STU vs B-Spec vs GTX pace at Buttonwillow Raceway Park
Quickest here:STU 1:50.913 Tony Rivera, Cal Club 2026 qualifying · B-Spec 2:09.353 Trenton Kramer, Cal Club 2026 qualifying · GTX 1:49.596 Rob Scholl, Cal Club 2025 race
STUB-SpecGTXsolid race · dashed qualifying · slower is lower
STUB-SpecGTXsolid race · dashed qualifying · each class's best lap as a share of STU's at the same event (the reference class, changeable above); 100% is level, higher is quicker
Event
STU
B-Spec
GTX
Qual best
Race best
Trap
Qual best
Race best
Trap
vs STU
% of STU
Qual best
Race best
Trap
vs STU
% of STU
Cal Club 2026 CALCL262026-02-21
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%)
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%)
+17.179squal +18.440s
115.2%qual 116.6%
1:54.892Moze Cowper · only car
1:55.330Moze Cowper · only car+5.734s (+5.23%)
146.0Moze Cowper+29.6 mph (+25.4%)
+2.593squal +3.979s
102.3%qual 103.6%
44 rule changes (STU: 17, B-Spec: 24, GTX: 3)11 weight · 5 cars added · 3 induction · 3 tyres & wheels · 2 engine · 2 suspension & brakes · 17 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. · 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. · GTX Misc Table 4 adds RCR T70 Coupe with 2200 lbs minimum weight, no restrictor specified. · STU Mazda MZR (LF, L3, L5) Turbo classified; Jack Spania Racing 70 mm intake manifold and Fab9 Tuning bottom-mount turbo kit approved. · 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. · 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. · STU Honda K24 engine swap weight increases by 2% effective November 1, 2025. · 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. · 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. · GTX Ligier LMP3 now allows any normally aspirated LS Chevrolet engine. · 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. · GTX Porsche GT2 RS Clubsport classified with factory specifications required at all race events. · 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. · 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. · 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. · 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.showhide
B-Spec C-Spec Rear Sway Bars #39652wordingwordingC-Spec rear sway bars approved for Chevrolet Cruze, Dodge Dart, Ford Focus, Honda Civic, Mazda3i, Toyota Corolla with specified part numbers.
B-Spec Notes section cleanup #39062wordingwordingB-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.
GTX Please Consider Adding a Spec Line to GTX Table 4 for the RCR T70 #39470cars addedcars addedGTX Misc Table 4 adds RCR T70 Coupe with 2200 lbs minimum weight, no restrictor specified.
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.
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.
B-Spec Alternate Shift Cable Bushings and Rear Spring Seats #38472wordingwordingB-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.
STU Non-Homologated Engine Swaps - Specifically K24A2 w/ Honda CRZ #38746weightslowerSTU Honda K24 engine swap weight increases by 2% effective November 1, 2025.
B-Spec Remove Asterisk from Rule 9 #38768wordingwordingB-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 #38354wordingwordingB-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.
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 #38422wordingwordingSTU Mazda MZR may use Goodwin 61-2510 or Gato Performance 31972 intake manifold.
STU Requesting Approval of the JDM Honda h23a #38489cars addedcars addedSTU 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 addedcars addedB-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. #38048wordingwordingB-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 #38306wordingwordingB-Spec Honda Fit AT 09-14 adds Weapon R Intake 301-166-301 to approved parts.
B-Spec Update Rule 46 #38307wordingwordingB-Spec and C-Spec shift linkage/cables no longer prohibited from any modification; approved aftermarket bushings now permitted.
GTX Ligier P3 LS Swap #38164engineunclearGTX Ligier LMP3 now allows any normally aspirated LS Chevrolet engine.
B-Spec Correct Hyundai/Kia Model Years #37943wordingwordingB-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 #38010wordingwordingHonda Fit 07-08 MT and AT approved for Bilstein B14 kit 47172401 in B-Spec.
