BoP Labbeta

BoP Lab / Buttonwillow Raceway Park

FE2 vs GT2 vs SRF3 vs F6 pace at Buttonwillow Raceway Park

Class · click a class to switch, + to compare alongside (up to 4: remove one to add another)
Reference class · the others' laps as a share of this one's at the same event, so years compare despite weather; + a class above to measure against it
Track configuration

Quickest here: FE2 1:12.402 Blake Pigeon, Cal Club 2023 qualifying · GT2 1:42.698 Tim Carroll, Cal Club 2026 qualifying · SRF3 1:50.233 Caleb Shrader, Cal Club 2025 qualifying

1:101:151:201:251:301:351:401:451:501:5537 rule changes between Cal Club 2023 and Cal Club 202537 ▾14 rule changes between Cal Club 2025 and Cal Club 202614 ▾FE2 race best at Cal Club 2025: 1:39.712 (Paul Marino)FE2 race best at Cal Club 2026: 1:40.253 (Jon McClintock)FE2 qualifying best at Cal Club 2023: 1:12.402 (Blake Pigeon)FE2 qualifying best at Cal Club 2025: 1:39.358 (Paul Marino)FE2 qualifying best at Cal Club 2026: 1:39.265 (Jon McClintock)GT2 race best at Cal Club 2025: 1:46.926 (Brad McAllister)GT2 race best at Cal Club 2026: 1:44.128 (Tim Carroll)GT2 qualifying best at Cal Club 2025: 1:45.818 (Brad McAllister)GT2 qualifying best at Cal Club 2026: 1:42.698 (Tim Carroll)SRF3 race best at Cal Club 2025: 1:50.825 (Caleb Shrader)SRF3 race best at Cal Club 2026: 1:52.070 (Asad Nikadambaev)SRF3 qualifying best at Cal Club 2025: 1:50.233 (Caleb Shrader)SRF3 qualifying best at Cal Club 2026: 1:50.913 (Asad Nikadambaev)Cal Club 20232023Cal Club 20252025Cal Club 20262026
FE2GT2SRF3F6solid race · dashed qualifying · slower is lower
100%102%104%106%108%110%112%37 rule changes between Cal Club 2023 and Cal Club 202537 ▾14 rule changes between Cal Club 2025 and Cal Club 202614 ▾FE2 race best at Cal Club 2025: 100.0% of FE2's (Paul Marino)FE2 race best at Cal Club 2026: 100.0% of FE2's (Jon McClintock)FE2 qualifying best at Cal Club 2023: 100.0% of FE2's (Blake Pigeon)FE2 qualifying best at Cal Club 2025: 100.0% of FE2's (Paul Marino)FE2 qualifying best at Cal Club 2026: 100.0% of FE2's (Jon McClintock)GT2 race best at Cal Club 2025: 107.2% of FE2's (Brad McAllister)GT2 race best at Cal Club 2026: 103.9% of FE2's (Tim Carroll)GT2 qualifying best at Cal Club 2025: 106.5% of FE2's (Brad McAllister)GT2 qualifying best at Cal Club 2026: 103.5% of FE2's (Tim Carroll)SRF3 race best at Cal Club 2025: 111.1% of FE2's (Caleb Shrader)SRF3 race best at Cal Club 2026: 111.8% of FE2's (Asad Nikadambaev)SRF3 qualifying best at Cal Club 2025: 110.9% of FE2's (Caleb Shrader)SRF3 qualifying best at Cal Club 2026: 111.7% of FE2's (Asad Nikadambaev)Cal Club 20232023Cal Club 20252025Cal Club 20262026
FE2GT2SRF3F6solid 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
EventFE2GT2SRF3F6
Qual bestRace bestTrapQual bestRace bestTrapvs FE2% of FE2Qual bestRace bestTrapvs FE2% of FE2Qual bestRace bestTrapvs FE2% of FE2
Cal Club 2026 CALCL262026-02-211:39.265Jon 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%)1:42.698Tim Carroll · fastest of 8 · top 5 within 7.4s-3.120s (-2.95%)1:44.128Tim Carroll · fastest of 8 · top 5 within 4.3s-2.798s (-2.62%)155.7Rocky Crocker+37.8 mph (+32.1%)+3.875squal +3.433s103.9%qual 103.5%1:50.913Asad Nikadambaev · fastest of 27 · top 5 within 1.1s+0.680s (+0.62%)1:52.070Asad Nikadambaev · fastest of 27 · top 5 within 0.8s+1.245s (+1.12%)138.9Paul Marino+20.7 mph (+17.5%)+11.817squal +11.648s111.8%qual 111.7%
14 rule changes (FE2: 2, GT2: 8, SRF3: 4)3 cars added · 1 aero · 1 engine · 1 induction · 7 wording · 1 other · GT2 Porsche 911 SC gains option of 4.0L 4V engine at 2350 lbs or 4.0L 2V at 2275 lbs. · M3 E92 classified in GT2 with 3999cc V8, 35mm restrictor, 3300 lbs minimum weight. · GT2 adds Cadillac CTS, Chevrolet Impala/Malibu/Monte Carlo/SS, Dodge Intrepid, Ford Fusion/Taurus, Lincoln MKS, Pontiac G8/GTO/Grand Prix, Toyota Camry, and Gen late Model Stock Car bodies. · GT2 Mazda BP engine 1839cc classified with 46mm turbo inlet restrictor, 2250 lbs minimum weight. · 991.2 GT3 Cup throttle body restrictor increases from 65mm to 70mm; 997.2 loses 100 lbs to 2800; Corvette LS engines get larger restrictors across multiple displacements and model years; LS3 and LT1 weight reduced 100 lbs each to 3150. · FE and FE2 Enterprises must use bubble tail P/N WM138014; FE2 allows only this configuration. · SRF3 adds HD Oil Cooler P/N G1148500 as alternative to standard cooler P/N G480503. · SRF3 brakes restructured: Hawk Blue 801993 pads, Wilwood 800065 rotors only; adds Girling 880358, Wilwood 880357, Tilton 880360 master cylinders. · GT2 Porsche 911 Coupe & Targa may use 993 3.8 RSR rear deck lid or approved aftermarket reproductions. · FE2 allows driver safety and comfort modifications for disabled drivers with SCCA approval, not transferable to other drivers. · SRF drivers with disabilities may modify seat and controls for safety and comfort with approval and logbook notation. · SRF SADEV-SRF3 6-speed sequential transmission gear ratios wording clarified, effective 2025-04-01. · GT2 Pontiac Fiero changes from FWD to RWD; hood bulge permitted for front engine relocation. · TA2 and STO OEM wings no longer exempt from rear wing height rule at roof peak.showhide
  • GT2 Allow Larger Air Cooled Engines in Porsche 911 GT2 #39249enginefasterGT2 Porsche 911 SC gains option of 4.0L 4V engine at 2350 lbs or 4.0L 2V at 2275 lbs.
