Quickest here:EP 1:53.088 Glen McCready, Cal Club 2025 qualifying · GT1 1:39.857 Michael McAleenan, Cal Club 2026 qualifying · T1 1:46.465 Ian Barberi, Cal Club 2025 qualifying
EPGT1T1solid race · dashed qualifying · slower is lower
EPGT1T1solid race · dashed qualifying · each class's best lap as a share of EP's at the same event (the reference class, changeable above); 100% is level, higher is quicker
Event
EP
GT1
T1
Qual best
Race best
Trap
Qual best
Race best
Trap
vs EP
% of EP
Qual best
Race best
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vs EP
% of EP
Cal Club 2026 CALCL262026-02-21
1:57.474Kurt Frietzsche · fastest of 4 · top 4 within 4.5s+4.386s (+3.88%)
1:57.999Kurt Frietzsche · fastest of 4 · top 4 within 4.9s+4.512s (+3.98%)
131.6Joe Carr+23.8 mph (+22.1%)
1:39.857Michael McAleenan · fastest of 2-4.110s (-3.95%)
1:41.045Michael McAleenan · fastest of 2-1.260s (-1.23%)
167.6Michael McAleenan+53.8 mph (+47.3%)
-16.954squal -17.617s
85.6%qual 85.0%
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%)
+1.124squal +2.286s
101.0%qual 101.9%
41 rule changes (EP: 23, GT1: 5, T1: 13)13 weight · 8 cars added · 5 induction · 2 engine · 1 removed · 1 tyres & wheels · 11 wording · GT1 adds Porsche 992.1 GT3 Cup (2022-2025) with OEM ABS, traction control, RSR bumper, canards, and any exhaust allowed. · T1 Corvette C6 LS1/LS6 Spec Line reinstated: 3200 lbs minimum weight, 70mm restrictor required. · EP BMW 325i/is E30 throttle body specified as 60mm in fuel injection notes. · GT1-ST Acura NSX GT3 EVO 22 weight drops 100 lbs to 3000 lbs. · T1 Spec Line restrictor changes from 70mm flat plate to unspecified new specification. · 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. · 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. · 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. · 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. · Acura NSX GT3 EVO 22 reclassified from GT1 to GT1-ST with 3100 lbs minimum weight. · GT1 LS Limited Prep Engine expands to include LS1, LS2, LS3, LS6 with 11:1 max compression. · 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. · HP Fiat X-1/9 base weights reduced 50–53 lbs across 1300 and 1500 spec lines. · 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. · 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. · 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. · 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. · Acura NSX GT3 EVO 22 classified in GT1 with 3500cc twin turbo V-6, 3100 lbs, max RPM 7500. · 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
GT1 Request for Addition of Porsche 992.1 GT3 Cup into GT1 #39322cars addedneutralGT1 adds Porsche 992.1 GT3 Cup (2022-2025) with OEM ABS, traction control, RSR bumper, canards, and any exhaust allowed.
T1 LS1 into Corvette C6 Spec Line Request #39716cars addedneutralT1 Corvette C6 LS1/LS6 Spec Line reinstated: 3200 lbs minimum weight, 70mm restrictor required.
EP Request to Update E30 BMW Throttle Body Diameter Verbiage #39363wordingneutralEP BMW 325i/is E30 throttle body specified as 60mm in fuel injection notes.
GT1 NSX Parity With Other GT3s Let Alone a GT1 Car #39311weight -100 lbsfasterGT1-ST Acura NSX GT3 EVO 22 weight drops 100 lbs to 3000 lbs.
T1 additional T1 adjustment #39520inductionunclearT1 Spec Line restrictor changes from 70mm flat plate to unspecified new specification.
EP TR2 Notes E&O #39180wordingunclearEP Triumph TR2-TR4A allows 5-speed gearbox without overdrive; removes Weber carb and weight specification.
EP 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.
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.
EP Please Lower Weight of 280Z #38871weight -160 lbsfasterEP Nissan 280Z minimum weight reduced from 2560 to 2400 lbs.
EP Miata Weight Adjustment Follow Up #38949weight -25 lbsfasterEP Mazda MX-5 1.8L 90-97 weight reduced to 2125 lbs from 2150 lbs.
EP Weight Break for 1098 Midget / Sprite #38970weight -80 lbsfasterHP Austin-Healey Sprite/Midget 1098cc minimum weight drops 80 lbs to 1550.
