F5 vs SRF vs GT1 pace at Buttonwillow Raceway Park
Quickest here:GT1 1:39.857 Michael McAleenan, Super Tour Feb 2026 qualifying
F5SRFGT1solid race · dashed qualifying · slower is lower
Event
F5
SRF
GT1
Qual best
Race best
Trap
Qual best
Race best
Trap
vs F5
Qual best
Race best
Trap
vs F5
Super Tour Feb 2026 CALCL262026-02-21
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%)
8 rule changes (SRF: 3, GT1: 5)3 cars added · 2 engine · 1 weight · 1 wording · 1 other · GT1 adds Porsche 992.1 GT3 Cup 2022–2025 with OEM ABS, traction control, RSR bumper, canards, and any exhaust. · GT1-ST Acura NSX GT3 EVO 22 minimum weight drops 100 lbs to 3000. · Acura NSX GT3 EVO 22 reclassified from GT1 to GT1-ST, 3500cc, 3100 lbs minimum weight. · SRF3 adds HD Oil Cooler P/N G1148500 option alongside standard P/N G480503, no fan permitted. · GT1 LS Limited Prep engine expanded to include LS2, LS3, LS6 alongside LS1; compression ratio capped at 11:1. · SRF drivers with disabilities may modify seat and controls for safety and comfort with SCCA approval, noted in logbook, for that driver only. · SRF SADEV-SRF3 6-speed sequential transmission: effective date clarified to 1 April 2025 onward. · Acura NSX GT3 EVO 22 classified in GT1 with 3500cc twin turbo crossflow V-6, 3100 lbs, 7500 rpm max.showhide
GT1 Request for Addition of Porsche 992.1 GT3 Cup into GT1 #39322cars addedaddedGT1 adds Porsche 992.1 GT3 Cup 2022–2025 with OEM ABS, traction control, RSR bumper, canards, and any exhaust.
GT1 NSX Parity With Other GT3s Let Alone a GT1 Car #39311weight -100 lbsfaster · weightGT1-ST Acura NSX GT3 EVO 22 minimum weight drops 100 lbs to 3000.
GT1 RM 25-06 GT1 reclassify the Acura NSX GT3 EVO 22 to GT1-ST #39101cars addedaddedAcura NSX GT3 EVO 22 reclassified from GT1 to GT1-ST, 3500cc, 3100 lbs minimum weight.
SRF Add HD Oil Cooler #38979engineadded · engineSRF3 adds HD Oil Cooler P/N G1148500 option alongside standard P/N G480503, no fan permitted.
GT1 Correction to Limited prep LS Chevy engine for GT1 #38902engineadded · engineGT1 LS Limited Prep engine expanded to include LS2, LS3, LS6 alongside LS1; compression ratio capped at 11:1.
SRF Driver Safety & Comfort #37966otheraddedSRF drivers with disabilities may modify seat and controls for safety and comfort with SCCA approval, noted in logbook, for that driver only.
SRF Update SADEV transmission specs #37992wordingwordingSRF SADEV-SRF3 6-speed sequential transmission: effective date clarified to 1 April 2025 onward.
GT1 Request to Classify Acura NSX GT3 Evo 22 #37367cars addedaddedAcura NSX GT3 EVO 22 classified in GT1 with 3500cc twin turbo crossflow V-6, 3100 lbs, 7500 rpm max.
