FE2 vs GT1 vs SM vs T1 pace at Buttonwillow Raceway Park
Quickest here:FE2 1:12.402 Blake Pigeon, Cal Club 2023 qualifying · GT1 1:39.857 Michael McAleenan, Cal Club 2026 qualifying · SM 2:00.831 William Wallis, Cal Club 2025 qualifying · T1 1:46.465 Ian Barberi, Cal Club 2025 qualifying
FE2GT1SMT1solid race · dashed qualifying · slower is lower
FE2GT1SMT1solid race · dashed qualifying · each class's best lap as a share of FE2's at the same event (the reference class, changeable above); 100% is level, higher is quicker
Event
FE2
GT1
SM
T1
Qual best
Race best
Trap
Qual best
Race best
Trap
vs FE2
% of FE2
Qual best
Race best
Trap
vs FE2
% of FE2
Qual best
Race best
Trap
vs FE2
% of FE2
Cal Club 2026 CALCL262026-02-21
1:39.265Jon McClintock · fastest of 3 · top 3 within 1.5s-0.093s (-0.09%)
1:40.253Jon McClintock · fastest of 3 · top 3 within 2.2s+0.541s (+0.54%)
156.6Paul Marino+29.4 mph (+23.1%)
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%)
+0.792squal +0.592s
100.8%qual 100.6%
2:01.392Ryan Busk · fastest of 18 · top 5 within 0.8s+0.561s (+0.46%)
2:02.486William Rasmussen · fastest of 18 · top 5 within 1.3s+0.836s (+0.69%)
127.3Sam Rezai+23.4 mph (+22.6%)
+22.233squal +22.127s
122.2%qual 122.3%
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%)
+18.870squal +20.495s
118.8%qual 120.6%
23 rule changes (FE2: 2, GT1: 5, SM: 3, T1: 13)7 cars added · 5 weight · 2 induction · 1 removed · 1 tyres & wheels · 7 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. · 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. · 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. · FE and FE2 Enterprises must use bubble tail P/N WM138014; FE2 allows only this configuration. · 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. · SMX drivers must submit data acquisition files on time or face suspension and $250 fine. · SMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fine; level 2 and 4 may carry $500 fine. · SM cars limited to one set of Hoosier SM 7.5 P205/50/ZR17 per Super Tour event weekend for dry sessions. · 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. · FE2 allows driver safety and comfort modifications for disabled drivers with SCCA approval, not transferable to other drivers. · Cadillac CT4-V Blackwing added to T1 Spec Line 1115, 3564cc, 3750 lbs minimum weight. · 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 addedcars addedGT1 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 addedcars addedT1 Corvette C6 LS1/LS6 Spec Line reinstated: 3200 lbs minimum weight, 70mm restrictor required.
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.
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 #39407removedremovedT1 BMW M3 E92 (08-13) Spec Line 1090 removed entirely.
FE2 FE & FE2 Bubble Tail #38978wordingwordingFE and FE2 Enterprises must use bubble tail P/N WM138014; FE2 allows only this configuration.
GT1 RM 25-06 GT1 reclassify the Acura NSX GT3 EVO 22 to GT1-ST #39101cars addedcars addedAcura 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 addedcars addedGT1 LS Limited Prep Engine expands to include LS1, LS2, LS3, LS6 with 11:1 max compression.
SM SMX Data Submission - Penalties #38248wordingwordingSMX drivers must submit data acquisition files on time or face suspension and $250 fine.
SM Committee) SMX Penaly Clarification updated language #38337wordingwordingSMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fine; level 2 and 4 may carry $500 fine.
SM Clarify Tire Marking Regs #38005wordingwordingSM cars limited to one set of Hoosier SM 7.5 P205/50/ZR17 per Super Tour event weekend for dry sessions.
T1 Acceptance of Porsche 981 GT4 Clubsport into T1 #36664cars addedcars addedPorsche 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 #37964wordingwordingT1 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.
FE2 Driver Safety & Comfort #37965wordingwordingFE2 allows driver safety and comfort modifications for disabled drivers with SCCA approval, not transferable to other drivers.
T1 Cadillac CT4-V Blackwing #38003cars addedcars addedCadillac CT4-V Blackwing added to T1 Spec Line 1115, 3564cc, 3750 lbs minimum weight.