EP HP Volvo 142 spec omission #38994engineslowerHP Volvo 142/142E gains compression ratio limit 12.0:1 and valve lift limit .425".
EP HP Mini DOHC 1.6 #38996engineslowerHP Mini Cooper 07-15 valve lift reduced to .390", from .450".
EP Add to Rabbit description #39019wordingneutralFP and HP Volkswagen Rabbit descriptions updated: Convertible changed to Cabriolet in FP; Cabriolet added to three HP engine variants.
EP 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.
EP Add TB size to Ford Mustang (94-98) Spec Line #39130wordingneutralEP Ford Mustang (94-98) fuel injected throttle body inside diameter specified at 60.
EP HP Plymouth Arrow spec omission #38995wordingneutralHP Plymouth Arrow transmission max speeds clarified to 4 or 5.
EP Add Wheel Diameter to Appendix G #39008wordingneutralEP, FP, HP wheel diameter added to Appendix G as absolute maximum specification.
EP 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.
GT1 RM 25-06 GT1 reclassify the Acura NSX GT3 EVO 22 to GT1-ST #39101cars addedneutralAcura NSX GT3 EVO 22 reclassified from GT1 to GT1-ST with 3100 lbs minimum weight.
GT1 Correction to Limited prep LS Chevy engine for GT1 #38902cars addedneutralGT1 LS Limited Prep Engine expands to include LS1, LS2, LS3, LS6 with 11:1 max compression.
EP BMW Z4 update #38490inductionslowerEP BMW Z4 03-05 restricted to 52mm flat plate intake restrictor.
EP 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.
EP 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.
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.
EP Request for Classification of Chevrolet Spark #37755cars addedneutralChevrolet Spark 16-22 classified HP Pre at 1850 lbs minimum weight, fuel injected, 1399 cc.
EP 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.
EP 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.
EP Interpretation of Production Rules on Mirrors #37235wordingneutralEP, FP, HP: interior or exterior mirrors meeting rule 9.3.36 now permitted.
EP Weight Reduction for Honda S2000 #37466weightfasterEP Honda S2000 1997cc base loses 75 lbs to 2375; 2157cc base loses 60 lbs to 2450.
EP 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.
GT1 Request to Classify Acura NSX GT3 Evo 22 #37367cars addedneutralAcura NSX GT3 EVO 22 classified in GT1 with 3500cc twin turbo V-6, 3100 lbs, max RPM 7500.
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
1:53.088Glen McCready · fastest of 5 · top 5 within 10.6s
1:53.487Glen McCready · fastest of 5 · top 5 within 10.6s
107.8Joe Carr
1:43.967Michael Lewis · only car
1:42.305Michael Lewis · only car
113.8Michael Lewis
-11.182squal -9.121s
90.1%qual 91.9%
1:46.465Ian Barberi · fastest of 2
1:47.434Ian Barberi · fastest of 3 · top 3 within 11.8s
139.3Drew Delmonico
-6.053squal -6.623s
94.7%qual 94.1%
241 earlier rule changes on record, in force before Cal Club 2025 (from 2019)52 cars added · 43 weight · 26 induction · 12 engine · 10 tyres & wheels · 7 aero · 6 suspension & brakes · 1 removed · 82 wording · 2 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. · 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. · EP BMW 325i/is E30 (84-91) weight reduced 50–52 lbs across three spec lines to 2150, 2204, 2258. · GT1 LS1 Limited Prep engine added, 2600 lbs with driver, 383 cubic inches max, hydraulic roller cam, 750 cfm carb. · TA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement. · GT1-ST restrictor sizes removed for 13 cars; new specs not printed in letter. · EP Triumph GT6 switches to three Weber 40 DCOE carbs with 28mm chokes, weight rises 50 lbs to 1990. · GT1-ST Lamborghini Huracan GT3 Evo and 2019+ GT3 both shift to Unrestricted from 39mm and 52mm restrictors. · 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. · HP Sprite and Midget 1275cc and 1098cc Level 2 compression ratio raised to 12.0:1. · EP Mazda Miata front and rear track widths increased to 1516/1534 mm (59.7/60.4 in.) across all generations. · GT1 Mazda 26B engine classified at 2850 lbs minimum weight. · HP Volkswagen Golf and Jetta 85-92 track correction: front 1537mm (60.5in), rear 1529mm (60.2in). · 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. · GT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR. · GT1 Camaro 1993-2002 classification updated; 2010- model separately classified. · Mercedes AMG-C63 S (2023) classified in T1 with 4000 lbs minimum weight and 3700 restrictor. · T1 Honda S2000 classified with 2400 lb minimum weight, 2950 cc displacement, 4.75" supercharger pulley. · HP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve, Scirocco 1588. · Pontiac GTO 2006-2009 LS1 added to T1 as Spec Line 1590, 5700 cc, 3400 lbs minimum. · HP Honda Civic 1.5 (88-91) weight reduced to 2175 lbs base, 2229 lbs with power adder, 2284 lbs with two. · 