GTX Request to Classify Porsche GT2 RS Clubsport #37972cars addedcars addedGTX Porsche GT2 RS Clubsport classified with factory specifications required at all race events.
STU Wheel Size Inconsistency #38018wordingwordingSTU 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.
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 #37534wordingwordingB-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 #37880wordingwordingB-Spec Hyundai Accent and Kia Rio (12-19) allow Bilstein B14 kit #47167490 front shocks and BabyFace Fabrication sump extension #BF-HYU-PAN.
B-Spec Toyota Yaris Hatchback (12-18) rear disc brakes #37530suspension & brakessuspension & brakesB-Spec Toyota Yaris Hatchback 12-18 rear brakes now allow 10.2 inch disc alternative to 7.9 drum.
B-Spec Yaris Speed Sensor #37536wordingwordingB-Spec Toyota Yaris Hatchback and Sedan may now disconnect speed sensor.
B-Spec Set Expiration Date For Fiat 500 #37689wordingwordingB-Spec Fiat 500 (12-17) spec line expires 1/1/26 unless appeal filed.
STU BMW N54/N55 Engine Allowance Follow Up #37447engineengineSTU 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.
Cal Club 2025 CALCL252025-02-22
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
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
+16.414squal +15.112s
114.4%qual 113.1%
1:49.596Rob Scholl · only car
116.4Rob Scholl
-4.044s
96.4%
238 earlier rule changes on record, in force before Cal Club 2025 (from 2019)46 cars added · 22 induction · 21 weight · 16 suspension & brakes · 13 engine · 13 tyres & wheels · 6 aero · 2 removed · 94 wording · 5 other · 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. · 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. · TA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement. · 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. · 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. · 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. · 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. · 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. · 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. · GT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR. · 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. · 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. · STU Mini Cooper S SC: alternate LEAP OMICRON hood scoop LEP-OMICRON3 permitted. · STU BMW S54 B32 OEM now permits dry sump oiling system. · 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. · GT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed. · GT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors. · GT2/3 Nissan, Mazda, Mitsubishi 4G93, QR25DE/DD, QE25DE/DD Direct Injection now permitted per 9.1.2.F.7.5.E. · STL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems. · 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… · GTX adds KTM X-Bow classification with restrictor and weight specifications effective 2024-01-01. · 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. · GTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL. · 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. · 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. · GTX Ligier LMP3 3.7L NA classified at 2203 lbs with 22 mm restrictor. · GTX Ligier JSP4 newly classified as GTX Misc with restrictor and weight specified. · Toyota GR Cup and GR86 Cup (2022-) newly classified in STU at 2700 lbs with 2387 cc engine. · 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. · B-Spec and C-Spec wording clarified: CATEGORY to CATEGORIES, rules priority clarified for tire sizes, rim widths, springs, anti-roll bars, performance equipment. · Fields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight. · STU Mazda BP5A classified at 1839 cc maximum displacement, 2023-04-01. · 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. · B-Spec Honda Fit 09-14 Automatic now allows aftermarket exhaust/header; Manual unchanged. · 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. · GT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870. · B-Spec Honda Fit 15-19 weight drops 225 lbs to 2575 lbs. · GT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only. · 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. · 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. · Porsche 992 GT3 Cup Car newly classified in GTX. · B-Spec Hyundai Accent GS and Kia Rio restrictor increased from 36mm to 39mm flat plate. · GTX Wolf GB08 F1 Ford 52XS V8 added to classification at 1725 lbs minimum weight. · C7 Corvette Grand Sport classified in GTX Misc at 3200 lbs with option to remove displacement on demand valve train. · GTX eligible prototypes expanded: IMSA GTP years changed to 1981-1993, five prototype categories added. · 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. · 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. · 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. · GTX McLaren 720s GT3 newly classified at 3000 lbs with 3000 mm restrictor. · 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. · 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. · GTX-FIA GT3 removes all intake restrictor requirements for fifteen car models; McLaren name corrected. · 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. · 