  • GT2 Classify T1 BMW in GT2 #39408cars addedcars addedM3 E92 classified in GT2 with 3999cc V8, 35mm restrictor, 3300 lbs minimum weight.
  • GT2 Additional Body Options to Replace Older Stock Car Bodies #39086cars addedcars addedGT2 adds Cadillac CTS, Chevrolet Impala/Malibu/Monte Carlo/SS, Dodge Intrepid, Ford Fusion/Taurus, Lincoln MKS, Pontiac G8/GTO/Grand Prix, Toyota Camry, and Gen late Model Stock Car bodies.
  • GT2 GT3 Turbo to GT2? #39365cars addedcars addedGT2 Mazda BP engine 1839cc classified with 46mm turbo inlet restrictor, 2250 lbs minimum weight.
  • GT2 Tech Bulletins for GT2 and GT2-ST #39537induction -100 lbsslower991.2 GT3 Cup throttle body restrictor increases from 65mm to 70mm; 997.2 loses 100 lbs to 2800; Corvette LS engines get larger restrictors across multiple displacements and model years; LS3 and LT1 weight reduced 100 lbs each to 3150.
  • FE2 FE & FE2 Bubble Tail #38978wordingwordingFE and FE2 Enterprises must use bubble tail P/N WM138014; FE2 allows only this configuration.
  • SRF3 Add HD Oil Cooler #38979otherotherSRF3 adds HD Oil Cooler P/N G1148500 as alternative to standard cooler P/N G480503.
  • SRF3 SRF Rule Updates #38853wordingwordingSRF3 brakes restructured: Hawk Blue 801993 pads, Wilwood 800065 rotors only; adds Girling 880358, Wilwood 880357, Tilton 880360 master cylinders.
  • GT2 Rear Deck Lid for Older Air-Cooled Porsche #38506wordingwordingGT2 Porsche 911 Coupe & Targa may use 993 3.8 RSR rear deck lid or approved aftermarket reproductions.
  • FE2 Driver Safety & Comfort #37965wordingwordingFE2 allows driver safety and comfort modifications for disabled drivers with SCCA approval, not transferable to other drivers.
  • SRF3 Driver Safety & Comfort #37966wordingwordingSRF drivers with disabilities may modify seat and controls for safety and comfort with approval and logbook notation.
  • SRF3 Update SADEV transmission specs #37992wordingwordingSRF SADEV-SRF3 6-speed sequential transmission gear ratios wording clarified, effective 2025-04-01.
  • GT2 Hood Bulge allowed #37000wordingunclearGT2 Pontiac Fiero changes from FWD to RWD; hood bulge permitted for front engine relocation.
  • GT2 OEM Wing Adjustment #37590aeroslowerTA2 and STO OEM wings no longer exempt from rear wing height rule at roof peak.
Cal Club 2025 CALCL252025-02-221:39.358Paul Marino · fastest of 4 · top 4 within 1.5s+26.956s (+37.23%)1:39.712Paul Marino · fastest of 4 · top 4 within 1.7s127.2Tom Hope1:45.818Brad McAllister · fastest of 6 · top 5 within 14.6s1:46.926Brad McAllister · fastest of 6 · top 5 within 13.3s117.9Guy Laidig+7.214squal +6.460s107.2%qual 106.5%1:50.233Caleb Shrader · fastest of 33 · top 5 within 0.4s1:50.825Caleb Shrader · fastest of 32 · top 5 within 0.8s118.2John Black+11.113squal +10.875s111.1%qual 110.9%
37 rule changes (GT2: 23, SRF3: 14)6 cars added · 6 weight · 5 induction · 3 tyres & wheels · 2 suspension & brakes · 1 aero · 1 engine · 12 wording · 1 other · GT2 STO aftermarket ABS weight penalty reduced from 100 lbs to 50 lbs. · GT2 Panoz Esperante GTS adds 2013-2016 Ford EcoBoost Twin Turbo V-6 3496cc engine, 2600 lbs. · TA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement. · GT2 Sunbeam Tiger gains Holly 650 cfm carburetor alternate options PN #80541-1 and #80541-2. · SRF3 air filter rule removes K&N RC-9160 option, leaving only P/N WM301020 allowed. · SRF brake rotor minimum thickness increases from 12.20mm to 13.25mm, Wilwood vented rotor P/N 800065. · SRF3 Hoosier logo placement changes from four decals to three decals in different locations. · SRF Hoosier decal requirement reduced from four decals in specific locations to three decals with simpler placement rules. · SRF wet tires: P185/60R13 H20/W2 option removed; P185/65R13 W2 front now required with P205/60R13 W2 rear. · GT2-ST allows aftermarket replacement differential housings if exact equivalents. · GT4 cars now permitted in GT2-ST with factory restrictor, must comply with 2012 STO rules, slicks allowed with 100-pound penalty. · SRF3 alternator pulley minimum weight reduced from 12 oz to 11 oz. · GT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR. · GT2-ST Corvette 14-19 LS2 restrictor increases from 78mm to 80mm flat plate. · Chevrolet Corvette C8 (2020–) classified into GT2-ST with 6162cc displacement, 3300 lbs minimum weight, 71mm restrictor. · 2015 Mitjet ST added to GT2, must run per VTS specifications with complete FIA form CdM008. · 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 Chevrolet Corvette 7011 OEM 7 liter weight reduced 150 lbs, to 3125 lbs. · GT2/3 Nissan, Mazda, Mitsubishi 4G93, QR25DE/DD, QE25DE/DD Direct Injection now permitted per 9.1.2.F.7.5.E. · GT2-ST Dodge Viper hybrid kit restrictor reduced from 50mm to 45mm flat plates. · SRF rain/brake light now requires Super Bright LEDs Inc. P/N PT-STRB-R24 with specific connector and rain light switch. · SRF requires Super Bright LEDs P/N PT-STRB-R24 rain/brake light with strobing capability and specific wiring. · SRF adds brake duct and pedal extension rules, rear shift cable clamp option, camber limit to 5.0°, radiator opening height 3.5" ±0.5", and P2 engine restrictor changes. · GTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL. · GT2-ST Dodge Viper including Comp Coupe, ACR/ACR-X with VRL front fascia loses 100 lbs. · SRF radiator rule clarified: P/N 480466 replaceable with Automotive P/N 1R698, CU698 or manufacturer equivalent with documentation. · GT2 Mazda 20B 3 rotor loses 220 lbs, to 2280, consolidating two spec lines. · GT2 BMW engines: 3.4L 6-cyl at 2575 lbs, 4.0L V8 at 2900 lbs, 4.5L V8 at 2950 lbs, 5.0L V8 at 3000 lbs; S54 with 97mm stroke permitted at 2800 lbs. · GT2 Corvette C7 restrictor increases from 73mm to 77mm flat plate, removing weight penalty. · SRF Hoosier wet front tire updated to P/N 46100 P185/60R13 H20 or W2. · 2009-2012 Porsche Cayman S classified in GT2, 3.4L, RWD, no PDK transmission allowed. · Fields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight. · SRF Hoosier front rain tyre part number changes from 46100 to 46101 P185/65R13 W2. · GT2 Ginetta G56 GTA may now use Factory installed ProMap ECU Map. · SRF Renault Alliance solid front rotors banned; restrictor reduced 35mm to 34mm for 2011+ Kawasaki; minimum weight increased to 1100 lbs for 2009+ stock engines. · SRF3 tail sections allowed on SRFs with GEN3 airbox shimming up to 19 mm; alternate dash panel P/N 180100 or 180101 relocated in rules.showhide
  • GT2 GT2/ST - Remove Aftermarket/Racing ABS penalty #36538weightfasterGT2 STO aftermarket ABS weight penalty reduced from 100 lbs to 50 lbs.
