BoP Lab / Buttonwillow Raceway Park

F5 vs FB vs FM vs FX pace at Buttonwillow Raceway Park

Lap times across years say as much about the weather as the class. % of F5 is each class's best lap as a share of F5's on the same day, so the conditions drop out: 100% is level, less is quicker, and a move in it is the class getting faster or slower against the field.

Quickest here: F5 1:51.129 Jeff Jorgenson, Super Tour Apr 2017 race · FB 1:38.870 Gary Hickman, Super Tour Apr 2018 race · FM 1:45.954 Mike Anderson, Super Tour Apr 2018 race · FX 1:48.518 Bill Weaver, Super Tour Feb 2020 race

% of F5Lap times

F5FBFMFXsolid race · dashed qualifying · slower is lower

F5FBFMFXsolid race · dashed qualifying · each class's best lap as a share of F5's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker

	Event	F5			FB					FM					FX
	Event	Qual best	Race best	Trap	Qual best	Race best	Trap	vs F5	% of F5	Qual best	Race best	Trap	vs F5	% of F5	Qual best	Race best	Trap	vs F5	% of F5
	Super Tour Feb 2022 CALCL222022-02-17														1:48.641Max Parker · fastest of 3 · top 3 within 5.1s-0.679s (-0.62%)	1:50.238Max Parker · fastest of 3 · top 3 within 3.9s+1.720s (+1.58%)	117.4Terrance Carraher-12.5 mph (-9.6%)
23 rule changes (F5: 9, FX: 14)7 cars added · 4 tyres & wheels · 2 engine · 8 wording · 2 other · Formula Mazda FX rule reference updated to current specifications document; tire marking no longer required. · FX Formula 4 tire choice unrestricted; must provide FIA certification rules upon request. · FX USF2000 Tube Frame front tyre changes from Hoosier radial 20.5 x 7.0 x 13 to any Hoosier 20.5 x 7.0 x 13. · FX Formula Renault 2.0 (00-09) and (10-17) tire choice unrestricted; no other component alterations except repairs. · 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. · FX USF2000 Tube Frame gains Hoosier radial tyre option, FC-compliant shocks, Wilwood brakes, and Bosch spark plugs. · F500 Rotax 593 HO engine now permitted; 875 lbs minimum weight, MA0242SP1020A or MA0242SP1063A restrictor, specific intake boots and piston required. · FX USF2000 Tube Frame now allows any Hoosier radial tire 20.5×7.0×13 front, 22.5×8.0×13 rear. · Formula Renault 2.0 / Fran-Am 2000 added to FX class at 1250 lbs with 8-inch front, 10-inch rear wheels, sealed engine. · FX adds 2010–2017 Formula Renault 2.0, must comply with Table 1 notes. · FX FormulaSPEED FS2.0 now references online specifications instead of requiring World Speed Inc. documentation by April 2020. · F500 Suzuki GSXR600 engine years extended from 2003-2013 to 2003-2019. · Formula Ireland / Formula FX added to FX class, must comply with Table 1 notes. · 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. · Formula Ireland/Formula FX cars pending specification submission for possible FX table addition. · Ex-Pro Formula Super Vee added to FX with 1600cc VW engine, 1190 lb minimum weight, 6-inch front and 8-inch rear wheels. · FormulaSPEED with 2.0L Mazda MZR engine, 8in front/10in rear wheels, adjustable dual rear planes, 1350 lbs moves from FA to FX. · FX Formula Mazda no longer requires tire marking; must comply with December 2019 GCR rules.showhide 2022-02-01 FX FM Rule Set Clarification #31881wordingwordingFormula Mazda FX rule reference updated to current specifications document; tire marking no longer required. 2022-02-01 FX E&O F4 Tires #31940tyres & wheelsaddedtyres & wheelsFX Formula 4 tire choice unrestricted; must provide FIA certification rules upon request. 2022-02-01 FX E&O USF2000 Tube Frame #31951tyres & wheelstyres & wheelsFX USF2000 Tube Frame front tyre changes from Hoosier radial 20.5 x 7.0 x 13 to any Hoosier 20.5 x 7.0 x 13. 2022-02-01 FX URGENT - FX- Formula Renault Tire #32058tyres & wheelsaddedtyres & wheelsFX Formula Renault 2.0 (00-09) and (10-17) tire choice unrestricted; no other component alterations except repairs. 2022-01-01 F5 Data Box Mounting Plate #31638otheraddedF5 cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs. 2021-08-01 F5 Clarify allowable assisted shifting systems #30871wordingwordingF5 clarifies mechanical shifting only; throttle-cut and flat-shifter devices permitted if driver retains full control. 2021-08-01 F5 Request to correct terminology #30976wordingwordingF5 single-seat open-wheel cars: rigid suspension becomes limited suspension in class definition. 2021-08-01 FX Rules Adjustment #30950otheraddedFX USF2000 Tube Frame gains Hoosier radial tyre option, FC-compliant shocks, Wilwood brakes, and Bosch spark plugs. 2021-06-01 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. 