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. · B-Spec upper strut slotted plates no longer require manufacturer's original bolt holes or serve as reinforcement. · GT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight. · B-Spec upper strut slotted plates no longer must use manufacturer's original bolt holes. · GTX SRO-GT4 Porsche 718 Club Sport MR GT4 classified, unrestricted, 2900 lbs minimum weight. · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix. · Grullon GT with 2.0L K20 moved from GTX to GT2-ST, minimum weight 2350 lbs, unrestricted. · B-Spec Mazda2 10-14 allows header PN 0000-06-2410 with 70 lb weight penalty. · GTX Grullon GT added, unrestricted, 2350 lbs, factory spec required. · 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. · 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. · STU fender flare rules clarified: maximum 2 inches, must cover tire contact patch from above, cannot alter body configuration or wheel opening geometry. · 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. · 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. · 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. · STU Mazda 13B Street Port classified at 2400 lbs minimum weight, replacing peripheral and bridge port variants. · 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. · ST aero devices and reference areas now include end plates but exclude fasteners protruding over 1/2 inch. · B-Spec Mini Cooper R56 40mm flat plate restrictor requirement removed, suspension and header parts now allowed. · GT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line. · STU fender flare rules reworded: up to 2" per corner allowed with 1% weight penalty total. · GTX Chevrolet Camaro ZL1 LT4 with factory supercharger classified at 3400 lbs minimum weight. · GTX adds KTM X-Bow GT4, turbocharged 2.5L Audi TFSI I5, 2000 lbs minimum weight. · 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. · TA2 Gurney flap wording clarified: terminology standardized to 'Gurney flap', height limits and thickness specifications remain 0.50 inch / 0.625 inch or 0.375 inch / 0.0625 inch depending on configuration. · STO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules. · GT classes clarify Gurney flap wording, replacing wickerbill/tab terminology with flap; specifications unchanged. · 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. · GTX tube frame cars must weigh 2780 pounds; stock car bodies now permitted. · STU Mazda 13B Bridge Port and Street Port engines added with 2550 and 2250 lbs minimum weights respectively. · 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. · GTX adds Lotus Evora GTS with 3.5L 2GR-FE engine, no restrictor, 2950 lbs minimum weight. · 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. · 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. · 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. · 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. · GT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications. · 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. · Factory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs. · B-Spec Mini Cooper production years corrected to 2011-13. · 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. · STU wing assembly wording corrected: no part higher than roof height. · 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. · 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. · GTX tube frame cars gain fuel injection with 90mm maximum throttle body size. · Ligier JS2 R classified in GTX, no performance parameters specified in filing. · STL and STU ride height measurement clarified: without driver, at rocker panel lowest point, excluding pinch weld. · GT1 and GT2/GT3/LITE ride height requirements removed from GCR sections 9.1.2.D.5.a.1 and 9.1.2.F.7.b. · 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. · B-Spec added to GCR 9.3.26 fuel cell exception list; stock fuel tank permitted. · GTX replaces all FIA GT4 references with SRO GT4. · 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. · 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. · GTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified. · STU Honda K20C1 Turbo I4 1996cc added at 3025 lbs minimum weight with 36mm TIR.showhide
B-Spec Remove Redundant Language from Notes Sections #37337wordingwordingB-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 #37517removedremovedB-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) #37519wordingwordingB-Spec Nissan Micra Cup Car spec line expires 7/1/25 unless appeal submitted by 6/30/25.
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 & brakessuspension & brakesB-Spec Hyundai Accent and Kia Rio approve Bilstein B8 shock 33-187112 for rear suspension use.
GTX Correct language regarding OEM Areo Devices #37137wordingwordingTA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement.
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 #37486wordingwordingSTU-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.
STU Request to Remove Miata Hubs from General category #37138wordingwordingSTL/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.
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.