GT1 Request to Classify Acura NSX GT3 Evo 22 #37367cars addedcars addedAcura 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
1:39.358Paul Marino · fastest of 4 · top 4 within 1.5s+26.956s (+37.23%)
1:39.712Paul Marino · fastest of 4 · top 4 within 1.7s
127.2Tom Hope
1:43.967Michael Lewis · only car
1:42.305Michael Lewis · only car
113.8Michael Lewis
+2.593squal +4.609s
102.6%qual 104.6%
2:00.831William Wallis · fastest of 16 · top 5 within 0.9s
2:01.650Nick Leverone · fastest of 16 · top 5 within 0.3s
103.9Evan Jacobs
+21.938squal +21.473s
122.0%qual 121.6%
1:46.465Ian Barberi · fastest of 2
1:47.434Ian Barberi · fastest of 3 · top 3 within 11.8s
139.3Drew Delmonico
+7.722squal +7.107s
107.7%qual 107.2%
62 rule changes (GT1: 15, SM: 5, T1: 42)16 cars added · 8 induction · 6 weight · 4 engine · 3 tyres & wheels · 2 aero · 1 removed · 21 wording · 1 other · 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. · 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. · GT1-ST Lamborghini Huracan GT3 Evo and 2019+ GT3 both shift to Unrestricted from 39mm and 52mm restrictors. · SMX allows OE instrument cluster relocation for aftermarket dash mounting, with wiring re-routed only; alternate gauges now permitted. · 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. · GT1 Mazda 26B engine classified at 2850 lbs minimum weight. · SMX Spec MX-5 camera requirement wording changed; non-functioning recorder now grounds for penalty or disqualification. · SMX Spec MX-5 must run latest AIM Data Logger Spec MX-5 ECU Protocol; wording clarification for technical compliance. · SMX Mazda Miata OE versus OEM definitions clarified in GCR Section 9.1.7.1. · SM and SMX shifter bushing rules clarified: alternate bushing at shift lever bottom now allowed. · 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. · Pontiac GTO 2006-2009 LS1 added to T1 as Spec Line 1590, 5700 cc, 3400 lbs minimum. · 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. · 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. · 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. · 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. · 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. · 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. · 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.showhide
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.
GT1 Addition of a limited prep LS Chevy engine for GT1 #37045cars addedcars addedGT1 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 #37137wordingwordingTA2 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.
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.
SM E&O SMX Regs 9.1.7.1.D.5.u-.w #37070wordingwordingSMX allows OE instrument cluster relocation for aftermarket dash mounting, with wiring re-routed only; alternate gauges now permitted.
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 addedcars addedBMW M4 GT4 (G82) added to T1 GT4 at 3525 lbs minimum weight with Red power stick control.
T1 Alt. Clutch Allowance #36606wordingwordingT1 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 addedcars addedMustang 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 #37173wordingwordingT1 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.
GT1 Request to Classify Mazda 26B Engine #36230cars addedcars addedGT1 Mazda 26B engine classified at 2850 lbs minimum weight.
SM SMX Camera Rule Correction #36496wordingwordingSMX Spec MX-5 camera requirement wording changed; non-functioning recorder now grounds for penalty or disqualification.
SM Committee) AIM ECU Protocol #36556wordingwordingSMX Spec MX-5 must run latest AIM Data Logger Spec MX-5 ECU Protocol; wording clarification for technical compliance.
SM Committee) OE versus OEM Definitons #36608wordingwordingSMX Mazda Miata OE versus OEM definitions clarified in GCR Section 9.1.7.1.
SM Committee) Shifter Bushing #36611wordingwordingSM and SMX shifter bushing rules clarified: alternate bushing at shift lever bottom now allowed.
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- #35652wordingwordingGT1 Camaro 1993-2002 classification updated; 2010- model separately classified.
T1 Please Expedite classing the C63 Mercedes #35987cars addedcars addedMercedes AMG-C63 S (2023) classified in T1 with 4000 lbs minimum weight and 3700 restrictor.
T1 Honda S2000 #35582cars addedcars addedT1 Honda S2000 classified with 2400 lb minimum weight, 2950 cc displacement, 4.75" supercharger pulley.