Super Tour Feb 2025 CALCL252025-02-22
1:43.967Michael Lewis · only car
1:42.305Michael Lewis · only car
113.8Michael Lewis
89 earlier rule changes on record, in force before Super Tour Feb 2025 (from 2019)16 cars added · 9 engine · 8 weight · 7 tyres & wheels · 3 aero · 2 induction · 2 suspension & brakes · 31 wording · 11 other · GT1 LS1 Limited Prep engine added, 2600 lbs with driver, 383 cubic inches maximum, hydraulic roller cam, 750 cfm carb. · TA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof height limit. · GT1-ST restrictor specifications removed for 13 cars; new values not provided. · GT1-ST Lamborghini Huracán GT3 Evo and GT3 both move to unrestricted intake, replacing 39mm and 52mm restrictors. · GT1 Mazda 26B engine approved; minimum weight set to 2850 lbs. · SRF3 air filter rule removes K&N RC-9160 option, specifies Weems P/N WM301020 only. · SRF Wilwood vented rotor minimum thickness increases to 13.25mm, 0.522 inches. · SRF3 Hoosier decal placement changed from four logos on nose and tail to three logos on sides and center front. · FE and SRF protest fee rules redirected to GCR section 8.3.1.D for fees and procedure. · SRF Hoosier contingency decal requirement reduced from four decals in specific locations to three decals with simplified placement. · SRF wet tyres: front P185/60R13 H20 or W2 and rear P205/60R13 H20 or W2 removed; front P185/65R13 W2 and rear P205/60R13 W2 now required. Hoosier decal placement specified. · GT2-ST Acura NSX minimum weight rises to 3000 lbs, restrictor increases to 45mm TIR. · GT1 Camaro 1993-2002 model years specified in GCR 9.1.2.E.1.b.3. · GT1-GTX rear blade spoiler: angle 50–75°, max 59.0 wide by 5.0 high inches; total area limit removed. · GT1, GT2, GT3, GTL, GTX Direct Injection now permitted if original equipment. · GT2 Nissan and GT3 Mazda, Mitsubishi 4G93, Nissan QR25DE/DD, QE25DE/DD now permit Direct Injection per 9.1.2.F.7.5.E. · GT1-ST adds Lamborghini Huracan GT3 EVO(1) 2018- at 3000 lbs, X39mm restrictor, and Huracan GT3 2019- at 3100 lbs, 52mm restrictor. · GT1 Trick Flow Specialties Ultra 18 Degree GM Cylinder Head Part #TFS-3181T001-CO1 allowed. · SRF rain/brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24; secondary filament must connect to rain light switch. · SRF brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24, with SCCA Enterprises P/N 180427A pigtail and strobing rain light kit. · SRF adds mandatory front brake ducts 12–36 inches, throttle pedal heel-toe extension, braided stainless flex lines, camber limit 5.0 degrees, radiator opening height 3½ ± ½ inches, rear shift cable clamp P/N WM302007A. · GTL spec lines moved contiguous with GT2 and GT3; GTA category and specs renumbered behind GTL; P2 engine tables reorganised with restrictor and weight specifications clarified. · SRF radiator options expanded: Enterprises P/N 480465 with baffle 480464, 480466, or Automotive 1R698 and CU698 allowed if cross-reference equivalent. · SRF wet front tyre changes to Hoosier P/N 46100 P185/60R13 H20 or W2 with 2.5" ground clearance. · Fields Cardinal V8 added to GT1 with Ford V8 engine, 4.9L, 2100 lbs, fuel injection. · SRF front W2 rain tyre Hoosier part number changes from 46100 to 46101 P185/65R13. · GT1 Mercedes AMG GT3 16-19 notes clarify FIA GT3 homologation compliance. · SRF removes 1985 Renault Alliance solid front rotor option; restrictor sizes decrease 1mm for newer Kawasaki and multi-brand engines; minimum weights increase to 1100 lbs. · GT1 sequential transmission weight penalty reduced from 50 lbs to 25 lbs. · GT1-ST Porsche 992 GT3 Cup added with 3997cc displacement, 2950 lb minimum weight, no restrictor. · GT2 TA2 and GTA throttle body part numbers updated to GM 12570790 or Edelbrock 33869/3870. · GT1 Trans Am bodywork weight penalty reduced from 100 lbs to 75 lbs. · GT1 Chevrolet RO7, Ford FR9, and Dodge R7 weight penalties cut from 50 lbs to 25 lbs each. · F500 Rotax 493 and 593 intake boots: removed Moto Tassinari V3124-873B-2 from 493/593 non-HO allowance, added Moto Tassinari V3120-794A-2 option for non-HO. · GT1, GT2, GT3, GTL, GTX tail lights may now be original style or