FE2 vs GT1 vs SM vs FF pace at Buttonwillow Raceway Park
Quickest here:FE2 1:39.265 Jon McClintock, Cal Club 2026 qualifying · GT1 1:39.857 Michael McAleenan, Cal Club 2026 qualifying · SM 2:00.831 William Wallis, Cal Club 2025 qualifying · FF 1:51.118 Eric Poulsen, Cal Club 2025 race
FE2GT1SMFFsolid race · dashed qualifying · slower is lower
FE2GT1SMFFsolid 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
FF
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%
1:53.098Edward Erlandson · fastest of 2+1.054s (+0.94%)
1:54.741Edward Erlandson · fastest of 2+3.623s (+3.26%)
133.7Edward Erlandson+19.0 mph (+16.5%)
+14.488squal +13.833s
114.5%qual 113.9%
13 rule changes (FE2: 2, GT1: 5, SM: 3, FF: 3)4 cars added · 2 tyres & wheels · 1 weight · 6 wording · GT1 adds Porsche 992.1 GT3 Cup (2022-2025) with OEM ABS, traction control, RSR bumper, canards, and any exhaust allowed. · FF clarifies alternative tire eligibility for cars homologated 1989 or earlier with rocker arm or outboard suspension on all four corners. · GT1-ST Acura NSX GT3 EVO 22 weight drops 100 lbs to 3000 lbs. · 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. · FF adds rocker arm and outboard suspension cars optional bias ply and VFF tires; removes front-as-rear rule, adds mixing restrictions. · SM cars limited to one set of Hoosier SM 7.5 P205/50/ZR17 per Super Tour event weekend for dry sessions. · FE2 allows driver safety and comfort modifications for disabled drivers with SCCA approval, not transferable to other drivers. · FF allows older cars with rocker arm or outboard suspension to use bias ply slicks or VFF tires instead of radials. · Acura NSX GT3 EVO 22 classified in GT1 with 3500cc twin turbo V-6, 3100 lbs, max RPM 7500.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.
FF Formula F Alternative Tire Rule Proposed Clarifications #39281wordingneutralFF clarifies alternative tire eligibility for cars homologated 1989 or earlier with rocker arm or outboard suspension on all four corners.
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.
FE2 FE & FE2 Bubble Tail #38978wordingneutralFE 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 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.
SM SMX Data Submission - Penalties #38248wordingneutralSMX drivers must submit data acquisition files on time or face suspension and $250 fine.
SM Committee) SMX Penaly Clarification updated language #38337wordingneutralSMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fine; level 2 and 4 may carry $500 fine.
FF Page 228, FF tire rule 9.1.1.10.e #38251tyres & wheelsneutralFF adds rocker arm and outboard suspension cars optional bias ply and VFF tires; removes front-as-rear rule, adds mixing restrictions.
SM Clarify Tire Marking Regs #38005wordingneutralSM cars limited to one set of Hoosier SM 7.5 P205/50/ZR17 per Super Tour event weekend for dry sessions.
FE2 Driver Safety & Comfort #37965wordingneutralFE2 allows driver safety and comfort modifications for disabled drivers with SCCA approval, not transferable to other drivers.
FF Formula F Proposal to Invite Older Cars Via a Tire Rule Change #37802tyres & wheelsfasterFF allows older cars with rocker arm or outboard suspension to use bias ply slicks or VFF tires instead of radials.
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.
