BoP Lab / Buttonwillow Raceway Park

FF vs GT3U pace at Buttonwillow Raceway Park

Quickest here: FF 1:51.118 Eric Poulsen, Cal Club 2025 race · GT3U 1:55.650 Michael Lewis, Cal Club 2025 race

Lap times% of FF

FFGT3Usolid race · dashed qualifying · slower is lower

FFGT3Usolid race · dashed qualifying · each class's best lap as a share of FF's at the same event (the reference class, changeable above); 100% is level, higher is quicker

	Event	FF			GT3U
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs FF	% of FF
	Cal Club 2026 CALCL262026-02-21	1:53.098Edward Erlandson · fastest of 2+1.054s (+0.94%)	1:54.741Edward Erlandson · fastest of 2+3.623s (+3.26%)	133.7Edward Erlandson+19.0 mph (+16.5%)
6 rule changes (FF: 3, GT3U: 3)3 weight · 2 tyres & wheels · 1 wording · FF clarifies alternative tire eligibility for cars homologated 1989 or earlier with rocker arm or outboard suspension on all four corners. · FF adds rocker arm and outboard suspension cars optional bias ply and VFF tires; removes front-as-rear rule, adds mixing restrictions. · STU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments. · STU-GT3U non-TCR cars may reduce weight by 4% after all other modifiers. · FF allows older cars with rocker arm or outboard suspension to use bias ply slicks or VFF tires instead of radials. · STU GT3U minimum weight increases 150 to 250 pounds.showhide 2026-01-01 FF Formula F Alternative Tire Rule Proposed Clarifications #39281wordingneutralFF clarifies alternative tire eligibility for cars homologated 1989 or earlier with rocker arm or outboard suspension on all four corners. 2025-05-01 FF Page 228, FF tire rule 9.1.1.10.e #38251tyres & wheelsneutralFF adds rocker arm and outboard suspension cars optional bias ply and VFF tires; removes front-as-rear rule, adds mixing restrictions. 2025-05-01 GT3U Table C: STU-GT3U Clarification #38268weightfasterSTU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments. 2025-04-01 GT3U TCR Rulesets #37981weightfasterSTU-GT3U non-TCR cars may reduce weight by 4% after all other modifiers. 2025-03-01 FF Formula F Proposal to Invite Older Cars Via a Tire Rule Change #37802tyres & wheelsfasterFF allows older cars with rocker arm or outboard suspension to use bias ply slicks or VFF tires instead of radials. 2025-03-01 GT3U Increase Minimum Weight #37919weight +100 lbsslowerSTU GT3U minimum weight increases 150 to 250 pounds.
	Cal Club 2025 CALCL252025-02-22	1:52.044Eric Poulsen · only car	1:51.118Eric Poulsen · only car	114.7Eric Poulsen	2:00.536Michael Lewis · fastest of 2	1:55.650Michael Lewis · fastest of 2	108.8Michael Lewis	+4.532squal +8.492s	104.1%qual 107.6%
15 earlier rule changes on record, in force before Cal Club 2025 (from 2019)2 engine · 1 tyres & wheels · 1 weight · 11 wording · FF and FC cars with sequential gearbox must add 10 lbs. to minimum weight, down from 25 lbs. · FF Honda Fit allows Fast Forward 0.25mm oversize pistons PN FF800-110 as alternative; piston diameter spec clarified to 2.8835 inches. · FF VTEC activation valve must function; EGR blanking plate rule clarified with Fast Forward part numbers. · FF Honda Fit gains Fast Forward FF800-100 oversize piston ring pack option. · FF Honda Fit engine adds Fast Forward part number alternatives for intake, exhaust, oil system, and scavenge pump components. · FF block relief permitted only as needed to fit allowed crankshaft. · FF class cylinder head may now have optional coolant bleed line fitting to top of head for air release. · FF Honda LC1 ECU by HPD permitted effective 12/1/2020, must use HPD lambda sensor. · FF Honda LC1 ECU implementation date changed from 3/1/2020 to pending availability of support materials. · FF alternator changes from not required to optional. · FF allows Honda HPD LC1 low-cost ECU with lambda sensor; E1 ECU no longer supported but existing units permitted if sealed. · FF rain tyres now allow Hoosier W3 Radial in addition to existing Hoosier Wet option. · FF Honda Fit permitted to use 0.25mm oversize pistons, cylinder honing increased to 73.315mm maximum. · FF heat shield rule clarified: thermal wrap allowed on manifold exterior if easily removable for inspection. · FF catch tank minimum capacity rules clarified: coolant catch tank now one U.S. pint minimum, oil catch tank one U.S. quart minimum.showhide 2024-11-01 FF Change FF/FC Weight with Sequential Gearbox #36651weightfasterFF and FC cars with sequential gearbox must add 10 lbs. to minimum weight, down from 25 lbs. 2024-11-01 FF Alternative Oversize Honda Fit Pistons #37064wordingneutralFF Honda Fit allows Fast Forward 0.25mm oversize pistons PN FF800-110 as alternative; piston diameter spec clarified to 2.8835 inches. 2024-10-01 FF Update to FF EGR Blanking Plate Rule #36633wordingneutralFF VTEC activation valve must function; EGR blanking plate rule clarified with Fast Forward part numbers. 2024-01-01 FF Honda Fit Oversize Piston Rings #35305wordingneutralFF Honda Fit gains Fast Forward FF800-100 oversize piston ring pack option. 2023-03-01 FF Add Fast Forward Part Numbers for Honda Fit Engine #33752wordingneutralFF Honda Fit engine adds Fast Forward part number alternatives for intake, exhaust, oil system, and scavenge pump components. 2021-04-01 FF Kent crankshaft clarification #30426wordingneutralFF block relief permitted only as needed to fit allowed crankshaft. 2020-12-01 FF Allow Optional Coolant Bleed Line to Correct a Known Problem #29673wordingneutralFF class cylinder head may now have optional coolant bleed line fitting to top of head for air release. 2020-12-01 FF Clarification regarding Honda LC1 ECU implementation date #29684wordingneutralFF Honda LC1 ECU by HPD permitted effective 12/1/2020, must use HPD lambda sensor. 2020-08-01 FF Clarification regarding Honda LC1 ECU implementation #29135wordingneutralFF Honda LC1 ECU implementation date changed from 3/1/2020 to pending availability of support materials. 2020-04-01 FF E&O FF Kent Engine alternator language #28204wordingneutralFF alternator changes from not required to optional. 2020-03-01 FF Honda Racing HPD low cost ECU proposal #27563engineneutralFF allows Honda HPD LC1 low-cost ECU with lambda sensor; E1 ECU no longer supported but existing units permitted if sealed. 2020-03-01 FF Update rain tire designation #28443tyres & wheelsneutralFF rain tyres now allow Hoosier W3 Radial in addition to existing Hoosier Wet option. 2019-02-01 FF Request for Oversize Honda Fit Pistons #25810enginefasterFF Honda Fit permitted to use 0.25mm oversize pistons, cylinder honing increased to 73.315mm maximum. 2019-02-01 FF Heat Shield - Fit Intake #26102wordingneutralFF heat shield rule clarified: thermal wrap allowed on manifold exterior if easily removable for inspection. 2019-02-01 FF Request catch cans/tanks clarification #26158wordingneutralFF catch tank minimum capacity rules clarified: coolant catch tank now one U.S. pint minimum, oil catch tank one U.S. quart minimum.

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