custom panel graphic with functioning red LED brake lamps. · F500 Rotax engines now permit Ingi Tech Sparker ignition DCP-CDI-P2 as alternate ECU. · GT1 allows current Trans Am bodywork with 100 lb weight penalty. · F500 clarifies stepped diameter exhaust headers prohibited except at cylinder head flange area. · F500 Rotax 593 intake boot options clarified; oil injection pump removal now permitted. · SRF tire rule wording clarified: tires must be run as delivered. · SRF brake rotor minimum thickness reduced from 13.25 mm to 12.20 mm; seals and air filter specs clarified. · F500 Majors and Runoffs cars must install AIM part #X47KPFSOLO2R0 data box mount for Solo or Solo 2. · GT1 Mercedes Benz AMG GT3 added, 3050 lbs, 6208cc V8, 40mm restrictors, FIA GT3 homologation. · GT1 wheel width limits change: 12in front/13in rear standard, 18in wheels get 13in front/14in rear maximum. · GT1 allows 17-inch wheels; 18-inch wheels now permitted with 50 lb penalty; 18-inch tyres use 13-inch front, 14-inch rear width. · F5 cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs. · SRF wet tyres front P185/65R13 W2 option added; air box clarified as-delivered; SRF3 restrictor plate G301048 mandatory Jan 1 2022; P2 motorcycle engines up to 1005cc with 35mm restrictor, 2009+ stock 1075 lbs, 2008 stock 1025 lbs, modifie… · GT3 Volkswagen Fun Cup Beetle EVO3 classified, sealed SOHC 1984cc engine, 2060 lbs minimum weight. · F5 clarifies mechanical shifting only; throttle-cut and flat-shifter devices permitted if driver retains full control. · F5 single-seat open-wheel cars: rigid suspension becomes limited suspension in class definition. · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two locations and 6010 to 6014X in TA2 Appendix. · SRF wet tyres add Hoosier W2 option alongside existing H20 from October 4, 2021. · SRF adds SADEV-SRF3 6-speed sequential transmission option with ratios 3.0–0.92:1 and 3.20 final drive. · SRF seal requirements clarified: seals now must be on driveline components in designated locations; unsealed components removed and inspected by CSR or Enterprises rather than engine shipped for testing. · F500 Rotax 593 HO engine now permitted; 875 lbs minimum weight, MA0242SP1020A or MA0242SP1063A restrictor, specific intake boots and piston required. · SRF3 alternator pulley specified as P/N G902130 or G902130A, minimum 12oz. · SRF and SRF3 mandatory identification revised: removed Ford Performance and Blue Oval decals, added Hoosier logo placement. · SRF rear springs limited to P/N 280390 only, previous part numbers no longer allowed; ground clearance wording clarified. · F500 Suzuki GSXR600 engine years extended from 2003-2013 to 2003-2019. · GT1/GT2/GT3/GTL/GTX turbocharging and supercharging now permitted if listed on spec line. · GT1 adds Trans Am spec engines: Chevrolet R07, Ford FR9, Dodge R7, each at base weight plus 50 lbs. · F5 request to adjust external jetting device cockpit control denied; no rule change made. · F5 driver adjustable carburettor mixture: refer to separate Fastrack letter #28359 for ruling. · F5 cockpit adjustment request response published in Fastrack letter 28359. · TA2 Gurney flap wording clarified: replace 'wicker bill' and 'wicker' with 'Gurney flap' throughout wing specifications. · STO rear wing rules clarify that wicker is called Gurney flap in two places; no performance change. · GT1 Gurney flap and wickerbill terminology clarified: 'lips' and 'tabs' and 'wicker' standardized to 'flaps' throughout section D and E. · GT Gurney flap wording clarified: wickerbill and tab terminology replaced with Gurney flap throughout sections 9.1.2.F.7.b. · SRF Penske shock P/N 280396 bump stop P/N 280407 becomes mandatory, maximum one per shock, effective 05/01/2020. · GT1, GT2, GT3, GTL, GTX may use bonded-glass factory windshields without clips or straps if attached per original specifications. · F500 Honda CBR600RR, Suzuki GSXR600, Yamaha R6 restrictor reduced to 28mm from 29mm. · GT2/ST Ford Coyote 5.0L third generation OEM gains Boss intake manifold option at 3200 lbs minimum. · GTX Misc. adds Factory Five Type 65 Coupe R Ford 302/351 and 