Cal Club 2025 CALCL252025-02-22
1:39.358Paul Marino · fastest of 4 · top 4 within 1.5s
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%
1:52.044Eric Poulsen · only car
1:51.118Eric Poulsen · only car
114.7Eric Poulsen
+11.406squal +12.686s
111.4%qual 112.8%
76 earlier rule changes on record, in force before Cal Club 2025 (from 2019)13 cars added · 10 weight · 4 engine · 4 induction · 3 tyres & wheels · 2 aero · 1 suspension & brakes · 39 wording · 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. · FF and FC cars with sequential gearbox must add 10 lbs. to minimum weight, down from 25 lbs. · FF Honda Fit allows Fast Forward 0.25mm oversize pistons PN FF800-110 as alternative; piston diameter spec clarified to 2.8835 inches. · GT1 Mazda 26B engine classified at 2850 lbs minimum weight. · FF VTEC activation valve must function; EGR blanking plate rule clarified with Fast Forward part numbers. · 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. · 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. · FF Honda Fit gains Fast Forward FF800-100 oversize piston ring pack option. · 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. · GTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL. · Fields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight. · GT1 Mercedes AMG GT3 16-19 preparation wording changed to per FIA GT3 homologation. · FF Honda Fit engine adds Fast Forward part number alternatives for intake, exhaust, oil system, and scavenge pump components. · 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. · SM Mazda MX-5 Miata 01-05 weight increases to 2450 lbs, or 2465 with alternate bore. · 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. · SM Majors must run authorized Penske shock and mount; Regional competitors' requirement eligibility clarified. · 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. · 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. · 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. · FF block relief permitted only as needed to fit allowed crankshaft. · SM adds procedures for testing obsolete part replacements and BOP updates in sanctioned events with CRB approval. · FF class cylinder head may now have optional coolant bleed line fitting to top of head for air release. · FF Honda LC1 ECU by HPD permitted effective 12/1/2020, must use HPD lambda sensor. · 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. · FF Honda LC1 ECU implementation date changed from 3/1/2020 to pending availability of support materials. · 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. · 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. · FF alternator changes from not required to optional. · FF allows Honda HPD LC1 low-cost ECU with lambda sensor; E1 ECU no longer supported but existing units permitted if sealed. · FF rain tyres now allow Hoosier W3 Radial in addition to existing Hoosier Wet option. · GT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications. · 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. · GT1 allows Trans Am rear wing, 12" chord, 72" span, 1/2" wicker, 100 sq in endplates, no weight penalty. · GTX tube frame cars gain fuel injection with 90mm maximum throttle body size. · Ligier JS2 R classified in GTX, no performance parameters specified in filing. · 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. · SM fuel pump and filter must be Mazda or OEM Equivalent part. · FF Honda Fit permitted to use 0.25mm oversize pistons, cylinder honing increased to 73.315mm maximum. · FF heat shield rule clarified: thermal wrap allowed on manifold exterior if easily removable for inspection. · FF catch tank minimum capacity rules clarified: coolant catch tank now one U.S. pint minimum, oil catch tank one U.S. quart minimum. · 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.showhide
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.
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 #37070wordingneutralSMX allows OE instrument cluster relocation for aftermarket dash mounting, with wiring re-routed only; alternate gauges now permitted.
FF Change FF/FC Weight with Sequential Gearbox #36651weightfasterFF and FC cars with sequential gearbox must add 10 lbs. to minimum weight, down from 25 lbs.
FF Alternative Oversize Honda Fit Pistons #37064wordingneutralFF Honda Fit allows Fast Forward 0.25mm oversize pistons PN FF800-110 as alternative; piston diameter spec clarified to 2.8835 inches.
GT1 Request to Classify Mazda 26B Engine #36230cars addedneutralGT1 Mazda 26B engine classified at 2850 lbs minimum weight.
FF Update to FF EGR Blanking Plate Rule #36633wordingneutralFF VTEC activation valve must function; EGR blanking plate rule clarified with Fast Forward part numbers.
SM SMX Camera Rule Correction #36496wordingneutralSMX Spec MX-5 camera requirement wording changed; non-functioning recorder now grounds for penalty or disqualification.
SM Committee) AIM ECU Protocol #36556wordingneutralSMX 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 #36608wordingneutralSMX Mazda Miata OE versus OEM definitions clarified in GCR Section 9.1.7.1.
SM Committee) Shifter Bushing #36611wordingneutralSM 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- #35652wordingneutralGT1 Camaro 1993-2002 classification updated; 2010- model separately classified.
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.