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 & wheelstyres & wheelsB-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 #36233wordingwordingB-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 #36238wordingwordingB-Spec and C-Spec Chevrolet Sonic and Cruze allow Babyface Fabrication brake caliper pistons.
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 #36068wordingwordingB-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) #36069wordingwordingB-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 #36174wordingwordingB-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 #35969wordingwordingB-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 #35970wordingwordingB-Spec Mazda2 and multiple Mini Cooper models eliminate redundant sway bar end link part number notes.
B-Spec Update Fiat 500 Spec line In #35990wordingwordingB-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.
B-Spec Delete trim levels/update language for spec lines #35746wordingwordingB-Spec model descriptions standardized: trim levels and door count designations removed or replaced with body style wording.
B-Spec Wheel Rules #36066wordingwordingB-Spec and C-Spec wheels must be same thickness spacers all four corners; wording clarified on offset and protrusion rules.
GTX Request for Spec Line 1010 Reconsideration #35009weight +300 lbsslowerGT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR.
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 #35742wordingwordingB-Spec Mini Cooper Countryman R60, Paceman R61, and Nissan Versa 1797cc spec lines expire 1/1/2025 unless appealed by 12/1/2024.
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 # #35473wordingwordingB-Spec Honda Fit 07-08 rear sway bar part number changed to Progress #62.1060.
STU Letter #35397 addendum #35453wordingwordingSTU Mini Cooper S SC: alternate LEAP OMICRON hood scoop LEP-OMICRON3 permitted.
STU S54 Drysump #35464wordingwordingSTU BMW S54 B32 OEM now permits dry sump oiling system.
B-Spec Eliminate Redundant Trans Cooler Rule #35353wordingwordingB-Spec and C-Spec eliminate case-by-case auxiliary transmission cooler approval requirement.
B-Spec Fix Sonic Hatchback MT Spec Line #35371wordingwordingB-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 #35251wordingwordingB-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 & brakessuspension & brakesB-Spec Nissan Versa and Versa Note 2013-2019 now permit Hardrace HR-Q0146 19mm rear sway bar.
GTX Rear Blade Spoiler Clarification #35261aerofasterGT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed.
GTX GT Direct Injection allowance and rules #35437enginefasterGT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors.
GTX GT2/3 remove Direction Injection not allowed in Spec line notes #35439inductionfasterGT2/3 Nissan, Mazda, Mitsubishi 4G93, QR25DE/DD, QE25DE/DD Direct Injection now permitted per 9.1.2.F.7.5.E.
STU ST Electric-Assisted Steering Systems #35066wordingwordingSTL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems.
B-Spec B-Spec Hankook Tire for Regionals #35055tyres & wheelstyres & wheelsB-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 #35236wordingwordingB-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…
GTX KTM X Bow GTX #34956cars addedcars addedGTX adds KTM X-Bow classification with restrictor and weight specifications effective 2024-01-01.
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 #34955wordingwordingC-Spec Dodge Dart 14-16 bore x stroke corrected to 88.0 x 82.0 mm, displacement to 1998 cc.
GTX Errors in GTCS Headings and Use of the Terms Category and ClassChange existing GTL and GTA Rules #34453wordingwordingGTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL.
B-Spec B-Spec Tire #35034tyres & wheelstyres & wheelsB-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 addedcars addedC-Spec adds Chevrolet Cruze, Ford Focus, Honda Civic, Mazda 3i, Toyota Corolla, VW Jetta; updates Dodge Dart, Mazda3s, Toyota Corolla specs.
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 #34332wordingwordingB-Spec Hyundai Accent GS Hatchback model years corrected from 13–19 to 12–19.
GTX Request Ligier LMP3 Classification #34043cars addedcars addedGTX Ligier LMP3 3.7L NA classified at 2203 lbs with 22 mm restrictor.
GTX Ligier JSP4 Request #34173cars addedcars addedGTX Ligier JSP4 newly classified as GTX Misc with restrictor and weight specified.
