BoP Lab / Buttonwillow Raceway Park

FE vs FM vs FB vs STL pace at Buttonwillow Raceway Park

Lap times across years say as much about the weather as the class. % of FE is each class's best lap as a share of FE'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: STL 1:54.845 Gavin Wardle, Super Tour Feb 2026 race

FEFMFBSTLsolid race · dashed qualifying · slower is lower

	Event	FE			FM					FB					STL
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs FE	% of FE	Qual best	Race best	Trap	vs FE	% of FE	Qual best	Race best	Trap	vs FE	% of FE
	Super Tour Feb 2026 CALCL262026-02-21														1:57.526Jared Korth · fastest of 10 · top 5 within 1.2s+2.563s (+2.23%)	1:54.845Gavin Wardle · fastest of 11 · top 5 within 4.7s-0.837s (-0.72%)	136.6Bryce Johnson+26.2 mph (+23.7%)
6 rule changes (FE: 3, STL: 3)4 weight · 1 engine · 1 othershowhide 2026-01-01 FE FE & FE2 Rule Updates #39484engine 2026-01-01 STL Weight adjustment for STL #39579weight 2025-10-01 FE FE & FE2 Bubble Tail #38978other 2025-09-01 FE FE & FE2 Rule Updates #38901weight 2025-08-01 STL Lotus Weight Reduction #38772weight -50 lbs 2025-05-01 STL E&O: SMX Allowance in STL #37945weight
	Super Tour Feb 2025 CALCL252025-02-22														1:54.963Nick Leverone · fastest of 16 · top 5 within 3.3s	1:55.682Nick Leverone · fastest of 17 · top 5 within 2.6s	110.4Ryan Gutile
68 rule changes (FE: 26, STL: 42)12 induction · 12 tyres & wheels · 8 suspension & brakes · 7 weight · 6 aero · 6 engine · 3 cars added · 5 wording · 9 othershowhide 2024-12-01 FE Brake Line to A-Arm Covers #37110suspension & brakes 2024-12-01 STL Request to Remove Miata Hubs from General category #37138tyres & wheels 2024-09-01 FE Protest Fee Clarification #36540wording 2024-09-01 FE Update on Letter 36620 with new Hoosier Contingency Decal Info #36625tyres & wheels 2024-08-01 FE Hoosier Tire Decal Placement #36435tyres & wheels 2024-02-01 STL ST Electric-Assisted Steering Systems #35066other 2024-02-01 STL BOP Adjustments #35112weight 2024-02-01 STL Mazda 12A #35320induction 2024-01-01 FE Update FE Rain Light Rule #34707other 2024-01-01 FE FE/FE2 rule update #35269other 2024-01-01 STL Alternate Carburetor Request for 79-85 RX7 12a #35181induction 2023-06-01 STL Clarify STL table B - IT spec notes on Tires #34187tyres & wheels 2023-04-01 FE Update FE SADEV Transmission Rule #33883other 2023-01-01 STL Spec MX5 in STL #33473tyres & wheels 2022-10-01 FE Brake bias adjuster clarification #33084suspension & brakes 2022-10-01 FE FE Front and Rear Wing Update & Clarification #33089aero 2022-09-01 FE Engine Heat Shield & Insulation #33019engine 2022-06-01 FE Update FE/FE2 Tire Rule #32613tyres & wheels 2022-06-01 FE Master cylinder clarification #32669engine 2022-03-01 STL Single TB Weight Modifiers #31449weight 2022-03-01 STL Improved Touring Tires #32063tyres & wheels 2022-01-01 STL Throttling Device Clarification #31323induction 2022-01-01 STL Mazda Renesis Restriction #31467induction 2022-01-01 STL Clarification of 79-85 RX7 Spec line #31621wording 2021-12-01 FE Two FE2 Rule Updates #31524other 2021-09-01 STL Request to clean up Spec MX-5 Redundancy #31069other 2021-07-01 FE FE Tire Rule Changes #30754tyres & wheels 2021-07-01 FE Radiator Screens Clarification #30792wording 2021-06-01 FE FE Radiator Screens #30575other 2021-06-01 STL VW Engine Request #30625engine 2021-05-01 STL Solstice Ride Height #30183suspension & brakes 2021-05-01 STL Request Mazda B5 DOHC #30420cars added 2021-05-01 STL Honda B16A (JDM) Restrictor change #30531induction 2021-04-01 STL ST Oil Coolers E&O Correction to 9.1.4.2.H #30388wording 2021-03-01 STL GM Ecotec engines in STL #30247engine 2021-03-01 STL Super Touring Alternate Miata Hubs #30345tyres & wheels 2021-02-01 STL Brake Component Relocation #29990suspension & brakes 2021-02-01 STL Super Touring Wing Clarification #30111aero 2021-02-01 STL Transmission Options #30118other 2021-01-01 STL Request for FWD and RWD Parity #29728weight 2021-01-01 STL Request to Remove Honda F20C 2% Weight Penalty #29815weight 2021-01-01 STL Request for FWD and RWD Parity #30023induction 2020-12-01 FE FE / FE2 Spring Updates #29689suspension & brakes 2020-12-01 STL Request clarification on wing measurement #29640aero 2020-10-01 FE FE Gurney Flap Spec Update #29445aero 2020-08-01 STL Minimum Weight Determination #27695weight 2020-08-01 STL ST Gurney flap Wicker clarification #29012aero 2020-07-01 STL Request for Addition to GT3 Approved Turbo List #27576induction 2020-06-01 FE FE Gurney flap wicker clarification #28885aero 2020-06-01 STL Request to add 2016-2019 GMX-5 Spec line #28604cars added 2020-06-01 STL Request to update PN for MX-5 #28622wording 2020-06-01 STL Correction - Clarification Honda/Acura B18B engine Letter # 26209 #28873engine 2020-05-01 FE FE spring rule update changed to November 1, 2020 #28814suspension & brakes 2020-05-01 STL STL Honda B18 restrictor changes #28794induction 2020-04-01 STL Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0 #27884engine 2020-04-01 STL Acura/Honda B18C engine chart. Reduce the current 54 mm flat plat #28663induction 2020-04-01 STL Mazda MZR engine chart. Reduce the current 55 mm flat plate to 53 #28664induction 2020-03-01 STL Request to add wheel part numbers #28342tyres & wheels 2020-01-01 FE Request for FE / FE2 preparation rules update #27722weight 2019-12-01 FE FE / FE2 Update Rules #27624weight 2019-10-01 FE FE Wet Tire E&O #27365tyres & wheels 2019-10-01 STL Request to Classify Spec MX-5 Challenge in STL #27399cars added 2019-07-01 FE FE Tire Update #27029tyres & wheels 2019-07-01 STL Request clarification for manifold and throttle in STU #27004induction 2019-05-31 FE FE Anti-Roll Bar Clarification #26912suspension & brakes 2019-05-31 FE FE / FE2 Updated Bubble Tail Rule #26913other 2019-05-31 STL Request Restrictor Plate correction #26779induction 2019-05-01 STL Request Ride Height Clarification #26597suspension & brakes
	Super Tour Apr 2019 ST19APR262019-04-26
8 earlier rule changes on record, in force before Super Tour Apr 2019 (from 2019)4 weight · 1 engine · 1 suspension & brakes · 1 tyres & wheels · 1 wordingshowhide 2019-03-01 FE Request to Update Hoosier Rain Tire Part Number for the FE cars #26235tyres & wheels 2019-03-01 STL Request to Allow VW 1.8L Engine #25614engine 2019-03-01 STL Request to reduce weight of RX8 with Renesis rotary #25781weight -100 lbs 2019-03-01 STL Request for Open Brake Pads On Mazda MX-5 Cup NC #25821suspension & brakes 2019-03-01 STL Request to clarify B18C1 GSR Honda B motor table #26209weight 2019-03-01 STL Port Matching #26415wording 2019-01-01 STL Request to equalize FPR Reduction on all B-Series Vtec Engines #24746weight 2019-01-01 STL Request E&O for Mazda Miata Spec Line #25955weight

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