T1 9.1.9.1 T1 new category item/ line 26 rule to expire Jan 1 2023 #35411cars addedcars addedPontiac GTO 2006-2009 LS1 added to T1 as Spec Line 1590, 5700 cc, 3400 lbs minimum.
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 #35379removedremovedT1 NEW class removes 23 spec lines including Acura NSX, Ferrari, Porsche 996, Nissan Z cars, and others; Porsche 997 spec line 1680 expiration removed.
GT1 Request for Acceptance of Lamborghini Huracan GT3 in GT1-ST #34929cars addedcars addedLamborghini Huracan GT3 EVO(1) and GT3 added to GT1-ST at 3000 and 3100 lbs minimum weight respectively.
GT1 Cylinder heads #35040wordingwordingGT1 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.
GT1 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.
T1 New T1 add spec line for C5 corvette LS2 engines (Copy from C6) #33764cars addedcars addedT1 Chevrolet Corvette C5 LS2 added with 6000cc displacement, 3300 lbs minimum weight, 72mm flat plate restrictor.
T1 C7 Corvette Rule Change Request #34897cars addedcars addedT1 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 #35105wordingwordingT1 Aston Martin Vantage permitted to use OEM Sportshift II transmission.
T1 2004 - 2006 Pontiac GTO Re-Integration Back Into T1 #34403cars addedcars addedPontiac 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 addedcars addedT1 Porsche 997-1 GT3 Cup added at spec line 4210, minimum weight 3050 lbs.
T1 Why no Camaro? #34421cars addedcars addedChevrolet 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 #34470wordingwordingT1 Dodge Viper ACR / SRT RT-10 and ACR/ACR-X spec lines 1350 and 1370 remove 12/23 expiration.
T1 Remove #34475wordingwordingT1 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- #34578wordingwordingT1 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.
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 #34450wordingwordingT1 Ford Mustang S197 05-14 now requires OEM 8.8 differential housing.
T1 Gen 5 Camaro Engine #33875cars addedcars addedT1 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.
T1 Request to reinstate T1 S197 Mustang #34048cars addedcars addedT1 Ford Mustang S197 (05-14) reinstated with 3550 lbs minimum weight, 75mm restrictor, Voodoo engine permitted.
GT1 Please classify Fields Cardinal V8 #33784cars addedcars addedFields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight.
T1 T1 GT4 adjustments #33786wordingwordingT1 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.
GT1 Mercedes AMG GT3 Notes #33804wordingwordingGT1 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 #33691wordingwordingT1 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. #33916wordingwordingT1 removes GCR Section 9.1.9.1.A. and T1 Spec Lines entirely, sunsetting pre-2023 Touring 1 rules.
Cal Club 2023 CALCL232023-02-24
1:12.402Blake Pigeon · fastest of 3 · top 3 within 1.6s
104 earlier rule changes on record, in force before Cal Club 2023 (from 2019)22 cars added · 22 weight · 7 induction · 5 tyres & wheels · 4 aero · 4 suspension & brakes · 2 engine · 38 wording · 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. · SM Mazda MX-5 Miata 01-05 weight increases to 2450 lbs, or 2465 with alternate bore. · 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. · 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. · 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. · SM Majors must run authorized Penske shock and mount; Regional competitors' requirement eligibility clarified. · 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. · 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. · 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. · 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. · GT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight. · 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. · 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. · 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. · 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. · SM adds procedures for testing obsolete part replacements and BOP updates in sanctioned events with CRB approval. · 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. · T1 Chevrolet Corvette Z06 years extended from 06-12 to 06-13. · T1 Corvette C8 Z51 gets wider wheels and tyres, weight drops 100 lbs to 3550. · SM aftermarket radiators must mount in original location, maintain core plane, require no body modifications, block openings, keep one OEM fan in stock location; 1990-1997 cars may install upper radiator seal NA75-50-OK7A. · FE2 oil cooler wording clarified: optional air-to-oil cooler allowed, Setrab 50-625-7612 or equivalent max 13 inches wide by 6.5 inches high. · GT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line. · GT1 adds Trans Am spec engines: Chevrolet R07, Ford FR9, Dodge R7, each with 50 lbs. weight penalty. · SM rear brake calipers may use single bracket under upper retaining bolt to prevent pin failure. · T1 rear wing Gurney flap wording clarified: Gurney flap in chord length and mounting height rules. · 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. · T1 and T2 Corvettes may convert leaf spring suspension to coilover with 800 lb max spring rate allowed. · 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. · 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. · T1 BMW E46 wagon with S54 engine allowed; displacement corrected from 3200 to 3250cc. · 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. · 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. · FE and FE2 minimum weight increased to 1270 lbs including driver; spring options and tire warmer ban added. · 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. · 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. · 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. · 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. · SM fuel pump and filter must be Mazda or OEM Equivalent part. · T1-LP Ford Mustang GT 5.0L 2018+ classified at 3400 lbs with 65mm flat plate restrictor. · SM 1999-2000 model year cars may use replacement Mazda ECU and injector harnesses, unmodified. · SM electrical rules reorganized and clarified; alternator external regulation now prohibited except via OEM ECU/kill switch. · SM removes tire tread protrusion beyond fender opening requirement from GCR 9.1.7.C.5. · 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
GT1 Sequential Transmission Weight Penalty #33503weightfasterGT1 sequential transmission weight penalty reduced from 50 to 25 lbs.