5.0/5.2L NA at 2600 lbs, plus Ferrari 458/488 Challenge, Ford FP350S, Chevrolet C6, Lamborghini Super Trofeo. · GT1 sequential shifting transmissions weight penalty reduced from 75 lbs to 50 lbs. · GT1 cars not specified for 18 inch wheels now have 50 pound penalty, down from 100. · GT1 adds 5 Star NASCAR Camaro 2018 and later body as allowed bodywork option. · SRF rain and brake rule supersedes GCR 9.3.32.B.2 effective 1/1/2024 through 12/31/2024. · SRF adds tire warmer prohibition and specifies Hoosier dry and wet tire part numbers. · SRF front nose weight minimum reduced from 35 to 32 lbs. · SRF2 becomes Regional Only; SRF3 nomenclature changed from GEN3 to Ford 1.6L conversion; SRF and SRF3 no longer compete together for points. · F500 Honda CBR600RR, Suzuki GSXR600, and Yamaha R6 minimum weights increase to 900 lbs. · GT1 Porsche 944/968 added: 2981cc twin-turbo four, 2585 lbs minimum weight. · GT1 allows Trans Am rear wing, 72" span, 12" chord, 1/2" wicker, 100 sq in endplates, no weight penalty; front undertray allowed with 50 lb penalty. · SRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102. · GTX tube frame cars now allowed fuel injection with maximum 90mm throttle body. · GTX adds Ligier JS2 R classification with restrictor and minimum weight. · GT1 and GT2/3/Lite remove ride height ground clearance rules; cars may now touch ground when tires deflate. · GTX FIA GT3: Audi R8 now 40 mm restrictor and 2900 lbs; BMW Z4 now 70 mm restrictor and 2800 lbs; Ferrari 488 now 35 mm restrictor, TIR, and 3025 lbs.showhide
GT1 Addition of a limited prep LS Chevy engine for GT1 #37045cars addedaddedGT1 LS1 Limited Prep engine added, 2600 lbs with driver, 383 cubic inches maximum, 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 height limit.
GT1 GT1-ST Adjustments #37481otherunclearGT1-ST restrictor specifications removed for 13 cars; new values not provided.
GT1 Lamborghini Huracan GT3 Evo Restrictor Help #36254inductionfaster · inductionGT1-ST Lamborghini Huracán GT3 Evo and GT3 both move to unrestricted intake, replacing 39mm and 52mm restrictors.
GT1 Request to Classify Mazda 26B Engine #36230cars addedaddedGT1 Mazda 26B engine approved; minimum weight set to 2850 lbs.
SRF Update SRF3 Air Filter Rule #36681wordingremovedSRF3 air filter rule removes K&N RC-9160 option, specifies Weems P/N WM301020 only.
SRF Hoosier Tire Decal Placement #36739wordingwordingSRF3 Hoosier decal placement changed from four logos on nose and tail to three logos on sides and center front.
SRF Protest Fee Clarification #36540wordingwordingFE and SRF protest fee rules redirected to GCR section 8.3.1.D for fees and procedure.
SRF Update to Letter 36619 with new Hoosier Contingency Decal Info #36624wordingwordingSRF Hoosier contingency decal requirement reduced from four decals in specific locations to three decals with simplified placement.
SRF Update Rain Tire Rule and Hoosier Decal Placement #36436tyres & wheelstyres & wheelsSRF wet tyres: front P185/60R13 H20 or W2 and rear P205/60R13 H20 or W2 removed; front P185/65R13 W2 and rear P205/60R13 W2 now required. Hoosier decal placement specified.
GT1 Request for Spec Line 1010 Reconsideration #35009weight +300 lbsslower · weightGT2-ST Acura NSX minimum weight rises to 3000 lbs, restrictor increases to 45mm TIR.
GT1 Camaro 1993- and 2010- #35652wordingwordingGT1 Camaro 1993-2002 model years specified in GCR 9.1.2.E.1.b.3.
GT1 Rear Blade Spoiler Clarification #35261aeroaeroGT1-GTX rear blade spoiler: angle 50–75°, max 59.0 wide by 5.0 high inches; total area limit removed.
GT1 GT Direct Injection allowance and rules #35437engineadded · engineGT1, GT2, GT3, GTL, GTX Direct Injection now permitted if original equipment.
GT1 GT2/3 remove Direction Injection not allowed in Spec line notes #35439engineadded · engineGT2 Nissan and GT3 Mazda, Mitsubishi 4G93, Nissan QR25DE/DD, QE25DE/DD now permit Direct Injection per 9.1.2.F.7.5.E.
GT1 Request for Acceptance of Lamborghini Huracan GT3 in GT1-ST #34929cars addedaddedGT1-ST adds Lamborghini Huracan GT3 EVO(1) 2018- at 3000 lbs, X39mm restrictor, and Huracan GT3 2019- at 3100 lbs, 52mm restrictor.