STU 2022 Toyota GR Cup for STU #34449cars addedcars addedToyota GR Cup and GR86 Cup (2022-) newly classified in STU at 2700 lbs with 2387 cc engine.
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 #33797wordingwordingB-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 #33806wordingwordingB-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 & brakessuspension & brakesB-Spec minimum ride height set to 6 inches, C-Spec to 5½ inches.
B-Spec T5 Spring Allowance #33557suspension & brakessuspension & brakesB-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 & wheelstyres & wheelsB-Spec wheels minimum weight set to 13 lbs, C-Spec to 17 lbs.
B-Spec Threaded Metal Inserts for Plastic Intake Manifolds #34164wordingwordingB-Spec and C-Spec allow metal threaded inserts in plastic intake manifolds for throttle body fasteners.
B-Spec T5 Rules Feedback #33595wordingwordingB-Spec and C-Spec wording clarified: CATEGORY to CATEGORIES, rules priority clarified for tire sizes, rim widths, springs, anti-roll bars, performance equipment.
GTX Please classify Fields Cardinal V8 #33784cars addedcars addedFields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight.
STU Alternate OEM Miata Intake Manifold #33827wordingwordingSTU Mazda BP5A classified at 1839 cc maximum displacement, 2023-04-01.
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.
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.
B-Spec Request to Split Spec Lines for Automatic Models #33270wordingwordingB-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 & wheelstyres & wheelsB-Spec tire rule adds Hankook 200/580R15 Z217 as alternative to 205/50R15 C51; no mixing wet and dry.
GTX GT2 (TA2)/GTA Part Number Update #33315wordingwordingGT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870.
B-Spec Utilize the Data - Make BoP Changes #32179weight -225 lbsfasterB-Spec Honda Fit 15-19 weight drops 225 lbs to 2575 lbs.
GTX Tail lights on all GT category race cars. #32799wordingwordingGT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only.
B-Spec Request new Mazda Rear Swaybar #32769wordingwordingB-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 addedcars addedSTU 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.
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 #32713wordingwordingST redundant language removed from balance shaft and pulley modification rules.
GTX Classify 992 GT3 Cup #32649cars addedcars addedPorsche 992 GT3 Cup Car newly classified in GTX.
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.
GTX Add Classification to the accepted Model Table #31981cars addedcars addedGTX Wolf GB08 F1 Ford 52XS V8 added to classification at 1725 lbs minimum weight.
GTX Request to classify C7 Corvette Grand Sport IN GTX Misc #32254cars addedcars addedC7 Corvette Grand Sport classified in GTX Misc at 3200 lbs with option to remove displacement on demand valve train.
GTX E&O list of eligible prototypes #32511cars addedcars addedGTX eligible prototypes expanded: IMSA GTP years changed to 1981-1993, five prototype categories added.
STU Opposed to the Proposed STU Weight Chart #32381wordingwordingSTU 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 #32414wordingwordingSTU splitter definition clarified: must be single-plane with no vertical deviations, attached to lowest front point.
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 addedcars addedSTU BMW S50B32 Euro classified at 3201 cc displacement, 3300 lbs minimum weight.
STU Engine Swap Origin Country #32209wordingwordingST 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.
B-Spec Request spring attachment #31351suspension & brakessuspension & brakesB-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 #32060wordingwordingB-Spec Mazda2 10-14 undertray part numbers corrected to DO8C-56-110A, DO8C-56-311, DO7A-56-321.
GTX McLaren 720s GT3 #31955cars addedcars addedGTX McLaren 720s GT3 newly classified at 3000 lbs with 3000 mm restrictor.
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 & wheelstyres & wheelsSTL and STU Improved Touring vehicles must conform to 9.1.4 Tires & Wheels requirements.
B-Spec Request to Classify 2020-21 Versa S #30759cars addedcars addedB-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 addedcars addedToyota/Scion IA Sedan (2016-2020) classified for B-Spec at 2700 lbs with 38mm FPR.
