BoP Lab / Classes / FM

FM vs SRF vs F500 vs GTL pace at every track

Lap times across years say as much about the weather as the class. % of FM is each class's best lap as a share of FM's on the same day, so the conditions drop out: 100% is level, less is quicker, and a move in it is the class getting faster or slower against the field.

Class · click a class to switch, + to compare alongside (up to 4: remove one to add another)

ASB-SpecEPvsF500 ×FAFCFE2FFFM×FPFVFXGT1GT2vsGTL ×GTXHPPP2SMSMXvsSRF ×SRF3STLSTUT1T2T3T4Show 47 inactive classes

Series Runoffs Super Tour Both

Reference class · the yardstick the % column and chart are measured against

Tracks · untick to narrow Auto Club Speedway Blackhawk Farms Raceway Buttonwillow Raceway Park Circuit of St. Louis (formerly Gateway Motorsports Circuit of the Americas Daytona International Speedway Grattan Raceway Hallett Motor Racing Circuit Homestead-Miami Speedway Indianapolis Motor Speedway Laguna Seca Michelin Raceway Road Atlanta Mid-Ohio Sports Car Course New Jersey Motorsports Park NOLA Motorsports Park Pacific Raceways Pittsburgh International Race Complex Portland International Raceway Pueblo Motorsports Park Road America Sebring International Raceway Sonoma Raceway Summit Point Raceway Thunderhill Raceway Park Virginia International Raceway Watkins Glen International Willow Springs Raceway World Wide Technology Raceway

Closest to the field: FM 100.0% of FM Joseph Burton-Harris, Daytona International Speedway Runoffs 2015 race · SRF 110.2% of FM Thomas Kirchman, Indianapolis Motor Speedway Runoffs 2017 qualifying · GTL 94.1% of FM Bill Ball, Virginia International Raceway Runoffs 2019 race

% of FMLap times

FMSRFF500GTLsolid race · dashed qualifying · slower is lower

FMSRFF500GTLsolid race · dashed qualifying · each class's best lap as a share of FM's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker

