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BoP Lab / Buttonwillow Raceway Park

F5 vs FB vs F6 vs P pace at Buttonwillow Raceway Park

Class · click a class to switch, + to compare alongside (up to 4: remove one to add another)
ASB-SpecEPF5×vsF6×FAvsFB×FCFE2FFFPFVFXGT1GT2GTXHPvsP×P2SMSMXSRF3STLSTUT1T2T3T4Show 12 inactive classes
Reference class · the others' laps as a share of this one's at the same event, so years compare despite weather; + a class above to measure against it
Track configuration

Quickest here: P 1:32.872 Jim Devenport, Super Tour Feb 2025 qualifying

1:331:341:351:361:371:381:396 rule changes between Super Tour Feb 2025 and Super Tour Feb 20266 ▾P race best at Super Tour Feb 2025: 1:33.972 (Jim Devenport)P race best at Super Tour Feb 2026: 1:37.287 (John Manfroy)P qualifying best at Super Tour Feb 2025: 1:32.872 (Jim Devenport)P qualifying best at Super Tour Feb 2026: 1:38.716 (Kevin Mitz)Super Tour Feb 2025Super Tour Feb2025Super Tour Feb 2026Super Tour Feb2026
F5FBF6Psolid race · dashed qualifying · slower is lower
EventF5FBF6P
Qual bestRace bestTrapQual bestRace bestTrapvs F5Qual bestRace bestTrapvs F5Qual bestRace bestTrapvs F5
Super Tour Feb 2026 CALCL262026-02-211:38.716Kevin 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)2 cars added · 2 engine · 1 wording · 1 other · Prototype carbon-carbon and carbon-ceramic brake rotors permitted; rotor material now unrestricted. · Prototype 13B rotary restrictor changes to 40mm SIR fuel injection or 41.5mm venturi carburetor. · Prototype class adds Radical SR3 to Table 1 Spec Line Cars. · Prototype P2 cars may now run P2 specification or modify to Prototype rules in Prototype class; Radical Cup series added as spec line car. · Prototype Engine Table A 2-cycle restrictor reduced from 40mm to 38mm venturi size. · Class P adds engine and car notes: Line D no restrictor at 1150 lbs; Line G CN Honda K20A-FD2 unrestricted ITBs at 1500 lbs; Beasley B2 Mazda 12A 40.5mm venturi; P2 2000cc auto rules clarified.showhide
  • P Request to Continue to Allow Carbon Brakes #39476otheraddedPrototype carbon-carbon and carbon-ceramic brake rotors permitted; rotor material now unrestricted.
  • P 13B Rotary Engine Rules Change Request #38856engineunclearPrototype 13B rotary restrictor changes to 40mm SIR fuel injection or 41.5mm venturi carburetor.
  • P Add Radical Cup series Radical SR3 spec line to Table 1 #38916cars addedaddedPrototype class adds Radical SR3 to Table 1 Spec Line Cars.
  • P Clarify spec line cars language #38943cars addedaddedPrototype P2 cars may now run P2 specification or modify to Prototype rules in Prototype class; Radical Cup series added as spec line car.
  • P RM 25-05 - Prototype Engine Table A, 2 Cycle Restrictor Change #38929engineslower · enginePrototype Engine Table A 2-cycle restrictor reduced from 40mm to 38mm venturi size.
  • P Add missing punctuation marks #38150wordingaddedClass P adds engine and car notes: Line D no restrictor at 1150 lbs; Line G CN Honda K20A-FD2 unrestricted ITBs at 1500 lbs; Beasley B2 Mazda 12A 40.5mm venturi; P2 2000cc auto rules clarified.
Super Tour Feb 2025 CALCL252025-02-221:32.872Jim Devenport · fastest of 3 · top 3 within 8.1s1:33.972Jim Devenport · fastest of 3 · top 3 within 7.7s141.7Jim Devenport
18 earlier rule changes on record, in force before Super Tour Feb 2025 (from 2019)3 engine · 1 cars added · 1 induction · 1 weight · 10 wording · 2 other · Prototype Spec Lines B and D: wording corrections to engine table notes; no performance change. · Prototype class renamed from P1 to P, with P1 and P2 designations removed throughout GCR sections 9.1, 9.2.2, 9.3.37, and appendices. · F500 Rotax 493 and 593 intake boots: removed Moto Tassinari V3124-873B-2 from 493/593 non-HO allowance, added Moto Tassinari V3120-794A-2 option for non-HO. · F500 Rotax engines now permit Ingi Tech Sparker ignition DCP-CDI-P2 as alternate ECU. · F500 clarifies stepped diameter exhaust headers prohibited except at cylinder head flange area. · F500 Rotax 593 intake boot options clarified; oil injection pump removal