GTX Remove restrictions from GTX-FIA GT3 #32039inductionfasterGTX-FIA GT3 removes all intake restrictor requirements for fifteen car models; McLaren name corrected.
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 #31916aeroaeroSTU hood vents allowed to include louvers within 200 sq. inch area.
B-Spec Request to add 2007-2008 Honda Fit #30853cars addedcars added2007-2008 Honda Fit automatic added to B-Spec at 2525 lbs with 1499 cc engine.
STU Request to Add Honda K23 Spec Line #30682cars addedcars addedSTU 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 #31323wordingwordingSTL and STU piston engines clarified: intake manifold and cylinder head porting remains free.
B-Spec Rules Clarification of Body and Camber Plates #30814suspension & brakessuspension & brakesB-Spec upper strut slotted plates no longer require manufacturer's original bolt holes or serve as reinforcement.
GTX Request car classification #31032cars addedcars addedGT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight.
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.
GTX Request to classify 2020 Porsche 718 GT4 Clubsport MR #30956cars addedcars addedGTX SRO-GT4 Porsche 718 Club Sport MR GT4 classified, unrestricted, 2900 lbs minimum weight.
GTX Request to Update GTA Obsolete Part Numbers #30615wordingwordingGTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix.
GTX GTX class correction to GT2/ST #30973cars addedcars addedGrullon GT with 2.0L K20 moved from GTX to GT2-ST, minimum weight 2350 lbs, unrestricted.
STU STU Fender flares #30696wordingwordingSTU 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.
B-Spec Transmission Cooler Requests #30079wordingwordingB-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 addedcars addedB-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 #30340otherotherB-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.
STU Request for Fender Flare Clarification #30375wordingwordingSTU fender flare rules clarified: maximum 2 inches, must cover tire contact patch from above, cannot alter body configuration or wheel opening geometry.
B-Spec Allow 4 lug hub conversion to R60 and R61 MINI #29863wordingwordingB-Spec Mini R60 and R61 allow 4-lug hub conversion with specified bearings and brake rotors.
B-Spec Honda Fit Years on Spec Line #30078wordingwordingB-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 & wheelstyres & wheelsB-Spec must use Hankook P205/50ZR15 Z214 C51 or Z217 rain tyres for SCCA Majors, Super Tour, Runoffs.
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 #30388wordingwordingST oil coolers and filters now explicitly allowed to be added or substituted; wording clarifies existing permissions.
B-Spec Spec Tire Recommendation #29480tyres & wheelstyres & wheelsB-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 #30345wordingwordingSTL/STU 90-05 Mazda Miata gains approval for Mazda Motorsports Development alternate front wheel hubs.
B-Spec Request to Classify Hyundai Accent (RB) 2012-2019 #29484cars addedcars addedB-Spec Hyundai Accent GS Hatchback 2013-2019 classified at 2525 lbs with 40mm flat plate restrictor.
B-Spec Countryman production years incorrect #29864wordingwordingB-Spec Mini Cooper Countryman R60 and Paceman R61 production years corrected from 11-13 to 11-16.
B-Spec Toyota Yaris Model Year Corrections #29896wordingwordingB-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 #29952wordingwordingB-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 & brakessuspension & brakesB-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 #29990wordingwordingST cars may relocate ABS actuation hardware and wiring anywhere in engine compartment.
STU Porsche PDK #30081wordingwordingSTU 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 #30087wordingwordingSTU driveshaft and half-shaft materials change from OEM-type to steel or aluminum.
STU 13B Rules Adjustment #29333cars addedslowerSTU Mazda 13B Street Port classified at 2400 lbs minimum weight, replacing peripheral and bridge port variants.
B-Spec Request clarification of B14 shock package for any and all cars #29483suspension & brakessuspension & brakesB-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 #29495removedremovedB-Spec removes Chevrolet Sonic 12-19, clarifies Toyota Yaris Hatch 07-12 and Sedan 07-12.