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. · 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. · EP BMW Z3 2.5L weight increases to 2500 lbs, 2563 lbs with turbo, 2625 lbs with supercharger. · 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. · 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. · Lamborghini Huracan GT3 EVO(1) and GT3 added to GT1-ST at 3000 and 3100 lbs minimum weight respectively. · GT1 Trick Flow Specialties Ultra 18 Degree GM Cylinder Head Part #TFS-3181T001-CO1 allowed. · 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. · EP Porsche 944/924S combines 2.5L and 2.7L variants with new weights: 2250–2415 lbs depending on engine and year. · EP Triumph GT6 minimum weight reduced to 1800 lbs. · GTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL. · 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. · EP Triumph TR8 78-81 removes alternate front hub allowance note; stock hubs now required. · EP Triumph GT6 carburetors change from SU or Stromberg to 1.5" Auto-type. · EP Triumph GT6 brakes may now use TR-6 standard or alternate calipers and discs. · 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. · FP and HP Sprite, Midget, and Spitfire 1500 intake valve size corrected to 36.6/(1.44). · 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. · EP Porsche 914-6 2.0L intake valves increase to 2.0 mm, exhaust valves corrected to 38.0 mm. · T1 Ford Mustang S197 (05-14) reinstated with 3550 lbs minimum weight, 75mm restrictor, Voodoo engine permitted. · Fields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight. · 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. · EP BMW Z3 2.5L intake restrictor reduced from 58mm to 56mm flat plate. · GT1 Mercedes AMG GT3 16-19 preparation wording changed to per FIA GT3 homologation. · T1 Chevrolet Camaro Gen5 LS3-6160 adds 70mm flat plate restrictor, weight 3550 lbs. · 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. · GT1 sequential transmission weight penalty reduced from 50 to 25 lbs. · GT1-ST Porsche 992 GT3 Cup classified with 3997cc displacement, 2950 lbs minimum weight. · GT4 McLaren 570S maximum tire size changes to 285 front, 315 rear. · EP 79-85 RX-7 12A/13B brake spec simplification removes hub/rotor weight minimum allowance. · EP 280Z carburetor option adds Hitachi-SU 1bbl 46mm throttle bores alongside fuel injection. · EP Mazda RX-2, RX-3, RX-4, and 12A RX-7 now allow 2 bbl fuel injected throttle body w/ 42mm chokes on dual-y manifold. · EP Mazda RX-2, RX-3, RX-3SP, and RX-4 minimum weights reduced 50–52 lbs across all spec lines. · EP Triumph TR8 78-81 now allowed to run dry sump. · EP, FP, HP cylinder head ports limited to 1 inch maximum depth matching from mating surface. · EP Prep 280ZX (79-83) added to spec lines with 2425–2546 lbs, 2760cc SOHC 6-cyl, fuel injection, 12.0:1 compression limit, .500" valve lift limit. · Eight GT4 models added to T1 with weights from 3200 to 3575 lbs and restricted power per SRO 2022 rules. · GT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870. · GT1 Trans Am bodywork weight penalty reduced from 100 lbs to 75 lbs. · GT1 Chevrolet RO7, Ford FR9, and Dodge R7 weight penalties reduced from 50 to 25 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. · GT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only. · GT1 TransAm bodywork allowed with 100 lb. weight penalty. · T1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird, Pontiac GTO 6162 OEM minimum weight reduced to 3475 lbs. · 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. · 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. · 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. · 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. · 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. · Mercedes Benz AMG GT3 classified in GT1 at 3050 lbs with 40mm restrictors, prepared per FIA GT3 homologation. · GT1 wheels: 18-inch tyres get wider rear allowance, from 13 to 14 MAX inches. · 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. · EP, FP, HP classes allow stock/original idle control devices unmodified or completely removed with openings blocked. · EP Porsche 968 (92-95) now allows dry sump. · EP 1979-1985 Mazda RX-7 12A and 13B weight reduced by 50-53 lbs across all configurations. · GT1 allows 17-inch wheels newly; 18-inch wheels require 50 lb penalty; maximum widths 12 front/13 rear, or 13/14 for 18-inch. · 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. · EP BMW Z3 2.5L allows alternate throttle body from 92-95 325i with Turner adapter; head casting 1738400 permitted with specific blocks. · 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. · HP Toyota MR-2 1.6L (85-89) track corrected to 15.47 inches front and