BoP Lab / Buttonwillow Raceway Park

P vs FE2 pace at Buttonwillow Raceway Park

Quickest here: P 1:32.872 Jim Devenport, Cal Club 2025 qualifying · FE2 1:08.250 Caleb Shrader, Cal Club 2023 qualifying

Lap times% of P

PFE2solid race · dashed qualifying · slower is lower

PFE2solid race · dashed qualifying · each class's best lap as a share of P's at the same event (the reference class, changeable above); 100% is level, higher is quicker

	Event	P			FE2
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs P	% of P
	Cal Club 2026 CALCL262026-02-21	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%)	1:39.265Jon McClintock · fastest of 3 · top 3 within 1.5s-0.093s (-0.09%)	1:40.253Jon McClintock · fastest of 3 · top 3 within 2.2s+0.541s (+0.54%)	156.6Paul Marino+29.4 mph (+23.1%)	+2.966squal +0.549s	103.0%qual 100.6%
8 rule changes (P: 6, FE2: 2)1 cars added · 1 engine · 1 induction · 1 suspension & brakes · 4 wording · Prototype carbon-carbon and carbon-ceramic brake rotors now permitted instead of prohibited. · FE and FE2 Enterprises must use bubble tail P/N WM138014; FE2 allows only this configuration. · 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. · Class P adds clarification notes on restrictor requirements, throttle bodies, Mazda 12A engine spec, and P2 auto-based engine rules. · FE2 allows driver safety and comfort modifications for disabled drivers with SCCA approval, not transferable to other drivers.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. 2025-10-01 FE2 FE & FE2 Bubble Tail #38978wordingneutralFE and FE2 Enterprises must use bubble tail P/N WM138014; FE2 allows only this configuration. 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 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 FE2 Driver Safety & Comfort #37965wordingneutralFE2 allows driver safety and comfort modifications for disabled drivers with SCCA approval, not transferable to other drivers.
	Cal Club 2025 CALCL252025-02-22	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	1:39.358Paul Marino · fastest of 4 · top 4 within 1.5s+31.108s (+45.58%)	1:39.712Paul Marino · fastest of 4 · top 4 within 1.7s	127.2Tom Hope	+5.740squal +6.486s	106.1%qual 107.0%
2 rule changes (P: 2)2 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.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.
	Cal Club 2023 CALCL232023-02-24				1:08.250Caleb Shrader · fastest of 4 · top 4 within 5.8s
2 earlier rule changes on record, in force before Cal Club 2023 (from 2019)1 weight · 1 wording · FE2 oil cooler wording clarified: optional air-to-oil cooler allowed, Setrab 50-625-7612 or equivalent max 13 inches wide by 6.5 inches high. · FE and FE2 minimum weight increased to 1270 lbs including driver; spring options and tire warmer ban added.showhide 2020-09-01 FE2 FE/FE2 Oil Cooler #29293wordingneutralFE2 oil cooler wording clarified: optional air-to-oil cooler allowed, Setrab 50-625-7612 or equivalent max 13 inches wide by 6.5 inches high. 2019-12-01 FE2 FE / FE2 Update Rules #27624weightslowerFE and FE2 minimum weight increased to 1270 lbs including driver; spring options and tire warmer ban added.

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