goodwin 61-2510 or Gato Performance 31972 intake manifold. · STU Honda JDM H23a added, 2259cc displacement, minimum weight per Chart, must meet ST engine regulations. · B-Spec adds Hyundai Accent Sedan (12-17) and Kia Rio Sedan (12-17), both 1591cc, 2525 lbs, 40mm FPR restrictor. · B-Spec Honda Fit MT 09-14 allows Acuity Shifter Base Bushing Kit 1954. · B-Spec Honda Fit AT 09-14 adds Weapon R Intake 301-166-301 to approved parts. · B-Spec and C-Spec shift linkage/cables no longer prohibited from any modification; approved aftermarket bushings now permitted. · HP Fiat X-1/9 base weights reduced 50–53 lbs across 1300 and 1500 spec lines. · B-Spec Hyundai Accent Hatchback and Kia Rio Hatchback model year ranges corrected. · B-Spec 07-08 Honda Fit MT minimum weight increases 50 lbs, to 2450. · Honda Fit 07-08 MT and AT approved for Bilstein B14 kit 47172401 in B-Spec. · STU wheel width rules clarified: cars ≤2,850 lbs max 8 inches, cars >2,850 lbs max 9 inches. · STU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments. · Porsche 981 GT4 Clubsport added to T1 as spec line 4085, minimum weight 3100 lbs with driver. · T1 Honda S2000 minimum weight reduced from 2950 lbs to 2900 lbs. · T1 BMW E46 M3 permits BMW #GS7D36SG aftermarket sequential transmission in SL# 1060 and 1070. · T1 BMW M3 E92 minimum weight reduced to 3300 lbs. · T1 Mustang Darkhorse R gets 315 front and rear tyres, loses 500 lbs minimum weight to 3600. · B-Spec Honda Fit MT intake now limited to three models with 25lb adder; Mazda2 exhaust headers allowed with up to 50lb adder; Mini Coopers FPR increased 1-2 points; Nissan Versa sedans 40lbs lighter, Yaris models 50lbs lighter. · B-Spec Hyundai Accent and Toyota Yaris weight adjustments: ±25 lbs based on rear brake type. · B-Spec Hyundai Accent and Kia Rio (12-19) allow Bilstein B14 kit #47167490 front shocks and BabyFace Fabrication sump extension #BF-HYU-PAN. · Chevrolet Spark 16-22 classified HP Pre at 1850 lbs minimum weight, fuel injected, 1399 cc. · HP Ford Festiva 88-93 minimum weight drops to 1600 lbs, variants to 1640 and 1680 lbs; compression ratio raised to 11.0:1. · Cadillac CT4-V Blackwing added to T1 Spec Line 1115, 3564cc, 3750 lbs minimum weight. · B-Spec Toyota Yaris Hatchback 12-18 rear brakes now allow 10.2 inch disc alternative to 7.9 drum. · B-Spec Toyota Yaris Hatchback and Sedan may now disconnect speed sensor. · B-Spec Fiat 500 (12-17) spec line expires 1/1/26 unless appeal filed. · EP BMW Z3 and 3-series models get smaller intake restrictors: Z3 2.5L to 52mm, Z3 2.8L to 55mm, 328i to 58mm, 325i to 56mm. · HP Mazda 2 11-14 base weight up 50 lbs to 2045; all VW 80s models up 50 lbs to 2150 base. · EP, FP, HP: interior or exterior mirrors meeting rule 9.3.36 now permitted. · EP Honda S2000 1997cc base loses 75 lbs to 2375; 2157cc base loses 60 lbs to 2450. · EP Mazda MX-5/Miata 99-05 minimum weight drops to 2100 lbs, 2153 lbs with power adder, 2205 lbs with two adders. · HP Mini Cooper 07-13 engine corrected to DOHC; valve lift limit reduced to 0.390 inches. · STU BMW N54/N55 3.0L classified at Chart +3% minimum weight; N54 twin turbo not allowed. · STU Mini Cooper S SC supercharger pulley diameter reduced from 2.285 to 2.185. · STU Honda K20C1 Turbo I4 exempted from 3% DI weight adder in Spec Lines Table A. · STU GT3U minimum weight increases 150 to 250 pounds. · T1 Mustang Spec 1430 restrictor opens 60mm to 65mm; Spec 1460 weight rises to 3500 lbs, restrictor 70mm; Corvette 1190 restrictor opens 67mm to 70mm; BMW 1090 restrictor narrows 40mm to 35mm; BMW 1100 weight rises to 3350 lbs.showhide
B-Spec C-Spec Rear Sway Bars #39652wordingneutralC-Spec rear sway bars approved for Chevrolet Cruze, Dodge Dart, Ford Focus, Honda Civic, Mazda3i, Toyota Corolla with specified part numbers.
HP Triumph Spitfire 1296cc Compression Ratio Increase to 12:1 #39589enginefasterHP Triumph Spitfire 1296cc compression ratio increases from 11.0 to 12.0:1.
T1 LS1 into Corvette C6 Spec Line Request #39716cars addedneutralT1 Corvette C6 LS1/LS6 Spec Line reinstated: 3200 lbs minimum weight, 70mm restrictor required.
B-Spec Notes section cleanup #39062wordingneutralB-Spec Chevrolet Sonic and Ford Fiesta, Honda Fit notes reorganized from individual allowances to approved parts lists; wording cleanup.
B-Spec 2026 BOP Recommendations #39475other +25 lbsunclearB-Spec: Sonic restrictors removed, Fit MT +25 lbs to 2550, Fit CVT restrictor removed, Mini Coopers restrictors increased 2-4 mm, Versa sedans -25 lbs to 2425, Versa/IA restrictors removed.
HP E/O: Improve Consistency of the Spec Lines #39500engineunclearHP Toyota MR-2 1.6L (85-89) compression ratio set to 11.0:1.
HP Request to Reclassify BMW 2002 Into H Production #39567cars addedneutralBMW 2002 newly classified to H Production at 2350 lbs with 1990cc iron block, 40 DCNF carburetor, 11.0:1 compression.
STU Request for Permission on Aftermarket Turbo Kit and Intake #39529cars addedfasterSTU Mazda MZR (LF, L3, L5) Turbo classified; Jack Spania Racing 70 mm intake manifold and Fab9 Tuning bottom-mount turbo kit approved.
T1 additional T1 adjustment #39520inductionunclearT1 Spec Line restrictor changes from 70mm flat plate to unspecified new specification.
HP Request to Re-Classsify Datsun SPL-311 to HP from FP #39116cars addedneutralDatsun SPL-311 newly classified to HP at 2050 lbs with 1595cc OHV iron engine and specified carburetors.
HP TR2 Notes E&O #39180wordingunclearEP Triumph TR2-TR4A allows 5-speed gearbox without overdrive; removes Weber carb and weight specification.
HP Balance of Power #39187induction +50 lbsslowerEP BMW Z3 2.5L restrictor reduced 52mm to 50mm, weight increased to 2550 lbs base; five other BMW models get smaller restrictors.
HP Alternative BOP Request for 84-87 Honda CRX/Civic #39223tyres & wheelsfasterHP Honda Civic and CRX models get wider 13-inch wheels: 6 to 7 inches.
STU Turbo Inlet Restrictor Table #38961inductionslowerSTU 36mm restrictor allows 2830 lbs (up 10 lbs from 2820); 37mm allows 2980 lbs (down 5 lbs from 2985).
STU 275 Tire Rule #38983tyres & wheelsslowerSTU cars over 3150 lbs lose 275-tire option with 2% weight adder.
STU STU Honda Engine weight penalty #39375weightfasterSTU Honda K20 and K24 engines lose 2% minimum weight penalty.
T1 Keep S2000 Classification #39344wordingunclearUnable to summarize: letter states intent but provides no actual rule changes to S2000 specification.
T1 Correcting and updating T1 GT4 spec lines #39394weight
T1 BOP adjustments to non GT4 T1 cars #39406induction +100 lbsfasterT1 non-GT4 cars: multiple restrictors enlarged (70mm to 73mm, 75mm to 78mm, 55mm to 60mm, 61mm to 70mm); one weight increased to 3600.
T1 Remove T1 Spec Line #39407removedneutralT1 BMW M3 E92 (08-13) Spec Line 1090 removed entirely.
B-Spec Alternate Shift Cable Bushings and Rear Spring Seats #38472wordingneutralB-Spec Honda Fit MT 07-08 allows Torque Solution Shifter Cable Bushing kit TS-SCB-506.
B-Spec Fiesta BOP Adjustment #38847weight +55 lbsslowerB-Spec Ford Fiesta Hatchback and Sedan gain 55 lbs to 2525; restrictors increase 1 mm.
B-Spec Request to Remove Rear Shock From Spec Line Hyundai Accents/Kia #39017suspension & brakesunclearB-Spec Hyundai Accent and Kia Rio remove Bilstein B8 shock 33-187112 rear suspension approval.
B-Spec Update Honda Fit MT (07-08) Runoffs Eligibility #39060wordingfasterB-Spec Honda Fit MT (07-08) becomes Runoffs-eligible; previous three-weekend Super Tour requirement removed.
HP Please Lower Weight of 280Z #38871weight -160 lbsfasterEP Nissan 280Z minimum weight reduced from 2560 to 2400 lbs.
HP Miata Weight Adjustment Follow Up #38949weight -25 lbsfasterEP Mazda MX-5 1.8L 90-97 weight reduced to 2125 lbs from 2150 lbs.
HP Weight Break for 1098 Midget / Sprite #38970weight -80 lbsfasterHP Austin-Healey Sprite/Midget 1098cc minimum weight drops 80 lbs to 1550.
HP HP Volvo 142 spec omission #38994engineslowerHP Volvo 142/142E gains compression ratio limit 12.0:1 and valve lift limit .425".
HP HP Mini DOHC 1.6 #38996engineslowerHP Mini Cooper 07-15 valve lift reduced to .390", from .450".
HP Add to Rabbit description #39019wordingneutralFP and HP Volkswagen Rabbit descriptions updated: Convertible changed to Cabriolet in FP; Cabriolet added to three HP engine variants.
HP Clean-up 9.1.5.E.7e #39025wordingneutralEP, FP, HP: rear drum brake to disc conversion clarified; rotors solid, diameter limited to largest front rotor permitted.
HP Add TB size to Ford Mustang (94-98) Spec Line #39130wordingneutralEP Ford Mustang (94-98) fuel injected throttle body inside diameter specified at 60.
STU Non-Homologated Engine Swaps - Specifically K24A2 w/ Honda CRZ #38746weightslowerSTU Honda K24 engine swap weight increases by 2% effective November 1, 2025.
HP HP Plymouth Arrow spec omission #38995wordingneutralHP Plymouth Arrow transmission max speeds clarified to 4 or 5.
HP Add Wheel Diameter to Appendix G #39008wordingneutralEP, FP, HP wheel diameter added to Appendix G as absolute maximum specification.
HP Add TB ID tolerance to general Prod rules #39009wordingneutralEP, FP, HP throttle body inside dimensions must remain stock with +/-.25mm tolerance; butterfly dimensions stock in FP, HP only.
B-Spec Remove Asterisk from Rule 9 #38768wordingneutralB-Spec and C-Spec: asterisk removed from public road usage note in rule 9.1.10.D.9.
STU Lotus Weight Reduction E&O #38919weightfasterSTU Lotus Elise SC and Exige SC weight reduced from 2450 to 2250 lbs.
B-Spec Disabling 2 Pedal Shutdown #38354wordingneutralB-Spec Honda Fit MT 09-14 two pedal shutdown may be disabled by cutting/de-pinning pin 42 BKSW at main ECU connector.
B-Spec Update Honda Fit MT (07-08) Intake Allowance #38530inductionslowerB-Spec Honda Fit MT 07-08 intake restricted to Injen SP1511 only, from any Cold Air Intake Package.
STU STU-TCR Adjustments #38723tyres & wheelsslowerSTU-TCR tire width increases to 275 with weight adder raised from 100 to 150 pounds.
STU Lotus Weight Reduction #38772weight -50 lbsfasterSTL/STU Lotus weight reduced: Evora GT4 to 2700 lbs, Elise Cup R to 2250 lbs, Elise/Exige SC to 2450-2550 lbs.
HP BMW Z4 update #38490inductionslowerEP BMW Z4 03-05 restricted to 52mm flat plate intake restrictor.
HP EP Fiat 124 Spider Competition Adjustment Request #38498weight -50 lbsfasterEP Fiat 124 Spider 1600 & 2000 weight drops 50 lbs to 2000; carburetors gain 2mm chokes to 36mm.
STU 2.8-3.2L N/A Engine Allowances #38007tyres & wheelsunclearSTU 2.8-3.2L N/A engines now allow 245 max tire width; over 3150 lbs may run 275 with 2% weight penalty.
STU 2006-2015 Mazda Miata Intake Manifold #38422wordingneutralSTU Mazda MZR may use Goodwin 61-2510 or Gato Performance 31972 intake manifold.
STU Requesting Approval of the JDM Honda h23a #38489cars addedneutralSTU Honda JDM H23a added, 2259cc displacement, minimum weight per Chart, must meet ST engine regulations.
B-Spec Add Sedan spec lines for Hyundai & Kia #37537cars addedneutralB-Spec adds Hyundai Accent Sedan (12-17) and Kia Rio Sedan (12-17), both 1591cc, 2525 lbs, 40mm FPR restrictor.
B-Spec Shifter Bushing Questions. #38048wordingneutralB-Spec Honda Fit MT 09-14 allows Acuity Shifter Base Bushing Kit 1954.
B-Spec Add Weapon R Intake to Honda Fit MT (09-14) Spec Line #38306wordingneutralB-Spec Honda Fit AT 09-14 adds Weapon R Intake 301-166-301 to approved parts.
B-Spec Update Rule 46 #38307wordingneutralB-Spec and C-Spec shift linkage/cables no longer prohibited from any modification; approved aftermarket bushings now permitted.
HP Base Weight Adjustment for H-Production X1/9 Spec Lines #38255weight -50 lbsfasterHP Fiat X-1/9 base weights reduced 50–53 lbs across 1300 and 1500 spec lines.
B-Spec Correct Hyundai/Kia Model Years #37943wordingneutralB-Spec Hyundai Accent Hatchback and Kia Rio Hatchback model year ranges corrected.
B-Spec 07-08 Honda Fit MT Requests #37974weight +50 lbsslowerB-Spec 07-08 Honda Fit MT minimum weight increases 50 lbs, to 2450.
B-Spec Add B14 Kit Part # to Honda Fit (07-08) Spec line #38010wordingneutralHonda Fit 07-08 MT and AT approved for Bilstein B14 kit 47172401 in B-Spec.
STU Wheel Size Inconsistency #38018wordingneutralSTU wheel width rules clarified: cars ≤2,850 lbs max 8 inches, cars >2,850 lbs max 9 inches.
STU Table C: STU-GT3U Clarification #38268weightfasterSTU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments.
T1 Acceptance of Porsche 981 GT4 Clubsport into T1 #36664cars addedneutralPorsche 981 GT4 Clubsport added to T1 as spec line 4085, minimum weight 3100 lbs with driver.
T1 Request to Restore T1 Honda S2000 to Proper Weights #37644weight -50 lbsfasterT1 Honda S2000 minimum weight reduced from 2950 lbs to 2900 lbs.
T1 DCT Transmission in E46 #37964wordingneutralT1 BMW E46 M3 permits BMW #GS7D36SG aftermarket sequential transmission in SL# 1060 and 1070.
T1 Reduce E92 M3 Minimum Weight to 3050 #38092weightfasterT1 BMW M3 E92 minimum weight reduced to 3300 lbs.
T1 Finalize Spec Line for T1 Darkhorse #38106tyres & wheelsfasterT1 Mustang Darkhorse R gets 315 front and rear tyres, loses 500 lbs minimum weight to 3600.
B-Spec 2025 BOP Recommendations #37520weightfasterB-Spec Honda Fit MT intake now limited to three models with 25lb adder; Mazda2 exhaust headers allowed with up to 50lb adder; Mini Coopers FPR increased 1-2 points; Nissan Versa sedans 40lbs lighter, Yaris models 50lbs lighter.
B-Spec Hyundai/Toyota Factory Rear Disc Models #37534wordingneutralB-Spec Hyundai Accent and Toyota Yaris weight adjustments: ±25 lbs based on rear brake type.
B-Spec Request to Update the Spec line for Hyundai Accent and Kia Rio #37880wordingneutralB-Spec Hyundai Accent and Kia Rio (12-19) allow Bilstein B14 kit #47167490 front shocks and BabyFace Fabrication sump extension #BF-HYU-PAN.
HP Request for Classification of Chevrolet Spark #37755cars addedneutralChevrolet Spark 16-22 classified HP Pre at 1850 lbs minimum weight, fuel injected, 1399 cc.
HP Request to Lower Ford Festiva Minimum Weight to 1600 LBS #37939weight -100 lbsfasterHP Ford Festiva 88-93 minimum weight drops to 1600 lbs, variants to 1640 and 1680 lbs; compression ratio raised to 11.0:1.
T1 Cadillac CT4-V Blackwing #38003cars addedneutralCadillac CT4-V Blackwing added to T1 Spec Line 1115, 3564cc, 3750 lbs minimum weight.
B-Spec Toyota Yaris Hatchback (12-18) rear disc brakes #37530suspension & brakesneutralB-Spec Toyota Yaris Hatchback 12-18 rear brakes now allow 10.2 inch disc alternative to 7.9 drum.
B-Spec Yaris Speed Sensor #37536wordingneutralB-Spec Toyota Yaris Hatchback and Sedan may now disconnect speed sensor.
B-Spec Set Expiration Date For Fiat 500 #37689wordingneutralB-Spec Fiat 500 (12-17) spec line expires 1/1/26 unless appeal filed.