2021-06-01 FX FX/FRP Tire Rule #30723tyres & wheelsaddedtyres & wheelsFX USF2000 Tube Frame now allows any Hoosier radial tire 20.5×7.0×13 front, 22.5×8.0×13 rear. 2021-05-01 FX Classify the 2000-2009 Formula Renault 2.0 / Fran-Am 2000 #30460cars addedaddedFormula Renault 2.0 / Fran-Am 2000 added to FX class at 1250 lbs with 8-inch front, 10-inch rear wheels, sealed engine. 2021-01-01 FX Request for Car Classification to Compete in Formula X #29933cars addedaddedFX adds 2010–2017 Formula Renault 2.0, must comply with Table 1 notes. 2020-12-01 FX Update specifications for FormulaSPEED cars #29674wordingwordingFX FormulaSPEED FS2.0 now references online specifications instead of requiring World Speed Inc. documentation by April 2020. 2020-10-01 F5 Request to Update Suzuki Engine Years for F500 #29453engineaddedengineF500 Suzuki GSXR600 engine years extended from 2003-2013 to 2003-2019. 2020-09-01 FX Follow up to to Letter#28991 Request for FX classification #29281cars addedaddedFormula Ireland / Formula FX added to FX class, must comply with Table 1 notes. 2020-07-01 F5 Request for Cockpit Adjustment of External Jetting Devices #28359wordingunclearF5 request to adjust external jetting device cockpit control denied; no rule change made. 2020-07-01 F5 Two Stroke Motors (reply to #28359 WDYT) #28816engine 2020-07-01 F5 Re letter requesting driver adjustable carb mixture #28840wordingunclearF5 driver adjustable carburettor mixture: refer to separate Fastrack letter #28359 for ruling. 2020-07-01 F5 #28359 WDYT Request for Cockpit Adjustment #28875wordingunclearF5 cockpit adjustment request response published in Fastrack letter 28359. 2020-07-01 FX Request to be added to FX group #28991cars addedaddedFormula Ireland/Formula FX cars pending specification submission for possible FX table addition. 2020-04-01 FX Request to classify FSV in FX #28057cars addedaddedEx-Pro Formula Super Vee added to FX with 1600cc VW engine, 1190 lb minimum weight, 6-inch front and 8-inch rear wheels. 2020-04-01 FX Classify FormulaSPEED in FX #28715cars addedaddedFormulaSPEED with 2.0L Mazda MZR engine, 8in front/10in rear wheels, adjustable dual rear planes, 1350 lbs moves from FA to FX. 2020-03-01 FX Request to remove tire marking language from FM #28415wordingwordingFX Formula Mazda no longer requires tire marking; must comply with December 2019 GCR rules.
	Super Tour Feb 2020 ST20FEB212020-02-21														1:49.320Steve Martin · fastest of 5 · top 5 within 6.7s	1:48.518Bill Weaver · fastest of 5 · top 5 within 6.8s	129.9Steve Martin
3 rule changes (F5: 2, FX: 1)1 induction · 1 weight · 1 wording · Pro Formula F 2000 and USF2000 Tube Frame engine and car rules simplified; FC rules and FRP MAZDA MZR F2000 specs now apply directly. · 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 2020-02-01 FX Change to FX Table 1 #28322wordingunclearPro Formula F 2000 and USF2000 Tube Frame engine and car rules simplified; FC rules and FRP MAZDA MZR F2000 specs now apply directly. 2020-01-01 F5 Change 600cc restrictor size #27883inductionslowerinductionF500 Honda CBR600RR, Suzuki GSXR600, Yamaha R6 restrictor reduced to 28mm from 29mm. 2019-08-31 F5 Request for Weight Increase for Motorcycle Powered Cars #27214weight +25 lbsslowerweightF500 Honda CBR600RR, Suzuki GSXR600, and Yamaha R6 minimum weights increase to 900 lbs.
	Super Tour Apr 2019 ST19APR262019-04-26									1:49.608Mike Anderson · fastest of 3 · top 3 within 5.6s+3.285s (+3.09%)	1:49.409Mike Anderson · fastest of 3 · top 3 within 4.9s+3.455s (+3.26%)	121.2Mike Anderson
No rule changes on record between these events
	Super Tour Apr 2018 BUTTRA182018-04-27				1:39.142Gary Hickman · fastest of 2-3.130s (-3.06%)	1:38.870Gary Hickman · fastest of 2-1.241s (-1.24%)				1:46.323Mike Anderson · fastest of 9 · top 5 within 2.1s+0.367s (+0.35%)	1:45.954Mike Anderson · fastest of 9 · top 5 within 3.3s-0.317s (-0.30%)
No rule changes on record between these events
	Super Tour Apr 2017 BUTTRA172017-04-28	1:52.268Jeff Jorgenson · fastest of 2	1:51.129Jeff Jorgenson · fastest of 2		1:42.272John LaBrie · fastest of 2	1:40.111Gary Hickman · fastest of 2		-11.018squal -9.996s	90.1%qual 91.1%	1:45.956Mike Anderson · fastest of 8 · top 5 within 2.0s	1:46.271Mike Anderson · fastest of 10 · top 5 within 2.1s		-4.858squal -6.312s	95.6%qual 94.4%

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. "% of F5" is the class's best as a share of F5'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 F5'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.