	Event	FM			SRF					F500					GTL
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs FM	% of FM	Qual best	Race best	Trap	vs FM	% of FM	Qual best	Race best	Trap	vs FM	% of FM
	Road America Runoffs 20242024-10-01														2:30.858Peter Shadowen · fastest of 14 · top 5 within 4.4s-1.085s (-0.71%)	2:30.844Chris Bovis · fastest of 13 · top 5 within 3.7s-0.757s (-0.50%)	133.3Peter Shadowen+1.8 mph (+1.4%)
26 rule changes (SRF: 10, GTL: 16)5 cars added · 3 engine · 3 weight · 2 suspension & brakes · 1 aero · 1 induction · 1 tyres & wheels · 6 wording · 4 other · 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. · GTL adds Toyota GR86 2021–2023, 2dr RWD, 101.3 in wheelbase. · GTL adds Spec Miata 1990–2005 with legal Spec Miata engine and intake system. · GTL adds Mazda MX5 RF 2017- model with 91.0 in wheelbase. · 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. · GTL added to GT3 choke option line in GCR 9.1.2.E.13.n. · GT2-ST Acura NSX minimum weight rises to 3000 lbs, restrictor increases to 45mm TIR. · GTL Datsun 510 Limited Prep fuel induction increased to 34 mm chokes, minimum weight rises to 2000 lbs. · 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. · GTL 12A rotary engines may machine and use 13B housing to O.E. 12A spec across all port types. · GTL Toyota DR86 2021–2024 added to class. · GTL BMW Mini model years changed to 2002-2013. · 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 small unrestricted engines under 1399cc lose 38–79 lbs across Alfa, AMC, Triumph, Mini, Sprite, Fiat, Ford, Honda, Mazda, Nissan, Subaru, Toyota, Volkswagen. · GTL Honda Fit 2009-13 2-door FWD added with 99.0 in wheelbase, alternate 94.0 and 97.0 in. · 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. · GTL Nissan Sentra/200SX A 1400 minimum weight reduced to 1800 lbs. · SRF radiator options expanded: Enterprises P/N 480465 with baffle 480464, 480466, or Automotive 1R698 and CU698 allowed if cross-reference equivalent.showhide 2024-10-01 SRF Update SRF3 Air Filter Rule #36681wordingremovedSRF3 air filter rule removes K&N RC-9160 option, specifies Weems P/N WM301020 only. 2024-10-01 SRF Update SRF Brake Rotor Thickness #36687suspension & brakessuspension & brakesSRF Wilwood vented rotor minimum thickness increases to 13.25mm, 0.522 inches. 2024-10-01 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. 2024-09-01 GTL Request to Include Toyota GR86 in GTL #36324cars addedaddedGTL adds Toyota GR86 2021–2023, 2dr RWD, 101.3 in wheelbase. 2024-09-01 GTL Inclusion of Modified Spec Miata for GTL competition #36325cars addedaddedGTL adds Spec Miata 1990–2005 with legal Spec Miata engine and intake system. 2024-09-01 GTL Include Mazda MX5 RF 2017- in GTL #36428cars addedaddedGTL adds Mazda MX5 RF 2017- model with 91.0 in wheelbase. 2024-09-01 SRF Protest Fee Clarification #36540wordingwordingFE and SRF protest fee rules redirected to GCR section 8.3.1.D for fees and procedure. 2024-09-01 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. 2024-08-01 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. 2024-07-01 GTL Add GTL to GT3 choke option line. #36236otheraddedGTL added to GT3 choke option line in GCR 9.1.2.E.13.n. 2024-05-01 GTL Request for Spec Line 1010 Reconsideration #35009weight +300 lbsslowerweightGT2-ST Acura NSX minimum weight rises to 3000 lbs, restrictor increases to 45mm TIR. 2024-05-01 GTL Allow 34 mm chokes for the Datsun 510 #35661induction +50 lbsfasterinductionGTL Datsun 510 Limited Prep fuel induction increased to 34 mm chokes, minimum weight rises to 2000 lbs. 2024-02-01 GTL 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. 2024-02-01 GTL GT Direct Injection allowance and rules #35437engineaddedengineGT1, GT2, GT3, GTL, GTX Direct Injection now permitted if original equipment. 2024-02-01 GTL GT2/3 remove Direction Injection not allowed in Spec line notes #35439engineaddedengineGT2 Nissan and GT3 Mazda, Mitsubishi 4G93, Nissan QR25DE/DD, QE25DE/DD now permit Direct Injection per 9.1.2.F.7.5.E. 2024-01-01 GTL Rotary Engine 12A Rotor Housings #35131engineaddedengineGTL 12A rotary engines may machine and use 13B housing to O.E. 12A spec across all port types. 