BoP Lab / Buttonwillow Raceway Park

FV vs P vs GT3U pace at Buttonwillow Raceway Park

Quickest here: FV 1:58.898 Mace Gjerman, Cal Club 2026 race · P 1:32.872 Jim Devenport, Cal Club 2025 qualifying · GT3U 1:55.650 Michael Lewis, Cal Club 2025 race

Lap times% of FV

FVPGT3Usolid race · dashed qualifying · slower is lower

FVPGT3Usolid race · dashed qualifying · each class's best lap as a share of FV's at the same event (the reference class, changeable above); 100% is level, higher is quicker

	Event	FV			P					GT3U
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs FV	% of FV	Qual best	Race best	Trap	vs FV	% of FV
	Cal Club 2026 CALCL262026-02-21	2:02.562Gavin Sweeney · fastest of 7 · top 5 within 3.3s+0.208s (+0.17%)	1:58.898Mace Gjerman · fastest of 7 · top 5 within 6.0s-2.299s (-1.90%)	124.6Gavin Sweeney+21.2 mph (+20.5%)	1:38.716Kevin Mitz · fastest of 3 · top 3 within 3.1s+5.844s (+6.29%)	1:37.287John Manfroy · fastest of 3 · top 3 within 3.5s+3.315s (+3.53%)	160.4John Manfroy+18.7 mph (+13.2%)	-21.611squal -23.846s	81.8%qual 80.5%
9 rule changes (P: 6, GT3U: 3)3 weight · 1 cars added · 1 engine · 1 induction · 1 suspension & brakes · 2 wording · Prototype carbon-carbon and carbon-ceramic brake rotors now permitted instead of prohibited. · P class 13B rotary engine restrictor changes to 40mm SIR fuel injection or 41.5mm venturi carburetor. · Prototype class adds Radical SR3 spec line to Table 1 effective 9/1/25. · Prototype P2 cars may now run P2 spec or modified Prototype spec in Prototype class; clarified language and added Radical Cup series table. · Prototype Engine Table A 2-cycle restrictor reduces from 40mm to 38mm venturi size. · STU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments. · Class P adds clarification notes on restrictor requirements, throttle bodies, Mazda 12A engine spec, and P2 auto-based engine rules. · STU-GT3U non-TCR cars may reduce weight by 4% after all other modifiers. · STU GT3U minimum weight increases 150 to 250 pounds.showhide 2026-01-01 P Request to Continue to Allow Carbon Brakes #39476suspension & brakesneutralPrototype carbon-carbon and carbon-ceramic brake rotors now permitted instead of prohibited. 2025-09-01 P 13B Rotary Engine Rules Change Request #38856engineunclearP class 13B rotary engine restrictor changes to 40mm SIR fuel injection or 41.5mm venturi carburetor. 2025-09-01 P Add Radical Cup series Radical SR3 spec line to Table 1 #38916cars addedneutralPrototype class adds Radical SR3 spec line to Table 1 effective 9/1/25. 2025-09-01 P Clarify spec line cars language #38943wordingneutralPrototype P2 cars may now run P2 spec or modified Prototype spec in Prototype class; clarified language and added Radical Cup series table. 2025-08-01 P RM 25-05 - Prototype Engine Table A, 2 Cycle Restrictor Change #38929inductionslowerPrototype Engine Table A 2-cycle restrictor reduces from 40mm to 38mm venturi size. 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. 2025-05-01 P Add missing punctuation marks #38150wordingneutralClass P adds clarification notes on restrictor requirements, throttle bodies, Mazda 12A engine spec, and P2 auto-based engine rules. 2025-04-01 GT3U TCR Rulesets #37981weightfasterSTU-GT3U non-TCR cars may reduce weight by 4% after all other modifiers. 2025-03-01 GT3U Increase Minimum Weight #37919weight +100 lbsslowerSTU GT3U minimum weight increases 150 to 250 pounds.
	Cal Club 2025 CALCL252025-02-22	2:02.354Gavin Sweeney · fastest of 5 · top 5 within 10.3s	2:01.197Gavin Sweeney · fastest of 5 · top 5 within 9.6s	103.5Gavin Sweeney	1:32.872Jim Devenport · fastest of 3 · top 3 within 8.1s	1:33.972Jim Devenport · fastest of 3 · top 3 within 7.7s	141.7Jim Devenport	-27.225squal -29.482s	77.5%qual 75.9%	2:00.536Michael Lewis · fastest of 2	1:55.650Michael Lewis · fastest of 2	108.8Michael Lewis	-5.547squal -1.818s	95.4%qual 98.5%
20 earlier rule changes on record, in force before Cal Club 2025 (from 2019)5 tyres & wheels · 1 aero · 1 suspension & brakes · 1 weight · 12 wording · Prototype Staudacher and unrestricted engine notes corrected for minimum weight wording. · Prototype class renamed from P1 to P, affecting designation throughout rules with no performance changes. · FV ferrous rotor no longer required to be smooth; may have up to three pad cleaning grooves per side. · FV front wheel bearings wording clarified in GCR 9.1.1.C.10.G. · FV connecting rod rules add Brian Crower part #BC6417 and Newland Group #4M113077 as allowed replacements. · FV connecting rods minimum weight 425.0 grams, center-to-center length 130 ± 0.10/-0.25 mm specified. · FV connecting rod suppliers clarified: Crower SP93280B and BrianCrower BC6417 allowed as direct replacements. · FV allows Crower SP93280B and Brian