  • GT2 Panoz Esperante GTS BOP #36686cars addedcars addedGT2 Panoz Esperante GTS adds 2013-2016 Ford EcoBoost Twin Turbo V-6 3496cc engine, 2600 lbs.
  • GT2 Correct language regarding OEM Areo Devices #37137wordingwordingTA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement.
  • GT2 GT2 Sunbeam Tiger Alternate Carburetor #37198inductioninductionGT2 Sunbeam Tiger gains Holly 650 cfm carburetor alternate options PN #80541-1 and #80541-2.
  • SRF3 Update SRF3 Air Filter Rule #36681wordingunclearSRF3 air filter rule removes K&N RC-9160 option, leaving only P/N WM301020 allowed.
  • SRF3 Update SRF Brake Rotor Thickness #36687suspension & brakesslowerSRF brake rotor minimum thickness increases from 12.20mm to 13.25mm, Wilwood vented rotor P/N 800065.
  • SRF3 Hoosier Tire Decal Placement #36739wordingwordingSRF3 Hoosier logo placement changes from four decals to three decals in different locations.
  • SRF3 Update to Letter 36619 with new Hoosier Contingency Decal Info #36624wordingwordingSRF Hoosier decal requirement reduced from four decals in specific locations to three decals with simpler placement rules.
  • SRF3 Update Rain Tire Rule and Hoosier Decal Placement #36436tyres & wheelsslowerSRF wet tires: P185/60R13 H20/W2 option removed; P185/65R13 W2 front now required with P205/60R13 W2 rear.
  • GT2 GT2-ST Rule Clarification #36093wordingwordingGT2-ST allows aftermarket replacement differential housings if exact equivalents.
  • GT2 GT4 cars may run in GT2-ST #36235cars addedcars addedGT4 cars now permitted in GT2-ST with factory restrictor, must comply with 2012 STO rules, slicks allowed with 100-pound penalty.
  • SRF3 SRF3 Alternator Pulley Update In #36095weightfasterSRF3 alternator pulley minimum weight reduced from 12 oz to 11 oz.
  • GT2 Request for Spec Line 1010 Reconsideration #35009weight +300 lbsslowerGT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR.
  • GT2 Request to Eliminate the FPR from the Corvette (-2013) with LS2 #35878inductionfasterGT2-ST Corvette 14-19 LS2 restrictor increases from 78mm to 80mm flat plate.
  • GT2 Classify Corvette C8 (2020- ) into GT2/ST #33759cars addedcars addedChevrolet Corvette C8 (2020–) classified into GT2-ST with 6162cc displacement, 3300 lbs minimum weight, 71mm restrictor.
  • GT2 Requesting classification for a 2015 Mitjet ST in GT2 #35408cars addedcars added2015 Mitjet ST added to GT2, must run per VTS specifications with complete FIA form CdM008.
  • GT2 Rear Blade Spoiler Clarification #35261aerofasterGT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed.
  • GT2 GT Direct Injection allowance and rules #35437enginefasterGT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors.
  • GT2 REDUCE C6 CORVETTE WEIGHT WITH OEM 7 LITER ENGINE REDUCE BY 150LB #35385weight -150 lbsfasterGT2 Chevrolet Corvette 7011 OEM 7 liter weight reduced 150 lbs, to 3125 lbs.
  • GT2 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.
  • GT2 Dodge Viper Gen 3 hybrid Kit Update Request #35200inductionslowerGT2-ST Dodge Viper hybrid kit restrictor reduced from 50mm to 45mm flat plates.
  • SRF3 Update SRF Rain / Brake Rule #34706wordingwordingSRF rain/brake light now requires Super Bright LEDs Inc. P/N PT-STRB-R24 with specific connector and rain light switch.
  • SRF3 Update SRF Brake Light Rule v1 #34853wordingwordingSRF requires Super Bright LEDs P/N PT-STRB-R24 rain/brake light with strobing capability and specific wiring.
  • SRF3 SRF / SRF3 Rule Updates #35268otherotherSRF adds brake duct and pedal extension rules, rear shift cable clamp option, camber limit to 5.0°, radiator opening height 3.5" ±0.5", and P2 engine restrictor changes.
  • GT2 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.
  • GT2 Late E & O #34966weightfasterGT2-ST Dodge Viper including Comp Coupe, ACR/ACR-X with VRL front fascia loses 100 lbs.
  • SRF3 SRF Radiator Rule Update #34805wordingwordingSRF radiator rule clarified: P/N 480466 replaceable with Automotive P/N 1R698, CU698 or manufacturer equivalent with documentation.
  • GT2 GT2 Mazda 20B 3 rotor ENO #34765weight -220 lbsfasterGT2 Mazda 20B 3 rotor loses 220 lbs, to 2280, consolidating two spec lines.
  • GT2 appendix letter #33635 #34206wordingwordingGT2 BMW engines: 3.4L 6-cyl at 2575 lbs, 4.0L V8 at 2900 lbs, 4.5L V8 at 2950 lbs, 5.0L V8 at 3000 lbs; S54 with 97mm stroke permitted at 2800 lbs.
  • GT2 Remove Weight and Restrictor Penalty for Corvette C7 Body #34342inductionfasterGT2 Corvette C7 restrictor increases from 73mm to 77mm flat plate, removing weight penalty.