GT1 Cylinder heads #35040engineadded · engineGT1 Trick Flow Specialties Ultra 18 Degree GM Cylinder Head Part #TFS-3181T001-CO1 allowed.
SRF Update SRF Rain / Brake Rule #34706otherotherSRF rain/brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24; secondary filament must connect to rain light switch.
SRF Update SRF Brake Light Rule v1 #34853otherotherSRF brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24, with SCCA Enterprises P/N 180427A pigtail and strobing rain light kit.
GT1 Errors in GTCS Headings and Use of the Terms Category and ClassChange existing GTL and GTA Rules #34453wordingwordingGTL spec lines moved contiguous with GT2 and GT3; GTA category and specs renumbered behind GTL; P2 engine tables reorganised with restrictor and weight specifications clarified.
SRF SRF Radiator Rule Update #34805otheraddedSRF radiator options expanded: Enterprises P/N 480465 with baffle 480464, 480466, or Automotive 1R698 and CU698 allowed if cross-reference equivalent.
SRF Hoosier SRF Wet Front Tire Rule Update #34189tyres & wheelstyres & wheelsSRF wet front tyre changes to Hoosier P/N 46100 P185/60R13 H20 or W2 with 2.5" ground clearance.
GT1 Please classify Fields Cardinal V8 #33784cars addedaddedFields Cardinal V8 added to GT1 with Ford V8 engine, 4.9L, 2100 lbs, fuel injection.
SRF Update SRF Front W2 Rain Tire Part Number #34118tyres & wheelstyres & wheelsSRF front W2 rain tyre Hoosier part number changes from 46100 to 46101 P185/65R13.
SRF Update SRF Brake Rule #33469enginefaster · engineSRF removes 1985 Renault Alliance solid front rotor option; restrictor sizes decrease 1mm for newer Kawasaki and multi-brand engines; minimum weights increase to 1100 lbs.
GT1 Sequential Transmission Weight Penalty #33503weightfaster · weightGT1 sequential transmission weight penalty reduced from 50 lbs to 25 lbs.
GT1 GT1 Porsche 992 #33730cars addedaddedGT1-ST Porsche 992 GT3 Cup added with 3997cc displacement, 2950 lb minimum weight, no restrictor.
GT1 GT2 (TA2)/GTA Part Number Update #33315wordingwordingGT2 TA2 and GTA throttle body part numbers updated to GM 12570790 or Edelbrock 33869/3870.
GT1 Request to Reduce Trans Am Bodywork Weight Penalty #33331weightfaster · weightGT1 Trans Am bodywork weight penalty reduced from 100 lbs to 75 lbs.
GT1 Request for Reduction in FR9 Weight Penalty #33332weightfaster · weightGT1 Chevrolet RO7, Ford FR9, and Dodge R7 weight penalties cut from 50 lbs to 25 lbs each.
F5 Intake Boots Correction #33028wordingwordingF500 Rotax 493 and 593 intake boots: removed Moto Tassinari V3124-873B-2 from 493/593 non-HO allowance, added Moto Tassinari V3120-794A-2 option for non-HO.
GT1 Tail lights on all GT category race cars. #32799wordingwordingGT1, GT2, GT3, GTL, GTX tail lights may now be original style or custom panel graphic with functioning red LED brake lamps.
F5 Ensure availability of ECU for Rotax engines #32695engineadded · engineF500 Rotax engines now permit Ingi Tech Sparker ignition DCP-CDI-P2 as alternate ECU.
GT1 GT-1/TransAm rules simplification/modernizing #32763cars addedaddedGT1 allows current Trans Am bodywork with 100 lb weight penalty.
F5 Clarify stepped exhaust header references #32743wordingwordingF500 clarifies stepped diameter exhaust headers prohibited except at cylinder head flange area.
SRF SRF Tire Rule Update #32614wordingwordingSRF tire rule wording clarified: tires must be run as delivered.
SRF Brake, seal, and air filter clarifications #32670otherfasterSRF brake rotor minimum thickness reduced from 13.25 mm to 12.20 mm; seals and air filter specs clarified.