STU Request clarification on wing measurement #29640aeroaeroST aero devices and reference areas now include end plates but exclude fasteners protruding over 1/2 inch.
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.
GTX GT Category Wording #29193wordingunclearGT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line.
STU Request for Advanced Aero Rule Wording Clarification. #29124wordingwordingSTU fender flare rules reworded: up to 2" per corner allowed with 1% weight penalty total.
GTX Request Car classification #28935cars addedcars addedGTX Chevrolet Camaro ZL1 LT4 with factory supercharger classified at 3400 lbs minimum weight.
STU Minimum Weight Determination #27695wordingwordingSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis adjustments.
STU ST Gurney flap Wicker clarification #29012wordingwordingSTL and STU rear wing rules clarify that wicker is a Gurney flap; no performance change.
GTX TA2 Gurney flap wicker clarification #28874wordingwordingTA2 Gurney flap wording clarified: terminology standardized to 'Gurney flap', height limits and thickness specifications remain 0.50 inch / 0.625 inch or 0.375 inch / 0.0625 inch depending on configuration.
GTX STO Gurney flap wicker clarification #28883wordingwordingSTO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules.
STU Request for Alternate Intake Manifold #26514wordingwordingSTU request for alternate intake manifold denied; no rule change issued.
STU Request for Addition to GT3 Approved Turbo List #27576wordingwordingGT3 and STU add Borg-Warner EFR6258 to approved turbocharger list.
STU Request BoP for my Car #29004wordingwordingSTU large displacement turbo engines limited by GCR turbo list; non-turbo trim suggested as more competitive.
STU Sequential Shifters in STU #29031wordingwordingSTU 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 #28786wordingwordingB-Spec wheelbase measurements converted from inches to millimeters for consistency across all cars.
GTX Request to Re-classify SP Stock car to GTX #28333cars addedcars addedGTX tube frame cars must weigh 2780 pounds; stock car bodies now permitted.
STU Rotary Help #27833cars addedcars addedSTU Mazda 13B Bridge Port and Street Port engines added with 2550 and 2250 lbs minimum weights respectively.
B-Spec Transmission cooler for automatic equipped cars #28171otherotherB-Spec Chevrolet Sonic 5dr Hatch and 4dr Sedan allow Setrab transmission cooler for automatic-equipped cars.
B-Spec Spring Update for all models #28384suspension & brakessuspension & brakesB-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.
GTX Request to Classify Lotus Evora GTS #27057cars addedcars addedGTX adds Lotus Evora GTS with 3.5L 2GR-FE engine, no restrictor, 2950 lbs minimum weight.
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.
B-Spec Request for Model Years Updating #27850wordingwordingB-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 addedcars addedB-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 #27947wordingwordingB-Spec fog lamps must now be removed and holes completely covered, reversing prior allowance.
B-Spec add sonic sedan #27948cars addedcars addedB-Spec Chevrolet Sonic 4dr Sedan (12-19) added at 2650 lbs with 32mm flat plate restrictor.
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 #28032wordingwordingSTU turbocharged engines now use base weight instead of minimum weight, with 3% DI increase applied to base weight.
B-Spec Request for Automatic Transmission Inclusion #27686wordingwordingB-Spec now permits automatic and CVT transmissions on all legal cars meeting spec line.
B-Spec Request to Add Transmission Coolers to Automatics #27687otherotherB-Spec automatic transmissions may use auxiliary coolers on case-by-case basis with part number approval.
GTX Windshield Clips #27323wordingwordingGT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications.
B-Spec Add Yaris Sedan #26797cars addedcars addedToyota Yaris Sedan 2007- added to B-Spec at 2400 lbs with 1491cc engine.
B-Spec Add 2011-2016 Fiesta Sedan #26798cars addedcars addedB-Spec adds 2011-2016 Ford Fiesta 4dr Sedan, 1596cc, 2495 lbs minimum weight.