  • SRF3 Hoosier SRF Wet Front Tire Rule Update #34189tyres & wheelsunclearSRF Hoosier wet front tire updated to P/N 46100 P185/60R13 H20 or W2.
  • GT2 Request to class 2011 Porsche Cayman S #33771cars addedcars added2009-2012 Porsche Cayman S classified in GT2, 3.4L, RWD, no PDK transmission allowed.
  • GT2 Please classify Fields Cardinal V8 #33784cars addedcars addedFields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight.
  • SRF3 Update SRF Front W2 Rain Tire Part Number #34118tyres & wheelstyres & wheelsSRF Hoosier front rain tyre part number changes from 46100 to 46101 P185/65R13 W2.
  • GT2 Adding Ginetta G56 GTA Factory ProTune for GT2 Class #33825wordingunclearGT2 Ginetta G56 GTA may now use Factory installed ProMap ECU Map.
  • SRF3 Update SRF Brake Rule #33469suspension & brakesslowerSRF Renault Alliance solid front rotors banned; restrictor reduced 35mm to 34mm for 2011+ Kawasaki; minimum weight increased to 1100 lbs for 2009+ stock engines.
  • SRF3 Update SRF Bodywork Fitment Rule #33765wordingwordingSRF3 tail sections allowed on SRFs with GEN3 airbox shimming up to 19 mm; alternate dash panel P/N 180100 or 180101 relocated in rules.
Cal Club 2023 CALCL232023-02-241:12.402Blake Pigeon · fastest of 3 · top 3 within 1.6s
111 earlier rule changes on record, in force before Cal Club 2023 (from 2019)25 cars added · 20 weight · 11 induction · 7 engine · 4 tyres & wheels · 3 suspension & brakes · 2 aero · 38 wording · 1 other · GT2 Mazda 13B Street Port turbo changes from EFR 76/70 to BW7670 or Garrett G30-660 with 46mm TIR at 2280 lbs. · GT2 Porsche SOHC 2478/2681/2992 turbo sizes increase from 42mm to 44mm SIR to TIR. · GT2-ST Chevrolet Corvette 14-19 L76 5967 restrictor increases from 70 to 73 mm. · GT2 Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines newly classified in spec line. · GT2 Mazda 13B Street/Bridge Port turbocharger changes from EFR 70/76 to 76/70, compressor from 42mm to 46mm. · GT2-ST BMW E36/46 spec line adds MA Shaw carbon/composite door offerings to Notes. · GT3 normally aspirated cars may use intake chokes instead of SIRs, fitted to each carburetor barrel, same size as required SIR. · GT3 2.0L 4-valve non-turbo engines may run unrestricted at 2060 lbs instead of with a choke restriction. · GT2 Porsche 991.1 TBR 70–72mm, 991.2 weight 3100–3000lbs TBR 65–67mm, ABS penalties removed; GT2-ST Corvette LS engines flat plate 75–78mm, LS7 65–68mm; Viper weights 3275–3125lbs. · GT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870. · GT2 Ginetta G56 GTA gains optional 18" x 9" and 18" x 10" wheels. · GT2/ST BMW E36/E46 now allows MAShaw body kit parts: wide body, bumpers, fenders, rockers, flairs. · GT2 Chevrolet Corvette L76 5967 restrictor increases from 73mm to 74mm. · GT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only. · Ginetta GTA G56 added to GT2 as spec car: 2600 lbs, 3.7L Ford V6 sealed, 6-speed Quaife sequential. · GT2 BMW E36/E46 carbon roof and door suppliers added to notes: Lang Racing, 2M Automotive, Flossmann, MA Shaw. · GT2-ST BMW E46 M3, E36, Z3, 5000cc V8 can use 95mm S54 crankshaft at +150 lbs. · Audi R8 GT4 classified to GT2 with 5.2L displacement, 3000 lbs minimum weight, per factory specs restrictor. · SRF tire rule wording changed from 'Tires: must be run as delivered' to 'Tires must be run as delivered.' · SRF brake rotor minimum thickness reduced from 13.25 to 12.20mm; seal and air filter rules clarified. · GT2 shock absorber attachment points clarified as moveable; wording correction only. · GT2 Porsche 104.0 x 88.0 engine weight increases from 1950 to 2090 lbs; 2V variants may use Borg Warner EFR 76/70 42mm turbo. · Ginetta G40 classified in GT2 with Mazda MZR/L5-VE engine, 2488cc or 2399cc, 1950 lbs base weight. · Toyota Supra GT4 added to GT2-ST: 3000cc, 3000 lbs minimum, factory restrictor. · GT2 Porsche 944/924 may use ERC 76/70 Turbo instead of Jayco super 50. · GT2 Porsche Cayman 05-15 turbo restrictor increases from 70mm to 75mm. · GT2 Porsche Cayman 05-15 uses Throttle Body Restrictor instead of Flat Plate Restrictor at 2700 lbs. · SRF front wet tire changes from P185/60R13 H20 to P185/65R13 W2; SRF3 adds mandatory G301048 restrictor plate Jan. 1, 2022. · GT2 Mazda 13B street port adds EFR 70/76 turbo with 42mm restrictor at 2280 lbs. · GT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight. · GT2 Dodge Viper Comp Coupe ACR/ACR-X loses 100 lbs minimum weight to 3275. · 04-06 World Challenge Pontiac GTO added to GT2-ST: 6062 cc, 3000 lbs minimum, unrestricted. · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix. · Grullon GT with 2.0L K20 moved from GTX to GT2-ST, minimum weight 2350 lbs, unrestricted. · SRF wet tyres add Hoosier P185/60R13 W2 front and P205/60R13 W2 rear as alternatives to H20. · SRF adds SADEV-SRF3 6-speed sequential option with final drive 3.20 versus OEM 5-speed 3.85. · SRF seal procedures clarified: unsealed components need CSR inspection and logbook notation instead of engine removal. · GT2-ST Porsche Cayman restrictor increases from 65mm to 75mm flat plate at 2700 lbs. · GT2 Dodge Viper including Comp Coupe, ACR/ACR-X minimum weight reduced 100 lbs to 3275 in VRL Spec. · TA2 minimum weight set to 2930 lbs with free tire make and size. · SRF3 alternator pulley restricted to P/N G902130 or G902130A, 12oz minimum weight. · GT2 Sunbeam SBF 302 engine firing order option now explicitly allows Boss 302 variant. · GT2-ST Corvette (-2019) LS2 and L76 5967cc gain 100 lbs minimum weight to 3100; 6162cc variants gain 50–100 lbs; 7011 gains 100–50 lbs; L76 restrictor opens 70 to 73 mm. · GT2 rear engine opening location requirement removed. · GT2 Ford Mustang/Thunderbird Boss 302 firing order now optional from later SBF 302 versions. · SRF and SRF3 mandatory identification simplified: removed Ford Performance and Blue Oval decals, kept Hoosier logo placement. · GT2 