2024-01-01 GTL Request to Include Toyota GR86 in GTL #35198cars addedaddedGTL Toyota DR86 2021–2024 added to class. 2024-01-01 GTL Errors and Omissions, GTL engines & Cars #35226wordingwordingGTL BMW Mini model years changed to 2002-2013. 2024-01-01 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. 2024-01-01 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. 2024-01-01 SRF SRF / SRF3 Rule Updates #35268suspension & brakessuspension & brakesSRF 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. 2023-12-01 GTL Small Engines in GT Lite #34842weightfasterweightGTL small unrestricted engines under 1399cc lose 38–79 lbs across Alfa, AMC, Triumph, Mini, Sprite, Fiat, Ford, Honda, Mazda, Nissan, Subaru, Toyota, Volkswagen. 2023-12-01 GTL Request to Classify Honda Fit body in GTL #35020cars addedaddedGTL Honda Fit 2009-13 2-door FWD added with 99.0 in wheelbase, alternate 94.0 and 97.0 in. 2023-12-01 GTL 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. 2023-11-01 GTL Weight for Nissan Sentra/200SX A 1400's #34918weight -50 lbsfasterweightGTL Nissan Sentra/200SX A 1400 minimum weight reduced to 1800 lbs. 2023-10-01 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.
	Virginia International Raceway Runoffs 20232023-09-23														2:09.564Peter Shadowen · fastest of 11 · top 5 within 4.9s+1.775s (+1.39%)	2:11.277Graham Fuller · fastest of 10 · top 5 within 2.4s-9.903s (-7.01%)	142.7Peter Shadowen+6.7 mph (+4.9%)
10 rule changes (SRF: 3, GTL: 7)4 cars added · 2 engine · 2 tyres & wheels · 1 weight · 1 wording · 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. · 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. · GTL 3K, 4K, 5K Toyota engines may now use 4Y block only. · GT2 and GTL add Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines as permitted options. · GTL Fiat X1/9 1500 Limited Prep minimum weight increases to 2000 lbs from 1835 lbs. · GT2 TA2 and GTA throttle body part numbers updated to GM 12570790 or Edelbrock 33869/3870. · GTL adds Ford Festiva 1988-1993 FWD hatchback with Mazda B3 1324cc engine. · GTL adds Toyota G16E-GTS 1618cc DOHC 3-cyl engine, 1945 lbs, SIR, no turbo or direct injection.showhide 2023-06-01 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. 2023-05-01 GTL Please classify Fields Cardinal V8 #33784cars addedaddedFields Cardinal V8 added to GT1 with Ford V8 engine, 4.9L, 2100 lbs, fuel injection. 2023-05-01 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. 2023-03-01 SRF Update SRF Brake Rule #33469enginefasterengineSRF 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. 2023-02-01 GTL Toyota 4Y Engine Classification Request #33562engineaddedengineGTL 3K, 4K, 5K Toyota engines may now use 4Y block only. 2023-01-01 GTL Toyota 4A-F and 4A-FE 1.6L DOHC 16V Engine Request #33415cars addedaddedGT2 and GTL add Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines as permitted options. 2022-12-01 GTL Fiat HP Limited Prep X1/9 Weight in GTL #33297weightslowerweightGTL Fiat X1/9 1500 Limited Prep minimum weight increases to 2000 lbs from 1835 lbs. 2022-12-01 GTL GT2 (TA2)/GTA Part Number Update #33315wordingwordingGT2 TA2 and GTA throttle body part numbers updated to GM 12570790 or Edelbrock 33869/3870. 2022-12-01 GTL Request to add Ford Festiva to GTL #33335cars addedaddedGTL adds Ford Festiva 1988-1993 FWD hatchback with Mazda B3 1324cc engine. 2022-11-01 GTL Engine Request #33064cars addedaddedGTL adds Toyota G16E-GTS 1618cc DOHC 3-cyl engine, 1945 lbs, SIR, no turbo or direct injection.
	Virginia International Raceway Runoffs 20222022-09-24														2:07.789Peter Shadowen · fastest of 14 · top 5 within 2.2s+0.792s (+0.62%)	2:21.180Michael Lewis · fastest of 13 · top 5 within 2.1s+13.343s (+10.44%)	136.0Peter Shadowen+4.9 mph (+3.7%)