F5 E&O class name #32194otheraddedF500 Majors and Runoffs cars must install AIM part #X47KPFSOLO2R0 data box mount for Solo or Solo 2.
GT1 Mercedes Benz AMG GT3 in GT1 #31883cars addedaddedGT1 Mercedes Benz AMG GT3 added, 3050 lbs, 6208cc V8, 40mm restrictors, FIA GT3 homologation.
GT1 Wheel Widths #31844tyres & wheelsadded · tyres & wheelsGT1 allows 17-inch wheels; 18-inch wheels now permitted with 50 lb penalty; 18-inch tyres use 13-inch front, 14-inch rear width.
F5 Data Box Mounting Plate #31638otheraddedF5 cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs.
SRF Three Updates to SRF Rules #31523otherotherSRF wet tyres front P185/65R13 W2 option added; air box clarified as-delivered; SRF3 restrictor plate G301048 mandatory Jan 1 2022; P2 motorcycle engines up to 1005cc with 35mm restrictor, 2009+ stock 1075 lbs, 2008 stock 1025 lbs, modifie…
GT1 Request car classification #31032cars addedaddedGT3 Volkswagen Fun Cup Beetle EVO3 classified, sealed SOHC 1984cc engine, 2060 lbs minimum weight.
F5 Clarify allowable assisted shifting systems #30871wordingwordingF5 clarifies mechanical shifting only; throttle-cut and flat-shifter devices permitted if driver retains full control.
F5 Request to correct terminology #30976wordingwordingF5 single-seat open-wheel cars: rigid suspension becomes limited suspension in class definition.
GT1 Request to Update GTA Obsolete Part Numbers #30615wordingwordingGTA part numbers updated: 0-80541-1 to 0-80541-2 in two locations and 6010 to 6014X in TA2 Appendix.
SRF SADEV-SRF3 Transmission #30926cars addedaddedSRF adds SADEV-SRF3 6-speed sequential transmission option with ratios 3.0–0.92:1 and 3.20 final drive.
SRF SRF Update Maintenance, Repairs and Seals #30961wordingwordingSRF seal requirements clarified: seals now must be on driveline components in designated locations; unsealed components removed and inspected by CSR or Enterprises rather than engine shipped for testing.
F5 Request to Allow Rotax 593 HO Engine #30712cars addedaddedF500 Rotax 593 HO engine now permitted; 875 lbs minimum weight, MA0242SP1020A or MA0242SP1063A restrictor, specific intake boots and piston required.
SRF SRF3 Alternator Pulley #30684engineadded · engineSRF3 alternator pulley specified as P/N G902130 or G902130A, minimum 12oz.
SRF Mandatory identification: #30223wordingwordingSRF and SRF3 mandatory identification revised: removed Ford Performance and Blue Oval decals, added Hoosier logo placement.
SRF SRF Shocks, Springs and Ride Height. #29688otherotherSRF rear springs limited to P/N 280390 only, previous part numbers no longer allowed; ground clearance wording clarified.
F5 Request to Update Suzuki Engine Years for F500 #29453engineadded · engineF500 Suzuki GSXR600 engine years extended from 2003-2013 to 2003-2019.
GT1 GT Category Wording #29193wordingaddedGT1/GT2/GT3/GTL/GTX turbocharging and supercharging now permitted if listed on spec line.
GT1 Request to Allow New Trans Am Legal Engines in GT1 #29002cars addedaddedGT1 adds Trans Am spec engines: Chevrolet R07, Ford FR9, Dodge R7, each at base weight plus 50 lbs.
F5 Request for Cockpit Adjustment of External Jetting Devices #28359wordingunclearF5 request to adjust external jetting device cockpit control denied; no rule change made.
F5 Two Stroke Motors (reply to #28359 WDYT) #28816engine
F5 Re letter requesting driver adjustable carb mixture #28840wordingunclearF5 driver adjustable carburettor mixture: refer to separate Fastrack letter #28359 for ruling.
F5 #28359 WDYT Request for Cockpit Adjustment #28875wordingunclearF5 cockpit adjustment request response published in Fastrack letter 28359.
GT1 TA2 Gurney flap wicker clarification #28874wordingwordingTA2 Gurney flap wording clarified: replace 'wicker bill' and 'wicker' with 'Gurney flap' throughout wing specifications.