ABS braking systems now allowed if shown on individual Spec Line. · GT2 Corvette C6 and C7 spec lines clarified and split; C7 LS2/L76/LS3/LT1/LS7 weights increased 100–150 lbs effective 3/1/2021. · GT2 Ford Mustang/Thunderbird Boss 302 firing order becomes unrestricted. · GT2 BMW E46 M3 weight reduced from 2600 to 2500 lbs. · GT2 Chrysler/Dodge/Plymouth 2429cc DOHC engine classified at 1950 lbs, unrestricted fuel induction. · SRF shocks, springs, bump stops sealed; rear springs 412-429 lbs/in P/N 280390 only; previous parts no longer allowed. · GT2 stock car bodies removal rescinded; 1997-current year commercially available stock car bodies remain allowed. · GT2 Appendix L renumbering eliminates sections .17 through .19 after 4.8.4.2.10.3.6. · GT2 TA2 wing width maximum set to 65 -5/16 inches, previously undefined. · 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. · GT2 Chevrolet Corvette -2019 LS1/LS6 allows DORMAN part # 615-900 alternate intake manifold. · GT2 Porsche 997.2 GT3 Cup minimum weight drops to 2900 lbs. · GT2 BMW E46 M3, E36, Z3, and 5000cc V8 gain Trans Am SGT spec allowance: regular shifter 3000 lbs., paddle shifter plus 150 lbs. · GT2 allows up to four hood/fender louvered panels, max 600 sq inches total, min five slots each, mounted in front of windscreen. · TA2 Gurney flap wording clarified: terminology standardized to 'Gurney flap', height limits and thickness specifications remain 0.50 inch / 0.625 inch or 0.375 inch / 0.0625 inch depending on configuration. · STO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules. · GT classes clarify Gurney flap wording, replacing wickerbill/tab terminology with flap; specifications unchanged. · GT2 Dodge Viper 8400 OEM minimum weight drops 50 lbs to 3275. · GT2 Chevrolet Corvette -2019 OEM minimum weight cut 50 lbs to 3275. · SRF3 shock absorber brand restriction removed; all shocks must be sealed by Enterprises. · GT2 Corvette LS6 may reduce weight by 50 lbs. · SRF3 bump stop now must be SCCA P/N 280407 only, no modifications, optional, max one per shock. · SRF shock absorber bump stop clarified: only SCCA P/N 280407 allowed as delivered, maximum one per shock, effective 05/01/2020. · GT2 Panoz GT-S now allowed to use TA2 Choice Engine with any 5-speed H-pattern transmission. · GT2-ST Corvette LS2 restrictor increases from 70mm to 75mm flat plate. · GT2-ST Corvette L76 added: 5967cc, 3000 lbs minimum, 70mm flat plate restrictor. · GT2 Porsche 991.2 GT3 Cup Car engine displacement increases from 3.8L to 4.0L. · GT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications. · GT2 Chevrolet SS replaces Dodge Charger; all stock car bodies removed from GT2 in 2021. · Factory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs. · 991.2 GT3 Cup Car classified in GT2 at 3100 lbs with 63mm throttle body restrictor. · GT2 Acura NSX minimum weight reduced from 3000 to 2700 lbs. · GT2 Porsche 991.1 GT3 Cup restrictor size increases from 67 mm to 70 mm. · GT2 Porsche 996/997.1 GT3 Cup minimum weight reduced 100 lbs, to 2800. · GT2/ST Corvette -2019 5967cc restrictor reduced from 75 mm to 70 mm. · SRF rain and brake rule wording updated; supersedes GCR 9.3.32.B.2 effective 1/1/202 through 12/31/2024. · FE and FE2 minimum weight increased to 1270 lbs including driver; spring options and tire warmer ban added. · SRF bans tire warmers and cooling methods other than natural air convection or conduction. · SRF front nose weight minimum reduced from 35 to 32 lbs. · SRF3 reclassified as Spec Racer Ford 3 with 1.6L conversion; SRF2 becomes Regional Only Class. · GT2 TA2 cars must weigh minimum 2930 lbs per current Trans Am rules or prior Appendix L. · SRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102. · GT2 Toyota Supra 3SGTE newly classified at 2900 lbs minimum weight, 43mm restrictor. · Acura NSX All Years classified to GT2-ST: 3.5L turbo, 3000 lbs minimum, 43mm restrictor. · GT2 TA2 minimum weight increases from 2830 to 2930 pounds. · SRF3 nose assembly must use approved multi-piece design; no modifications allowed except as specified. · GT2 BMW E36/E46 4.5L V8 classified at 2950 lbs minimum weight. · 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. · SRF3 brakes now allow Hawk Blue 9012 pads P/N 801993 only; shocks simplified to Penske P/N 280396 sealed assembly only, with optional SCCA Enterprises bump rubber P/N 280407 from 05/01/2020. · GT2 Ford Mustang 5.2L classified at 3300 lbs minimum with 82mm single throttle body restrictor. · 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. · GT2 Porsche Cayman model years change from 05-11 to 05-15. · GT2 Porsche Cayman adds 4.0L engine with 65mm flat plate restrictor at 2700 lbs minimum weight. · GT2 BMW E46 M3, E36, Z3, and 5000cc V8 now permit Flossman body kit. · GT2 TA2 cars: wheels cost cap drops to $175 each, carbon fiber allowed on rear wing, engine setback maximum 21.75 inches (A-F) or 24 inches (G), various nomenclature and clarification updates. · BMW 1 Series E82 classified into GT2 with N52B30 engine, 2996 cc, 2140 lbs minimum weight. · GT2 Porsche Cayman 05-11 base weight drops 75 lbs to 2800; adds STO/X51 motor notes. · GT2 Ford Mustang 05- with 5.2L Aluminator engine classified: 3400 lbs minimum weight, 2×41mm flat plate restrictor. · GT2 Porsche 996/997.1 GT3 Cup adds 3.6L displacement and 2900 lbs minimum weight; removes aftermarket exhaust header allowance for 996. · GT2 Ford Mustang FP350S minimum weight reduced 100 lbs, to 3400. · GT2 Ford Mustang 05- EcoBoost classified: 3500cc, 3200 lbs minimum, 41mm restrictor. · GT2 Mazda RX7 Downing GTS body kit allowed without 75 lbs. weight penalty. · GTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified.showhide
  • GT2 GT2 Mazda 13B Turbo #33729engineunclearGT2 Mazda 13B Street Port turbo changes from EFR 76/70 to BW7670 or Garrett G30-660 with 46mm TIR at 2280 lbs.