FF Honda Fit Oversize Piston Rings #35305wordingneutralFF Honda Fit gains Fast Forward FF800-100 oversize piston ring pack option.
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.
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.
GT1 Please classify Fields Cardinal V8 #33784cars addedneutralFields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight.
GT1 Mercedes AMG GT3 Notes #33804wordingneutralGT1 Mercedes AMG GT3 16-19 preparation wording changed to per FIA GT3 homologation.
FF Add Fast Forward Part Numbers for Honda Fit Engine #33752wordingneutralFF Honda Fit engine adds Fast Forward part number alternatives for intake, exhaust, oil system, and scavenge pump components.
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.
SM BOP for NB1 and NB2 #32309weightslowerSM Mazda MX-5 Miata 01-05 weight increases to 2450 lbs, or 2465 with alternate bore.
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.
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.
SM Update GCR Section 9.1.7.3.A.1. #32217wordingneutralSM Majors must run authorized Penske shock and mount; Regional competitors' requirement eligibility clarified.
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.
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.
GT1 Request car classification #31032cars addedneutralGT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight.
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.
FF Kent crankshaft clarification #30426wordingneutralFF block relief permitted only as needed to fit allowed crankshaft.
SM Updates - Obsolete Parts & BOP Parts #30438wordingneutralSM adds procedures for testing obsolete part replacements and BOP updates in sanctioned events with CRB approval.
FF Allow Optional Coolant Bleed Line to Correct a Known Problem #29673wordingneutralFF class cylinder head may now have optional coolant bleed line fitting to top of head for air release.
FF Clarification regarding Honda LC1 ECU implementation date #29684wordingneutralFF Honda LC1 ECU by HPD permitted effective 12/1/2020, must use HPD lambda sensor.
SM Radiator E&O Clarifications #29294wordingneutralSM 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 #29293wordingneutralFE2 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.
FF Clarification regarding Honda LC1 ECU implementation #29135wordingneutralFF Honda LC1 ECU implementation date changed from 3/1/2020 to pending availability of support materials.
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 & brakesneutralSM rear brake calipers may use single bracket under upper retaining bolt to prevent pin failure.
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.
FF E&O FF Kent Engine alternator language #28204wordingneutralFF alternator changes from not required to optional.
FF Honda Racing HPD low cost ECU proposal #27563engineneutralFF allows Honda HPD LC1 low-cost ECU with lambda sensor; E1 ECU no longer supported but existing units permitted if sealed.
FF Update rain tire designation #28443tyres & wheelsneutralFF rain tyres now allow Hoosier W3 Radial in addition to existing Hoosier Wet option.
GT1 Windshield Clips #27323wordingneutralGT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications.
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.
FE2 FE / FE2 Update Rules #27624weightslowerFE and FE2 minimum weight increased to 1270 lbs including driver; spring options and tire warmer ban added.
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.
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.
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.
SM Request to allow aftermarket fuel filters. #26370wordingneutralSM fuel pump and filter must be Mazda or OEM Equivalent part.
FF Request for Oversize Honda Fit Pistons #25810enginefasterFF Honda Fit permitted to use 0.25mm oversize pistons, cylinder honing increased to 73.315mm maximum.
FF Heat Shield - Fit Intake #26102wordingneutralFF heat shield rule clarified: thermal wrap allowed on manifold exterior if easily removable for inspection.
FF Request catch cans/tanks clarification #26158wordingneutralFF catch tank minimum capacity rules clarified: coolant catch tank now one U.S. pint minimum, oil catch tank one U.S. quart minimum.
SM Request 99-00 replacement Wire harnesses #25602wordingneutralSM 1999-2000 model year cars may use replacement Mazda ECU and injector harnesses, unmodified.
SM Organize and Clarify 9.1.7.C.1.o. #25913wordingneutralSM electrical rules reorganized and clarified; alternator external regulation now prohibited except via OEM ECU/kill switch.
SM Strike Tire Tread Language #26123wordingneutralSM removes tire tread protrusion beyond fender opening requirement from GCR 9.1.7.C.5.
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.
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.