GT1 STO Gurney flap wicker clarification #28883wordingwordingSTO rear wing rules clarify that wicker is called Gurney flap in two places; no performance change.
GT1 GT1 Gurney flap wicker clarification #28886wordingwordingGT1 Gurney flap and wickerbill terminology clarified: 'lips' and 'tabs' and 'wicker' standardized to 'flaps' throughout section D and E.
GT1 GT Gurney flap wicker clarification #28909wordingwordingGT Gurney flap wording clarified: wickerbill and tab terminology replaced with Gurney flap throughout sections 9.1.2.F.7.b.
SRF SRF Bump Stop Correction #27019wordingwordingSRF Penske shock P/N 280396 bump stop P/N 280407 becomes mandatory, maximum one per shock, effective 05/01/2020.
GT1 Windshield Clips #27323otheraddedGT1, GT2, GT3, GTL, GTX may use bonded-glass factory windshields without clips or straps if attached per original specifications.
F5 Change 600cc restrictor size #27883inductionslower · inductionF500 Honda CBR600RR, Suzuki GSXR600, Yamaha R6 restrictor reduced to 28mm from 29mm.
GT1 Request to classify the Ford Coyote 3rd Gen OEM #27146cars addedaddedGT2/ST Ford Coyote 5.0L third generation OEM gains Boss intake manifold option at 3200 lbs minimum.
GT1 Request Factory Five Daytona coupe classification #26308cars addedaddedGTX Misc. adds Factory Five Type 65 Coupe R Ford 302/351 and 5.0/5.2L NA at 2600 lbs, plus Ferrari 458/488 Challenge, Ford FP350S, Chevrolet C6, Lamborghini Super Trofeo.
GT1 Request to Adjust Transmission Penalty #27750weightfaster · weightGT1 sequential shifting transmissions weight penalty reduced from 75 lbs to 50 lbs.
GT1 Request to Reduce Additional Weight for 18 #27751weightfaster · weightGT1 cars not specified for 18 inch wheels now have 50 pound penalty, down from 100.
GT1 Request for Five Star Nascar Compliant Bodywork #27756cars addedaddedGT1 adds 5 Star NASCAR Camaro 2018 and later body as allowed bodywork option.
SRF SRF Rain / Brake Rule - BoD approved as follows #34958wordingwordingSRF rain and brake rule supersedes GCR 9.3.32.B.2 effective 1/1/2024 through 12/31/2024.
SRF SRF Tire Warmer Rule #27622tyres & wheelstyres & wheelsSRF adds tire warmer prohibition and specifies Hoosier dry and wet tire part numbers.
SRF SRF / SRF3 Nose Weight Reduction #27706weightfaster · weightSRF front nose weight minimum reduced from 35 to 32 lbs.
SRF SRF / SRF3 Majors & Regional Class Updates #27723wordingwordingSRF2 becomes Regional Only; SRF3 nomenclature changed from GEN3 to Ford 1.6L conversion; SRF and SRF3 no longer compete together for points.
F5 Request for Weight Increase for Motorcycle Powered Cars #27214weight +25 lbsslower · weightF500 Honda CBR600RR, Suzuki GSXR600, and Yamaha R6 minimum weights increase to 900 lbs.
GT1 Clarify Trans Am Legal Bodywork and Wing #26953aeroadded · aeroGT1 allows Trans Am rear wing, 72" span, 12" chord, 1/2" wicker, 100 sq in endplates, no weight penalty; front undertray allowed with 50 lb penalty.
SRF SRF Dash Windscreen Kit #27028aeroadded · aeroSRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102.
GT1 Request GTX Fuel injection for previous GT-1 tube frame cars #26141engineadded · engineGTX tube frame cars now allowed fuel injection with maximum 90mm throttle body.
GT1 Request to Classify Ligier JS2 R #26535cars addedaddedGTX adds Ligier JS2 R classification with restrictor and minimum weight.
GT1 Request Ride Height Clarification #26600wordingfasterGT1 and GT2/3/Lite remove ride height ground clearance rules; cars may now touch ground when tires deflate.
GT1 GTX Homologation table update #26034otherunclearGTX FIA GT3: Audi R8 now 40 mm restrictor and 2900 lbs; BMW Z4 now 70 mm restrictor and 2800 lbs; Ferrari 488 now 35 mm restrictor, TIR, and 3025 lbs.
About this data
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. 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.