  • GT2 Request Permission to Use a Substitute Turbo #33337inductionfasterGT2 Porsche SOHC 2478/2681/2992 turbo sizes increase from 42mm to 44mm SIR to TIR.
  • GT2 Request to Reduce Restriction on C7 GT2 Corvette #33342inductionfasterGT2-ST Chevrolet Corvette 14-19 L76 5967 restrictor increases from 70 to 73 mm.
  • GT2 Toyota 4A-F and 4A-FE 1.6L DOHC 16V Engine Request #33415cars addedcars addedGT2 Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines newly classified in spec line.
  • GT2 GT2 Mazda 13b turbocharger part # update #33437enginefasterGT2 Mazda 13B Street/Bridge Port turbocharger changes from EFR 70/76 to 76/70, compressor from 42mm to 46mm.
  • GT2 GT2-ST BMW E36/46 spec line remove #33610wordingwordingGT2-ST BMW E36/46 spec line adds MA Shaw carbon/composite door offerings to Notes.
  • GT2 GT3 Choke option effective 1-01-2023 #33669inductioninductionGT3 normally aspirated cars may use intake chokes instead of SIRs, fitted to each carburetor barrel, same size as required SIR.
  • GT2 GT3 2.0L choke/weight option #33670inductionfasterGT3 2.0L 4-valve non-turbo engines may run unrestricted at 2060 lbs instead of with a choke restriction.
  • GT2 BOP adjustment for GT2 & GT2-ST #33681inductionfasterGT2 Porsche 991.1 TBR 70–72mm, 991.2 weight 3100–3000lbs TBR 65–67mm, ABS penalties removed; GT2-ST Corvette LS engines flat plate 75–78mm, LS7 65–68mm; Viper weights 3275–3125lbs.
  • GT2 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.
  • GT2 Ginetta G56 GTA - Optional Wheels #33357tyres & wheelstyres & wheelsGT2 Ginetta G56 GTA gains optional 18" x 9" and 18" x 10" wheels.
  • GT2 Allow the MAShaw Body Kit on the GT2/ST Spec Line for BMW E36/E46 #32447aerofasterGT2/ST BMW E36/E46 now allows MAShaw body kit parts: wide body, bumpers, fenders, rockers, flairs.
  • GT2 Request for C5/C6 Corvette Restrictor Size Review #32982inductionfasterGT2 Chevrolet Corvette L76 5967 restrictor increases from 73mm to 74mm.
  • GT2 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.
  • GT2 Addendum to letter #32514 Ginetta GTA G56 #33076cars addedcars addedGinetta GTA G56 added to GT2 as spec car: 2600 lbs, 3.7L Ford V6 sealed, 6-speed Quaife sequential.
  • GT2 Information requested for carbon roofs on BMW E36/E46 cars in GT2 #32682wordingwordingGT2 BMW E36/E46 carbon roof and door suppliers added to notes: Lang Racing, 2M Automotive, Flossmann, MA Shaw.
  • GT2 Request to Allow the 95mm S54 BMW Crankshaft in GT2-ST #32698weightslowerGT2-ST BMW E46 M3, E36, Z3, 5000cc V8 can use 95mm S54 crankshaft at +150 lbs.
  • GT2 Request to classify Audi R8 FIA GT4 to GT2 #32805cars addedcars addedAudi R8 GT4 classified to GT2 with 5.2L displacement, 3000 lbs minimum weight, per factory specs restrictor.
  • SRF3 SRF Tire Rule Update #32614wordingwordingSRF tire rule wording changed from 'Tires: must be run as delivered' to 'Tires must be run as delivered.'
  • SRF3 Brake, seal, and air filter clarifications #32670suspension & brakesfasterSRF brake rotor minimum thickness reduced from 13.25 to 12.20mm; seal and air filter rules clarified.
  • GT2 Typo in rules for shocks #32308wordingwordingGT2 shock absorber attachment points clarified as moveable; wording correction only.
  • GT2 additional response to letters #31898 & 32083 #32424weight +140 lbsslowerGT2 Porsche 104.0 x 88.0 engine weight increases from 1950 to 2090 lbs; 2V variants may use Borg Warner EFR 76/70 42mm turbo.
  • GT2 Request to Classify Ginetta G40 in GT2 #31597cars addedcars addedGinetta G40 classified in GT2 with Mazda MZR/L5-VE engine, 2488cc or 2399cc, 1950 lbs base weight.
  • GT2 2021 Supra GR GT4 #31737cars addedcars addedToyota Supra GT4 added to GT2-ST: 3000cc, 3000 lbs minimum, factory restrictor.
  • GT2 Proposed Technical Bulletin #31900wordingunclearGT2 Porsche 944/924 may use ERC 76/70 Turbo instead of Jayco super 50.
  • GT2 GT2/ST Porsche Cayman #31451 correct TBR size error #31991enginefasterGT2 Porsche Cayman 05-15 turbo restrictor increases from 70mm to 75mm.
  • GT2 Restrictor Clarification for 2015 Cayman #31451wordingunclearGT2 Porsche Cayman 05-15 uses Throttle Body Restrictor instead of Flat Plate Restrictor at 2700 lbs.
  • SRF3 Three Updates to SRF Rules #31523tyres & wheelsunclearSRF front wet tire changes from P185/60R13 H20 to P185/65R13 W2; SRF3 adds mandatory G301048 restrictor plate Jan. 1, 2022.
  • GT2 Turbo Request for 13B Engine #30656engineunclearGT2 Mazda 13B street port adds EFR 70/76 turbo with 42mm restrictor at 2280 lbs.
  • GT2 Request car classification #31032cars addedcars addedGT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight.
  • GT2 Correct letter 30565 GT2/ST #31088weightfasterGT2 Dodge Viper Comp Coupe ACR/ACR-X loses 100 lbs minimum weight to 3275.
  • GT2 Request the 04-06 Pontiac GTO WC Car Be Added to the GT2/ST Chart #30339cars addedcars added04-06 World Challenge Pontiac GTO added to GT2-ST: 6062 cc, 3000 lbs minimum, unrestricted.
  • GT2 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.
  • GT2 GTX class correction to GT2/ST #30973cars addedcars addedGrullon GT with 2.0L K20 moved from GTX to GT2-ST, minimum weight 2350 lbs, unrestricted.
  • SRF3 SRF Wet Tires #30849tyres & wheelstyres & wheelsSRF wet tyres add Hoosier P185/60R13 W2 front and P205/60R13 W2 rear as alternatives to H20.