HP Request Competition Adjustment to BMW Z3 2.5L #37120inductionslowerEP BMW Z3 and 3-series models get smaller intake restrictors: Z3 2.5L to 52mm, Z3 2.8L to 55mm, 328i to 58mm, 325i to 56mm.
HP HP Class Adjustments #37459weight +50 lbsslowerHP Mazda 2 11-14 base weight up 50 lbs to 2045; all VW 80s models up 50 lbs to 2150 base.
HP Interpretation of Production Rules on Mirrors #37235wordingneutralEP, FP, HP: interior or exterior mirrors meeting rule 9.3.36 now permitted.
HP Weight Reduction for Honda S2000 #37466weightfasterEP Honda S2000 1997cc base loses 75 lbs to 2375; 2157cc base loses 60 lbs to 2450.
HP Mazda 1999 Miata 1.8L #37488weight -50 lbsfasterEP Mazda MX-5/Miata 99-05 minimum weight drops to 2100 lbs, 2153 lbs with power adder, 2205 lbs with two adders.
HP MINI Cooper (07-13) Spec Line Correction: Errors and Omissions #37560engineslowerHP Mini Cooper 07-13 engine corrected to DOHC; valve lift limit reduced to 0.390 inches.
STU BMW N54/N55 Engine Allowance Follow Up #37447engineneutralSTU BMW N54/N55 3.0L classified at Chart +3% minimum weight; N54 twin turbo not allowed.
STU STU Mini Cooper pulley size clarification re: letter #36980 #37717inductionfasterSTU Mini Cooper S SC supercharger pulley diameter reduced from 2.285 to 2.185.
STU Question About a Weight Modifier #37782weightfasterSTU Honda K20C1 Turbo I4 exempted from 3% DI weight adder in Spec Lines Table A.
STU Increase Minimum Weight #37919weight +100 lbsslowerSTU GT3U minimum weight increases 150 to 250 pounds.
T1 Correct and make new T1 BOP adjustments. #37737weight +75 lbsunclearT1 Mustang Spec 1430 restrictor opens 60mm to 65mm; Spec 1460 weight rises to 3500 lbs, restrictor 70mm; Corvette 1190 restrictor opens 67mm to 70mm; BMW 1090 restrictor narrows 40mm to 35mm; BMW 1100 weight rises to 3350 lbs.
Cal Club 2025 CALCL252025-02-22
2:06.770Lee Fleming · fastest of 4 · top 4 within 4.3s
2:03.082Lee Fleming · fastest of 5 · top 5 within 6.2s
100.4Lee Fleming
1:55.401Wilson Powell · fastest of 4 · top 4 within 8.7s
1:53.640Rylan Hazelton · fastest of 5 · top 5 within 8.0s
113.3Rylan Hazelton
-9.442squal -11.369s
92.3%qual 91.0%
2:10.513Joseph Gersch · fastest of 4 · top 4 within 6.8s
2:10.054Thomas Lepper · fastest of 4 · top 4 within 7.4s
98.1Ali Naimi
+6.972squal +3.743s
105.7%qual 103.0%
1:46.465Ian Barberi · fastest of 2
1:47.434Ian Barberi · fastest of 3 · top 3 within 11.8s
139.3Drew Delmonico
-15.648squal -20.305s
87.3%qual 84.0%
417 earlier rule changes on record, in force before Cal Club 2025 (from 2019)75 cars added · 64 weight · 39 induction · 25 suspension & brakes · 21 tyres & wheels · 20 engine · 10 aero · 3 removed · 154 wording · 6 other · EP BMW Z3 2.5L requires 52mm flat plate intake restrictor; Z3 2.8L 55mm; 328i/is E36 58mm; 328i/ci E46 58mm; 325i/is E46 56mm; 325i/is E36 56mm; 325is M-Technic 56mm. · B-Spec Honda Fit AT, Fit CVT, Mazda2, Mini Cooper R50 MT and CVT, Toyota Yaris remove redundant notes language. · B-Spec removes Mini Cooper Countryman R60, Cooper Paceman R61, and two Nissan Versa generations effective 2/1/25. · B-Spec Nissan Micra Cup Car spec line expires 7/1/25 unless appeal submitted by 6/30/25. · T1 Mustang gains 125 lbs to 3600, restrictor shrinks 65mm to 60mm. Corvette gains 50 lbs to 3500, restrictor shrinks 70mm to 67mm. BMW deleted. · T1 E46 M3 Spec Line 1050 allows VAC Motorsports throttle body VAC-TB-S54 on 3.250L engine instead of Dinan. · T1 Chevrolet Corvette C8 (2023-23) minimum weight reduced from 3600 lbs to 3500 lbs. · T1 Chevrolet Camaro Gen 5 restrictor increases from 75mm to 80mm flat plate. · T1 Audi R8 GT4 Spec Line #4020 maximum tyre size changes to 315 DOT, 305/645, or 30/65-18 (f), 33/68-18 (r) Non-DOT. · B-Spec and C-Spec cars replace wheelbase spec with induction restrictor (mm) values, effective 2025-01-01. · B-Spec Hyundai Accent and Kia Rio approve Bilstein B8 shock 33-187112 for rear suspension use. · EP BMW 325i/is E30 (84-91) weight reduced 50–52 lbs across three spec lines to 2150, 2204, 2258. · HP Honda Civic 1.5 88-91 weight reduced to 2175 lbs base, 2229 lbs with one asterisk, 2284 lbs with two asterisks. · STU Audi 1.8T wagon deleted; Porsche 944 1800 weight to Chart, turbo inlet restrictor removed. · STU-GT3 reclassified as STU-GT3U effective January 1, 2026. · STU GT3 TCR gains 275-width tire option with 100 lb weight penalty, but not in A compound. · HP Mini Cooper 02-06 rear brake rotor increases from 239/9.4 mm/in to 259/10.2. · STL/STU: 90-05 Mazda Miata alternate front wheel hubs moved from General to specific part approval. · STU BMW N54/N55 turbo inlet restrictors now required per GCR definition; turbo swapping prohibited. · T1 GT4 tire sizes adjusted across ten cars: most non-DOT rear to 305/660, Audi and McLaren 305/645, Camaro and Mustang 305/680. · BMW M4 GT4 (G82) added to T1 GT4 at 3525 lbs minimum weight with Red power stick control. · T1 Spec Lines now permits 5.5 inch clutch in Engine Notes. · T1 GT4 Spec Line 4020 restrictor opens from 44mm to 45mm, minimum weight drops to 3400 lbs. · Mustang Darkhorse R added to T1 homologated cars at 3,250 lbs minimum with 305/315 tires, ineligible for Runoffs until 3 Super Tour events. · T1 Corvette may roll or flatten wheel opening lips for tire clearance; plastic fenders may remove lips if edge thickness matches basic material. · T1 E46 M3 S54 can now use Dinan Throttle Body #D760-3400 on 3.250L engine. · B-Spec Toyota/Scion IA Sedan 16-20 allows ST Suspension Kit 13275022, requires three Super Tour weekends and OBD-II data submission. · Honda Fit AT 07-08 B-Spec and C-Spec: rear sway bar Progress #62.1060 and any cold air intake package now allowed. · HP Sprite and Midget 1275cc and 1098cc Level 2 compression ratio raised to 12.0:1. · Suzuki Swift GT 89-94 newly classified to HP Pre at 1900 lbs, 1298cc DOHC fuel injected. · STU Mini Cooper S SC 1900 restricts to 2.565 diameter pulley; 2100 allows 2.285 diameter pulley. · B-Spec and C-Spec restricted to Goodyear Eagle RS/RS-R P205/50R15 and 225/45R17 tires respectively; Hankook tires removed; wet/dry mixing prohibited. · B-Spec Sonic restrictors increased to 5-6mm, Fit weight cut 50-25 lbs, Mini Cooper weight reduced 45 lbs, various restrictor adjustments. · B-Spec and C-Spec hood pins change from optional to recommended; factory release cable may be removed if pins used. · B-Spec and C-Spec Chevrolet Sonic and Cruze allow Babyface Fabrication brake caliper pistons. · HP Volkswagen Golf and Jetta 85-92 track correction: front 1537mm (60.5in), rear 1529mm (60.2in). · STU RWD turbo cars no longer required to reduce restrictor by 1 mm from table. · B-Spec Honda Fit MT & CVT 15-19: cleaned up allowed parts notes, CVT gains Setrab transmission cooler option. · B-Spec Nissan Versa (09-11) spec line expires 1/1/2025 unless appeal filed by 12/1/2024. · B-Spec deletes redundant rule 25 in GCR Section 9.1.10.E. · B-Spec Hyundai Accent rear brakes corrected to 10.3 disc; Kia Rio rear brakes corrected to 10.3 disc. · B-Spec and C-Spec Chevrolet Sonic Bilstein B14 kit #47-171725 verified compatible, suspension wording clarified. · B-Spec Mazda2 and multiple Mini Cooper models eliminate redundant sway bar end link part number notes. · B-Spec Fiat 500 spec line changes from model year 2012–15 to 2012–17. · B-Spec Honda Fit 15-19 CVT weight increases to 2550 lbs, restrictor to 31mm. · Nissan 300ZX 84-89 classified to EP at 2550 lbs minimum, 2960cc 6-cyl SOHC, fuel injection, 12.0:1 compression limit, 0.500" valve lift limit. · Mazda RX-7 92-97 newly classified EP Prep Level 2 at 2200–2310 lbs with 13B 6-port rotary engine. · EP Mazda RX-8 (04-11) alternate spec line removed; one primary line remains. · B-Spec model descriptions standardized: trim levels and door count designations removed or replaced with body style wording. · B-Spec and C-Spec wheels must be same thickness spacers all four corners; wording clarified on offset and protrusion rules. · HP Honda CRX/Si 84-87 plastic panels can be replaced with replica alternate material if stock appearance maintained. · Mercedes AMG-C63 S (2023) classified in T1 with 4000 lbs minimum weight and 3700 restrictor. · B-Spec Honda Fit MT 2015-19 restrictor increases 30mm to 31mm, weight rises 2525 to 2550 lbs. · B-Spec and C-Spec now permit wheels of any offset if tire doesn't protrude beyond fender; spacers allowed with differing left-right offsets per axle. · B-Spec Mini Cooper Countryman R60, Paceman R61, and Nissan Versa 1797cc spec lines expire 1/1/2025 unless appealed by 12/1/2024. · T1 Honda S2000 classified with 2400 lb minimum weight, 2950 cc displacement, 4.75" supercharger pulley. · B-Spec Honda Fit 07-08 loses 125 lbs to 2400; Versa S 2020+ loses 150 lbs to 2550; Yaris iA 16-20 loses 250 lbs to 2450. · B-Spec Honda Fit 07-08 rear sway bar part number changed to Progress #62.1060. · HP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve, Scirocco 1588. · STU Mini Cooper S SC: alternate LEAP OMICRON hood scoop LEP-OMICRON3 permitted. · STU BMW S54 B32 OEM now permits dry sump oiling system. · Pontiac GTO 2006-2009 LS1 added to T1 as Spec Line 1590, 5700 cc, 3400 lbs minimum. · B-Spec and C-Spec eliminate case-by-case auxiliary transmission cooler approval requirement. · B-Spec Chevrolet Sonic 5dr Hatch MT allows aluminum radiator #ZZP-ZZ013. · B-Spec Honda Fit MT (09-14) and AT now split into separate spec lines with distinct allowances. · B-Spec Mazda 2 10-14 weight increases 70 lbs to 2350, cat-delete headers now permitted. · B-Spec Nissan Versa and Versa Note 2013-2019 now permit Hardrace HR-Q0146 19mm rear sway bar. · HP Honda Civic 1.5 (88-91) weight reduced to 2175 lbs base, 2229 lbs with power adder, 2284 lbs with two. · STL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems. · C8 Corvette T1 restrictor plate increases from 70mm to 72mm flat plate. · T1 NEW class removes 23 spec lines including Acura NSX, Ferrari, Porsche 996, Nissan Z cars, and others; Porsche 997 spec line 1680 expiration removed. · B-Spec allows Hankook tires at regionals only through 6-30-2024; Goodyear only from 7-1-2024 for all events. · B-Spec Nissan Versa Note Hatchback (2013) minimum weight drops 60 lbs to 2490. · B-Spec and C-Spec ECU and data acquisition rules clarified: ECU must be unaltered OE, no device capable of altering ECU characteristics permitted; data acquisition expanded to allow tachometer, air-fuel ratio, cylinder head temperature sen… · EP BMW Z3 2.5L weight increases to 2500 lbs, 2563 lbs with turbo, 2625 lbs with supercharger. · HP Sprite/Midget Mk I–IV, Mk 1500 compression ratio raised to 12.0:1 at Prep Level 1/2. · HP Triumph Spitfire 1500 valve spec changes from 36.6/5.5/(1.44/0) to 36.6/(1.44). · EP Mazda MX-5 1.8L 1990-97 minimum weight drops to 2150 lbs; 1994-97 variants to 2000, 2050, 2100 lbs respectively. · EP Triumph GT6 dual 1.75" carbs weight drops to 1940 lbs; triple Weber 40 DCOE options consolidated. · EP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm. · HP Honda CRX/Si 84-87 front header/nose panel may use alternate material if appearance remains stock. · EP Triumph TR8 dry sump allowance moved from carburetor line to notes section. · EP Porsche 944/924S 2.5L and 2.7L weight minimums corrected: 2479cc to 2306/2363 lbs, 2681cc to 2358/2415 lbs. · HP Mazda 2 (11-14) minimum weight increases to 1995 lbs, 2045 lbs with*, 2095 lbs with**. · T1-GT4 batch adjustments: five cars lighter, two heavier, restrictors and ECU maps changed, five models now eligible for Runoffs. · T1 spec lines 1000, 1010, 1020, 1040, 1360, 1400–1410, 1520–1680, 1700–1720 deleted entirely. · C-Spec Mazda 3i 10-13 third gear ratio corrected from 3.84 to 1.84. · C-Spec Dodge Dart 14-16 bore x stroke corrected to 88.0 x 82.0 mm, displacement to 1998 cc. · HP Honda CRX 1.5 (88-91) weight reduced to 2175 lbs, 2229 lbs, and 2284 lbs across three spec lines. · EP Porsche 944/924S combines 2.5L and 2.7L variants with new weights: 2250–2415 lbs depending on engine and year. · FP Toyota Corolla 2TC loses 43 lbs to 1810; HP Corolla loses 50–52 lbs to 1910–2006. · HP Mazda 626 84-87 weight reduced to 2200 lbs, 2255 lbs, and 2310 lbs across three configurations. · EP Triumph GT6 minimum weight reduced to 1800 lbs. · T1 Chevrolet Corvette C5 LS2 added with 6000cc displacement, 3300 lbs minimum weight, 72mm flat plate restrictor. · T1 Chevrolet Corvette C7 (14-19) including Z51, Grandsport newly classified as homologated car. · T1 Gen 5 Camaro minimum weight drops 75 lbs to 3475; restrictor increases 70mm to 75mm. · T1 Aston Martin Vantage permitted to use OEM Sportshift II transmission. · Pontiac GTO 2006-2009 re-integrated into T1 with LS2 at 3400 lbs, 72mm restrictor, and LS3 at 3500 lbs, 61mm restrictor. · T1 Porsche 997-1 GT3 Cup added at spec line 4210, minimum weight 3050 lbs. · B-Spec adds Goodyear Eagle RS dry and wet tires as options alongside Hankook; Hankook restricted to regional events from 2024. · C-Spec adds Chevrolet Cruze, Ford Focus, Honda Civic, Mazda 3i, Toyota Corolla, VW Jetta; updates Dodge Dart, Mazda3s, Toyota Corolla specs. · HP Nissan/Datsun PL510 carburetors allow larger 4mm chokes, replacing 2mm specification. · Chevrolet Camaro GT4-R classified in T1 GT4 Spec Line 4035, minimum weight 3375 lbs, 315 max tire, 63mm restrictor, ineligible for Runoffs. · T1 Dodge Viper ACR / SRT RT-10 and ACR/ACR-X spec lines 1350 and 1370 remove 12/23 expiration. · T1 GT4 McLaren 570S, Mercedes AMG GT4, and Porsche 718 Cayman GT4 CS MR now eligible for Runoffs competition. · T1 GT4 BMW M4 Spec Line Number changed from 4050 to 4030. · T1 Corvette C5 gains approved aero parts: carbon rear spoiler, vented front splitter, side skirts, with 50 lb weight reduction allowed. · B-Spec Hyundai Accent GS Hatchback restrictor plate increases from 39mm to 41mm. · B-Spec Hyundai Accent GS Hatchback model years corrected from 13–19 to 12–19. · FP and HP Sprite, Midget, and Spitfire 1500 intake valve size corrected to 36.6/(1.44). · HP Volkswagen Rabbit Cabriolet 1780 removed; Rabbit 1588 and 1715 reclassified with engine sizes and year ranges specified. · Toyota GR Cup and GR86 Cup (2022-) newly classified in STU at 2700 lbs with 2387 cc engine. · T1 Dodge Viper ACR/ACR-X restrictor increases from 50mm to 60mm flat plate. · T1 Dodge Viper ACR/ACR-X: Spec Line 1370 restrictor increases to 55mm, Line 1390 decreases to 55mm. · T1 Ford Mustang S197 05-14 now requires OEM 8.8 differential housing. · T1 Chevrolet Camaro Gen 5 LS7 gets two spec lines: 1131 with 70mm restrictor, 1136 with 53mm restrictor, both 3450 lbs minimum. · T1 Chevrolet Camaro Gen 5, Corvette C5 and C6: engine resleeve restricted to stock parameters only, no longer LS3 bore/stroke. · B-Spec adds Hankook 200/580R15 Z217 tire option alongside 205/50R15 C51; C-Spec specifies 225/45R17. · B-Spec and C-Spec Chevrolet Sonic allows ZZP aluminum radiator #ZZP-ZZ013; Hatch MT restrictor increases to 34mm. · B-Spec and C-Spec bumper caps now allow positive fasteners like machine screws and T-nuts or rivet-nuts; self-drilling and sheet metal screws prohibited. · B-Spec and C-Spec allow CAN bus connections to data systems for monitoring only; systems must not send data. · B-Spec Ford Fiesta 5dr and 4dr lose 25 lbs each, to 2470 lbs minimum weight. · B-Spec Ford Fiesta 5dr and 4dr lose 25 lbs each to 2470; Honda Fit MT and CVT lose 50 lbs each to 2525; Mazda2 loses 50 lbs to 2280; Kia Rio restrictor increases from 39 to 41 mm; Mini Cooper variants gain 75 lbs to 2675 with larger restri… · C-Spec Mazda 3i Touring 2.0 Skyactive MT (12-13) newly classified with 155 hp, 148 lb-ft torque, 2900 lbs. · B-Spec minimum ride height set to 6 inches, C-Spec to 5½ inches. · B-Spec springs capped at 500# front and rear; C-Spec at 600# front, 800# rear; both