6 rule changes (SRF: 3, GTL: 3)2 cars added · 2 wording · 2 other · GT1, GT2, GT3, GTL, GTX tail lights may now be original style or custom panel graphic with functioning red LED brake lamps. · 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. · Ginetta G40 added to GTL with Ford Zetec 1796cc engine, 2050 lbs minimum weight, 22.5mm SIR. · 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.showhide 2022-09-01 GTL 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. 2022-06-01 SRF SRF Tire Rule Update #32614wordingwordingSRF tire rule wording clarified: tires must be run as delivered. 2022-06-01 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. 2022-03-01 GTL Request to Classify Ginetta G40 in GTL #31599cars addedaddedGinetta G40 added to GTL with Ford Zetec 1796cc engine, 2050 lbs minimum weight, 22.5mm SIR. 2021-12-01 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… 2021-10-01 GTL Request car classification #31032cars addedaddedGT3 Volkswagen Fun Cup Beetle EVO3 classified, sealed SOHC 1984cc engine, 2060 lbs minimum weight.
	Indianapolis Motor Speedway Runoffs 20212021-09-25														1:51.819Christopher Bovis · fastest of 22 · top 5 within 1.8s+1.488s (+1.35%)	1:51.952Scott Twomey · fastest of 19 · top 5 within 1.7s-0.116s (-0.10%)	129.5Brian Linn
14 rule changes (SRF: 6, GTL: 8)4 cars added · 2 induction · 1 aero · 1 engine · 1 tyres & wheels · 3 wording · 2 other · 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. · GTL Honda B18 split into B18A/B at 1797 cc 2050 lbs and B18C at 1834 cc 2065 lbs. · GTL Nissan B13 Sentra may have hood bulge maximum 1.5 inches high by 10.0 long by 6.0 wide. · unclear · SRF3 alternator pulley specified as P/N G902130 or G902130A, minimum 12oz. · GTL Mazda 12A SIR increases to 29mm, minimum weight rises to 2000 lbs, 28mm SIR option with 175 lb penalty removed. · SRF and SRF3 mandatory identification revised: removed Ford Performance and Blue Oval decals, added Hoosier logo placement. · GTL adds FIAT X-1/9 Bertone 1500 SOHC, 1498 cc, 2000 lbs, fuel injection or carburetors permitted. · GTL Nissan MRA8DE 1.8L engine added, 1797 cc, DOHC, 2050 lbs minimum weight. · GTL Mazda 13B SIR increases from 26 mm to 28 mm; 27 mm option with 175 lbs removed. · SRF rear springs limited to P/N 280390 only, previous part numbers no longer allowed; ground clearance wording clarified.showhide 2021-08-01 GTL 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. 2021-08-01 SRF SRF Wet Tires #30849tyres & wheelsaddedtyres & wheelsSRF wet tyres add Hoosier W2 option alongside existing H20 from October 4, 2021. 2021-08-01 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. 2021-08-01 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. 2021-07-01 GTL Request clarification for the Honda B18a,bVS B18c #30482cars addedaddedGTL Honda B18 split into B18A/B at 1797 cc 2050 lbs and B18C at 1834 cc 2065 lbs. 2021-07-01 GTL Request to Allow Hood Bulge on Nissan B13 Sentra #30504aeroaddedaeroGTL Nissan B13 Sentra may have hood bulge maximum 1.5 inches high by 10.0 long by 6.0 wide. 2021-07-01 GTL Request BMW E21 Classing #30582otherunclearunclear 2021-06-01 SRF SRF3 Alternator Pulley #30684engineaddedengineSRF3 alternator pulley specified as P/N G902130 or G902130A, minimum 12oz. 2021-03-01 GTL Request for Help for Mazda 12A #29754induction +50 lbsslowerinductionGTL Mazda 12A SIR increases to 29mm, minimum weight rises to 2000 lbs, 28mm SIR option with 175 lb penalty removed. 2021-03-01 SRF Mandatory identification: #30223wordingwordingSRF and SRF3 mandatory identification revised: removed Ford Performance and Blue Oval decals, added Hoosier logo placement. 2021-02-01 GTL Request LP HP Fiat X1/9 & Bertone 1500 to GTL #30058cars addedaddedGTL adds FIAT X-1/9 Bertone 1500 SOHC, 1498 cc, 2000 lbs, fuel injection or carburetors permitted. 2021-01-01 GTL Please Add GTL Nissan 1.8L Engine MRA8DE #29805cars addedaddedGTL Nissan MRA8DE 1.8L engine added, 1797 cc, DOHC, 2050 lbs minimum weight. 2021-01-01 GTL Increase 13b SIR size #29867inductionfasterinductionGTL Mazda 13B SIR increases from 26 mm to 28 mm; 27 mm option with 175 lbs removed. 2020-12-01 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.