GT1 GT1 Porsche 992 #33730cars addedcars addedGT1-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.
SM BOP for NB1 and NB2 #32309weightslowerSM Mazda MX-5 Miata 01-05 weight increases to 2450 lbs, or 2465 with alternate bore.
T1 GT4 section to Current T1 Rules. #33632cars addedcars addedEight 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 #33315wordingwordingGT2 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.
GT1 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.
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.
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 addedcars addedMercedes Benz AMG GT4 2017-2021 classified T1 Maximum at 3400 lbs minimum weight with HP-controlled SRO Power Level 2 engine.
SM Update GCR Section 9.1.7.3.A.1. #32217wordingwordingSM Majors must run authorized Penske shock and mount; Regional competitors' requirement eligibility clarified.
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 #32293wordingwordingT1 Limited T1 wording changed to clarify all T1 cars permitted specifications.
GT1 Mercedes Benz AMG GT3 in GT1 #31883cars addedcars addedMercedes 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.
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.
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 #31528wordingwordingT1 Chevrolet Corvette Cadillac XLR classified for model years through 2019.
GT1 Request car classification #31032cars addedcars addedGT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight.
GT1 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.
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.
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 #30074wordingwordingT1 Chevrolet Corvette Cadillac XLR LS6 engine now permits Casting #799 heads with no other head modifications.
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 #30589wordingwordingT1-LP Corvette Z06 06-13 now allows aluminum chassis replacement with equivalent OE steel chassis.
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 #30596wordingwordingT1-LP Chevrolet Corvettes C5 Z06, C6 Grand Sport, and Z06 dry sump kit notes clarified to remove contradictions.
SM Updates - Obsolete Parts & BOP Parts #30438wordingwordingSM adds procedures for testing obsolete part replacements and BOP updates in sanctioned events with CRB approval.
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 #30001wordingwordingT1 Ford Mustang/Thunderbird limited to Shelby/Shelby GT350/GT500 models through 2018.
T1 Class BMW M2CS Club Sport #30195cars addedcars addedBMW M2CS Club Sport classified in T1-LP Spec Lines effective 2021-02-01.
T1 997.1 GT3 Cup #30229cars addedcars addedPorsche 997.1 GT3 Cup (2006-2011) classified in T1 at 3600cc, 3150 lbs minimum weight.
T1 Correct T1 Limited Prep Years #29708wordingwordingT1 Chevrolet Corvette Z06 years extended from 06-12 to 06-13.
T1 Changes to Corvette C8 #29898tyres & wheels -100 lbsfasterT1 Corvette C8 Z51 gets wider wheels and tyres, weight drops 100 lbs to 3550.
SM Radiator E&O Clarifications #29294wordingwordingSM aftermarket radiators must mount in original location, maintain core plane, require no body modifications, block openings, keep one OEM fan in stock location; 1990-1997 cars may install upper radiator seal NA75-50-OK7A.
FE2 FE/FE2 Oil Cooler #29293wordingwordingFE2 oil cooler wording clarified: optional air-to-oil cooler allowed, Setrab 50-625-7612 or equivalent max 13 inches wide by 6.5 inches high.
GT1 GT Category Wording #29193wordingunclearGT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line.
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.