rear. · GT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight. · 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. · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix. · T1 BMW E46/E36/Z3 minimum weight increases to 2700 lbs, 3.4L engine car to 2750 lbs. · EP Lotus/Caterham 7 America carburetor changed from IT fuel injection prep to fuel injection. · Daimler SP 250 classified in EP at 2165 lbs with 2548 cc OHV 8-cylinder engine. · 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. · EP, FP, HP clarifies percentage weight penalties sum first, then apply to base weight, rounding to nearest pound. · 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. · 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. · EP Mazda MX-5 year range corrected from 06-14 to 06-15. · 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. · Mazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC, 12.0:1 compression, .500" valve lift limit. · T1 LP removes 50 lbs weight allowance for stock headers, adds aero device allowance up to 100 lbs, permits headers. · 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. · T1 Chevrolet Corvette Z06 years extended from 06-12 to 06-13. · 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. · 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. · GT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line. · EP BMW Z3 2.5L iron block casting 1738566-C designation removed, wording clarification only. · GT1 adds Trans Am spec engines: Chevrolet R07, Ford FR9, Dodge R7, each with 50 lbs. weight penalty. · 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. · 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. · GT1 Gurney flap wicker clarification: terminology standardized from lips/tabs/wicker to flaps throughout specifications. · GT classes clarify Gurney flap wording, replacing wickerbill/tab terminology with flap; specifications unchanged. · EP BMW 2.8L, 328i E36/E46, and 325i E36 blocks now iron only; 325i E46 aluminum only. · T1 and T2 Corvettes may convert leaf spring suspension to coilover with 800 lb max spring rate allowed. · 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. · 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. · EP BMW Z3 2.5L compression ratio capped 12.0:1, valve lift .500, 59mm restrictor required; Z3 2.8L same limits added; 944S2 compression 12.0:1, valve lift .500, 56mm restrictor required. · EP BMW 325is M-Technic loses 100–105 lbs across three weight configurations, to 2550–2678. · HP Datsun 510 gains 40 DCOE carburetor option alongside existing 40 DCN and 36mm DCNVH choices. · EP BMW fuel injected throttle body maximum inside diameter set to 64mm. · T1 BMW E46 wagon with S54 engine allowed; displacement corrected from 3200 to 3250cc. · HP Datsun 1200 carburetor choke size increases from 26mm to 30mm. · GT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications. · 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. · FP and EP Mazda Miata models standardized to 55mm throttle body diameter; brake spec clarified. · GT2/ST Ford 5.0L Coyote 3rd Gen OEM added at 3200 lbs with Boss intake manifold permitted. · Factory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs. · GT1 sequential shifting transmission weight penalty reduced from 75 to 50 lbs. · GT1 non-18-inch-wheel cars now get 18-inch wheels with 50 lb penalty, down from 100 lb. · GT1 Spec Lines allows 5 Star NASCAR Camaro 2018+ body for General Motors Corporation. · EP, FP, HP cylinder head rules reorganized for clarity; no performance change. · 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. · GT1 Porsche 944/968 classified: 2981cc twin turbo, 2585 lbs minimum weight. · 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. · GT1 allows Trans Am rear wing, 12" chord, 72" span, 1/2" wicker, 100 sq in endplates, no weight penalty. · T1 Camaro, CTS, Firebird, GTO restrictor increases from 67mm to 70mm flat plate. · T2-T4 clarifies DOT tire requirements; must have minimum U speed rating and be DOT certified; touring spec line supersedes other rules. · EP Mazda RX-8 firewall modification allowed for 13B engine fitment in stock location. · 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. · 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. · 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. · Porsche 928 S4/928 GTS-R newly classified in T1 at 3500 lbs minimum with 60mm flat plate restrictor. · EP Mazda RX-7 12A and 13B (79-85) lose up to 80 lbs; 13B (86-91) loses up to 79 lbs. · T1-LP Ford Mustang GT 5.0L 2018+ classified at 3400 lbs with 65mm flat plate restrictor. · GTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified. · 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
EP 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.