	Road America Runoffs 20202020-10-02														2:31.943Chris Bovis · fastest of 14 · top 5 within 6.3s	2:31.601Peter Shadowen · fastest of 14 · top 5 within 7.2s	131.4Peter Shadowen
22 rule changes (SRF: 5, GTL: 17)4 aero · 3 cars added · 2 weight · 1 induction · 1 suspension & brakes · 1 tyres & wheels · 9 wording · 1 other · GT1/GT2/GT3/GTL/GTX turbocharging and supercharging now permitted if listed on spec line. · GTL Mazda 13B restrictor increases from 24mm to 26mm SIR, minimum weight rises to 2125 lbs, alternative 27mm SIR option adds 175 lbs. · GTL: Toyota MR2 Spyder 1999–2007 newly classified for GTL competition. · 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. · GT Gurney flap wording clarified: wickerbill and tab terminology replaced with Gurney flap throughout sections 9.1.2.F.7.b. · GTL Mazda 13B restrictor size addressed in response to letter 28518; see that letter for details. · GTL SIR stall test procedure clarified: system tested as raced, competitor must prevent air bypass behind restrictor. · GTL wing mount openings excluded from square inch area limit. · SRF Penske shock P/N 280396 bump stop P/N 280407 becomes mandatory, maximum one per shock, effective 05/01/2020. · GTL wing mounting posts limited to 85 square inches exposed area each, measured flat from side view. · GTL wing mounting posts limited to 85 square inches each, measured flat from side view. · GTL wing endplates maximum area increased to 64 square inches from 8.5 by 3.0 inches rectangle. · GTL Mazda 12A street port minimum weight drops to 1950 lbs. · GT1, GT2, GT3, GTL, GTX may use bonded-glass factory windshields without clips or straps if attached per original specifications. · 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. · GTL adds Jetta Mk1 two-door classification effective 2020-01-01. · SRF rain and brake rule supersedes GCR 9.3.32.B.2 effective 1/1/2024 through 12/31/2024. · GTL Honda CRX 84-87 and 88-91 lose permission to use IRS with 2.5% weight penalty. · 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.showhide 2020-09-01 GTL GT Category Wording #29193wordingaddedGT1/GT2/GT3/GTL/GTX turbocharging and supercharging now permitted if listed on spec line. 2020-08-01 GTL Request to change the Mazda 13b restrictor size #28518induction +175 lbsfasterinductionGTL Mazda 13B restrictor increases from 24mm to 26mm SIR, minimum weight rises to 2125 lbs, alternative 27mm SIR option adds 175 lbs. 2020-07-01 GTL Request to classify 1999-2007 Toyota MR2 Spyder body #28870cars addedaddedGTL: Toyota MR2 Spyder 1999–2007 newly classified for GTL competition. 2020-07-01 GTL TA2 Gurney flap wicker clarification #28874wordingwordingTA2 Gurney flap wording clarified: replace 'wicker bill' and 'wicker' with 'Gurney flap' throughout wing specifications. 2020-07-01 GTL STO Gurney flap wicker clarification #28883wordingwordingSTO rear wing rules clarify that wicker is called Gurney flap in two places; no performance change. 2020-07-01 GTL 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. 2020-07-01 GTL Mazda 13b Restrictor Size Follow up to Letter 28518 #29015wordingunclearGTL Mazda 13B restrictor size addressed in response to letter 28518; see that letter for details. 2020-06-01 GTL Stall Test #28709wordingwordingGTL SIR stall test procedure clarified: system tested as raced, competitor must prevent air bypass behind restrictor. 2020-05-01 GTL GTL Wing Rule #28754aeroaddedaeroGTL wing mount openings excluded from square inch area limit. 2020-05-01 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. 2020-03-01 GTL Wing Mounting Upright Size #27641aeroaeroGTL wing mounting posts limited to 85 square inches exposed area each, measured flat from side view. 2020-03-01 GTL Wing Mounting Upright Size #27641aeroaeroGTL wing mounting posts limited to 85 square inches each, measured flat from side view. 2020-03-01 GTL GTL wing end plates addition #28243aerofasteraeroGTL wing endplates maximum area increased to 64 square inches from 8.5 by 3.0 inches rectangle. 