may be strapped to body. · B-Spec wheels minimum weight set to 13 lbs, C-Spec to 17 lbs. · B-Spec and C-Spec allow metal threaded inserts in plastic intake manifolds for throttle body fasteners. · Ford Fiesta HP and Chevrolet Sonic FP model year ranges extended from 2016 to 2019. · T1 Ford Mustang S197 (05-14) reinstated with 3550 lbs minimum weight, 75mm restrictor, Voodoo engine permitted. · B-Spec and C-Spec wording clarified: CATEGORY to CATEGORIES, rules priority clarified for tire sizes, rim widths, springs, anti-roll bars, performance equipment. · T1 GT4 weights clarified for nine cars, ranging from 3200 lbs Porsche 718 Cayman to 3575 lbs Aston Martin. · T1-GT4 McLaren 570S and Mercedes AMG GT4 front tires widen to 315 mm. · STU Mazda BP5A classified at 1839 cc maximum displacement, 2023-04-01. · T1 Chevrolet Camaro Gen5 LS3-6160 adds 70mm flat plate restrictor, weight 3550 lbs. · B-Spec Mini Cooper R56 MT/AT and Clubman R55 fuel pressure regulator increased from 40mm to 41mm with OE catalyst. · B-Spec may use helper springs up to 500 pounds rate; tender springs now prohibited. · STU minimum weight chart updated: 2450cc to 2595lbs, 2600cc to 2710lbs. · T1 cars with aftermarket sequential transmissions get 10-inch max bellhousing; non-sequential cars gain 100 lbs weight break. · T1 GT4 all nine cars lose 125 lbs minimum weight with driver, from 3200–3575 to 3075–3450. · T1 removes GCR Section 9.1.9.1.A. and T1 Spec Lines entirely, sunsetting pre-2023 Touring 1 rules. · B-Spec Honda Fit 09-14 Automatic now allows aftermarket exhaust/header; Manual unchanged. · GT4 McLaren 570S maximum tire size changes to 285 front, 315 rear. · B-Spec Chevrolet Sonic and Honda Fit and Mini Cooper split into separate manual and automatic spec lines with distinct transmission ratios and final drives. · B-Spec tire rule adds Hankook 200/580R15 Z217 as alternative to 205/50R15 C51; no mixing wet and dry. · MGB & MGB-GT HP weight breaks reduced to 2000, 2050, 2100 lbs; new MGB HP Prep 1/2 hybrid added at 2175 lbs. · HP Nissan/Datsun PL510 weight reduced: base 1960 to 1910 lbs, * 2009 to 1958 lbs, ** 2058 to 2006 lbs. · EP, FP, HP cylinder head ports limited to 1 inch maximum depth matching from mating surface. · Eight GT4 models added to T1 with weights from 3200 to 3575 lbs and restricted power per SRO 2022 rules. · B-Spec Honda Fit 15-19 weight drops 225 lbs to 2575 lbs. · VW New Beetle 2.5L 5-cyl added to EP at 2400–2520 lbs, 2480 cc, fuel injection, comp ratio 12.0:1 max, valve lift 0.500" max. · EP Mazda RX-7 12A/13B gains fuel injection option on dual-y manifold with 42mm choke(s). · EP VW Corrado 92-95 stroke corrected to 90.3 mm, displacement to 2792 cc. · B-Spec Mazda2 10-14 rear sway bar now allows part 0000-04-2203-RR or 0000-04-2312. · STU Mazda 13B Turbo classified, streetport only, stock turbos prohibited, alternatives allowed. · STU OEM louver vents now exempt from vent count and 200 square inch allowance. · STU 2400cc non-4-valve engines gain 9% base weight reduction; DI turbo prep limits removed. · T1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird, Pontiac GTO 6162 OEM minimum weight reduced to 3475 lbs. · STU normally-aspirated 2976–3200 cc single-throttle engines lose 10% base engine weight reduction. · ST redundant language removed from balance shaft and pulley modification rules. · EP Subaru BRZ and Toyota 86/Scion FR-S model year ranges updated to 13-20. · T1-LP Ford Mustang FP350S restrictor increases from 70mm to 75mm. · Mercedes Benz AMG GT4 2017-2021 classified T1 Maximum at 3400 lbs minimum weight with HP-controlled SRO Power Level 2 engine. · B-Spec Hyundai Accent GS and Kia Rio restrictor increased from 36mm to 39mm flat plate. · EP Mazda MX-5 Global Cup 16-22 minimum weight set to 2400 lbs; sequential gearbox allowed with +150 lbs penalty. · BMW 128i (08-13) classified in EP at 2700 lbs minimum with stock throttle body, 11.0:1 compression ratio, 0.400 in. valve lift limits. · EP/FP/HP open cars may now use carbon fiber hardtops if they retain OEM appearance in all exterior profiles. · STU cars that qualified for 9 inch wheels in 2021 may continue through 2022 only. · STU splitter definition clarified: must be single-plane with no vertical deviations, attached to lowest front point. · EP Mazda RX-8 13B carburetor rules clarified: dual 2bbl carb, fuel injected throttle body, or stock fuel injection permitted. · EP and FP Production clarifies idle control valve rules: stock devices allowed original, removed with blocked ports, or mechanical replaced with electronic stock type. · HP Volkswagen New Beetle (98-05) classified at 2350 lbs minimum, 1984cc SOHC, fuel injection, 11.0:1 compression limit. · STU BMW S52B32 minimum weight drops 90 lbs to 3110; max displacement cut to 3152 cc. · STU BMW S50B32 Euro classified at 3201 cc displacement, 3300 lbs minimum weight. · ST engine swap origin country requirement changes from North America to the United States for case-by-case approval. · STU Honda CRX (84-91) and Civic Del Sol (93-97) ineligible for front wheel drive weight reductions. · STU vehicles at or over 2950 lbs base weight may use 9 inch wide wheels instead of 8.0 inch maximum. · STU minimum weights reduced: 2450cc to 2596 lbs, 2500cc to 2635 lbs, 2550cc to 2675 lbs. · T1 Dodge Viper ACR displacement rises to 8400 OEM, minimum weight drops to 3550 lbs. · T1 Limited T1 wording changed to clarify all T1 cars permitted specifications. · T1 Mazda RX-7 classified: 2700 lbs minimum weight, 44mm restrictor, 13B Rotary with single Garrett Turbo #3076. · B-Spec allows springs strapped to body for rebound control; removes requirement for OEM or kit bump stops. · B-Spec strut tower modifications permitted for camber adjustment only, limited to 1.75 degrees. · B-Spec Mazda2 10-14 undertray part numbers corrected to DO8C-56-110A, DO8C-56-311, DO7A-56-321. · HP Triumph Spitfire 1500 minimum weight increases to 1605 lbs, 1645 lbs, or 1685 lbs. · EP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate. · Ford Mustang 99-03 classified to EP at 2700/2768/2835 lbs; 94-98 Mustang weight reduced to 2550/2614/2678 lbs. · EP, FP, HP Improved Touring cars may use any DOT-approved tire per section 9.3.45 in Production class. · STU normally aspirated engines: minimum weights reduced up to 310 lbs; single throttle body weight reduction removed. · STU Audi A4 1.8T minimum weight fixed at 3050 lbs, VF30 turbo with 35mm restrictor now required only. · STL and STU Improved Touring vehicles must conform to 9.1.4 Tires & Wheels requirements. · T1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird, Pontiac GTO LS3 minimum weight reduced to 3475 lbs. · T1 Camaro maximum displacement 7011 loses 50 lbs, to 3500. · T1 removes 33mm brake rotor thickness limit; rotors now unrestricted on thickness. · B-Spec Nissan Versa S 2020- classified at 2700 lbs with 38mm restrictor, 1598cc engine. · Toyota/Scion IA Sedan (2016-2020) classified for B-Spec at 2700 lbs with 38mm FPR. · B-Spec Mazda 2 (10-14) replaces Bilstein B14 suspension kit with Powerflex rear bushings; adds radiator, exhaust headers, undertray. · EP, FP, HP classes allow stock/original idle control devices unmodified or completely removed with openings blocked. · HP Fiat X1/9 intake valves corrected to 36.3mm/1.43in; exhaust valves to 33.3mm/1.31in or 31.2mm/1.23in depending on level. · STU engines may delete balance shafts and plug openings; alternate pulleys allowed for timing belt or chain operation only. · STU hood vents allowed to include louvers within 200 sq. inch area. · 2007-2008 Honda Fit automatic added to B-Spec at 2525 lbs with 1499 cc engine. · EP Porsche 968 intake valve size increased from 37 to 39.0 mm. · EP, FP, HP front-wheel-drive cars may alter body and suspension to install alternate transmission, transaxle, and axle shaft. · HP Fiat X1/9 1500 loses 50 lbs to 1950; 1300 loses 45–47 lbs; Bertone 1500 loses 50–52 lbs. · Austin-Healey Sprite Mk I, II, III, IV and MG Midget classified in HP Prep with 1510–1586 lbs depending on prep level. · EP BMW Z3 2.5L allows alternate throttle body from 92-95 325i with Turner adapter; head casting 1738400 permitted with specific blocks. · Austin-Healey Sprite Mk I–IV and MG Midget classified in HP with 1655 lbs minimum weight. · STU adds Honda K23 with 2354cc displacement and minimum weight per chart, K24 block allowed with K23 internals and head. · STU Honda K23 internals rule relaxed to require only K23 crankshaft, allowing other internal modifications. · STL and STU piston engines clarified: intake manifold and cylinder head porting remains free. · EP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; comp ratio max 12.0:1, valve lift max 0.500". · HP Corolla GTS RWD (84-87) added at 2300 lbs; HP Corolla FX16 FWD (87-88) added at 2260 lbs; old Corolla (84-87) removed. · T1 Mazda MX-5 Miata MazdaSpeed minimum weight rises to 2550 lbs, restrictor increases to 42mm. · T1 Chevrolet Corvette Cadillac XLR classified for model years through 2019. · B-Spec upper strut slotted plates no longer require manufacturer's original bolt holes or serve as reinforcement. · HP Toyota MR-2 1.6L (85-89) track corrected to 15.47 inches front and rear. · B-Spec upper strut slotted plates no longer must use manufacturer's original bolt holes. · Honda S2000 (00-03) reclassified as EP Prep with F22c engine option: 1997cc or 2157cc, weight 2450–2636 lbs depending on displacement. · EP Nissan 240-SX S13/S14 loses 200-210 lbs minimum weight; comp ratio rises to 12.0:1, valve lift to .500. · T1 BMW E46/E36/Z3 minimum weight increases to 2700 lbs, 3.4L engine car to 2750 lbs. · B-Spec Mazda2 10-14 allows header PN 0000-06-2410 with 70 lb weight penalty. · EP Lotus/Caterham 7 America carburetor changed from IT fuel injection prep to fuel injection. · Plymouth Arrow 1598cc four-cylinder classified to HP at 1800 lbs minimum weight. · BMW 318i E30 (84-85) reclassified from FP to HP at 2200–2310 lbs with fuel injection and .425" valve lift limit. · Daimler SP 250 classified in EP at 2165 lbs with 2548 cc OHV 8-cylinder engine. · STU fender flare wording clarified: exterior contour of any wheel opening may not change opening size, location or shape from side view. · STU Mazda 12A Bridge Port Miata weight reduced from 2550 lbs to 2350 lbs. · T1 Dodge Viper SRT-10 restrictor increases from 45mm to 57mm. · T1 Chevrolet Corvette Cadillac XLR LS6 engine now permits Casting #799 heads with no other head modifications. · B-Spec Honda Fit and Mini Cooper models gain alternate transmission ratios and final drives to allow Setrab 50-119-7612 cooler. · B-Spec Honda Fit 2007-08 classified with 1499cc displacement, 2450mm wheelbase, 2525 lbs minimum weight. · B-Spec Ford Fiesta 5dr Hatchback allowed Eibach rear sway bar #35143.312 or #35143.320. · B-Spec restrictor range changes from 0.060" ±0.005" to 0.050"-0.079". · B-Spec rear window wipers and wiper motor removal now allowed. · HP Spec Line Porsche 924 (76-84) brakes change from solid to vented disc. · EP, FP, HP clarifies percentage weight penalties sum first, then apply to base weight, rounding to nearest pound. · HP Mazda 626 (84-87) induction changed from dual 32mm sidedraft carbs to carburation or fuel injection. · T1 Ford Mustang Shelby/GT350/GT500 5.0L Coyote restrictor opens from 65mm to 70mm flat plate. · T1 Dodge Viper SRT-10 restrictor increases from 45mm to 57mm. · T1-LP Chevrolet Corvette C7 restrictor increases from 70 to 73 mm. · T1-LP Corvette Z06 06-13 now allows aluminum chassis replacement with equivalent OE steel chassis. · Volvo 142/142E moves from HP Spec P-1800 Engine to HP Prep with 1989cc OHV four-cylinder, 2450–2573 lbs. · Volkswagen Golf III/Jetta III 93-98 classified to HP at 2325–2441 lbs with 1984cc SOHC engine. · Porsche 924 (76-84) newly classified to HP with 2400-2520 lbs weight, fuel injection, 1984cc engine. · 84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lbs weight, 1998cc SOHC, dual 32mm carbs. · FP Fiat X1/9 brake rotors change to 257 (10.1) x 12 (.407) solid disc. · STU fender flare rules clarified: maximum 2 inches, must cover tire contact patch from above, cannot alter body configuration or wheel opening geometry. · T1 Chevrolet Camaro with 6162 displacement minimum weight reduced to 3500 lbs. · T1-LP Chevrolet Corvettes C5 Z06, C6 Grand Sport, and Z06 dry sump kit notes clarified to remove contradictions. · B-Spec Mini R60 and R61 allow 4-lug hub conversion with specified bearings and brake rotors. · B-Spec Mazda2 10-14 header replacement allowed, minimum weight increases 2330 to 2380 lbs. · B-Spec Honda Fit model years expand from 09-12 to 09-14. · B-Spec Hyundai Accent GS and Kia Rio restrictor reduced from 40mm to 36mm flat plate. · B-Spec must use Hankook P205/50ZR15 Z214 C51 or Z217 rain tyres for SCCA Majors, Super Tour, Runoffs. · HP Mini Cooper classification expands to include 12-15 Coupe model in existing spec line. · HP Volkswagen Rabbit GTI 1780 (83-84) permits Mk2 VW front spindles, hubs and bearings. · STU Honda S2000 allows F20/F22 K24 crankshaft with chart weight for achieved displacement. · ST oil coolers and filters now explicitly allowed to be added or substituted; wording clarifies existing permissions. · B-Spec tire rules clarified: Hankook Z214 dry and Z217 rain required at Majors/Super Tour/Runoffs after 6-1-2021; regional racing allows any DOT race tire through 2021. · B-Spec restrictor thickness set to 0.060 inches plus or minus 0.005 inches. · STL/STU 90-05 Mazda Miata gains approval for Mazda Motorsports Development alternate front wheel hubs. · T1 LP removes 50 lbs weight allowance for stock headers, adds aero device allowance up to 100 lbs, permits headers. · B-Spec Hyundai Accent GS Hatchback 2013-2019 classified at 2525 lbs with 40mm flat plate restrictor. · B-Spec Mini Cooper Countryman R60 and Paceman R61 production years corrected from 11-13 to 11-16. · B-Spec Toyota Yaris Hatch model year spans corrected from 07-12 to 07-11 and 12-18 added. · B-Spec Mini Cooper all models ride height minimum 5 inches measured from metal under door rocker molding. · B-Spec allows removal or material modification of metal or plastic brake dust shields. · B-Spec Mini Cooper Clubman R55 11-15 permitted OBX header with 40mm flat plate restrictor. · ST cars may relocate ABS actuation hardware and wiring anywhere in engine compartment. · STU Porsche PDK automatic transmission limited to 8 forward speeds instead of torque converter restriction. · STU Mazda 13B Street Port 2400 removes choke location restriction, allows auto-type 2bbl with dual-Y manifold. · STU driveshaft and half-shaft materials change from OEM-type to steel or aluminum. · T1 Ford Mustang Challenge 3-valve maximum displacement changes to 4600/5000. · T1 BMW E46 now allows carbon or fiberglass OEM-style dashboards with 25 pound penalty. · T1 Ford Mustang/Thunderbird limited to Shelby/Shelby GT350/GT500 models through 2018. · Dodge Viper ACR classified in T1 with 8400cc displacement, 3600 lbs minimum weight, 55mm restrictor. · BMW M2CS Club Sport classified in T1-LP Spec Lines effective 2021-02-01. · Porsche 997.1 GT3 Cup (2006-2011) classified in T1 at 3600cc, 3150 lbs minimum weight. · EP Austin-Healey 3000 Mk. I, II, III now allows TR-6 front calipers and discs as alternate. · STU Mazda 13B Street Port classified at 2400 lbs minimum weight, replacing peripheral and bridge port variants. · T1 Chevrolet Corvette Z06 years extended from 06-12 to 06-13. · B-Spec: Bilstein B14 suspension kits removed from all car spec lines; clarified B14 shock or strut use requires CRB approval of mounting adaptors. · B-Spec removes Chevrolet Sonic 12-19, clarifies Toyota Yaris Hatch 07-12 and Sedan 07-12. · FP Volkswagen Golf and Jetta 1.8 lose 50 