  • SRF3 SADEV-SRF3 Transmission #30926cars addedunclearSRF adds SADEV-SRF3 6-speed sequential option with final drive 3.20 versus OEM 5-speed 3.85.
  • SRF3 SRF Update Maintenance, Repairs and Seals #30961wordingwordingSRF seal procedures clarified: unsealed components need CSR inspection and logbook notation instead of engine removal.
  • GT2 Porsche Cayman Engine Modification and Engine Request #30472inductionfasterGT2-ST Porsche Cayman restrictor increases from 65mm to 75mm flat plate at 2700 lbs.
  • GT2 Request weight clarification Viper CC #30565weightfasterGT2 Dodge Viper including Comp Coupe, ACR/ACR-X minimum weight reduced 100 lbs to 3275 in VRL Spec.
  • GT2 Variance, 2021 TA2 Rules vs GCR Appendix L #30641wordingwordingTA2 minimum weight set to 2930 lbs with free tire make and size.
  • SRF3 SRF3 Alternator Pulley #30684engineslowerSRF3 alternator pulley restricted to P/N G902130 or G902130A, 12oz minimum weight.
  • GT2 GT2 tiger firing order #30421wordingwordingGT2 Sunbeam SBF 302 engine firing order option now explicitly allows Boss 302 variant.
  • GT2 GT2-ST CORVETTE CHANGES #30029weight +100 lbsslowerGT2-ST Corvette (-2019) LS2 and L76 5967cc gain 100 lbs minimum weight to 3100; 6162cc variants gain 50–100 lbs; 7011 gains 100–50 lbs; L76 restrictor opens 70 to 73 mm.
  • GT2 Request underfloor clarification #30121wordingwordingGT2 rear engine opening location requirement removed.
  • GT2 29742 Change new wording to read as: #30329wordingwordingGT2 Ford Mustang/Thunderbird Boss 302 firing order now optional from later SBF 302 versions.
  • SRF3 Mandatory identification: #30223wordingwordingSRF and SRF3 mandatory identification simplified: removed Ford Performance and Blue Oval decals, kept Hoosier logo placement.
  • GT2 ABS Restrictions #30064wordingwordingGT2 ABS braking systems now allowed if shown on individual Spec Line.
  • GT2 RM 21-01 C6 & C7 clarification #30192weightslowerGT2 Corvette C6 and C7 spec lines clarified and split; C7 LS2/L76/LS3/LT1/LS7 weights increased 100–150 lbs effective 3/1/2021.
  • GT2 Request change to engine firing order rule #29742engineunclearGT2 Ford Mustang/Thunderbird Boss 302 firing order becomes unrestricted.
  • GT2 Request E-46 BMW M3 balance of performance #29833weight -100 lbsfasterGT2 BMW E46 M3 weight reduced from 2600 to 2500 lbs.
  • GT2 Request for Bigger Engine in Plymouth Breeze #29380cars addedcars addedGT2 Chrysler/Dodge/Plymouth 2429cc DOHC engine classified at 1950 lbs, unrestricted fuel induction.
  • SRF3 SRF Shocks, Springs and Ride Height. #29688suspension & brakessuspension & brakesSRF shocks, springs, bump stops sealed; rear springs 412-429 lbs/in P/N 280390 only; previous parts no longer allowed.
  • GT2 rescind GT2 stock car bodies removal #29219cars addedfasterGT2 stock car bodies removal rescinded; 1997-current year commercially available stock car bodies remain allowed.
  • GT2 E&O Typos in Appendix L #29447wordingwordingGT2 Appendix L renumbering eliminates sections .17 through .19 after 4.8.4.2.10.3.6.
  • GT2 GT2 wing width wording correction #29469wordingwordingGT2 TA2 wing width maximum set to 65 -5/16 inches, previously undefined.
  • 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.
  • GT2 GT Category Wording #29193wordingunclearGT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line.
  • GT2 Corvette GT2-ST intake manifold #29221wordingwordingGT2 Chevrolet Corvette -2019 LS1/LS6 allows DORMAN part # 615-900 alternate intake manifold.
  • GT2 997.2 E&O link to 27915 #29373weightfasterGT2 Porsche 997.2 GT3 Cup minimum weight drops to 2900 lbs.
  • GT2 Request for allowance Trans Am SGT #28951wordingwordingGT2 BMW E46 M3, E36, Z3, and 5000cc V8 gain Trans Am SGT spec allowance: regular shifter 3000 lbs., paddle shifter plus 150 lbs.
  • GT2 Omitted GT2 fender/hood openings #29171aeroaeroGT2 allows up to four hood/fender louvered panels, max 600 sq inches total, min five slots each, mounted in front of windscreen.
  • GT2 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.
  • GT2 STO Gurney flap wicker clarification #28883wordingwordingSTO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules.
  • GT2 GT Gurney flap wicker clarification #28909wordingwordingGT classes clarify Gurney flap wording, replacing wickerbill/tab terminology with flap; specifications unchanged.
  • GT2 Request to Adjust Weight of OEM 8.4 Viper #28739weight -50 lbsfasterGT2 Dodge Viper 8400 OEM minimum weight drops 50 lbs to 3275.
  • GT2 Request to Adjust Weight of OEM Chevrolet Corvette #28896weight -50 lbsfasterGT2 Chevrolet Corvette -2019 OEM minimum weight cut 50 lbs to 3275.
  • SRF3 SRF Shocks #28791wordingwordingSRF3 shock absorber brand restriction removed; all shocks must be sealed by Enterprises.
  • GT2 Request Corvette engine parity #28576weightfasterGT2 Corvette LS6 may reduce weight by 50 lbs.
  • SRF3 Update Bump Stop Rule #28712suspension & brakessuspension & brakesSRF3 bump stop now must be SCCA P/N 280407 only, no modifications, optional, max one per shock.
  • SRF3 SRF Bump Stop Correction #27019wordingwordingSRF shock absorber bump stop clarified: only SCCA P/N 280407 allowed as delivered, maximum one per shock, effective 05/01/2020.
  • GT2 Request to revisit Panoz GT-S BoP #28280wordingunclearGT2 Panoz GT-S now allowed to use TA2 Choice Engine with any 5-speed H-pattern transmission.
  • GT2 GT2-ST Corvette LS2 & L76 #28583inductionfasterGT2-ST Corvette LS2 restrictor increases from 70mm to 75mm flat plate.
  • GT2 GT2-ST Corvette L76 #28584cars addedcars addedGT2-ST Corvette L76 added: 5967cc, 3000 lbs minimum, 70mm flat plate restrictor.