SM Modifications to prevent failures of Rear Brake Caliper Pin #28953suspension & brakessuspension & brakesSM rear brake calipers may use single bracket under upper retaining bolt to prevent pin failure.
GT1 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.
GT1 STO Gurney flap wicker clarification #28883wordingwordingSTO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules.
GT1 GT1 Gurney flap wicker clarification #28886wordingwordingGT1 Gurney flap wicker clarification: terminology standardized from lips/tabs/wicker to flaps throughout specifications.
T1 Consider coil spring conversion Corvette in T2 #28824suspension & brakessuspension & brakesT1 and T2 Corvettes may convert leaf spring suspension to coilover with 800 lb max spring rate allowed.
T1 Additional Clarification on 996 Cup in T1 From Letter #28040 #28060wordingwordingT1 Porsche 996 GT3 Cup eligible model years changed from 2002-2005 to 1998-2004.
T1 Request SPEC Corvette Rear Spolier #28182aeroaeroT1 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 #28402wordingwordingT1 Gen 5 Camaro allowed 366mm OEM rear rotor and caliper without weight penalty.
T1 Request 996 GT3 Trunk for Wing Allowance. #28153wordingwordingT1 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 #28452wordingwordingT1 Acura NSX Turbo World Challenge and Audi TTRS GTS 2011 now require DOT tires per GCR section 9.3.
T1 Request for E46 wagon with S54 engine in T1 #27427wordingwordingT1 BMW E46 wagon with S54 engine allowed; displacement corrected from 3200 to 3250cc.
GT1 Windshield Clips #27323wordingwordingGT1, 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 addedcars addedT1 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.
GT1 Request to classify the Ford Coyote 3rd Gen OEM #27146cars addedcars addedGT2/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 addedcars addedFactory 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 addedcars addedGT1 Spec Lines allows 5 Star NASCAR Camaro 2018+ body for General Motors Corporation.
FE2 FE / FE2 Update Rules #27624weightslowerFE and FE2 minimum weight increased to 1270 lbs including driver; spring options and tire warmer ban added.
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.
T1 Request to return Ford Mustang Challenge Car to T1 #26751cars addedcars addedFord Mustang Challenge returns to T1 as E&O, 4600 cc, 3300 lbs minimum, no restrictor.
T1 Correct years in T1 FP Corvette spec #27023wordingwordingT1 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 & wheelstyres & wheelsT2-T4 clarifies DOT tire requirements; must have minimum U speed rating and be DOT certified; touring spec line supersedes other rules.
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 addedcars addedLigier JS2 R classified in GTX, no performance parameters specified in filing.
T1 Request to Classify EcoBoost Mustang #25841cars addedcars addedFord 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 #26599wordingwordingT1 minimum ride height established at 3.5 inches, measured at rocker panel without driver.
GT1 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.
T1 Request to classify the Porsche 928GTS/S4 in Touring 1 #26315cars addedcars addedPorsche 928 S4/928 GTS-R newly classified in T1 at 3500 lbs minimum with 60mm flat plate restrictor.
SM Request to allow aftermarket fuel filters. #26370wordingwordingSM fuel pump and filter must be Mazda or OEM Equivalent part.
T1 Request Mustang GT Limited Prep 2018 Classification #24431cars addedcars addedT1-LP Ford Mustang GT 5.0L 2018+ classified at 3400 lbs with 65mm flat plate restrictor.
SM Request 99-00 replacement Wire harnesses #25602wordingwordingSM 1999-2000 model year cars may use replacement Mazda ECU and injector harnesses, unmodified.
SM Organize and Clarify 9.1.7.C.1.o. #25913wordingwordingSM electrical rules reorganized and clarified; alternator external regulation now prohibited except via OEM ECU/kill switch.
SM Strike Tire Tread Language #26123wordingwordingSM removes tire tread protrusion beyond fender opening requirement from GCR 9.1.7.C.5.
GT1 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.
T1 Class 2015+ Mustang GT350(R) #21466wordingwordingT1-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 addedcars addedFord Mustang FP350S (2018) classified in T1-LP at 3600 lbs with 18×11 wheels and 315 tires.
T1 Amendment to Request #25555 #25556wordingwordingT1 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 #25668wordingwordingPorsche 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 #25774wordingwordingT1-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 FE2" is the class's best as a share of FE2'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 FE2'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.