lbs each, to 1900. HP Jetta GLI engine code removed. · EP, FP, HP Level 1 and Level 2 induction systems: clarified carburetor and fuel injection rules, jets/needles/rods unrestricted in Level 2. · EP Datsun SRL 311U Roadster minimum weight reduced to 1925 lbs from 2000 lbs. · EP Triumph TR8 78-81 weight reduced from 2600 to 2500 lbs. · ST aero devices and reference areas now include end plates but exclude fasteners protruding over 1/2 inch. · T1 Corvette C8 Z51 gets wider wheels and tyres, weight drops 100 lbs to 3550. · HP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches. · B-Spec Mini Cooper R56 40mm flat plate restrictor requirement removed, suspension and header parts now allowed. · STU fender flare rules reworded: up to 2" per corner allowed with 1% weight penalty total. · EP BMW Z3 2.5L iron block casting 1738566-C designation removed, wording clarification only. · STL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis adjustments. · STL and STU rear wing rules clarify that wicker is a Gurney flap; no performance change. · T1 rear wing Gurney flap wording clarified: Gurney flap in chord length and mounting height rules. · Porsche 911 S 67-68 classified in EP at three weight levels: 1800, 1845, or 1890 lbs. · 1.8 VW GTI Mk1 dual carb request denied; remains stock fuel injection only. · STU request for alternate intake manifold denied; no rule change issued. · GT3 and STU add Borg-Warner EFR6258 to approved turbocharger list. · STU large displacement turbo engines limited by GCR turbo list; non-turbo trim suggested as more competitive. · STU sequential shifters referred to Board of Directors for approval; no change implemented yet. · B-Spec wheelbase measurements converted from inches to millimeters for consistency across all cars. · EP BMW 2.8L, 328i E36/E46, and 325i E36 blocks now iron only; 325i E46 aluminum only. · STU Mazda 13B Bridge Port and Street Port engines added with 2550 and 2250 lbs minimum weights respectively. · T1 and T2 Corvettes may convert leaf spring suspension to coilover with 800 lb max spring rate allowed. · B-Spec Chevrolet Sonic 5dr Hatch and 4dr Sedan allow Setrab transmission cooler for automatic-equipped cars. · B-Spec: multiple models allow specific suspension kits and damper assemblies. · B-Spec sunroof retention wording removed, simplifying rules. · B-Spec Ford Fiesta 5dr gets 36mm restrictor, 4dr gets 34mm, Honda Fit 09-12 loses 25 lbs to 2525, Fit 15-20 restrictor reduced 32mm to 30mm, Mini Cooper 07-10 gets 40mm restrictor. · 1990-1994 Mazda Protege classified in FP Pre at 2150–2258 lbs with 1839cc DOHC engine, fuel injection. · HP Mini Cooper model year ranges for convertibles revised: 02-06 now includes 05-08, 07-13 now includes 09-15. · T1 Porsche 996 GT3 Cup eligible model years changed from 2002-2005 to 1998-2004. · T1 Corvette and Cadillac XLR permitted to install SCRSPLR-001 rear spoiler with OE bodywork. · T1 Gen 5 Camaro allowed 366mm OEM rear rotor and caliper without weight penalty. · EP Caterham 7 Spec Line removes redundant suspension note, clarifies engine prep limits and comp ratio to 10.0:1. · STU Honda S2000 adds HKS Supercharger kits 12001-AH006 and 12001-AH010 as allowed. · STU Lotus Elise Cup R and SC models, plus Exige SC, gain 100–200 lbs minimum weight. · STU Volkswagen GTI/GLI MK5 and Jetta Mk4 may install turbo inlet restrictor in OEM turbo inlet housing. · STU Honda K20C1 Turbo I4 restrictor reduces from 36mm to 35mm. · STU GM Ecotech LNF now allowed with turbo removed or with LE5 head and intake manifold, meeting STL specs. · STU Porsche 944 now permits VW/Audi 1.8L and 2.0L turbo engines as alternates. · T1 Porsche 996 Spec Lines now allows 996 Cup Replica Rear deck lid. · T1 Acura NSX Turbo World Challenge and Audi TTRS GTS 2011 now require DOT tires per GCR section 9.3. · B-Spec Sonic extended to 2019, Fiat 500 limited to 2015, Fiesta models extended to 2019, Fit expanded to 2015-2019. · B-Spec Mini Cooper R50, R55, R58, R60, R61 models newly classified at 2545–2625 lbs with 40mm restrictor for 12+ models. · B-Spec fog lamps must now be removed and holes completely covered, reversing prior allowance. · B-Spec Chevrolet Sonic 4dr Sedan (12-19) added at 2650 lbs with 32mm flat plate restrictor. · HP Volkswagen Rabbit and Scirocco 1588 remove 32mm choke requirement, clarify carburetor options and weight penalties. · HP Mini Cooper Convertible (07-13) newly classified; (05-08) convertible spec consolidated into main listing. · HP Datsun 510 Level 2 brakes changed from factory spec to 9.1 disc front, 9.0 drum rear, allowing 240Z/260Z/280Z parts. · HP Datsun 510 gains 40 DCOE carburetor option alongside existing 40 DCN and 36mm DCNVH choices. · HP Ford Fiesta 78-80 minimum weight drops 50 lbs to 1725; both asterisk tiers drop 51 lbs. · STU vehicles over 2951 lbs base weight may use 9 inch wide wheels, up from 2950 lbs. · STU turbocharged engines now use base weight instead of minimum weight, with 3% DI increase applied to base weight. · T1 BMW E46 wagon with S54 engine allowed; displacement corrected from 3200 to 3250cc. · B-Spec now permits automatic and CVT transmissions on all legal cars meeting spec line. · B-Spec automatic transmissions may use auxiliary coolers on case-by-case basis with part number approval. · HP Datsun 1200 carburetor choke size increases from 26mm to 30mm. · T1 adds Subaru WRX/WRX STI 2005-2020 at 3000 lbs minimum weight with 46 mm restrictor. · T1 Ford Mustang GT (15-17) and GT5.0L (2018-) weight raised to 3500 lbs; Brembo BBK 380mm now at no penalty; restrictors removed from notes. · T1 Ford Mustang/Thunderbird 5000 Coyote OEM reclassified to include 2015–2017 and 2018+ model years with 65mm restrictor for 18+. · T1 BMW M3 E92 carbon dash allowed with 25 lb penalty. · T1 Corvette C5 Z06, C6 coupe, C6 Grand Sport, and Z06 may convert leaf springs to conventional coilover suspension. · Toyota Yaris Sedan 2007- added to B-Spec at 2400 lbs with 1491cc engine. · B-Spec adds 2011-2016 Ford Fiesta 4dr Sedan, 1596cc, 2495 lbs minimum weight. · B-Spec Kia Rio 5-door/LX years expanded to 2012-2019. · B-Spec Mazda2 (10-14) allows specific suspension, intake, exhaust, and bushing parts; removes air duct Mz26-117-33100. · HP Mazda2 updates to 11-14, Honda Fit to 15-19, Mini Cooper to 07-13. · HP Porsche 914-4 1.8L now allows 2-stage dry sump if cam-driven and OEM-located. · HP Toyota Corolla 71-74 permitted to use rear axle housing from 84-87 Corolla. · FP and EP Mazda Miata models standardized to 55mm throttle body diameter; brake spec clarified. · HP VW Rabbit Convertible and Scirocco 1.6L lose 50 lbs minimum weight, to 1735. · B-Spec Mini Cooper production years corrected to 2011-13. · FP and HP Honda Civic and CRX 1988–91 track specifications corrected to 61.3/61.7 inches. · EP, FP, HP cylinder head rules reorganized for clarity; no performance change. · STU cars with manual OEM throttle bodies may convert to OEM electronic throttle body of same inner diameter. · B-Spec Mazda 2, Fiat 500, 2007-10 Mini Cooper permitted to replace primary cat/exhaust manifold with approved header. · B-Spec removes year-specific eligibility and twelve-year competition window wording. · B-Spec Honda Fit model year expanded to include 2013, now covers 2009–2013. · FP and HP Austin-Healey Sprite Mk I and MG Midget variants may replace rear bodywork aft of cockpit with stock-appearing alternate material components. · EP Mazda MX-5 Global Cup classification year changes from 16-18 to 16-19. · Production suspension rule clarifies spindles, hubs, bushings, bearings, ball joints unrestricted. · Production carb rules clarified: carburetor options, fuel injection throttle body dimensions, and intake manifold restrictions reorganised and refined. · EP, FP, HP carburetors clarified: jets, needles, metering rods, needle valves unrestricted; choke parts removable; permitted optional carburetors listed. · STU wing assembly wording corrected: no part higher than roof height. · T1-LP Chevrolet Camaro 1LE 2016- weight drops to 3500 lbs, restrictor increases to 70mm flat plate. · EP Mazda MX-5/Miata eligibility years expanded from 1999-2002 to 1999-2005. · Ford Mustang Challenge returns to T1 as E&O, 4600 cc, 3300 lbs minimum, no restrictor. · T1 Chevrolet Corvette Cadillac XLR year range corrected from 04-09. · B-Spec 2007-10 Mini Cooper gains OBX header part #10-2101-2S as permitted E&O. · STU Nissan SR20DET removes -2mm penalty in Table B. · STU alternate intake manifolds now allowed case-by-case instead of prohibited. · T1 Camaro, CTS, Firebird, GTO restrictor increases from 67mm to 70mm flat plate. · STU aftermarket side skirts must meet 3-inch ride height, no openings except jacks or side exhaust, no wider than fascias, not higher than door bottom, no chassis reinforcement. · STU fender flare wording clarified: each fender may be flared up to 2" for tire clearance with 1% weight penalty. · T2-T4 clarifies DOT tire requirements; must have minimum U speed rating and be DOT certified; touring spec line supersedes other rules. · STL and STU ride height measurement clarified: without driver, at rocker panel lowest point, excluding pinch weld. · Ford Mustang EcoBoost 3.5L classified in T1 at 3300 lbs minimum weight with 31mm restrictor. · T1 Corvette C5 body allowed C7 carbon aero parts, plus 50 lbs. · T1 Audi TTRS must conform to July 24th, 2015 revision 7 GTS rules instead of December 14th, 2011 revision 3. · T1 minimum ride height established at 3.5 inches, measured at rocker panel without driver. · T1 Porsche 928 S4/GTS-R minimum weight reduced to 3200 lbs, throttle restrictor removed. · EP, FP, HP clarified: tapered holes in ball joints now allowed for bolt conversion; wheel bearings and hubs unrestricted at any wheel. · EP open cars may now use aftermarket hardtops if they retain OEM appearance; specific model hardtop allowances removed. · STU Mazda 13B Bridge Port may use ELITE ROTARY SHOP FD V2.0 intake manifold instead of stock. · STU Mazda MZR LF/L3/L5 may use Goodwin Part #61-2510 intake manifold with stock or Acura throttle body. · STU suspension rules clarified: alternate components from same manufacturer moved from section E to section D. · STU Honda/Acura B20 classified at 1973 cc, now permits VTEC B16 or B18 cylinder head and intake manifold. · STU flared fenders up to 2" with 1% weight penalty moved from base to Advanced Aero rules. · TCA Honda Civic Si (2017-) must run 37mm TIR maximum as of June 1, 2019. · STU BMW S54B32 OEM reclassified from E46 designation, 3246 cc, 3300 lbs minimum weight. · Porsche 928 S4/928 GTS-R newly classified in T1 at 3500 lbs minimum with 60mm flat plate restrictor. · B-Spec added to GCR 9.3.26 fuel cell exception list; stock fuel tank permitted. · HP Toyota Yaris 06-11, 07-12 sedan, 12-18 add 130-136 lbs minimum weight. · HP Ford Fiesta years corrected to 11-16; Mazda hubs D651-33-06 front and D651-26-15XE rear allowed. · Honda Civic Si 2017- classified STU at 1500cc, 2800 lbs minimum with OEM engine and bodywork. · STU BMW E46 S54 OEM 3246cc added at 3300 lbs minimum weight, no Super Touring allowances. · STU Mazda 13B and 13B Bridge Port may use RE or REW housings and intake with turbo removed. · STU Honda K24 may use intake part #s 17100-RRB-A00 or 17100-PRB-A10. · STU Mazda 12A Bridge Port engine classified at 2550 lbs minimum weight with specified carburetor induction options. · STU World Challenge car weight calculation method removed; new basis unclear from text provided. · STU AWD cars no longer required to reduce restrictor 1 mm from table. · STU rear wing maximum cord length set to 12 inches, end plates to 72.0 square inches each. · T1-LP Ford Mustang GT 5.0L 2018+ classified at 3400 lbs with 65mm flat plate restrictor. · Canadian Nissan Micra Cup Car classified in B-Spec at 2450 lbs with 1598cc engine, Micra Cup suspension kit allowed. · Toyota Yaris (12-18) newly classified in B-Spec with 1491cc engine, 2400 lbs minimum weight, specified suspension and intake allowed. · B-Spec exhaust system wording clarified: OEM or exact replacement catalysts permitted, stock oxygen sensors required, primary converter unmodified. · STU Honda K20C1 Turbo I4 1996cc added at 3025 lbs minimum weight with 36mm TIR. · T1-LP Mustang GT350(R) spec line replaced with 2015+ model parameters including 5163cc engine, 3650 lbs curb weight, 315 tire size. · Ford Mustang FP350S (2018) classified in T1-LP at 3600 lbs with 18×11 wheels and 315 tires. · T1 suspension rules clarified: spherical bearings and bushings now explicitly permitted, alternate control arms allowed. · T1 Porsche 996 drops 200 lbs to 3000; 996 GT3 Cup drops 150 lbs to 3000; 997 drops 50 lbs to 3100. · Porsche 997 T1 Maximum now allows OEM PDK transmission alongside existing drivetrain options. · T1 Acura NSX Turbo World Challenge weight to 3100 lbs, restrictor to 44mm. · T1-T3 spec cars receive clarifications on permitted modifications, documentation requirements, and rule conformance; no performance changes.showhide
HP Effective date for Jan 2025 GCR updates #37654inductionslowerEP BMW Z3 2.5L requires 52mm flat plate intake restrictor; Z3 2.8L 55mm; 328i/is E36 58mm; 328i/ci E46 58mm; 325i/is E46 56mm; 325i/is E36 56mm; 325is M-Technic 56mm.
B-Spec Remove Redundant Language from Notes Sections #37337wordingneutralB-Spec Honda Fit AT, Fit CVT, Mazda2, Mini Cooper R50 MT and CVT, Toyota Yaris remove redundant notes language.
B-Spec Expire designated spec lines #37517removedneutralB-Spec removes Mini Cooper Countryman R60, Cooper Paceman R61, and two Nissan Versa generations effective 2/1/25.
B-Spec Set expiration date for Nissan Micra Cup Cars (Canadian) #37519wordingneutralB-Spec Nissan Micra Cup Car spec line expires 7/1/25 unless appeal submitted by 6/30/25.
T1 T1 Parity Compared to GT4 #37170weight +125 lbsslowerT1 Mustang gains 125 lbs to 3600, restrictor shrinks 65mm to 60mm. Corvette gains 50 lbs to 3500, restrictor shrinks 70mm to 67mm. BMW deleted.
T1 Clarification of Request Approval #37273 #37399engineunclearT1 E46 M3 Spec Line 1050 allows VAC Motorsports throttle body VAC-TB-S54 on 3.250L engine instead of Dinan.
T1 C8 Corvette Facts #37400weight -100 lbsfasterT1 Chevrolet Corvette C8 (2023-23) minimum weight reduced from 3600 lbs to 3500 lbs.
T1 Camaro Gen 5 Competitive Disadvantage #37440inductionfasterT1 Chevrolet Camaro Gen 5 restrictor increases from 75mm to 80mm flat plate.
T1 Tire Changes in the Rules for GT4 #37497tyres & wheelsunclearT1 Audi R8 GT4 Spec Line #4020 maximum tyre size changes to 315 DOT, 305/645, or 30/65-18 (f), 33/68-18 (r) Non-DOT.
B-Spec Remove wheelbase from spec lines and replace with Restrictor #36074inductionunclearB-Spec and C-Spec cars replace wheelbase spec with induction restrictor (mm) values, effective 2025-01-01.
B-Spec Bilstein Rear Shock Request for Hyundai Accent/Kia Rio #36965suspension & brakesneutralB-Spec Hyundai Accent and Kia Rio approve Bilstein B8 shock 33-187112 for rear suspension use.
HP Request to Reduce Weight of BMW 325i/is E30 (84-91) Spec Line #37119weight -50 lbsfasterEP BMW 325i/is E30 (84-91) weight reduced 50–52 lbs across three spec lines to 2150, 2204, 2258.
HP Request to Update 1988-1991 Civic to Match 1988-1991 CRX #37444weight -70 lbsfasterHP Honda Civic 1.5 88-91 weight reduced to 2175 lbs base, 2229 lbs with one asterisk, 2284 lbs with two asterisks.
STU Audi 1.8t Wagon STU Table B #36685cars addedfasterSTU Audi 1.8T wagon deleted; Porsche 944 1800 weight to Chart, turbo inlet restrictor removed.
STU Merger GT3 to STU #37486wordingneutralSTU-GT3 reclassified as STU-GT3U effective January 1, 2026.
STU GT3 TCR Tire allowance #37494tyres & wheelsslowerSTU GT3 TCR gains 275-width tire option with 100 lb weight penalty, but not in A compound.
