BoP Lab / Buttonwillow Raceway Park

P pace at Buttonwillow Raceway Park

Quickest here: P 1:32.872 Jim Devenport, Cal Club 2025 qualifying

Psolid race · dashed qualifying · slower is lower

	Event	P
	Event	Qual best	Race best	Trap
	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%)
6 rule changes (P: 6)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. · Class P adds clarification notes on restrictor requirements, throttle bodies, Mazda 12A engine spec, and P2 auto-based engine rules.showhide 2026-01-01 Request to Continue to Allow Carbon Brakes #39476suspension & brakesneutralPrototype carbon-carbon and carbon-ceramic brake rotors now permitted instead of prohibited. 2025-09-01 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 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 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 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 Add missing punctuation marks #38150wordingneutralClass P adds clarification notes on restrictor requirements, throttle bodies, Mazda 12A engine spec, and P2 auto-based engine rules.
	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
2 earlier rule changes on record, in force before Cal Club 2025 (from 2025)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 Correct text in engine table notes #37606wordingneutralPrototype Staudacher and unrestricted engine notes corrected for minimum weight wording. 2025-02-01 Update Prototype class designation #37653wordingneutralPrototype class renamed from P1 to P, affecting designation throughout rules with no performance changes.

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. 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.