B-Spec add 2015-2019 Kia Rio #26799cars addedcars addedB-Spec Kia Rio 5-door/LX years expanded to 2012-2019.
B-Spec Error and Omissions #27858suspension & brakessuspension & brakesB-Spec Mazda2 (10-14) allows specific suspension, intake, exhaust, and bushing parts; removes air duct Mz26-117-33100.
GTX Request Factory Five Daytona coupe classification #26308cars addedcars addedFactory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs.
B-Spec Request for Correction of Production Years for Mini Cooper #27226wordingwordingB-Spec Mini Cooper production years corrected to 2011-13.
STU Request for an electronic throttle body #27342wordingwordingSTU 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 #27388wordingwordingB-Spec removes year-specific eligibility and twelve-year competition window wording.
B-Spec Request to add 2013 Honda Fit model year #27491cars addedcars addedB-Spec Honda Fit model year expanded to include 2013, now covers 2009–2013.
STU Request to correct E&O advanced aerodynamics #27290wordingwordingSTU wing assembly wording corrected: no part higher than roof height.
B-Spec Request to allow OBX Header for 2007-10 Mini Cooper #26977wordingwordingB-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.
STU Request to clarify afterrmarket side skirts exhaust exit #26814wordingwordingSTU 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 #26872wordingwordingSTU fender flare wording clarified: each fender may be flared up to 2" for tire clearance with 1% weight penalty.
GTX Request GTX Fuel injection for previous GT-1 tube frame cars #26141inductionfasterGTX tube frame cars gain fuel injection with 90mm maximum throttle body size.
GTX Request to Classify Ligier JS2 R #26535cars addedcars addedLigier JS2 R classified in GTX, no performance parameters specified in filing.
STU Request Ride Height Clarification #26597wordingwordingSTL and STU ride height measurement clarified: without driver, at rocker panel lowest point, excluding pinch weld.
GTX Request Ride Height Clarification #26600wordingwordingGT1 and GT2/GT3/LITE ride height requirements removed from GCR sections 9.1.2.D.5.a.1 and 9.1.2.F.7.b.
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 #26424wordingwordingSTU 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 #26564aeroaeroSTU 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 #26620wordingwordingSTU BMW S54B32 OEM reclassified from E46 designation, 3246 cc, 3300 lbs minimum weight.
B-Spec Request to add B-Spec to GCR 9.3.26 fuel cell #26132wordingwordingB-Spec added to GCR 9.3.26 fuel cell exception list; stock fuel tank permitted.
GTX Replace FIA references with SRO #26427wordingwordingGTX replaces all FIA GT4 references with SRO GT4.
STU Request to Class Assignment for 2017 Civic #24287cars addedcars addedHonda Civic Si 2017- classified STU at 1500cc, 2800 lbs minimum with OEM engine and bodywork.
STU Request to run E46 3246cc in STU #25126cars addedcars addedSTU 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 #25899wordingwordingSTU Honda K24 may use intake part #s 17100-RRB-A00 or 17100-PRB-A10.
STU Request to Classify 12a Bridge Ported Rotary Engine #25985cars addedcars addedSTU 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 #26413aeroaeroSTU rear wing maximum cord length set to 12 inches, end plates to 72.0 square inches each.
B-Spec Request to classify Canadian Nissan Micra Cup cars #25216cars addedcars addedCanadian 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 addedcars addedToyota 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 #26022wordingwordingB-Spec exhaust system wording clarified: OEM or exact replacement catalysts permitted, stock oxygen sensors required, primary converter unmodified.
GTX GTX Homologation table update #26034cars addedcars addedGTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified.
STU Request to Equalize Direct Injected Turbo Cars #24890cars addedcars addedSTU Honda K20C1 Turbo I4 1996cc added at 3025 lbs minimum weight with 36mm TIR.
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 STU" is the class's best as a share of STU'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 STU'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.