HP MINI Cooper Spec Line Correction - Rear Brake Rotor Diameter #37176suspension & brakesneutralHP Mini Cooper 02-06 rear brake rotor increases from 239/9.4 mm/in to 259/10.2.
STU Request to Remove Miata Hubs from General category #37138wordingneutralSTL/STU: 90-05 Mazda Miata alternate front wheel hubs moved from General to specific part approval.
STU BMW N54/N55 Engine Allowance #37146inductionslowerSTU BMW N54/N55 turbo inlet restrictors now required per GCR definition; turbo swapping prohibited.
T1 Changes to T1 Tires for GT4 and Other Cars #35383tyres & wheelsunclearT1 GT4 tire sizes adjusted across ten cars: most non-DOT rear to 305/660, Audi and McLaren 305/645, Camaro and Mustang 305/680.
T1 G82 M4 GT4 inclusion in T1 #35864cars addedneutralBMW M4 GT4 (G82) added to T1 GT4 at 3525 lbs minimum weight with Red power stick control.
T1 Alt. Clutch Allowance #36606wordingneutralT1 Spec Lines now permits 5.5 inch clutch in Engine Notes.
T1 BOP Changes Need Updates #36667weight -150 lbsfasterT1 GT4 Spec Line 4020 restrictor opens from 44mm to 45mm, minimum weight drops to 3400 lbs.
T1 Request Ford Performance Darkhorse R in T1 #37136cars addedneutralMustang Darkhorse R added to T1 homologated cars at 3,250 lbs minimum with 305/315 tires, ineligible for Runoffs until 3 Super Tour events.
T1 Car Mods for T1 Corvette under line item 1150 #37173wordingneutralT1 Corvette may roll or flatten wheel opening lips for tire clearance; plastic fenders may remove lips if edge thickness matches basic material.
T1 Increased Bore Throttle Bodies for E46 M3 S54 Engine #37273enginefasterT1 E46 M3 S54 can now use Dinan Throttle Body #D760-3400 on 3.250L engine.
B-Spec Scion IA/Toyota Yaris/Mazda 2 DY chassis suspension #35780suspension & brakesunclearB-Spec Toyota/Scion IA Sedan 16-20 allows ST Suspension Kit 13275022, requires three Super Tour weekends and OBD-II data submission.
B-Spec Clean up 07-08 Honda Fit AT Notes Section #36542suspension & brakesfasterHonda Fit AT 07-08 B-Spec and C-Spec: rear sway bar Progress #62.1060 and any cold air intake package now allowed.
HP 1275 HP Spridget Level 2 Only #36518enginefasterHP Sprite and Midget 1275cc and 1098cc Level 2 compression ratio raised to 12.0:1.
HP Request for Classification of 1989-1994 Suzuki Swift GT 16V Twin #36858cars addedneutralSuzuki Swift GT 89-94 newly classified to HP Pre at 1900 lbs, 1298cc DOHC fuel injected.
STU R53 15% Pulley Request #36980inductionslowerSTU Mini Cooper S SC 1900 restricts to 2.565 diameter pulley; 2100 allows 2.285 diameter pulley.
B-Spec Update Tire Rules #35984tyres & wheelsneutralB-Spec and C-Spec restricted to Goodyear Eagle RS/RS-R P205/50R15 and 225/45R17 tires respectively; Hankook tires removed; wet/dry mixing prohibited.
B-Spec BOP help for the automatic B-Specs #36161weight -50 lbsfasterB-Spec Sonic restrictors increased to 5-6mm, Fit weight cut 50-25 lbs, Mini Cooper weight reduced 45 lbs, various restrictor adjustments.
B-Spec Require hood pins #36233wordingneutralB-Spec and C-Spec hood pins change from optional to recommended; factory release cable may be removed if pins used.
B-Spec Sonic Caliper Pistons #36238wordingneutralB-Spec and C-Spec Chevrolet Sonic and Cruze allow Babyface Fabrication brake caliper pistons.
HP Errant entry in HP production line item #36231wordingneutralHP Volkswagen Golf and Jetta 85-92 track correction: front 1537mm (60.5in), rear 1529mm (60.2in).
STU RWD Turbo Disadvantage #36255inductionfasterSTU RWD turbo cars no longer required to reduce restrictor by 1 mm from table.
B-Spec Clean up (15-19) Honda Fit MT & CVT Notes Sections #36068wordingneutralB-Spec Honda Fit MT & CVT 15-19: cleaned up allowed parts notes, CVT gains Setrab transmission cooler option.
B-Spec Set expiration date for Nissan Versa (09-11) #36069wordingneutralB-Spec Nissan Versa (09-11) spec line expires 1/1/2025 unless appeal filed by 12/1/2024.
B-Spec Correct error for rear brakes of Hyundai/Kia #36174wordingneutralB-Spec Hyundai Accent rear brakes corrected to 10.3 disc; Kia Rio rear brakes corrected to 10.3 disc.
B-Spec Add B14 Kit Part # to Sonic Spec line In #35969wordingneutralB-Spec and C-Spec Chevrolet Sonic Bilstein B14 kit #47-171725 verified compatible, suspension wording clarified.
B-Spec Eliminate redundant sway bar end link part #s from notes In #35970wordingneutralB-Spec Mazda2 and multiple Mini Cooper models eliminate redundant sway bar end link part number notes.
B-Spec Update Fiat 500 Spec line In #35990wordingneutralB-Spec Fiat 500 spec line changes from model year 2012–15 to 2012–17.
B-Spec Update (15-19) Honda Fit #36067weight +25 lbsslowerB-Spec Honda Fit 15-19 CVT weight increases to 2550 lbs, restrictor to 31mm.
HP NIssan 300ZX Z31 to EP #35830cars addedneutralNissan 300ZX 84-89 classified to EP at 2550 lbs minimum, 2960cc 6-cyl SOHC, fuel injection, 12.0:1 compression limit, 0.500" valve lift limit.
HP RX7 1993 and Up Request In EP Spec Lines, classify #36031cars addedneutralMazda RX-7 92-97 newly classified EP Prep Level 2 at 2200–2310 lbs with 13B 6-port rotary engine.
HP Clean-up Multiple EP RX-8 Spec Lines In EP #36156wordingneutralEP Mazda RX-8 (04-11) alternate spec line removed; one primary line remains.
B-Spec Delete trim levels/update language for spec lines #35746wordingneutralB-Spec model descriptions standardized: trim levels and door count designations removed or replaced with body style wording.
B-Spec Wheel Rules #36066wordingneutralB-Spec and C-Spec wheels must be same thickness spacers all four corners; wording clarified on offset and protrusion rules.
HP Replace plastic panels #35875wordingneutralHP Honda CRX/Si 84-87 plastic panels can be replaced with replica alternate material if stock appearance maintained.
T1 Please Expedite classing the C63 Mercedes #35987cars addedneutralMercedes AMG-C63 S (2023) classified in T1 with 4000 lbs minimum weight and 3700 restrictor.
B-Spec Change restrictor from 30mm to 31mm (2015+ Honda Fit) and add 50# #34857inductionfasterB-Spec Honda Fit MT 2015-19 restrictor increases 30mm to 31mm, weight rises 2525 to 2550 lbs.
B-Spec Wheel Offset and Spacer Revision #35466tyres & wheelsfasterB-Spec and C-Spec now permit wheels of any offset if tire doesn't protrude beyond fender; spacers allowed with differing left-right offsets per axle.
B-Spec Set Expiration Date for Unused Spec Lines #35742wordingneutralB-Spec Mini Cooper Countryman R60, Paceman R61, and Nissan Versa 1797cc spec lines expire 1/1/2025 unless appealed by 12/1/2024.
T1 Honda S2000 #35582cars addedneutralT1 Honda S2000 classified with 2400 lb minimum weight, 2950 cc displacement, 4.75" supercharger pulley.
B-Spec BOP Adjustment for Yaris iA, 2020+ Versa, and 07-08 Honda Fit #35382weight -125 lbsfasterB-Spec Honda Fit 07-08 loses 125 lbs to 2400; Versa S 2020+ loses 150 lbs to 2550; Yaris iA 16-20 loses 250 lbs to 2450.
B-Spec 07-08 Honda Fit Rear Sway Bar part # #35473wordingneutralB-Spec Honda Fit 07-08 rear sway bar part number changed to Progress #62.1060.
HP GCR Correction - Redundant HP Spec Lines #35623wordingneutralHP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve, Scirocco 1588.
STU Letter #35397 addendum #35453wordingneutralSTU Mini Cooper S SC: alternate LEAP OMICRON hood scoop LEP-OMICRON3 permitted.
STU S54 Drysump #35464wordingneutralSTU BMW S54 B32 OEM now permits dry sump oiling system.
T1 9.1.9.1 T1 new category item/ line 26 rule to expire Jan 1 2023 #35411cars addedneutralPontiac GTO 2006-2009 LS1 added to T1 as Spec Line 1590, 5700 cc, 3400 lbs minimum.
B-Spec Eliminate Redundant Trans Cooler Rule #35353wordingneutralB-Spec and C-Spec eliminate case-by-case auxiliary transmission cooler approval requirement.
B-Spec Fix Sonic Hatchback MT Spec Line #35371wordingneutralB-Spec Chevrolet Sonic 5dr Hatch MT allows aluminum radiator #ZZP-ZZ013.
B-Spec Split Spec Line of Automatic and Manual 2nd Gen (09-14) Fit #35251wordingneutralB-Spec Honda Fit MT (09-14) and AT now split into separate spec lines with distinct allowances.
B-Spec Equalize Mazda 2 Headers and clean up spec line #35259weightslowerB-Spec Mazda 2 10-14 weight increases 70 lbs to 2350, cat-delete headers now permitted.
B-Spec Rear Sway Bar Request for Nissan Versa and Versa Note 2013- #35323suspension & brakesneutralB-Spec Nissan Versa and Versa Note 2013-2019 now permit Hardrace HR-Q0146 19mm rear sway bar.
HP Update 1988-1991 Civic to Match 1988-1991 CRX #35399weightfasterHP Honda Civic 1.5 (88-91) weight reduced to 2175 lbs base, 2229 lbs with power adder, 2284 lbs with two.
STU ST Electric-Assisted Steering Systems #35066wordingneutralSTL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems.
T1 C8 Corvette T1 Restrictor Plate Request #35213inductionfasterC8 Corvette T1 restrictor plate increases from 70mm to 72mm flat plate.
T1 The Cars Have Expired #35379removedneutralT1 NEW class removes 23 spec lines including Acura NSX, Ferrari, Porsche 996, Nissan Z cars, and others; Porsche 997 spec line 1680 expiration removed.
B-Spec B-Spec Hankook Tire for Regionals #35055tyres & wheelsneutralB-Spec allows Hankook tires at regionals only through 6-30-2024; Goodyear only from 7-1-2024 for all events.
B-Spec Clarifying the ECU and Data Acquisition language #35236wordingneutralB-Spec and C-Spec ECU and data acquisition rules clarified: ECU must be unaltered OE, no device capable of altering ECU characteristics permitted; data acquisition expanded to allow tachometer, air-fuel ratio, cylinder head temperature sen…
HP Request to Review Z3 2.5 Spec Line #35073weight +50 lbsslowerEP BMW Z3 2.5L weight increases to 2500 lbs, 2563 lbs with turbo, 2625 lbs with supercharger.
HP Parity in HP #35138enginefasterHP Sprite/Midget Mk I–IV, Mk 1500 compression ratio raised to 12.0:1 at Prep Level 1/2.
HP Spitfire classification #35224wordingunclearHP Triumph Spitfire 1500 valve spec changes from 36.6/5.5/(1.44/0) to 36.6/(1.44).
HP Miata Alternate Head #35253weight -50 lbsfasterEP Mazda MX-5 1.8L 1990-97 minimum weight drops to 2150 lbs; 1994-97 variants to 2000, 2050, 2100 lbs respectively.
HP Honda S2000 throttle body #35272inductionfasterEP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm.
HP Front Header/Nose Panel Alternate Material For 84-87 CRX #35301wordingneutralHP Honda CRX/Si 84-87 front header/nose panel may use alternate material if appearance remains stock.
HP Correction within Triumph TR8 Spec Line #35315wordingneutralEP Triumph TR8 dry sump allowance moved from carburetor line to notes section.
HP Correction to EP 924S/944 Spec Line #35317wordingneutralEP Porsche 944/924S 2.5L and 2.7L weight minimums corrected: 2479cc to 2306/2363 lbs, 2681cc to 2358/2415 lbs.
HP Review Classification of HP Mazda 2 #35318weight +75 lbsslowerHP Mazda 2 (11-14) minimum weight increases to 1995 lbs, 2045 lbs with*, 2095 lbs with**.
T1 GT4 batch adjustment in T1 #35162other -85 lbsunclearT1-GT4 batch adjustments: five cars lighter, two heavier, restrictors and ECU maps changed, five models now eligible for Runoffs.
B-Spec Mazda 3i 2010-2013 5-Speed Manual Gear Ratios #34820wordingunclearC-Spec Mazda 3i 10-13 third gear ratio corrected from 3.84 to 1.84.
B-Spec Error Correction #34955wordingneutralC-Spec Dodge Dart 14-16 bore x stroke corrected to 88.0 x 82.0 mm, displacement to 1998 cc.
HP Request to Adjust Weight of 1988-1991 CRX/Civic #35115weight -70 lbsfasterHP Honda CRX 1.5 (88-91) weight reduced to 2175 lbs, 2229 lbs, and 2284 lbs across three spec lines.
HP Porsche 944/924S Rule Change Request #35002cars addedneutralEP Porsche 944/924S combines 2.5L and 2.7L variants with new weights: 2250–2415 lbs depending on engine and year.
HP FP and HP Toyota Corolla #35030weight -43 lbsfasterFP Toyota Corolla 2TC loses 43 lbs to 1810; HP Corolla loses 50–52 lbs to 1910–2006.
HP Weight Reduction for Mazda 626 #35031weight -100 lbsfasterHP Mazda 626 84-87 weight reduced to 2200 lbs, 2255 lbs, and 2310 lbs across three configurations.
HP Triumph GT6 Adjustments #35054weight -30 lbsfasterEP Triumph GT6 minimum weight reduced to 1800 lbs.
T1 New T1 add spec line for C5 corvette LS2 engines (Copy from C6) #33764cars addedneutralT1 Chevrolet Corvette C5 LS2 added with 6000cc displacement, 3300 lbs minimum weight, 72mm flat plate restrictor.
T1 C7 Corvette Rule Change Request #34897cars addedneutralT1 Chevrolet Corvette C7 (14-19) including Z51, Grandsport newly classified as homologated car.
T1 Camaro Gen 5 Weight Reduction Due to Competitive Disadvantage #35092weight -75 lbsfasterT1 Gen 5 Camaro minimum weight drops 75 lbs to 3475; restrictor increases 70mm to 75mm.
T1 Addendum to Letter #35022: Drivetrain Rule #35105wordingneutralT1 Aston Martin Vantage permitted to use OEM Sportshift II transmission.
T1 2004 - 2006 Pontiac GTO Re-Integration Back Into T1 #34403cars addedneutralPontiac GTO 2006-2009 re-integrated into T1 with LS2 at 3400 lbs, 72mm restrictor, and LS3 at 3500 lbs, 61mm restrictor.
T1 Request to Classify Porsche 997-1 GT3 Cup #34561cars addedneutralT1 Porsche 997-1 GT3 Cup added at spec line 4210, minimum weight 3050 lbs.
B-Spec B-Spec Tire #35034tyres & wheelsneutralB-Spec adds Goodyear Eagle RS dry and wet tires as options alongside Hankook; Hankook restricted to regional events from 2024.
B-Spec Initial car classifications and spec lines #34461cars addedneutralC-Spec adds Chevrolet Cruze, Ford Focus, Honda Civic, Mazda 3i, Toyota Corolla, VW Jetta; updates Dodge Dart, Mazda3s, Toyota Corolla specs.
T1 Why no Camaro? #34421cars addedneutralChevrolet Camaro GT4-R classified in T1 GT4 Spec Line 4035, minimum weight 3375 lbs, 315 max tire, 63mm restrictor, ineligible for Runoffs.
T1 Request to Remove Expiration from T1 spec lines #1350 & #1370 #34470wordingneutralT1 Dodge Viper ACR / SRT RT-10 and ACR/ACR-X spec lines 1350 and 1370 remove 12/23 expiration.
T1 Remove #34475wordingneutralT1 GT4 McLaren 570S, Mercedes AMG GT4, and Porsche 718 Cayman GT4 CS MR now eligible for Runoffs competition.
T1 Error in T1 GT4 numbering scheme- #34578wordingneutralT1 GT4 BMW M4 Spec Line Number changed from 4050 to 4030.
T1 C5 Approved Aero That Was Mistakenly Deleted #34374aerofasterT1 Corvette C5 gains approved aero parts: carbon rear spoiler, vented front splitter, side skirts, with 50 lb weight reduction allowed.
B-Spec Hyundai Accent Restrictor Plate #34331inductionfasterB-Spec Hyundai Accent GS Hatchback restrictor plate increases from 39mm to 41mm.
B-Spec Hyundai Accent 2012 Model #34332wordingneutralB-Spec Hyundai Accent GS Hatchback model years corrected from 13–19 to 12–19.
HP Correct Intake Valve Size on 1500cc Midget/Spitfire #34419wordingneutralFP and HP Sprite, Midget, and Spitfire 1500 intake valve size corrected to 36.6/(1.44).
HP ITC to FP? #34286cars addedneutralHP Volkswagen Rabbit Cabriolet 1780 removed; Rabbit 1588 and 1715 reclassified with engine sizes and year ranges specified.
STU 2022 Toyota GR Cup for STU #34449cars addedneutralToyota GR Cup and GR86 Cup (2022-) newly classified in STU at 2700 lbs with 2387 cc engine.