now permitted. · F500 Majors and Runoffs cars must install AIM part #X47KPFSOLO2R0 data box mount for Solo or Solo 2. · F5 cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs. · F5 clarifies mechanical shifting only; throttle-cut and flat-shifter devices permitted if driver retains full control. · F5 single-seat open-wheel cars: rigid suspension becomes limited suspension in class definition. · F500 Rotax 593 HO engine now permitted; 875 lbs minimum weight, MA0242SP1020A or MA0242SP1063A restrictor, specific intake boots and piston required. · F500 Suzuki GSXR600 engine years extended from 2003-2013 to 2003-2019. · F5 request to adjust external jetting device cockpit control denied; no rule change made. · F5 driver adjustable carburettor mixture: refer to separate Fastrack letter #28359 for ruling. · F5 cockpit adjustment request response published in Fastrack letter 28359. · F500 Honda CBR600RR, Suzuki GSXR600, Yamaha R6 restrictor reduced to 28mm from 29mm. · F500 Honda CBR600RR, Suzuki GSXR600, and Yamaha R6 minimum weights increase to 900 lbs.showhide
  • P Correct text in engine table notes #37606wordingwordingPrototype Spec Lines B and D: wording corrections to engine table notes; no performance change.
  • P Update Prototype class designation #37653wordingwordingPrototype class renamed from P1 to P, with P1 and P2 designations removed throughout GCR sections 9.1, 9.2.2, 9.3.37, and appendices.
  • F5 Intake Boots Correction #33028wordingwordingF500 Rotax 493 and 593 intake boots: removed Moto Tassinari V3124-873B-2 from 493/593 non-HO allowance, added Moto Tassinari V3120-794A-2 option for non-HO.
  • F5 Ensure availability of ECU for Rotax engines #32695engineadded · engineF500 Rotax engines now permit Ingi Tech Sparker ignition DCP-CDI-P2 as alternate ECU.
  • F5 Clarify stepped exhaust header references #32743wordingwordingF500 clarifies stepped diameter exhaust headers prohibited except at cylinder head flange area.
  • F5 593 carb boot availability and oil pump clarification #32527wordingwordingF500 Rotax 593 intake boot options clarified; oil injection pump removal now permitted.
  • F5 E&O class name #32194otheraddedF500 Majors and Runoffs cars must install AIM part #X47KPFSOLO2R0 data box mount for Solo or Solo 2.
  • F5 Data Box Mounting Plate #31638otheraddedF5 cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs.
  • F5 Clarify allowable assisted shifting systems #30871wordingwordingF5 clarifies mechanical shifting only; throttle-cut and flat-shifter devices permitted if driver retains full control.
  • F5 Request to correct terminology #30976wordingwordingF5 single-seat open-wheel cars: rigid suspension becomes limited suspension in class definition.
  • F5 Request to Allow Rotax 593 HO Engine #30712cars addedaddedF500 Rotax 593 HO engine now permitted; 875 lbs minimum weight, MA0242SP1020A or MA0242SP1063A restrictor, specific intake boots and piston required.
  • F5 Request to Update Suzuki Engine Years for F500 #29453engineadded · engineF500 Suzuki GSXR600 engine years extended from 2003-2013 to 2003-2019.
  • F5 Request for Cockpit Adjustment of External Jetting Devices #28359wordingunclearF5 request to adjust external jetting device cockpit control denied; no rule change made.
  • F5 Two Stroke Motors (reply to #28359 WDYT) #28816engine
  • F5 Re letter requesting driver adjustable carb mixture #28840wordingunclearF5 driver adjustable carburettor mixture: refer to separate Fastrack letter #28359 for ruling.
  • F5 #28359 WDYT Request for Cockpit Adjustment #28875wordingunclearF5 cockpit adjustment request response published in Fastrack letter 28359.
  • F5 Change 600cc restrictor size #27883inductionslower · inductionF500 Honda CBR600RR, Suzuki GSXR600, Yamaha R6 restrictor reduced to 28mm from 29mm.
  • F5 Request for Weight Increase for Motorcycle Powered Cars #27214weight +25 lbsslower · weightF500 Honda CBR600RR, Suzuki GSXR600, and Yamaha R6 minimum weights increase to 900 lbs.
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. 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.