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.
EP 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.
GT1 Addition of a limited prep LS Chevy engine for GT1 #37045cars addedneutralGT1 LS1 Limited Prep engine added, 2600 lbs with driver, 383 cubic inches max, hydraulic roller cam, 750 cfm carb.
GT1 Correct language regarding OEM Areo Devices #37137wordingneutralTA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement.
GT1 GT1-ST Adjustments #37481inductionunclearGT1-ST restrictor sizes removed for 13 cars; new specs not printed in letter.
EP Triumph GT6 Adjustments #37112inductionslowerEP Triumph GT6 switches to three Weber 40 DCOE carbs with 28mm chokes, weight rises 50 lbs to 1990.
GT1 Lamborghini Huracan GT3 Evo Restrictor Help #36254inductionfasterGT1-ST Lamborghini Huracan GT3 Evo and 2019+ GT3 both shift to Unrestricted from 39mm and 52mm restrictors.
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.
EP 1275 HP Spridget Level 2 Only #36518enginefasterHP Sprite and Midget 1275cc and 1098cc Level 2 compression ratio raised to 12.0:1.
EP NA Miata Track Width Correction #36902wordingneutralEP Mazda Miata front and rear track widths increased to 1516/1534 mm (59.7/60.4 in.) across all generations.
GT1 Request to Classify Mazda 26B Engine #36230cars addedneutralGT1 Mazda 26B engine classified at 2850 lbs minimum weight.
EP Errant entry in HP production line item #36231wordingneutralHP Volkswagen Golf and Jetta 85-92 track correction: front 1537mm (60.5in), rear 1529mm (60.2in).
EP 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.
EP 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.
EP Clean-up Multiple EP RX-8 Spec Lines In EP #36156wordingneutralEP Mazda RX-8 (04-11) alternate spec line removed; one primary line remains.
GT1 Request for Spec Line 1010 Reconsideration #35009weight +300 lbsslowerGT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR.
GT1 Camaro 1993- and 2010- #35652wordingneutralGT1 Camaro 1993-2002 classification updated; 2010- model separately classified.
T1 Please Expedite classing the C63 Mercedes #35987cars addedneutralMercedes AMG-C63 S (2023) classified in T1 with 4000 lbs minimum weight and 3700 restrictor.
T1 Honda S2000 #35582cars addedneutralT1 Honda S2000 classified with 2400 lb minimum weight, 2950 cc displacement, 4.75" supercharger pulley.
EP GCR Correction - Redundant HP Spec Lines #35623wordingneutralHP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve, Scirocco 1588.
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.
EP 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.
GT1 Rear Blade Spoiler Clarification #35261aerofasterGT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed.
GT1 GT Direct Injection allowance and rules #35437enginefasterGT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors.
GT1 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.
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.
EP 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.
EP 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.
EP Honda S2000 throttle body #35272inductionfasterEP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm.
EP Correction within Triumph TR8 Spec Line #35315wordingneutralEP Triumph TR8 dry sump allowance moved from carburetor line to notes section.
EP 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.
GT1 Request for Acceptance of Lamborghini Huracan GT3 in GT1-ST #34929cars addedneutralLamborghini Huracan GT3 EVO(1) and GT3 added to GT1-ST at 3000 and 3100 lbs minimum weight respectively.
GT1 Cylinder heads #35040wordingneutralGT1 Trick Flow Specialties Ultra 18 Degree GM Cylinder Head Part #TFS-3181T001-CO1 allowed.
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.
EP 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.
EP Triumph GT6 Adjustments #35054weight -30 lbsfasterEP Triumph GT6 minimum weight reduced to 1800 lbs.
GT1 Errors in GTCS Headings and Use of the Terms Category and ClassChange existing GTL and GTA Rules #34453wordingneutralGTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL.
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.
EP Hub Note Clean Up In EP TR8 Spec Line #34649wordingneutralEP Triumph TR8 78-81 removes alternate front hub allowance note; stock hubs now required.