T1 Viper Cleanup #34107inductionfasterT1 Dodge Viper ACR/ACR-X restrictor increases from 50mm to 60mm flat plate.
T1 Viper 8300 OEM FPR Size #34268inductionunclearT1 Dodge Viper ACR/ACR-X: Spec Line 1370 restrictor increases to 55mm, Line 1390 decreases to 55mm.
T1 Ford Mustang S197 (05-14) Clarification #34450wordingneutralT1 Ford Mustang S197 05-14 now requires OEM 8.8 differential housing.
T1 Gen 5 Camaro Engine #33875cars addedneutralT1 Chevrolet Camaro Gen 5 LS7 gets two spec lines: 1131 with 70mm restrictor, 1136 with 53mm restrictor, both 3450 lbs minimum.
T1 Inquiry to letter #33682 #34071engineslowerT1 Chevrolet Camaro Gen 5, Corvette C5 and C6: engine resleeve restricted to stock parameters only, no longer LS3 bore/stroke.
B-Spec Allow ZZP Sonic Aluminum Radiator 1.68 #33660otherfasterB-Spec and C-Spec Chevrolet Sonic allows ZZP aluminum radiator #ZZP-ZZ013; Hatch MT restrictor increases to 34mm.
B-Spec Fasteners for Bumper Caps #33797wordingneutralB-Spec and C-Spec bumper caps now allow positive fasteners like machine screws and T-nuts or rivet-nuts; self-drilling and sheet metal screws prohibited.
B-Spec Allow CAN Bus Connection to Data Systems #33806wordingneutralB-Spec and C-Spec allow CAN bus connections to data systems for monitoring only; systems must not send data.
B-Spec Request Ford Fiesta weight reduction 25lbs #33890weight -25 lbsfasterB-Spec Ford Fiesta 5dr and 4dr lose 25 lbs each, to 2470 lbs minimum weight.
B-Spec BoB Adjustments #34208weight -25 lbsunclearB-Spec Ford Fiesta 5dr and 4dr lose 25 lbs each to 2470; Honda Fit MT and CVT lose 50 lbs each to 2525; Mazda2 loses 50 lbs to 2280; Kia Rio restrictor increases from 39 to 41 mm; Mini Cooper variants gain 75 lbs to 2675 with larger restri…
B-Spec T5 Ride Height Rules. #33552suspension & brakesneutralB-Spec minimum ride height set to 6 inches, C-Spec to 5½ inches.
B-Spec T5 Spring Allowance #33557suspension & brakesneutralB-Spec springs capped at 500# front and rear; C-Spec at 600# front, 800# rear; both may be strapped to body.
B-Spec T5 Wheel Minimum Weight #33558tyres & wheelsneutralB-Spec wheels minimum weight set to 13 lbs, C-Spec to 17 lbs.
B-Spec Threaded Metal Inserts for Plastic Intake Manifolds #34164wordingneutralB-Spec and C-Spec allow metal threaded inserts in plastic intake manifolds for throttle body fasteners.
HP Request to Classify Sonic and Fiesta in HP #34264wordingneutralFord Fiesta HP and Chevrolet Sonic FP model year ranges extended from 2016 to 2019.
T1 Request to reinstate T1 S197 Mustang #34048cars addedneutralT1 Ford Mustang S197 (05-14) reinstated with 3550 lbs minimum weight, 75mm restrictor, Voodoo engine permitted.
B-Spec T5 Rules Feedback #33595wordingneutralB-Spec and C-Spec wording clarified: CATEGORY to CATEGORIES, rules priority clarified for tire sizes, rim widths, springs, anti-roll bars, performance equipment.
T1 T1 GT4 adjustments #33786wordingneutralT1 GT4 weights clarified for nine cars, ranging from 3200 lbs Porsche 718 Cayman to 3575 lbs Aston Martin.
T1 Touring 1 Tire Sizes #34191tyres & wheelsfasterT1-GT4 McLaren 570S and Mercedes AMG GT4 front tires widen to 315 mm.
STU Alternate OEM Miata Intake Manifold #33827wordingneutralSTU Mazda BP5A classified at 1839 cc maximum displacement, 2023-04-01.
T1 Clarification for Camaro Gen5 2010-2015 #33739inductionslowerT1 Chevrolet Camaro Gen5 LS3-6160 adds 70mm flat plate restrictor, weight 3550 lbs.
B-Spec Early Model Mini #33363inductionfasterB-Spec Mini Cooper R56 MT/AT and Clubman R55 fuel pressure regulator increased from 40mm to 41mm with OE catalyst.
B-Spec Helper Versus Tender springs. #33866suspension & brakesslowerB-Spec may use helper springs up to 500 pounds rate; tender springs now prohibited.
STU E&O STU NA Weight Chart. #33737weightfasterSTU minimum weight chart updated: 2450cc to 2595lbs, 2600cc to 2710lbs.
T1 Sequential Gearbox Limitations in T1 #33691wordingneutralT1 cars with aftermarket sequential transmissions get 10-inch max bellhousing; non-sequential cars gain 100 lbs weight break.
T1 T1 GT4 adjustments #33786weightfasterT1 GT4 all nine cars lose 125 lbs minimum weight with driver, from 3200–3575 to 3075–3450.
T1 Sunset of pre 2023 Touring 1 Rules. #33916wordingneutralT1 removes GCR Section 9.1.9.1.A. and T1 Spec Lines entirely, sunsetting pre-2023 Touring 1 rules.
B-Spec Split up Spec lines for Automatic/Manual 2nd Gen Fit #33292enginefasterB-Spec Honda Fit 09-14 Automatic now allows aftermarket exhaust/header; Manual unchanged.
T1 Corrections to T1 Spec Lines #33678tyres & wheelsunclearGT4 McLaren 570S maximum tire size changes to 285 front, 315 rear.
B-Spec Request to Split Spec Lines for Automatic Models #33270wordingneutralB-Spec Chevrolet Sonic and Honda Fit and Mini Cooper split into separate manual and automatic spec lines with distinct transmission ratios and final drives.
B-Spec Tire Rule Request #33350tyres & wheelsneutralB-Spec tire rule adds Hankook 200/580R15 Z217 as alternative to 205/50R15 C51; no mixing wet and dry.
HP MGB HP Weight Break and/or Hybrid 1/2 Prep in HP #33127weightfasterMGB & MGB-GT HP weight breaks reduced to 2000, 2050, 2100 lbs; new MGB HP Prep 1/2 hybrid added at 2175 lbs.
HP Datsun 510 Help #33568weight -50 lbsfasterHP Nissan/Datsun PL510 weight reduced: base 1960 to 1910 lbs, * 2009 to 1958 lbs, ** 2058 to 2006 lbs.
HP Review Limited Prep Port Matching Rules #33600wordingneutralEP, FP, HP cylinder head ports limited to 1 inch maximum depth matching from mating surface.
T1 GT4 section to Current T1 Rules. #33632cars addedneutralEight GT4 models added to T1 with weights from 3200 to 3575 lbs and restricted power per SRO 2022 rules.
B-Spec Utilize the Data - Make BoP Changes #32179weight -225 lbsfasterB-Spec Honda Fit 15-19 weight drops 225 lbs to 2575 lbs.
HP Request to classify VW New Beetle 2.5L in EP #32725cars addedneutralVW New Beetle 2.5L 5-cyl added to EP at 2400–2520 lbs, 2480 cc, fuel injection, comp ratio 12.0:1 max, valve lift 0.500" max.
HP Request Rotary Injection on Dual Y manifold #32775inductionunclearEP Mazda RX-7 12A/13B gains fuel injection option on dual-y manifold with 42mm choke(s).
HP Request for Corrado Stroke & Displacement Correction #32985wordingneutralEP VW Corrado 92-95 stroke corrected to 90.3 mm, displacement to 2792 cc.
B-Spec Request new Mazda Rear Swaybar #32769wordingneutralB-Spec Mazda2 10-14 rear sway bar now allows part 0000-04-2203-RR or 0000-04-2312.
STU Request Mazda 13 B turbo #32668cars addedneutralSTU Mazda 13B Turbo classified, streetport only, stock turbos prohibited, alternatives allowed.
STU Hood Vents and Intercooler Scoops #32733aerofasterSTU OEM louver vents now exempt from vent count and 200 square inch allowance.
STU Non 4 valve weight reduction removed #32808enginefasterSTU 2400cc non-4-valve engines gain 9% base weight reduction; DI turbo prep limits removed.
T1 Correct Camaro Spec Line From Letter #30791 response to 3475lbs #32824weight -25 lbsfasterT1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird, Pontiac GTO 6162 OEM minimum weight reduced to 3475 lbs.
STU Error in new minimum weight table when combined with other text #32711engineslowerSTU normally-aspirated 2976–3200 cc single-throttle engines lose 10% base engine weight reduction.
STU Redundant Language in May GCR #32713wordingneutralST redundant language removed from balance shaft and pulley modification rules.
HP Subaru BRZ Model Years #32500wordingneutralEP Subaru BRZ and Toyota 86/Scion FR-S model year ranges updated to 13-20.
T1 Fix FP350S limited prep and Shelby 350 full prep issues #31680inductionfasterT1-LP Ford Mustang FP350S restrictor increases from 70mm to 75mm.
T1 Request to Classify AMG GT4 #32610cars addedneutralMercedes Benz AMG GT4 2017-2021 classified T1 Maximum at 3400 lbs minimum weight with HP-controlled SRO Power Level 2 engine.
B-Spec Request to Remove Part Numbers from Kia/Hyundai Spec Lines #32378inductionslowerB-Spec Hyundai Accent GS and Kia Rio restrictor increased from 36mm to 39mm flat plate.
HP EP MX-5 Global Cup Car #32218weightslowerEP Mazda MX-5 Global Cup 16-22 minimum weight set to 2400 lbs; sequential gearbox allowed with +150 lbs penalty.
HP Please Class BMW 128i in EP #32370cars addedneutralBMW 128i (08-13) classified in EP at 2700 lbs minimum with stock throttle body, 11.0:1 compression ratio, 0.400 in. valve lift limits.
HP Inconsistency in Body Work Descriptions #32396aerofasterEP/FP/HP open cars may now use carbon fiber hardtops if they retain OEM appearance in all exterior profiles.
STU Opposed to the Proposed STU Weight Chart #32381wordingneutralSTU cars that qualified for 9 inch wheels in 2021 may continue through 2022 only.
STU Clarification request for GCR 9.1.4.D.3.a Splitter Definition #32414wordingneutralSTU splitter definition clarified: must be single-plane with no vertical deviations, attached to lowest front point.
HP Mazda RX8 with 13b Rotary #32170wordingneutralEP Mazda RX-8 13B carburetor rules clarified: dual 2bbl carb, fuel injected throttle body, or stock fuel injection permitted.
HP Request Idle control valve clarification #32178wordingneutralEP and FP Production clarifies idle control valve rules: stock devices allowed original, removed with blocked ports, or mechanical replaced with electronic stock type.
HP Classify VW New Beetle in HP. #32241cars addedneutralHP Volkswagen New Beetle (98-05) classified at 2350 lbs minimum, 1984cc SOHC, fuel injection, 11.0:1 compression limit.
STU Request Adjustment to Min Weight for STU BMW E36 M3 (95-99) #31535weight -90 lbsfasterSTU BMW S52B32 minimum weight drops 90 lbs to 3110; max displacement cut to 3152 cc.
STU BMW E36 M3 Canadian (North American) S50B32 engine #31866cars addedneutralSTU BMW S50B32 Euro classified at 3201 cc displacement, 3300 lbs minimum weight.
STU Engine Swap Origin Country #32209wordingneutralST engine swap origin country requirement changes from North America to the United States for case-by-case approval.
STU CRX/Civic Del Sol #32214weightslowerSTU Honda CRX (84-91) and Civic Del Sol (93-97) ineligible for front wheel drive weight reductions.
STU Error correction #32383tyres & wheelsfasterSTU vehicles at or over 2950 lbs base weight may use 9 inch wide wheels instead of 8.0 inch maximum.
STU Single TB Weight Modifiers Add to Chart #32393weightfasterSTU minimum weights reduced: 2450cc to 2596 lbs, 2500cc to 2635 lbs, 2550cc to 2675 lbs.
T1 Viper/Z06 Parity #31942weight -50 lbsfasterT1 Dodge Viper ACR displacement rises to 8400 OEM, minimum weight drops to 3550 lbs.
T1 Discrepancy in T1 allowances #32293wordingneutralT1 Limited T1 wording changed to clarify all T1 cars permitted specifications.
B-Spec Request spring attachment #31351suspension & brakesneutralB-Spec allows springs strapped to body for rebound control; removes requirement for OEM or kit bump stops.
B-Spec Limit Rear Camber to 1.75 Degrees Section 9.1.10.E.35 #31393suspension & brakesslowerB-Spec strut tower modifications permitted for camber adjustment only, limited to 1.75 degrees.
B-Spec Letter 31442 Part# Correction #32060wordingneutralB-Spec Mazda2 10-14 undertray part numbers corrected to DO8C-56-110A, DO8C-56-311, DO7A-56-321.
HP Weight Change for Competition Adjustment #31182weight +45 lbsslowerHP Triumph Spitfire 1500 minimum weight increases to 1605 lbs, 1645 lbs, or 1685 lbs.
HP EP Adjustments #31858inductionslowerEP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate.
HP 1999 3.8L Ford Mustang to EP? #31635weightfasterFord Mustang 99-03 classified to EP at 2700/2768/2835 lbs; 94-98 Mustang weight reduced to 2550/2614/2678 lbs.
HP Improved Touring Tires #32064tyres & wheelsneutralEP, FP, HP Improved Touring cars may use any DOT-approved tire per section 9.3.45 in Production class.
STU Single TB Weight Modifiers #31449weightfasterSTU normally aspirated engines: minimum weights reduced up to 310 lbs; single throttle body weight reduction removed.
STU Request to Remove A4 1.8t from STU Spec Line Tables #31465weightslowerSTU Audi A4 1.8T minimum weight fixed at 3050 lbs, VF30 turbo with 35mm restrictor now required only.
STU Improved Touring Tires #32063tyres & wheelsneutralSTL and STU Improved Touring vehicles must conform to 9.1.4 Tires & Wheels requirements.
B-Spec Request to Classify 2020-21 Versa S #30759cars addedneutralB-Spec Nissan Versa S 2020- classified at 2700 lbs with 38mm restrictor, 1598cc engine.
B-Spec Request to Classify the Toyota IA sedan & Scion IA Sedan for 2022 #31045cars addedneutralToyota/Scion IA Sedan (2016-2020) classified for B-Spec at 2700 lbs with 38mm FPR.
HP Throttle Body and Idle Air #31800wordingneutralEP, FP, HP classes allow stock/original idle control devices unmodified or completely removed with openings blocked.
HP Incorrect Valve Size Changes in Jan 2022 GCR for FIAT X1/9 #31990wordingunclearHP Fiat X1/9 intake valves corrected to 36.3mm/1.43in; exhaust valves to 33.3mm/1.31in or 31.2mm/1.23in depending on level.
STU Request Allowance for Balance Shaft Delete in STU #31434enginefasterSTU engines may delete balance shafts and plug openings; alternate pulleys allowed for timing belt or chain operation only.
STU Request Louvers in hood vents #31916aeroneutralSTU hood vents allowed to include louvers within 200 sq. inch area.
B-Spec Request to add 2007-2008 Honda Fit #30853cars addedneutral2007-2008 Honda Fit automatic added to B-Spec at 2525 lbs with 1499 cc engine.
HP Porsche 968 Engine Questions #31478enginefasterEP Porsche 968 intake valve size increased from 37 to 39.0 mm.
HP PCS E. 2. n. 4. Add Axle Shaft to Allow FWD the Same Freedom #31592wordingneutralEP, FP, HP front-wheel-drive cars may alter body and suspension to install alternate transmission, transaxle, and axle shaft.
HP Weight Adjustment To Fiat X1/9 Spec Lines, H-Production #31653weight -50 lbsfasterHP Fiat X1/9 1500 loses 50 lbs to 1950; 1300 loses 45–47 lbs; Bertone 1500 loses 50–52 lbs.
HP 1500 Midget #31665cars addedneutralAustin-Healey Sprite Mk I, II, III, IV and MG Midget classified in HP Prep with 1510–1586 lbs depending on prep level.
HP BMW Z3 2.5L Spec Line #31724wordingneutralEP BMW Z3 2.5L allows alternate throttle body from 92-95 325i with Turner adapter; head casting 1738400 permitted with specific blocks.
HP Request weight requirement for 1500 MG Midget #31802cars addedneutralAustin-Healey Sprite Mk I–IV and MG Midget classified in HP with 1655 lbs minimum weight.
STU Request to Add Honda K23 Spec Line #30682cars addedneutralSTU adds Honda K23 with 2354cc displacement and minimum weight per chart, K24 block allowed with K23 internals and head.
STU RE: Aug FT letter 30682 #31060enginefasterSTU Honda K23 internals rule relaxed to require only K23 crankshaft, allowing other internal modifications.
STU Throttling Device Clarification #31323wordingneutralSTL and STU piston engines clarified: intake manifold and cylinder head porting remains free.
HP 944S2 Restrictor #31396inductionslowerEP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; comp ratio max 12.0:1, valve lift max 0.500".
HP Classing Clarification for 1986 Toyota Corolla FX16 #31527cars addedneutralHP Corolla GTS RWD (84-87) added at 2300 lbs; HP Corolla FX16 FWD (87-88) added at 2260 lbs; old Corolla (84-87) removed.
T1 Turbo Miata Help #31315weight +200 lbsslowerT1 Mazda MX-5 Miata MazdaSpeed minimum weight rises to 2550 lbs, restrictor increases to 42mm.
T1 Fix the T1 Corvette heading #31528wordingneutralT1 Chevrolet Corvette Cadillac XLR classified for model years through 2019.