2020-03-01 GTL Clarification to letter #27406 #28309weight -50 lbsfasterweightGTL Mazda 12A street port minimum weight drops to 1950 lbs. 2020-02-01 GTL Windshield Clips #27323otheraddedGT1, GT2, GT3, GTL, GTX may use bonded-glass factory windshields without clips or straps if attached per original specifications. 2020-01-01 GTL 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. 2020-01-01 GTL Request to Classify the MK1 two door Jetta #27648cars addedaddedGTL adds Jetta Mk1 two-door classification effective 2020-01-01. 202-01-01 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. 2019-12-01 GTL 88-91 Honda CRX Spec Line Correction #27233suspension & brakesremovedsuspension & brakesGTL Honda CRX 84-87 and 88-91 lose permission to use IRS with 2.5% weight penalty. 2019-12-01 SRF SRF Tire Warmer Rule #27622tyres & wheelstyres & wheelsSRF adds tire warmer prohibition and specifies Hoosier dry and wet tire part numbers. 2019-12-01 SRF SRF / SRF3 Nose Weight Reduction #27706weightfasterweightSRF front nose weight minimum reduced from 35 to 32 lbs. 2019-12-01 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.
	Virginia International Raceway Runoffs 20192019-10-05	1:55.124Bryce Cornet · fastest of 8 · top 5 within 2.3s	2:15.816Bryce Cornet · fastest of 8 · top 5 within 4.9s	135.7Bryce Cornet											2:06.997Peter Shadowen · fastest of 19 · top 5 within 4.0s	2:07.837Bill Ball · fastest of 18 · top 5 within 4.2s	131.1Peter Shadowen	-7.979squal +11.873s	94.1%qual 110.3%
14 rule changes (SRF: 1, GTL: 13)4 cars added · 2 engine · 1 aero · 1 induction · 1 removed · 1 weight · 3 wording · 1 other · GTL Fun Cup Beetle engine weight set to 1850 lbs with Weber DMTL 32/34 induction. · GTL Fun Cup Beetle removes reference to VW engine table; Fun Cup engines only permitted. · GTL Honda CRZ 10-14, CRZ 15-16, and Insight 00-06 gain alternate wheelbase option of 90.6 inches. · SRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102. · GTL Fun Cup Beetle added, all model years, 2-door RWD, 94.5 in wheelbase, VW Fun Cup spec chassis. · GTX tube frame cars now allowed fuel injection with maximum 90mm throttle body. · GTX adds Ligier JS2 R classification with restrictor and minimum weight. · GTL Mazda 13B may use 25mm SIR with 175 lbs weight penalty added. · GT1 and GT2/3/Lite remove ride height ground clearance rules; cars may now touch ground when tires deflate. · GTL Mazda 12A may use 28mm SIR plus 175 lbs. · GTL: Ford Mustang 94-04 body newly classified for GTL racing. · GTL Mini 1275–1399 Iron and Aluminum Crossflow with OE common sump gearbox reduce weight by 125 lbs, up from 50 lbs. · GTL BMC thru Rover Group removes four long inactive Mini engines: 948, 970, 1071, 1098. · 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 2019-08-31 GTL Fun Cup Beetle #27334wordingwordingGTL Fun Cup Beetle engine weight set to 1850 lbs with Weber DMTL 32/34 induction. 2019-08-01 GTL GTL #26960wordingwordingGTL Fun Cup Beetle removes reference to VW engine table; Fun Cup engines only permitted. 2019-07-01 GTL Request CRZ wheelbase change #26896cars addedaddedGTL Honda CRZ 10-14, CRZ 15-16, and Insight 00-06 gain alternate wheelbase option of 90.6 inches. 2019-07-01 SRF SRF Dash Windscreen Kit #27028aeroaddedaeroSRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102. 2019-05-01 GTL Request to Classify VW Fun Cup Beetle #25986cars addedaddedGTL Fun Cup Beetle added, all model years, 2-door RWD, 94.5 in wheelbase, VW Fun Cup spec chassis. 2019-05-01 GTL Request GTX Fuel injection for previous GT-1 tube frame cars #26141engineaddedengineGTX tube frame cars now allowed fuel injection with maximum 90mm throttle body. 2019-05-01 GTL Request to Classify Ligier JS2 R #26535cars addedaddedGTX adds Ligier JS2 R classification with restrictor and minimum weight. 2019-05-01 GTL Request for GTL Mazda 13B SIR Increase with Penalty #26572engineaddedengineGTL Mazda 13B may use 25mm SIR with 175 lbs weight penalty added. 