EP Triumph GT6 Adjustments #34662wordingunclearEP Triumph GT6 carburetors change from SU or Stromberg to 1.5" Auto-type.
EP Triumph GT6 Adjustments: Brakes #34663wordingneutralEP Triumph GT6 brakes may now use TR-6 standard or alternate calipers and discs.
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.
EP 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).
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.
EP 914-6 Valve Size Correction #34185enginefasterEP Porsche 914-6 2.0L intake valves increase to 2.0 mm, exhaust valves corrected to 38.0 mm.
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.
GT1 Please classify Fields Cardinal V8 #33784cars addedneutralFields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight.
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.
EP Investigate Parity of Z3 #33343inductionslowerEP BMW Z3 2.5L intake restrictor reduced from 58mm to 56mm flat plate.
GT1 Mercedes AMG GT3 Notes #33804wordingneutralGT1 Mercedes AMG GT3 16-19 preparation wording changed to per FIA GT3 homologation.
T1 Clarification for Camaro Gen5 2010-2015 #33739inductionslowerT1 Chevrolet Camaro Gen5 LS3-6160 adds 70mm flat plate restrictor, weight 3550 lbs.
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.
GT1 Sequential Transmission Weight Penalty #33503weightfasterGT1 sequential transmission weight penalty reduced from 50 to 25 lbs.
GT1 GT1 Porsche 992 #33730cars addedneutralGT1-ST Porsche 992 GT3 Cup classified with 3997cc displacement, 2950 lbs minimum weight.
T1 Corrections to T1 Spec Lines #33678tyres & wheelsunclearGT4 McLaren 570S maximum tire size changes to 285 front, 315 rear.
EP Revise 79-85 RX7 Brake Spec Line Allowance #33293wordingunclearEP 79-85 RX-7 12A/13B brake spec simplification removes hub/rotor weight minimum allowance.
EP Request alternate carburetors for EP 280z #33405wordingneutralEP 280Z carburetor option adds Hitachi-SU 1bbl 46mm throttle bores alongside fuel injection.
EP Fuel Injection 12a Mazda RX3 #33434inductionneutralEP Mazda RX-2, RX-3, RX-4, and 12A RX-7 now allow 2 bbl fuel injected throttle body w/ 42mm chokes on dual-y manifold.
EP Mazda RX3 - Weight Reduction #33436weight -50 lbsfasterEP Mazda RX-2, RX-3, RX-3SP, and RX-4 minimum weights reduced 50–52 lbs across all spec lines.
EP Request TR8 Dry Sump Allowance #33460enginefasterEP Triumph TR8 78-81 now allowed to run dry sump.
EP Review Limited Prep Port Matching Rules #33600wordingneutralEP, FP, HP cylinder head ports limited to 1 inch maximum depth matching from mating surface.
EP 280ZX Classification Request #33611cars addedneutralEP Prep 280ZX (79-83) added to spec lines with 2425–2546 lbs, 2760cc SOHC 6-cyl, fuel injection, 12.0:1 compression limit, .500" valve lift limit.
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.
GT1 GT2 (TA2)/GTA Part Number Update #33315wordingneutralGT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870.
GT1 Request to Reduce Trans Am Bodywork Weight Penalty #33331weightfasterGT1 Trans Am bodywork weight penalty reduced from 100 lbs to 75 lbs.
GT1 Request for Reduction in FR9 Weight Penalty #33332weightfasterGT1 Chevrolet RO7, Ford FR9, and Dodge R7 weight penalties reduced from 50 to 25 lbs.
EP 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.
EP 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).
EP Request for Corrado Stroke & Displacement Correction #32985wordingneutralEP VW Corrado 92-95 stroke corrected to 90.3 mm, displacement to 2792 cc.
GT1 Tail lights on all GT category race cars. #32799wordingneutralGT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only.
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.
EP 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.
EP 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.
EP 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.
EP 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.
EP 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.
EP 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.
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.
EP EP Adjustments #31858inductionslowerEP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate.
EP 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.
EP Improved Touring Tires #32064tyres & wheelsneutralEP, FP, HP Improved Touring cars may use any DOT-approved tire per section 9.3.45 in Production class.
GT1 Mercedes Benz AMG GT3 in GT1 #31883cars addedneutralMercedes Benz AMG GT3 classified in GT1 at 3050 lbs with 40mm restrictors, prepared per FIA GT3 homologation.