B-Spec Rules Clarification of Body and Camber Plates #30814suspension & brakesneutralB-Spec upper strut slotted plates no longer require manufacturer's original bolt holes or serve as reinforcement.
HP E&O; MR2 Track #31120wordingneutralHP Toyota MR-2 1.6L (85-89) track corrected to 15.47 inches front and rear.
B-Spec Rules Clarification of Body and Camber Plates #30814suspension & brakesfasterB-Spec upper strut slotted plates no longer must use manufacturer's original bolt holes.
HP Request to Allow F22c Engine for 2000-2003 Honda S2000 #30548cars addedunclearHonda S2000 (00-03) reclassified as EP Prep with F22c engine option: 1997cc or 2157cc, weight 2450–2636 lbs depending on displacement.
HP Request a review of the S14 240SX in EP. #30873weight -200 lbsfasterEP Nissan 240-SX S13/S14 loses 200-210 lbs minimum weight; comp ratio rises to 12.0:1, valve lift to .500.
T1 T1 E46 BOP E&O for Letter # 29970 #30934weight +100 lbsslowerT1 BMW E46/E36/Z3 minimum weight increases to 2700 lbs, 3.4L engine car to 2750 lbs.
HP Lotus/Caterham 7 America Request #30392wordingunclearEP Lotus/Caterham 7 America carburetor changed from IT fuel injection prep to fuel injection.
HP Request to classify ITC Plymouth Arrow #30588cars addedneutralPlymouth Arrow 1598cc four-cylinder classified to HP at 1800 lbs minimum weight.
HP Reclassification of the 1984/85 BMW 318i from FP to HP #30661cars addedneutralBMW 318i E30 (84-85) reclassified from FP to HP at 2200–2310 lbs with fuel injection and .425" valve lift limit.
HP Reclassify Daimler SP 250 #30721cars addedneutralDaimler SP 250 classified in EP at 2165 lbs with 2548 cc OHV 8-cylinder engine.
STU STU Fender flares #30696wordingneutralSTU fender flare wording clarified: exterior contour of any wheel opening may not change opening size, location or shape from side view.
STU Request weight reduction for 12A bridgeport motor in Miata #30751weight -200 lbsfasterSTU Mazda 12A Bridge Port Miata weight reduced from 2550 lbs to 2350 lbs.
T1 Request BoP for the Viper in 1 LP #29968inductionfasterT1 Dodge Viper SRT-10 restrictor increases from 45mm to 57mm.
T1 LS6 Alternative Head Question #30074wordingneutralT1 Chevrolet Corvette Cadillac XLR LS6 engine now permits Casting #799 heads with no other head modifications.
B-Spec Transmission Cooler Requests #30079wordingneutralB-Spec Honda Fit and Mini Cooper models gain alternate transmission ratios and final drives to allow Setrab 50-119-7612 cooler.
B-Spec Request to classify the 07 Honda Fit #30083cars addedneutralB-Spec Honda Fit 2007-08 classified with 1499cc displacement, 2450mm wheelbase, 2525 lbs minimum weight.
B-Spec Request Ford Fiesta Eibach Rear Sway Bar Part Number 35143.320 #30340otherneutralB-Spec Ford Fiesta 5dr Hatchback allowed Eibach rear sway bar #35143.312 or #35143.320.
B-Spec Restrictor rule #30474inductionfasterB-Spec restrictor range changes from 0.060" ±0.005" to 0.050"-0.079".
B-Spec Rear wipers on all cars #30585weightfasterB-Spec rear window wipers and wiper motor removal now allowed.
HP 924 Brakes- and Thank You. #30614suspension & brakesfasterHP Spec Line Porsche 924 (76-84) brakes change from solid to vented disc.
HP Clarify Application of Percentage Based Weight Penalties #30669weightslowerEP, FP, HP clarifies percentage weight penalties sum first, then apply to base weight, rounding to nearest pound.
HP Correct Induction Error on new HP Mazda 626 Spec Line #30702inductionunclearHP Mazda 626 (84-87) induction changed from dual 32mm sidedraft carbs to carburation or fuel injection.
T1 T1-LP - Add Performance Pack, Bullet, Mach 1 to 18+ Mustang #29849inductionfasterT1 Ford Mustang Shelby/GT350/GT500 5.0L Coyote restrictor opens from 65mm to 70mm flat plate.
T1 Request BoP for the Viper in 1 LP #29968inductionfasterT1 Dodge Viper SRT-10 restrictor increases from 45mm to 57mm.
T1 Request to classify C7 and 13Viper in T1 LP #29969inductionfasterT1-LP Chevrolet Corvette C7 restrictor increases from 70 to 73 mm.
T1 Request LP Z06 steel chassis #30589wordingneutralT1-LP Corvette Z06 06-13 now allows aluminum chassis replacement with equivalent OE steel chassis.
HP Volvo 142 spec line complete. #29479cars addedneutralVolvo 142/142E moves from HP Spec P-1800 Engine to HP Prep with 1989cc OHV four-cylinder, 2450–2573 lbs.
HP Request to Classify 93-98 Volkswagen Golf to HP #29790cars addedneutralVolkswagen Golf III/Jetta III 93-98 classified to HP at 2325–2441 lbs with 1984cc SOHC engine.
HP Appeal of Request to Move Porsche 924 to HP #30132cars addedneutralPorsche 924 (76-84) newly classified to HP with 2400-2520 lbs weight, fuel injection, 1984cc engine.
HP Change Classification of 84-87 Mazda 626 from FP to HP #30350cars addedneutral84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lbs weight, 1998cc SOHC, dual 32mm carbs.
HP Fiat X1/9 brake rotors #30423suspension & brakesneutralFP Fiat X1/9 brake rotors change to 257 (10.1) x 12 (.407) solid disc.
STU Request for Fender Flare Clarification #30375wordingneutralSTU fender flare rules clarified: maximum 2 inches, must cover tire contact patch from above, cannot alter body configuration or wheel opening geometry.
T1 Request For Reduction in Weight/Penalties for Camaro #30443weightfasterT1 Chevrolet Camaro with 6162 displacement minimum weight reduced to 3500 lbs.
T1 Fix dry sump Contradictions in T1-LP vs T2 #30596wordingneutralT1-LP Chevrolet Corvettes C5 Z06, C6 Grand Sport, and Z06 dry sump kit notes clarified to remove contradictions.
B-Spec Allow 4 lug hub conversion to R60 and R61 MINI #29863wordingneutralB-Spec Mini R60 and R61 allow 4-lug hub conversion with specified bearings and brake rotors.
B-Spec Honda Fit Years on Spec Line #30078wordingneutralB-Spec Honda Fit model years expand from 09-12 to 09-14.
B-Spec Hyundai/Kia restrictor size incorrect #30380inductionslowerB-Spec Hyundai Accent GS and Kia Rio restrictor reduced from 40mm to 36mm flat plate.
B-Spec Clarify tire compound in rules #30387tyres & wheelsneutralB-Spec must use Hankook P205/50ZR15 Z214 C51 or Z217 rain tyres for SCCA Majors, Super Tour, Runoffs.
HP Request to Classify 2012-2015 MINI Cooper Coupe in HP #30167cars addedneutralHP Mini Cooper classification expands to include 12-15 Coupe model in existing spec line.
HP Request clarification on VW 1.8 Rabbit GTI Spec Line #30368wordingneutralHP Volkswagen Rabbit GTI 1780 (83-84) permits Mk2 VW front spindles, hubs and bearings.
STU Provision for Interchangeable Engine Components Already Allowed #30342engineunclearSTU Honda S2000 allows F20/F22 K24 crankshaft with chart weight for achieved displacement.
STU ST Oil Coolers E&O Correction to 9.1.4.2.H #30388wordingneutralST oil coolers and filters now explicitly allowed to be added or substituted; wording clarifies existing permissions.
B-Spec Spec Tire Recommendation #29480tyres & wheelsneutralB-Spec tire rules clarified: Hankook Z214 dry and Z217 rain required at Majors/Super Tour/Runoffs after 6-1-2021; regional racing allows any DOT race tire through 2021.
B-Spec Make restrictor thickness unique for B Spec #30349wordingunclearB-Spec restrictor thickness set to 0.060 inches plus or minus 0.005 inches.
STU Super Touring Alternate Miata Hubs #30345wordingneutralSTL/STU 90-05 Mazda Miata gains approval for Mazda Motorsports Development alternate front wheel hubs.
T1 T1 LP Aero adjustments #30196aerounclearT1 LP removes 50 lbs weight allowance for stock headers, adds aero device allowance up to 100 lbs, permits headers.
B-Spec Request to Classify Hyundai Accent (RB) 2012-2019 #29484cars addedneutralB-Spec Hyundai Accent GS Hatchback 2013-2019 classified at 2525 lbs with 40mm flat plate restrictor.
B-Spec Countryman production years incorrect #29864wordingneutralB-Spec Mini Cooper Countryman R60 and Paceman R61 production years corrected from 11-13 to 11-16.
B-Spec Toyota Yaris Model Year Corrections #29896wordingneutralB-Spec Toyota Yaris Hatch model year spans corrected from 07-12 to 07-11 and 12-18 added.
B-Spec Correction spec lines for ride height Mini Cooper all models #29952wordingneutralB-Spec Mini Cooper all models ride height minimum 5 inches measured from metal under door rocker molding.
B-Spec Request to Allow Removal of Stock Brake Dust Shields #29981suspension & brakesneutralB-Spec allows removal or material modification of metal or plastic brake dust shields.
B-Spec Request to allow OBX header and restrictor to R55 Clubman 08-10 #30024engineunclearB-Spec Mini Cooper Clubman R55 11-15 permitted OBX header with 40mm flat plate restrictor.
STU Brake Component Relocation #29990wordingneutralST cars may relocate ABS actuation hardware and wiring anywhere in engine compartment.
STU Porsche PDK #30081wordingneutralSTU Porsche PDK automatic transmission limited to 8 forward speeds instead of torque converter restriction.
STU Reference Letter #29333 Proposed STU 13B Spec Line Changes #30086inductionfasterSTU Mazda 13B Street Port 2400 removes choke location restriction, allows auto-type 2bbl with dual-Y manifold.
STU Drive Shaft Request #30087wordingneutralSTU driveshaft and half-shaft materials change from OEM-type to steel or aluminum.
T1 Request to Clarify Miller Mustang Classification #28728engineunclearT1 Ford Mustang Challenge 3-valve maximum displacement changes to 4600/5000.
T1 BMW E46 Carbon Dash #29806weightslowerT1 BMW E46 now allows carbon or fiberglass OEM-style dashboards with 25 pound penalty.
T1 Request to Update T1 Mustang Spec Line #30001wordingneutralT1 Ford Mustang/Thunderbird limited to Shelby/Shelby GT350/GT500 models through 2018.
T1 Class BMW M2CS Club Sport #30195cars addedneutralBMW M2CS Club Sport classified in T1-LP Spec Lines effective 2021-02-01.
T1 997.1 GT3 Cup #30229cars addedneutralPorsche 997.1 GT3 Cup (2006-2011) classified in T1 at 3600cc, 3150 lbs minimum weight.
HP Alternate Front Brake Rotors and Calipers for EP AH 3000 #29893suspension & brakesneutralEP Austin-Healey 3000 Mk. I, II, III now allows TR-6 front calipers and discs as alternate.
STU 13B Rules Adjustment #29333cars addedslowerSTU Mazda 13B Street Port classified at 2400 lbs minimum weight, replacing peripheral and bridge port variants.
T1 Correct T1 Limited Prep Years #29708wordingneutralT1 Chevrolet Corvette Z06 years extended from 06-12 to 06-13.
B-Spec Request clarification of B14 shock package for any and all cars #29483suspension & brakesneutralB-Spec: Bilstein B14 suspension kits removed from all car spec lines; clarified B14 shock or strut use requires CRB approval of mounting adaptors.
B-Spec Cleanup of spec lines #29495removedneutralB-Spec removes Chevrolet Sonic 12-19, clarifies Toyota Yaris Hatch 07-12 and Sedan 07-12.
HP Mk2 VW Consistency and Cleanup of FP and HP Spec Lines #29195weight -50 lbsfasterFP Volkswagen Golf and Jetta 1.8 lose 50 lbs each, to 1900. HP Jetta GLI engine code removed.
HP Correct Wording for Level 1 and Level 2 Induction Systems #29406wordingneutralEP, FP, HP Level 1 and Level 2 induction systems: clarified carburetor and fuel injection rules, jets/needles/rods unrestricted in Level 2.
HP Weight Reduction for Datsun Roadster #29409weight -75 lbsfasterEP Datsun SRL 311U Roadster minimum weight reduced to 1925 lbs from 2000 lbs.
HP EP TR8 Adjustment #29512weight -100 lbsfasterEP Triumph TR8 78-81 weight reduced from 2600 to 2500 lbs.
STU Request clarification on wing measurement #29640aeroneutralST aero devices and reference areas now include end plates but exclude fasteners protruding over 1/2 inch.
T1 Changes to Corvette C8 #29898tyres & wheels -100 lbsfasterT1 Corvette C8 Z51 gets wider wheels and tyres, weight drops 100 lbs to 3550.
HP 84-87 Toyota Corolla HP Wheel Diameter Allowance Proposal E&O #29458tyres & wheelsfasterHP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches.
B-Spec Allowance Versus Requirement for R56 Mini Cooper #29127suspension & brakesfasterB-Spec Mini Cooper R56 40mm flat plate restrictor requirement removed, suspension and header parts now allowed.
STU Request for Advanced Aero Rule Wording Clarification. #29124wordingneutralSTU fender flare rules reworded: up to 2" per corner allowed with 1% weight penalty total.
HP EP BMW Z3 Rule Clarification #28998wordingneutralEP BMW Z3 2.5L iron block casting 1738566-C designation removed, wording clarification only.
STU Minimum Weight Determination #27695wordingneutralSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis adjustments.
STU ST Gurney flap Wicker clarification #29012wordingneutralSTL and STU rear wing rules clarify that wicker is a Gurney flap; no performance change.
STU Request for Alternate Intake Manifold #26514wordingneutralSTU request for alternate intake manifold denied; no rule change issued.
STU Request for Addition to GT3 Approved Turbo List #27576wordingneutralGT3 and STU add Borg-Warner EFR6258 to approved turbocharger list.
STU Request BoP for my Car #29004wordingneutralSTU large displacement turbo engines limited by GCR turbo list; non-turbo trim suggested as more competitive.
STU Sequential Shifters in STU #29031wordingneutralSTU sequential shifters referred to Board of Directors for approval; no change implemented yet.
B-Spec Request to change units on wheelbase for consistency with wording #28786wordingneutralB-Spec wheelbase measurements converted from inches to millimeters for consistency across all cars.
HP BMW Cylinder Head Casting and Part Numbers #28708engineslowerEP BMW 2.8L, 328i E36/E46, and 325i E36 blocks now iron only; 325i E46 aluminum only.
STU Rotary Help #27833cars addedneutralSTU Mazda 13B Bridge Port and Street Port engines added with 2550 and 2250 lbs minimum weights respectively.
T1 Consider coil spring conversion Corvette in T2 #28824suspension & brakesneutralT1 and T2 Corvettes may convert leaf spring suspension to coilover with 800 lb max spring rate allowed.
B-Spec Transmission cooler for automatic equipped cars #28171otherneutralB-Spec Chevrolet Sonic 5dr Hatch and 4dr Sedan allow Setrab transmission cooler for automatic-equipped cars.
B-Spec Spring Update for all models #28384suspension & brakesneutralB-Spec: multiple models allow specific suspension kits and damper assemblies.
B-Spec B-Spec Balance of Performance based on 2018 and 2019 seasons #28394induction -25 lbsslowerB-Spec Ford Fiesta 5dr gets 36mm restrictor, 4dr gets 34mm, Honda Fit 09-12 loses 25 lbs to 2525, Fit 15-20 restrictor reduced 32mm to 30mm, Mini Cooper 07-10 gets 40mm restrictor.
HP Request to Classify 1990-1994 Mazda Protege #28381cars addedneutral1990-1994 Mazda Protege classified in FP Pre at 2150–2258 lbs with 1839cc DOHC engine, fuel injection.
HP Error in Mini Cooper Spec Line #28713wordingneutralHP Mini Cooper model year ranges for convertibles revised: 02-06 now includes 05-08, 07-13 now includes 09-15.
T1 Additional Clarification on 996 Cup in T1 From Letter #28040 #28060wordingneutralT1 Porsche 996 GT3 Cup eligible model years changed from 2002-2005 to 1998-2004.
T1 Request SPEC Corvette Rear Spolier #28182aeroneutralT1 Corvette and Cadillac XLR permitted to install SCRSPLR-001 rear spoiler with OE bodywork.
T1 T1 Rear Brake Rotor Size Exemption for Gen 5 Camaro #28402wordingneutralT1 Gen 5 Camaro allowed 366mm OEM rear rotor and caliper without weight penalty.
HP Caterham 7 Spec Line #28498wordingneutralEP Caterham 7 Spec Line removes redundant suspension note, clarifies engine prep limits and comp ratio to 10.0:1.
STU Request to approve Honda S2000 HKS supercharger #27281enginefasterSTU Honda S2000 adds HKS Supercharger kits 12001-AH006 and 12001-AH010 as allowed.
STU Request BoP on the Lotus #27637weight +100 lbsslowerSTU Lotus Elise Cup R and SC models, plus Exige SC, gain 100–200 lbs minimum weight.
STU Turbo Inlet Restrictor On MK5 Volkswagen #27704inductionslowerSTU Volkswagen GTI/GLI MK5 and Jetta Mk4 may install turbo inlet restrictor in OEM turbo inlet housing.
STU Honda K20C1 removal #27732inductionslowerSTU Honda K20C1 Turbo I4 restrictor reduces from 36mm to 35mm.
