BoP Lab / Buttonwillow Raceway Park

F6 vs FB vs FM vs GTL pace at Buttonwillow Raceway Park

Lap times across years say as much about the weather as the class. % of F6 is each class's best lap as a share of F6'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.

Quickest here: F6 1:59.670 Jeff Jorgenson, Super Tour Feb 2024 race · FB 1:38.870 Gary Hickman, Super Tour Apr 2018 race · FM 1:45.954 Mike Anderson, Super Tour Apr 2018 race · GTL 1:57.623 Brian Linn, Super Tour Feb 2022 race

% of F6Lap times

F6FBFMGTLsolid race · dashed qualifying · slower is lower

F6FBFMGTLsolid race · dashed qualifying · each class's best lap as a share of F6's at the same event (the reference class, changeable above); 100% is level, higher is quicker

	Event	F6			FB					FM					GTL
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs F6	% of F6	Qual best	Race best	Trap	vs F6	% of F6	Qual best	Race best	Trap	vs F6	% of F6
	Super Tour Feb 2024 CALCL242024-02-23	2:00.926Jeff Jorgenson · only car	1:59.670Jeff Jorgenson · only car	104.7Jeff Jorgenson											1:57.793Brian Linn · fastest of 3 · top 3 within 7.8s-1.723s (-1.44%)	1:59.526Brian Linn · fastest of 3 · top 3 within 8.6s+1.903s (+1.62%)	110.9Brian Linn-0.9 mph (-0.8%)	-0.144squal -3.133s	99.9%qual 97.4%
19 rule changes (GTL: 19)7 cars added · 4 engine · 3 weight · 1 aero · 4 wording · 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. · 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. · Fields Cardinal V8 added to GT1 with Ford V8 engine, 4.9L, 2100 lbs, fuel injection. · 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. · GT1, GT2, GT3, GTL, GTX tail lights may now be original style or custom panel graphic with functioning red LED brake lamps. · Ginetta G40 added to GTL with Ford Zetec 1796cc engine, 2050 lbs minimum weight, 22.5mm SIR.showhide 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 #35437engineadded · engineGT1, 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 #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. 2024-01-01 GTL Rotary Engine 12A Rotor Housings #35131engineadded · engineGTL 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. 2023-12-01 GTL Small Engines in GT Lite #34842weightfaster · weightGTL 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 lbsfaster · weightGTL Nissan Sentra/200SX A 1400 minimum weight reduced to 1800 lbs. 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. 2023-02-01 GTL Toyota 4Y Engine Classification Request #33562engineadded · engineGTL 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 #33297weightslower · weightGTL 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. 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. 2022-03-01 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.
	Super Tour Feb 2022 CALCL222022-02-17														1:59.516Brian Linn · fastest of 4 · top 4 within 10.6s+0.454s (+0.38%)	1:57.623Brian Linn · fastest of 5 · top 5 within 12.5s-0.646s (-0.55%)	111.8Brian Linn-13.9 mph (-11.0%)
22 rule changes (GTL: 22)5 aero · 5 cars added · 3 induction · 1 weight · 7 wording · 1 other · GT3 Volkswagen Fun Cup Beetle EVO3 classified, sealed SOHC 1984cc engine, 2060 lbs minimum weight. · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two locations and 6010 to 6014X in TA2 Appendix. · 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 · GTL Mazda 12A SIR increases to 29mm, minimum weight rises to 2000 lbs, 28mm SIR option with 175 lb penalty removed. · 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. · 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. · 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.showhide 2021-10-01 GTL Request car classification #31032cars addedaddedGT3 Volkswagen Fun Cup Beetle EVO3 classified, sealed SOHC 1984cc engine, 2060 lbs minimum weight. 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. 2021-07-01 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 #30504aeroadded · aeroGTL 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 2021-03-01 GTL Request for Help for Mazda 12A #29754induction +50 lbsslower · inductionGTL Mazda 12A SIR increases to 29mm, minimum weight rises to 2000 lbs, 28mm SIR option with 175 lb penalty removed. 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 #29867inductionfaster · inductionGTL Mazda 13B SIR increases from 26 mm to 28 mm; 27 mm option with 175 lbs removed. 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 lbsfaster · inductionGTL 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 #28754aeroadded · aeroGTL wing mount openings excluded from square inch area limit. 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 #28243aerofaster · aeroGTL 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 lbsfaster · weightGTL Mazda 12A street port minimum weight drops to 1950 lbs.
	Super Tour Feb 2020 ST20FEB212020-02-21														1:59.062Joe Huffaker · fastest of 5 · top 5 within 10.7s-1.294s (-1.08%)	1:58.269Joe Huffaker · fastest of 5 · top 5 within 13.1s-1.806s (-1.50%)	125.6Joe Huffaker+15.1 mph (+13.6%)
11 rule changes (GTL: 11)5 cars added · 2 engine · 1 suspension & brakes · 2 wording · 1 other · 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. · GTL Honda CRX 84-87 and 88-91 lose permission to use IRS with 2.5% weight penalty. · 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. · 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.showhide 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. 2019-12-01 GTL 88-91 Honda CRX Spec Line Correction #27233suspension & brakesremoved · suspension & brakesGTL Honda CRX 84-87 and 88-91 lose permission to use IRS with 2.5% weight penalty. 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. 2019-05-01 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 #26141engineadded · engineGTX 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 #26572engineadded · engineGTL Mazda 13B may use 25mm SIR with 175 lbs weight penalty added.
	Super Tour Apr 2019 ST19APR262019-04-26									1:49.608Mike Anderson · fastest of 3 · top 3 within 5.6s+3.285s (+3.09%)	1:49.409Mike Anderson · fastest of 3 · top 3 within 4.9s+3.455s (+3.26%)	121.2Mike Anderson			2:00.356Joe Huffaker · fastest of 2+1.537s (+1.29%)	2:00.075Joe Huffaker · fastest of 2+1.716s (+1.45%)	110.6Taz Harvey
6 rule changes (GTL: 6)1 cars added · 1 induction · 1 removed · 1 weight · 1 wording · 1 other · 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 2019-04-01 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 #26081inductionadded · inductionGTL 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 #25754weightfaster · weightGTL 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.
	Super Tour Apr 2018 BUTTRA182018-04-27				1:39.142Gary Hickman · fastest of 2-3.130s (-3.06%)	1:38.870Gary Hickman · fastest of 2-1.241s (-1.24%)				1:46.323Mike Anderson · fastest of 9 · top 5 within 2.1s+0.367s (+0.35%)	1:45.954Mike Anderson · fastest of 9 · top 5 within 3.3s-0.317s (-0.30%)				1:58.819Joe Huffaker · fastest of 4 · top 4 within 11.5s-6.719s (-5.35%)	1:58.359Joe Huffaker · fastest of 5 · top 5 within 10.8s-7.836s (-6.21%)
No rule changes on record between these events
	Super Tour Apr 2017 BUTTRA172017-04-28				1:42.272John LaBrie · fastest of 2	1:40.111Gary Hickman · fastest of 2				1:45.956Mike Anderson · fastest of 8 · top 5 within 2.0s	1:46.271Mike Anderson · fastest of 10 · top 5 within 2.1s				2:05.538John Bower · fastest of 4 · top 4 within 7.0s	2:06.195Bill Okell · fastest of 4 · top 4 within 6.1s

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. "% of F6" is the class's best as a share of F6'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 F6'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.