GT1 Wheel Widths #32205tyres & wheelsfasterGT1 wheels: 18-inch tyres get wider rear allowance, from 13 to 14 MAX inches.
EP Throttle Body and Idle Air #31800wordingneutralEP, FP, HP classes allow stock/original idle control devices unmodified or completely removed with openings blocked.
EP Porsche 968 Engine Questions #31831otherneutralEP Porsche 968 (92-95) now allows dry sump.
EP Request weight reduction for 1979-1985 Mazda RX-7 #31833weightfasterEP 1979-1985 Mazda RX-7 12A and 13B weight reduced by 50-53 lbs across all configurations.
GT1 Wheel Widths #31844tyres & wheelsslowerGT1 allows 17-inch wheels newly; 18-inch wheels require 50 lb penalty; maximum widths 12 front/13 rear, or 13/14 for 18-inch.
EP Porsche 968 Engine Questions #31478enginefasterEP Porsche 968 intake valve size increased from 37 to 39.0 mm.
EP 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.
EP 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.
EP 944S2 Restrictor #31396inductionslowerEP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; comp ratio max 12.0:1, valve lift max 0.500".
EP 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.
EP E&O; MR2 Track #31120wordingneutralHP Toyota MR-2 1.6L (85-89) track corrected to 15.47 inches front and rear.
GT1 Request car classification #31032cars addedneutralGT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight.
EP 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.
EP 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.
GT1 Request to Update GTA Obsolete Part Numbers #30615wordingneutralGTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix.
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.
EP Lotus/Caterham 7 America Request #30392wordingunclearEP Lotus/Caterham 7 America carburetor changed from IT fuel injection prep to fuel injection.
EP Reclassify Daimler SP 250 #30721cars addedneutralDaimler SP 250 classified in EP at 2165 lbs with 2548 cc OHV 8-cylinder engine.
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.
EP 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.
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.
EP 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.
EP Fiat X1/9 brake rotors #30423suspension & brakesneutralFP Fiat X1/9 brake rotors change to 257 (10.1) x 12 (.407) solid disc.
EP NC MX-5 year range correction E&O #30503wordingneutralEP Mazda MX-5 year range corrected from 06-14 to 06-15.
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.
EP Please Classify Mazda3 in FP #30165cars addedneutralMazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC, 12.0:1 compression, .500" valve lift limit.
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.
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.
EP 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.
T1 Correct T1 Limited Prep Years #29708wordingneutralT1 Chevrolet Corvette Z06 years extended from 06-12 to 06-13.
EP 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.
EP 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.
EP Weight Reduction for Datsun Roadster #29409weight -75 lbsfasterEP Datsun SRL 311U Roadster minimum weight reduced to 1925 lbs from 2000 lbs.
EP EP TR8 Adjustment #29512weight -100 lbsfasterEP Triumph TR8 78-81 weight reduced from 2600 to 2500 lbs.
T1 Changes to Corvette C8 #29898tyres & wheels -100 lbsfasterT1 Corvette C8 Z51 gets wider wheels and tyres, weight drops 100 lbs to 3550.
EP 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.
GT1 GT Category Wording #29193wordingunclearGT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line.
EP EP BMW Z3 Rule Clarification #28998wordingneutralEP BMW Z3 2.5L iron block casting 1738566-C designation removed, wording clarification only.
GT1 Request to Allow New Trans Am Legal Engines in GT1 #29002engineslowerGT1 adds Trans Am spec engines: Chevrolet R07, Ford FR9, Dodge R7, each with 50 lbs. weight penalty.
EP Request to Classify Porsche 911 2.0L #28456cars addedneutralPorsche 911 S 67-68 classified in EP at three weight levels: 1800, 1845, or 1890 lbs.
GT1 TA2 Gurney flap wicker clarification #28874wordingneutralTA2 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.
GT1 STO Gurney flap wicker clarification #28883wordingneutralSTO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules.
GT1 GT1 Gurney flap wicker clarification #28886wordingneutralGT1 Gurney flap wicker clarification: terminology standardized from lips/tabs/wicker to flaps throughout specifications.
EP 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.
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.
EP 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.
EP 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.
EP Caterham 7 Spec Line #28498wordingneutralEP Caterham 7 Spec Line removes redundant suspension note, clarifies engine prep limits and comp ratio to 10.0:1.