STU Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0 #27884engineslowerSTU GM Ecotech LNF now allowed with turbo removed or with LE5 head and intake manifold, meeting STL specs.
STU Alternate Engine for Porsche 944 #28259engineunclearSTU Porsche 944 now permits VW/Audi 1.8L and 2.0L turbo engines as alternates.
T1 Request 996 GT3 Trunk for Wing Allowance. #28153wordingneutralT1 Porsche 996 Spec Lines now allows 996 Cup Replica Rear deck lid.
T1 All Touring, Change DOT Tire Language 9.1.9.1, 9.3.45 #28452wordingneutralT1 Acura NSX Turbo World Challenge and Audi TTRS GTS 2011 now require DOT tires per GCR section 9.3.
B-Spec Request for Model Years Updating #27850wordingneutralB-Spec Sonic extended to 2019, Fiat 500 limited to 2015, Fiesta models extended to 2019, Fit expanded to 2015-2019.
B-Spec Request to classify Min Cooper models #27861cars addedneutralB-Spec Mini Cooper R50, R55, R58, R60, R61 models newly classified at 2545–2625 lbs with 40mm restrictor for 12+ models.
B-Spec remove fog lights #27947wordingneutralB-Spec fog lamps must now be removed and holes completely covered, reversing prior allowance.
B-Spec add sonic sedan #27948cars addedneutralB-Spec Chevrolet Sonic 4dr Sedan (12-19) added at 2650 lbs with 32mm flat plate restrictor.
HP Letter #27917 #28085wordingneutralHP Volkswagen Rabbit and Scirocco 1588 remove 32mm choke requirement, clarify carburetor options and weight penalties.
HP Request to Classify 2007 - 2013 Mini Cooper Convertible #28111cars addedneutralHP Mini Cooper Convertible (07-13) newly classified; (05-08) convertible spec consolidated into main listing.
HP Allow HP Datsun 510 Under Level 2 to Utilize Datsun Z Brakes #28121suspension & brakesneutralHP Datsun 510 Level 2 brakes changed from factory spec to 9.1 disc front, 9.0 drum rear, allowing 240Z/260Z/280Z parts.
HP Request to allow 40 DCOE carb for the Datsun 510 #28195inductionfasterHP Datsun 510 gains 40 DCOE carburetor option alongside existing 40 DCN and 36mm DCNVH choices.
HP Request Ford Fiesta Weight Adjustment #28337weightfasterHP Ford Fiesta 78-80 minimum weight drops 50 lbs to 1725; both asterisk tiers drop 51 lbs.
STU Please Modify the STU Wheel Size Rule for Clarity #27694weightfasterSTU vehicles over 2951 lbs base weight may use 9 inch wide wheels, up from 2950 lbs.
STU Turbo Engine Cars Base Weight #28032wordingneutralSTU turbocharged engines now use base weight instead of minimum weight, with 3% DI increase applied to base weight.
T1 Request for E46 wagon with S54 engine in T1 #27427wordingneutralT1 BMW E46 wagon with S54 engine allowed; displacement corrected from 3200 to 3250cc.
B-Spec Request for Automatic Transmission Inclusion #27686wordingneutralB-Spec now permits automatic and CVT transmissions on all legal cars meeting spec line.
B-Spec Request to Add Transmission Coolers to Automatics #27687otherneutralB-Spec automatic transmissions may use auxiliary coolers on case-by-case basis with part number approval.
HP Request for Help for Datsun 1200 #27934inductionfasterHP Datsun 1200 carburetor choke size increases from 26mm to 30mm.
T1 Request to include Subaru WRX/STI 02-18 in T1 #24916cars addedneutralT1 adds Subaru WRX/WRX STI 2005-2020 at 3000 lbs minimum weight with 46 mm restrictor.
T1 Request Ford Mustang FP350S T1-LP weight and restrictor change #26662weight +100 lbsslowerT1 Ford Mustang GT (15-17) and GT5.0L (2018-) weight raised to 3500 lbs; Brembo BBK 380mm now at no penalty; restrictors removed from notes.
T1 Request to classify Ford Coyote 3rd Gen OEM #27145cars addedslowerT1 Ford Mustang/Thunderbird 5000 Coyote OEM reclassified to include 2015–2017 and 2018+ model years with 65mm restrictor for 18+.
T1 Request alternate dashboard #27276weightslowerT1 BMW M3 E92 carbon dash allowed with 25 lb penalty.
T1 Request for Allowance of Coil Springs on Limited Prep C6 Corvette #27713suspension & brakesfasterT1 Corvette C5 Z06, C6 coupe, C6 Grand Sport, and Z06 may convert leaf springs to conventional coilover suspension.
B-Spec Add Yaris Sedan #26797cars addedneutralToyota Yaris Sedan 2007- added to B-Spec at 2400 lbs with 1491cc engine.
B-Spec Add 2011-2016 Fiesta Sedan #26798cars addedneutralB-Spec adds 2011-2016 Ford Fiesta 4dr Sedan, 1596cc, 2495 lbs minimum weight.
B-Spec add 2015-2019 Kia Rio #26799cars addedneutralB-Spec Kia Rio 5-door/LX years expanded to 2012-2019.
B-Spec Error and Omissions #27858suspension & brakesneutralB-Spec Mazda2 (10-14) allows specific suspension, intake, exhaust, and bushing parts; removes air duct Mz26-117-33100.
HP Update years for the Mazda2, Honda Fit, & Mini #27782wordingneutralHP Mazda2 updates to 11-14, Honda Fit to 15-19, Mini Cooper to 07-13.
HP Allow Dry Sump, Limited Prep Porsche 914 #27814wordingneutralHP Porsche 914-4 1.8L now allows 2-stage dry sump if cam-driven and OEM-located.
HP Please Allow Alternate Rear Axle Housing for RWD Toyota Corolla #27854wordingneutralHP Toyota Corolla 71-74 permitted to use rear axle housing from 84-87 Corolla.
HP Request to List Mazda Miata Throttle Body Size #27907wordingneutralFP and EP Mazda Miata models standardized to 55mm throttle body diameter; brake spec clarified.
HP HP VW Rabbit Convertible 1.6L #1922 and 32mm chokes #27917weightfasterHP VW Rabbit Convertible and Scirocco 1.6L lose 50 lbs minimum weight, to 1735.
B-Spec Request for Correction of Production Years for Mini Cooper #27226wordingneutralB-Spec Mini Cooper production years corrected to 2011-13.
HP Request to Correct Track of 1988-91 Honda Civic #27487wordingneutralFP and HP Honda Civic and CRX 1988–91 track specifications corrected to 61.3/61.7 inches.
HP Re-organize Prep2 Cylinder Head Rules for Clarity & Consistency #27661wordingneutralEP, FP, HP cylinder head rules reorganized for clarity; no performance change.
STU Request for an electronic throttle body #27342wordingneutralSTU cars with manual OEM throttle bodies may convert to OEM electronic throttle body of same inner diameter.
B-Spec Request for Corrections to 9.1.10 E Item #27 D and E #27224inductionfasterB-Spec Mazda 2, Fiat 500, 2007-10 Mini Cooper permitted to replace primary cat/exhaust manifold with approved header.
B-Spec Remove wording in the B-spec rules #27388wordingneutralB-Spec removes year-specific eligibility and twelve-year competition window wording.
B-Spec Request to add 2013 Honda Fit model year #27491cars addedneutralB-Spec Honda Fit model year expanded to include 2013, now covers 2009–2013.
HP Request bodywork for Austin Healey Bugeye Sprite MK1 #27106wordingneutralFP and HP Austin-Healey Sprite Mk I and MG Midget variants may replace rear bodywork aft of cockpit with stock-appearing alternate material components.
HP Request to classify the GMX5 2019 #27263wordingneutralEP Mazda MX-5 Global Cup classification year changes from 16-18 to 16-19.
HP level one susp. component rule #27270wordingneutralProduction suspension rule clarifies spindles, hubs, bushings, bearings, ball joints unrestricted.
HP Clarification of Carb Rules - Prep 1 #27300wordingneutralProduction carb rules clarified: carburetor options, fuel injection throttle body dimensions, and intake manifold restrictions reorganised and refined.
HP Clarification of Carb Rules - Prep 2 #27301wordingneutralEP, FP, HP carburetors clarified: jets, needles, metering rods, needle valves unrestricted; choke parts removable; permitted optional carburetors listed.
STU Request to correct E&O advanced aerodynamics #27290wordingneutralSTU wing assembly wording corrected: no part higher than roof height.
T1 T1 LP 2016 Camaro and Later #27198weight -100 lbsfasterT1-LP Chevrolet Camaro 1LE 2016- weight drops to 3500 lbs, restrictor increases to 70mm flat plate.
HP Request Miata Eligibility - 2003 #27121cars addedneutralEP Mazda MX-5/Miata eligibility years expanded from 1999-2002 to 1999-2005.
T1 Request to return Ford Mustang Challenge Car to T1 #26751cars addedneutralFord Mustang Challenge returns to T1 as E&O, 4600 cc, 3300 lbs minimum, no restrictor.
T1 Correct years in T1 FP Corvette spec #27023wordingneutralT1 Chevrolet Corvette Cadillac XLR year range corrected from 04-09.
B-Spec Request to allow OBX Header for 2007-10 Mini Cooper #26977wordingneutralB-Spec 2007-10 Mini Cooper gains OBX header part #10-2101-2S as permitted E&O.
STU Remove -2mm penalty from SR20DET Nissan #26982enginefasterSTU Nissan SR20DET removes -2mm penalty in Table B.
STU Request clarification for manifold and throttle in STU #27004inductionfasterSTU alternate intake manifolds now allowed case-by-case instead of prohibited.
T1 Request BoP Baten - T1 Camaro - Follow up to Letter # 26145 #26900inductionfasterT1 Camaro, CTS, Firebird, GTO restrictor increases from 67mm to 70mm flat plate.
STU Request to clarify afterrmarket side skirts exhaust exit #26814wordingneutralSTU aftermarket side skirts must meet 3-inch ride height, no openings except jacks or side exhaust, no wider than fascias, not higher than door bottom, no chassis reinforcement.
STU Wheel Flare wording #26872wordingneutralSTU fender flare wording clarified: each fender may be flared up to 2" for tire clearance with 1% weight penalty.
T1 Clarify DOT tires touring #26556tyres & wheelsneutralT2-T4 clarifies DOT tire requirements; must have minimum U speed rating and be DOT certified; touring spec line supersedes other rules.
STU Request Ride Height Clarification #26597wordingneutralSTL and STU ride height measurement clarified: without driver, at rocker panel lowest point, excluding pinch weld.
T1 Request to Classify EcoBoost Mustang #25841cars addedneutralFord Mustang EcoBoost 3.5L classified in T1 at 3300 lbs minimum weight with 31mm restrictor.
T1 Request Corvette aerodynamic aids #26265aeroslowerT1 Corvette C5 body allowed C7 carbon aero parts, plus 50 lbs.
T1 Audi TTRS VTS Documentation Revision #26578wordingunclearT1 Audi TTRS must conform to July 24th, 2015 revision 7 GTS rules instead of December 14th, 2011 revision 3.
T1 Request Ride Height Clarification #26599wordingneutralT1 minimum ride height established at 3.5 inches, measured at rocker panel without driver.
HP Rollcenter Correction Clarification #25873suspension & brakesfasterEP, FP, HP clarified: tapered holes in ball joints now allowed for bolt conversion; wheel bearings and hubs unrestricted at any wheel.
HP Hardtops #26476wordingneutralEP open cars may now use aftermarket hardtops if they retain OEM appearance; specific model hardtop allowances removed.
STU Request to Use Japanese Mazda 13b Intake Manifold #25790inductionfasterSTU Mazda 13B Bridge Port may use ELITE ROTARY SHOP FD V2.0 intake manifold instead of stock.
STU Request Alternate Intake for Mazda MZR In a Rear Wheel Drive App. #26352inductionunclearSTU Mazda MZR LF/L3/L5 may use Goodwin Part #61-2510 intake manifold with stock or Acura throttle body.
STU E&O Suspension #26424wordingneutralSTU suspension rules clarified: alternate components from same manufacturer moved from section E to section D.
STU Revisit B20 VTEC #26530enginefasterSTU Honda/Acura B20 classified at 1973 cc, now permits VTEC B16 or B18 cylinder head and intake manifold.
STU Move Flared Fenders to STU Advanced Aero #26564aeroneutralSTU flared fenders up to 2" with 1% weight penalty moved from base to Advanced Aero rules.
STU TCA Civic SI E&O #26606tyres & wheelsslowerTCA Honda Civic Si (2017-) must run 37mm TIR maximum as of June 1, 2019.
STU S54 Spec line #26620wordingneutralSTU BMW S54B32 OEM reclassified from E46 designation, 3246 cc, 3300 lbs minimum weight.
T1 Request to classify the Porsche 928GTS/S4 in Touring 1 #26315cars addedneutralPorsche 928 S4/928 GTS-R newly classified in T1 at 3500 lbs minimum with 60mm flat plate restrictor.
B-Spec Request to add B-Spec to GCR 9.3.26 fuel cell #26132wordingneutralB-Spec added to GCR 9.3.26 fuel cell exception list; stock fuel tank permitted.
HP Do Something About the Toyota Yaris In H Production #25834weight +130 lbsslowerHP Toyota Yaris 06-11, 07-12 sedan, 12-18 add 130-136 lbs minimum weight.
HP Request to Allow 2011+ Fiesta to Change Bolt Pattern on Wheels #25929wordingneutralHP Ford Fiesta years corrected to 11-16; Mazda hubs D651-33-06 front and D651-26-15XE rear allowed.
STU Request to Class Assignment for 2017 Civic #24287cars addedneutralHonda Civic Si 2017- classified STU at 1500cc, 2800 lbs minimum with OEM engine and bodywork.
STU Request to run E46 3246cc in STU #25126cars addedneutralSTU BMW E46 S54 OEM 3246cc added at 3300 lbs minimum weight, no Super Touring allowances.
STU Engine Classification for Rotary #25564wordingunclearSTU Mazda 13B and 13B Bridge Port may use RE or REW housings and intake with turbo removed.
STU K24/K20 Head Swap Clarification/Amendment #25899wordingneutralSTU Honda K24 may use intake part #s 17100-RRB-A00 or 17100-PRB-A10.
STU Request to Classify 12a Bridge Ported Rotary Engine #25985cars addedneutralSTU Mazda 12A Bridge Port engine classified at 2550 lbs minimum weight with specified carburetor induction options.
STU World Challenge Car Eligibility #26387wordingunclearSTU World Challenge car weight calculation method removed; new basis unclear from text provided.
STU Request a phone call for discussion regarding weight #26398inductionfasterSTU AWD cars no longer required to reduce restrictor 1 mm from table.
STU Advanced Aero E&O #26413aeroneutralSTU rear wing maximum cord length set to 12 inches, end plates to 72.0 square inches each.
T1 Request Mustang GT Limited Prep 2018 Classification #24431cars addedneutralT1-LP Ford Mustang GT 5.0L 2018+ classified at 3400 lbs with 65mm flat plate restrictor.
B-Spec Request to classify Canadian Nissan Micra Cup cars #25216cars addedneutralCanadian Nissan Micra Cup Car classified in B-Spec at 2450 lbs with 1598cc engine, Micra Cup suspension kit allowed.
B-Spec Request updated Toyota Yaris Spec Lines #25483cars addedneutralToyota Yaris (12-18) newly classified in B-Spec with 1491cc engine, 2400 lbs minimum weight, specified suspension and intake allowed.
B-Spec Update wording of exhaust #26022wordingneutralB-Spec exhaust system wording clarified: OEM or exact replacement catalysts permitted, stock oxygen sensors required, primary converter unmodified.
STU Request to Equalize Direct Injected Turbo Cars #24890cars addedneutralSTU Honda K20C1 Turbo I4 1996cc added at 3025 lbs minimum weight with 36mm TIR.
T1 Class 2015+ Mustang GT350(R) #21466wordingneutralT1-LP Mustang GT350(R) spec line replaced with 2015+ model parameters including 5163cc engine, 3650 lbs curb weight, 315 tire size.
T1 Request to Classify Ford FP350S in T1-LP #25341cars addedneutralFord Mustang FP350S (2018) classified in T1-LP at 3600 lbs with 18×11 wheels and 315 tires.
T1 Amendment to Request #25555 #25556wordingneutralT1 suspension rules clarified: spherical bearings and bushings now explicitly permitted, alternate control arms allowed.
T1 Request to balance 996 v 997 T1 weight #25658weightfasterT1 Porsche 996 drops 200 lbs to 3000; 996 GT3 Cup drops 150 lbs to 3000; 997 drops 50 lbs to 3100.
T1 Request to Add PDK Transmission to 997 Porsche Spec Line #25668wordingneutralPorsche 997 T1 Maximum now allows OEM PDK transmission alongside existing drivetrain options.
T1 T1 World Challenge/Grand AM Spec Cars #25687weightslowerT1 Acura NSX Turbo World Challenge weight to 3100 lbs, restrictor to 44mm.
T1 Add Clarification to Spec Car Classifications Vehicle Spec #25774wordingneutralT1-T3 spec cars receive clarifications on permitted modifications, documentation requirements, and rule conformance; no performance changes.
Best is the class's fastest lap in that event's qualifying or race sessions, with the driver who set it, how many cars set a time that session and how close the top five were; a best from fewer than three cars is greyed. With two or more classes, "vs" is the gap of each class's best to the first class's at the same event. "% of HP" is the class's best as a share of HP's best at the same event (100% is level, less is quicker): weather and track condition move every class together, so this compares across years where the raw times do not. It still breaks when HP's own field changes or one session was wet and another dry. Newest event first. The coloured figure under each value is the change from the previous event that has one (green is quicker, red slower). Whole laps only, so events with different sector layouts still compare. Weather and track condition are not accounted for.