  • GT2 Request 991.2 Porsche engine displacement verify typo #28194enginefasterGT2 Porsche 991.2 GT3 Cup Car engine displacement increases from 3.8L to 4.0L.
  • GT2 Windshield Clips #27323wordingwordingGT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications.
  • GT2 Request to Add Chevrolet SS Body to Appendix L #27898cars addedcars addedGT2 Chevrolet SS replaces Dodge Charger; all stock car bodies removed from GT2 in 2021.
  • GT2 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.
  • GT2 Porsche 991.2 GT3 Cup GT2 Classification #27701cars addedcars added991.2 GT3 Cup Car classified in GT2 at 3100 lbs with 63mm throttle body restrictor.
  • GT2 Request for Acura NSX Spec Line Changes #27755weightfasterGT2 Acura NSX minimum weight reduced from 3000 to 2700 lbs.
  • GT2 GT2 991.1 restrictor size change #27914inductionfasterGT2 Porsche 991.1 GT3 Cup restrictor size increases from 67 mm to 70 mm.
  • GT2 GT2 996/997.1 weight change #27915weight -100 lbsfasterGT2 Porsche 996/997.1 GT3 Cup minimum weight reduced 100 lbs, to 2800.
  • GT2 GT2/ST Corvette comp adjustment #27920inductionslowerGT2/ST Corvette -2019 5967cc restrictor reduced from 75 mm to 70 mm.
  • SRF3 SRF Rain / Brake Rule - BoD approved as follows #34958wordingwordingSRF rain and brake rule wording updated; supersedes GCR 9.3.32.B.2 effective 1/1/202 through 12/31/2024.
  • FE2 FE / FE2 Update Rules #27624weightslowerFE and FE2 minimum weight increased to 1270 lbs including driver; spring options and tire warmer ban added.
  • SRF3 SRF Tire Warmer Rule #27622tyres & wheelsslowerSRF bans tire warmers and cooling methods other than natural air convection or conduction.
  • SRF3 SRF / SRF3 Nose Weight Reduction #27706weightfasterSRF front nose weight minimum reduced from 35 to 32 lbs.
  • SRF3 SRF / SRF3 Majors & Regional Class Updates #27723wordingwordingSRF3 reclassified as Spec Racer Ford 3 with 1.6L conversion; SRF2 becomes Regional Only Class.
  • GT2 TA2 Weight Clarification #27077weightslowerGT2 TA2 cars must weigh minimum 2930 lbs per current Trans Am rules or prior Appendix L.
  • SRF3 SRF Dash Windscreen Kit #27028wordingwordingSRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102.
  • GT2 Request to classify Toyota Supra with 3SGTE engine #25185cars addedcars addedGT2 Toyota Supra 3SGTE newly classified at 2900 lbs minimum weight, 43mm restrictor.
  • GT2 Request to Classify Acura NSX from T1 to GT2? #26121cars addedcars addedAcura NSX All Years classified to GT2-ST: 3.5L turbo, 3000 lbs minimum, 43mm restrictor.
  • GT2 Request for TA2 BOP in GT2 #26509weightslowerGT2 TA2 minimum weight increases from 2830 to 2930 pounds.
  • SRF3 New SRF Sectional Nose Rule Addition #26914wordingwordingSRF3 nose assembly must use approved multi-piece design; no modifications allowed except as specified.
  • GT2 Request for e36/e46 bmw 4500 cc v8 at 2950lbs in GT2/ST #26106cars addedcars addedGT2 BMW E36/E46 4.5L V8 classified at 2950 lbs minimum weight.
  • GT2 Request GTX Fuel injection for previous GT-1 tube frame cars #26141inductionfasterGTX tube frame cars gain fuel injection with 90mm maximum throttle body size.
  • GT2 Request to Classify Ligier JS2 R #26535cars addedcars addedLigier JS2 R classified in GTX, no performance parameters specified in filing.
  • SRF3 SRF Brakes and Shock Rule Changes #26629wordingwordingSRF3 brakes now allow Hawk Blue 9012 pads P/N 801993 only; shocks simplified to Penske P/N 280396 sealed assembly only, with optional SCCA Enterprises bump rubber P/N 280407 from 05/01/2020.
  • GT2 Request Ford Perfomance 5.2L crate engine FPR clarification #26159cars addedcars addedGT2 Ford Mustang 5.2L classified at 3300 lbs minimum with 82mm single throttle body restrictor.
  • GT2 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.
  • GT2 Request Porsche Cayman year classification #26241wordingwordingGT2 Porsche Cayman model years change from 05-11 to 05-15.
  • GT2 GT2/ST Porsche Cayman engine #26250cars addedcars addedGT2 Porsche Cayman adds 4.0L engine with 65mm flat plate restrictor at 2700 lbs minimum weight.
  • GT2 ST/GT2 BMW Flossman Kit Clarification #22138wordingunclearGT2 BMW E46 M3, E36, Z3, and 5000cc V8 now permit Flossman body kit.
  • GT2 Request Clarification/Revision of Appendix L (2013 TA2 Rules) #25110otherfasterGT2 TA2 cars: wheels cost cap drops to $175 each, carbon fiber allowed on rear wing, engine setback maximum 21.75 inches (A-F) or 24 inches (G), various nomenclature and clarification updates.
  • GT2 Request to classify BMW E82 (1 series) into GT2 #25539cars addedcars addedBMW 1 Series E82 classified into GT2 with N52B30 engine, 2996 cc, 2140 lbs minimum weight.
  • GT2 2010 Cayman Street Tuner Into an STO Car,Addendum #25545weightfasterGT2 Porsche Cayman 05-11 base weight drops 75 lbs to 2800; adds STO/X51 motor notes.
  • GT2 Request - Classify Ford Performance 5.2l #25716cars addedcars addedGT2 Ford Mustang 05- with 5.2L Aluminator engine classified: 3400 lbs minimum weight, 2×41mm flat plate restrictor.
  • GT2 Add missing displacement, minimum weight. Remove #25765wordingwordingGT2 Porsche 996/997.1 GT3 Cup adds 3.6L displacement and 2900 lbs minimum weight; removes aftermarket exhaust header allowance for 996.
  • GT2 Request for Ford FP 350s Weight Reduction #25806weightfasterGT2 Ford Mustang FP350S minimum weight reduced 100 lbs, to 3400.
  • GT2 Request to Classify EcoBoost Mustang #25842cars addedcars addedGT2 Ford Mustang 05- EcoBoost classified: 3500cc, 3200 lbs minimum, 41mm restrictor.
  • GT2 Request to Remove Mazda RX 7 Body Work Penalty #26024weightfasterGT2 Mazda RX7 Downing GTS body kit allowed without 75 lbs. weight penalty.
  • GT2 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.

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.