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.
EP Request to Review Horsepower Parity #27662engineslowerEP BMW Z3 2.5L compression ratio capped 12.0:1, valve lift .500, 59mm restrictor required; Z3 2.8L same limits added; 944S2 compression 12.0:1, valve lift .500, 56mm restrictor required.
EP E36 (92-95) Brakes Errors and Omissions #28058weightfasterEP BMW 325is M-Technic loses 100–105 lbs across three weight configurations, to 2550–2678.
EP 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.
EP Add Throttle Body Size these EP BMW Spec Lines #28422inductionslowerEP BMW fuel injected throttle body maximum inside diameter set to 64mm.
T1 Request for E46 wagon with S54 engine in T1 #27427wordingneutralT1 BMW E46 wagon with S54 engine allowed; displacement corrected from 3200 to 3250cc.
EP Request for Help for Datsun 1200 #27934inductionfasterHP Datsun 1200 carburetor choke size increases from 26mm to 30mm.
GT1 Windshield Clips #27323wordingneutralGT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications.
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.
EP Request to List Mazda Miata Throttle Body Size #27907wordingneutralFP and EP Mazda Miata models standardized to 55mm throttle body diameter; brake spec clarified.
GT1 Request to classify the Ford Coyote 3rd Gen OEM #27146cars addedneutralGT2/ST Ford 5.0L Coyote 3rd Gen OEM added at 3200 lbs with Boss intake manifold permitted.
GT1 Request Factory Five Daytona coupe classification #26308cars addedneutralFactory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs.
GT1 Request to Adjust Transmission Penalty #27750weightfasterGT1 sequential shifting transmission weight penalty reduced from 75 to 50 lbs.
GT1 Request to Reduce Additional Weight for 18 #27751weightfasterGT1 non-18-inch-wheel cars now get 18-inch wheels with 50 lb penalty, down from 100 lb.
GT1 Request for Five Star Nascar Compliant Bodywork #27756cars addedneutralGT1 Spec Lines allows 5 Star NASCAR Camaro 2018+ body for General Motors Corporation.
EP Re-organize Prep2 Cylinder Head Rules for Clarity & Consistency #27661wordingneutralEP, FP, HP cylinder head rules reorganized for clarity; no performance change.
EP 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.
EP Request to classify the GMX5 2019 #27263wordingneutralEP Mazda MX-5 Global Cup classification year changes from 16-18 to 16-19.
EP level one susp. component rule #27270wordingneutralProduction suspension rule clarifies spindles, hubs, bushings, bearings, ball joints unrestricted.
EP Clarification of Carb Rules - Prep 1 #27300wordingneutralProduction carb rules clarified: carburetor options, fuel injection throttle body dimensions, and intake manifold restrictions reorganised and refined.
EP 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.
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.
EP 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.
GT1 Clarify Trans Am Legal Bodywork and Wing #26953aerofasterGT1 allows Trans Am rear wing, 12" chord, 72" span, 1/2" wicker, 100 sq in endplates, no weight penalty.
T1 Request BoP Baten - T1 Camaro - Follow up to Letter # 26145 #26900inductionfasterT1 Camaro, CTS, Firebird, GTO restrictor increases from 67mm to 70mm flat plate.
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.
EP Allow Firewall Modification for Fitment of 13B into RX8 #26726wordingneutralEP Mazda RX-8 firewall modification allowed for 13B engine fitment in stock location.
GT1 Request GTX Fuel injection for previous GT-1 tube frame cars #26141inductionfasterGTX tube frame cars gain fuel injection with 90mm maximum throttle body size.
GT1 Request to Classify Ligier JS2 R #26535cars addedneutralLigier JS2 R classified in GTX, no performance parameters specified in filing.
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.
EP 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.
EP Hardtops #26476wordingneutralEP open cars may now use aftermarket hardtops if they retain OEM appearance; specific model hardtop allowances removed.
GT1 Request Ride Height Clarification #26600wordingneutralGT1 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.
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.
EP Request for Competition Adjustment for 2nd Generation RX7 #25935weight -50 lbsfasterEP Mazda RX-7 12A and 13B (79-85) lose up to 80 lbs; 13B (86-91) loses up to 79 lbs.
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.
GT1 GTX Homologation table update #26034cars addedneutralGTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified.
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 EP" is the class's best as a share of EP'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 EP'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.