Crower Racing Rods as direct replacement connecting rods, must meet OEM minimum weight. · FV now allows 4 bolt wheels, previously restricted to 5 bolt wheels. · FV now supports 4-bolt pattern wheels in addition to existing wheel specifications. · FV rain tire requirement changed to Hoosier #44266 22.5 x 5.0 x 15 WET or W3. · FV allows non-spec Hoosier tires in Regional races until 2020-01-01, when spec tires become required. · FV allows rear tires on front of car; mandates Hoosier #43337 fronts and #43353 rears, plus #44266 rain tire from 2020-01-01. · FV wheels clarified: 15" x 4J standard or 15" x 4.5J steel VW, 5-bolt pattern, same track dimensions. · FV exhaust outlet location tightened to 1–4 inches behind rearmost body part. · FV wheels now permit 15-inch 4.5J steel wheels within C.2 track dimensions, adding to standard 4J options. · FV exhaust opening can now extend to 4 inches behind body rear, previously 3 inches maximum. · FV front track maximum 52.500" and rear track 49.125"-50.750" no longer prohibits spacers. · FV disc brake assembly minimum weight clarified to 16.5 lbs total; caliper minimum weight requirement removed. · FV intake manifold horizontal tube measurement locations clarified between 1.500" and 8.000" on short side.showhide 2025-02-01 P Correct text in engine table notes #37606wordingneutralPrototype Staudacher and unrestricted engine notes corrected for minimum weight wording. 2025-02-01 P Update Prototype class designation #37653wordingneutralPrototype class renamed from P1 to P, affecting designation throughout rules with no performance changes. 2024-10-01 FV Disc Brakes #36822suspension & brakesneutralFV ferrous rotor no longer required to be smooth; may have up to three pad cleaning grooves per side. 2023-12-01 FV FV Wheel Bearing Clarification #35150wordingneutralFV front wheel bearings wording clarified in GCR 9.1.1.C.10.G. 2022-03-01 FV Connecting Rod Update Request for 9.1.1.C Formula Vee (FV) 5.C.6 #32160wordingneutralFV connecting rod rules add Brian Crower part #BC6417 and Newland Group #4M113077 as allowed replacements. 2022-03-01 FV E&O clarification of connecting rod center-to-center length #32183wordingneutralFV connecting rods minimum weight 425.0 grams, center-to-center length 130 ± 0.10/-0.25 mm specified. 2022-01-01 FV Update direct replacement connecting rod information #31843wordingneutralFV connecting rod suppliers clarified: Crower SP93280B and BrianCrower BC6417 allowed as direct replacements. 2021-12-01 FV Formula V Connecting Rod Replacement #31448wordingneutralFV allows Crower SP93280B and Brian Crower Racing Rods as direct replacement connecting rods, must meet OEM minimum weight. 2020-07-01 FV Support for Recommended Item - 4 bolt wheels in FV #29084tyres & wheelsneutralFV now allows 4 bolt wheels, previously restricted to 5 bolt wheels. 2020-07-01 FV Support for 4-bolt pattern wheels #28955 #29118wordingneutralFV now supports 4-bolt pattern wheels in addition to existing wheel specifications. 2020-03-01 FV Update rain tire designation #28444tyres & wheelsneutralFV rain tire requirement changed to Hoosier #44266 22.5 x 5.0 x 15 WET or W3. 2020-01-01 FV FV Allow non-spec tire in Regional competition #26284tyres & wheelsneutralFV allows non-spec Hoosier tires in Regional races until 2020-01-01, when spec tires become required. 2020-01-01 FV Request to Allow Rear Tires on the Front of Formula Vee #26537tyres & wheelsneutralFV allows rear tires on front of car; mandates Hoosier #43337 fronts and #43353 rears, plus #44266 rain tire from 2020-01-01. 2019-12-01 FV Clarification on Wheel Bolt Pattern #27603wordingneutralFV wheels clarified: 15" x 4J standard or 15" x 4.5J steel VW, 5-bolt pattern, same track dimensions. 2019-10-01 FV Allowed Modifications E&O #27398wordingneutralFV exhaust outlet location tightened to 1–4 inches behind rearmost body part. 2019-08-31 FV E&O Wheels #27230tyres & wheelsneutralFV wheels now permit 15-inch 4.5J steel wheels within C.2 track dimensions, adding to standard 4J options. 2019-05-31 FV Exhaust termination rule E&O #26702aeroneutralFV exhaust opening can now extend to 4 inches behind body rear, previously 3 inches maximum. 2019-05-01 FV E&O Dimensions #26674wordingneutralFV front track maximum 52.500" and rear track 49.125"-50.750" no longer prohibits spacers. 2019-04-01 FV Request to clarify Disc Brake rules bearing retainer & weights #26262weightslowerFV disc brake assembly minimum weight clarified to 16.5 lbs total; caliper minimum weight requirement removed. 2019-02-01 FV FV Intake Manifold Clarification #26008wordingneutralFV intake manifold horizontal tube measurement locations clarified between 1.500" and 8.000" on short side.

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