2019-04-01 GTL Request Ride Height Clarification #26600wordingfasterGT1 and GT2/3/Lite remove ride height ground clearance rules; cars may now touch ground when tires deflate. 2019-03-01 GTL Request Mazda 12a Rotary SIR Increase #26081inductionaddedinductionGTL Mazda 12A may use 28mm SIR plus 175 lbs. 2019-03-01 GTL Request to Classify Mustang 2 Body in GTL #26222cars addedaddedGTL: Ford Mustang 94-04 body newly classified for GTL racing. 2019-01-01 GTL Request for GTL Mini Adjustments #25754weightfasterweightGTL Mini 1275–1399 Iron and Aluminum Crossflow with OE common sump gearbox reduce weight by 125 lbs, up from 50 lbs. 2019-01-01 GTL BMC thru Rover Group remove long inactive mini #25771removedremovedGTL BMC thru Rover Group removes four long inactive Mini engines: 948, 970, 1071, 1098. 2019-01-01 GTL 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.
	Sonoma Raceway Runoffs 20182018-10-10	1:37.598Bryce Cornet · fastest of 13 · top 5 within 0.9s	1:37.909Bryce Cornet · fastest of 12 · top 5 within 1.3s	124.1Melvin David Kemper Jr											1:47.885Troy Ermish · fastest of 20 · top 5 within 4.5s	1:49.458Troy Ermish · fastest of 19 · top 5 within 3.6s	109.3Charles Leonard	+11.549squal +10.287s	111.8%qual 110.5%
No rule changes on record between these events
	Indianapolis Motor Speedway Runoffs 20172017-09-25	1:41.231Jarret Voorhies · fastest of 16 · top 5 within 1.7s	1:41.146Jarret Voorhies · fastest of 16 · top 5 within 1.2s		1:51.573Thomas Kirchman · fastest of 50 · top 5 within 2.8s	1:53.769Todd Harris · fastest of 45 · top 5 within 0.2s		+12.623squal +10.342s	112.5%qual 110.2%						1:50.331Christopher Bovis · fastest of 26 · top 5 within 1.5s	1:52.068Christopher Bovis · fastest of 20 · top 5 within 1.0s		+10.922squal +9.100s	110.8%qual 109.0%
No rule changes on record between these events
	Mid-Ohio Sports Car Course Runoffs 20162016-09-19	1:26.043Jacob Loomis · fastest of 8 · top 5 within 3.1s	1:27.922Jacob Loomis · fastest of 8 · top 5 within 2.7s		1:37.344Mike Miserendino · fastest of 27 · top 5 within 0.8s	1:37.621Todd Harris · fastest of 27 · top 5 within 0.6s		+9.699squal +11.301s	111.0%qual 113.1%						1:35.377Wilson Wright · fastest of 28 · top 5 within 1.2s	1:35.912Kyle Disque · fastest of 28 · top 5 within 1.1s		+7.990squal +9.334s	109.1%qual 110.8%
No rule changes on record between these events
	Daytona International Speedway Runoffs 20152015-09-21	1:57.804Joseph Burton-Harris · fastest of 10 · top 5 within 2.3s	1:58.029Joseph Burton-Harris · fastest of 10 · top 5 within 1.7s		2:14.306Cliff White · fastest of 39 · top 5 within 1.2s	2:16.700Cliff White · fastest of 38 · top 5 within 0.5s		+18.671squal +16.502s	115.8%qual 114.0%						2:11.387Jim Dentici · fastest of 10 · top 5 within 2.2s	2:13.564Jim Dentici · fastest of 9 · top 5 within 2.0s		+15.535squal +13.583s	113.2%qual 111.5%

By track

Track	Events	Typical % of FM	Best	Latest
Virginia International Raceway	3	100.0%1 of 3 with FM	100.0%Runoffs 2019	100.0%Runoffs 2019
Indianapolis Motor Speedway	2	100.0%1 of 2 with FM	100.0%Runoffs 2017	100.0%Runoffs 2017
Road America	2	0 of 2 with FM
Daytona International Speedway	1	100.0%	100.0%Runoffs 2015	100.0%Runoffs 2015
Mid-Ohio Sports Car Course	1	100.0%	100.0%Runoffs 2016	100.0%Runoffs 2016
Sonoma Raceway	1	100.0%	100.0%Runoffs 2018	100.0%Runoffs 2018

About this data

Every event the class ran, at any track, oldest to newest on the chart and newest first in the table. Each point is the class's best lap as a share of FM's best on the same day: the weather and the day cancel out, so one figure compares across years where lap times cannot; a class that suits one track more than another still reads differently there. It still moves when the yardstick's own balance changes or its field thins, and an event the yardstick did not run has no point. A best from fewer than three cars is greyed. The rule changes that took effect between two events are folded between their rows.