BoP Lab / Buttonwillow Raceway Park
FE vs FM vs F5 vs STL pace at Buttonwillow Raceway Park
Quickest here: STL 1:54.845 Gavin Wardle, Super Tour Feb 2026 race
| Event | FE | FM | F5 | STL | ||||||||||||||||
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| Qual best | Race best | Trap | Qual best | Race best | Trap | vs FE | % of FE | Qual best | Race best | Trap | vs FE | % of FE | Qual best | Race best | Trap | vs FE | % of FE | |||
| Super Tour Feb 2026 CALCL262026-02-21 | 1:57.526Jared Korth · fastest of 10 · top 5 within 1.2s+2.563s (+2.23%) | 1:54.845Gavin Wardle · fastest of 11 · top 5 within 4.7s-0.837s (-0.72%) | 136.6Bryce Johnson+26.2 mph (+23.7%) | |||||||||||||||||
6 rule changes (FE: 3, STL: 3)2 weight · 1 cars added · 3 wording · FE adds engine modification restrictions, testing requirements, and drivetrain violation penalties with competition suspension. · STL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs. · FE and FE2 Enterprise bubble tail part WM138014 now allowed; FE2 must use this configuration only. · FE2 minimum weight stays 1270 lbs; intake manifold part number changes to WM301061; ECU to G992012; mandatory spec parts expanded; bubble tail WM138014 now FE only; SADEV transmission no modifications allowed; brake rotor part numbers to W… · Lotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs. · STL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1; mandatory component spec list removed, alternative tires only allowed.show
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| Super Tour Feb 2025 CALCL252025-02-22 | 1:54.963Nick Leverone · fastest of 16 · top 5 within 3.3s | 1:55.682Nick Leverone · fastest of 17 · top 5 within 2.6s | 110.4Ryan Gutile | |||||||||||||||||
84 rule changes (FE: 26, F5: 16, STL: 42)14 engine · 11 cars added · 6 aero · 6 weight · 4 suspension & brakes · 3 tyres & wheels · 2 induction · 31 wording · 7 other · FE must use SCCA Part # WM803010 Brake Line to Control Arm covers if used, as delivered, fastened with zip ties or tape only. · STL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved. · FE and SRF protest fee rules redirected to GCR section 8.3.1.D for fees and procedure. · FE Hoosier contingency decal requirement reduced from five decals in specific locations to three decals on sides and front. · FE requires five Hoosier decals: one small on nose or front shock cover, one 12" on each front wing plate, one 12" on each lower floor panel before rear wheels. · STL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems. · STL normally aspirated minimum weights reduced: 1900cc to 2540 lbs, 1950cc to 2583 lbs, 2000cc to 2625 lbs; short-wheelbase FWD adds 1.25%; Honda B16/B17/B18C1 throttle to 51mm, B18C Type R and Mazda MZR to 50mm. · STL Mazda 12A: 5th and 6th intake port actuators and valves may no longer be removed or disabled. · FE rain light now must meet FIA Standard 8874-2019, Technical List No. 76, effective 1/1/2024. · FE allows racer's tape for crash repair, panel security, and heat exchanger opening control; seam taping banned. · STL 79-85 RX7 12A now allows auto-type 2 bbl carburetor with 42mm choke on dual-y manifold, not just stock Nikki. · STL ITA and ITS RX7, and ITS/ITA/ITB/ITC 1985+ models clarified to require tires per 9.1.4.2. · FE SADEV transmission rule removes note that all ratios under review and could be updated prior to sealing. · Spec MX5 in STL allows ACT clutch 0000-02-5004-G6, wheels 17x8, Toyo RR and RA1 235-40-17 tyres, or alternatives on 17x7 per rules. · FE drivers may now adjust brake bias manually during the race. · FE front and rear wing specifications clarified: adjustment ranges, shimming, Gurney flap sizes, mounting hardware, and measurement references refined. · 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. · FE engine heat shield and insulation between block and exhaust now permitted to protect fuel cell, filter, rail, lines. · 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. · FE tires must be run as delivered in sets of 4. · FE master cylinders clarified: Girling front .700" piston WM802005, rear .750" piston WM802006. · F500 Majors and Runoffs cars must install AIM part #X47KPFSOLO2R0 data box mount for Solo or Solo 2. · STU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs. · STL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels. · F5 cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs. · STL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed. · STL Mazda Renesis flat plate restrictor increases from 55mm to 60mm. · STL 79-85 RX7 12A allows emissions removal and jet correction on stock Nikki carb. · STL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations. · 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. · FE removes qualifying tire marking requirements and rain tire set rules; renumbers tire warmer prohibition. · FE radiator screens may not protrude more than ¼ inch in front of the outside vertical plane of the sidepods. · F500 Rotax 593 HO engine now permitted; 875 lbs minimum weight, MA0242SP1020A or MA0242SP1063A restrictor, specific intake boots and piston required. · FE radiator screens now allowed, maximum ¼ inch from sidepod front vertical plane. · STL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs. · STL Pontiac Solstice/Saturn Sky allowed 4 inch ride height. · STL Mazda B5 DOHC added to class; must meet all STL regulations. · STL Honda B16A (JDM) restrictor reduced from 54mm to 53mm. · ST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section. · STL GM Ecotec LNF now permits any Ecotec engine family with 55mm flat plate restrictor. · ST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1. · ST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment. · STL rear wing trailing edge may be mounted no further rearward than the center of the rearmost part approved bodywork. · STL alternate transmissions now allow OEM gear sets and input shaft modifications for fitment. · STL RWD strut-front cars lose 2.5% weight penalty, others lose 3% penalty for FWD parity. · STL Honda F20C drops 2% weight penalty, minimum weight reduced. · STL Honda B16/B17/B18C1 restrictor reduced to 53mm, B18C variants and Mazda MZR to 52mm. · FE front springs change to 800 lbs Hypercoil WM203013 Silver; rear to 900 lbs Hypercoil WM203014 Silver. · ST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion. · F500 Suzuki GSXR600 engine years extended from 2003-2013 to 2003-2019. · FE Gurney flaps clarified: front wing secondary only at 0.500" ±0.030", rear wing at 0.250" ±0.030". · STL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds. · STL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules. · 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. · GT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. · FE Gurney flap wicker bill clarified: permitted on front wing secondary elements only, not main plane. · STL adds Mazda MX-5 Global Cup 16-18 at 2450 lbs minimum and 2019 at 2550 lbs minimum. · STL Mazda MX-5 Club 06-15 allowed header part number 0000-06-5407-NC. · STL Acura/Honda B18 and B18C engines: restrictor sizes swapped, B18C1 removed from allowed variants. · FE2 and FE spring part numbers WM203013 front and WM203014 rear required date moved to November 1, 2020. · STL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants. · STU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs. · STL Mazda MZR restrictor reduced from 54 mm to 53 mm. · STL Mazda MZR restrictor reduces from 55 mm to 53 mm. · STL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL to notes. · F500 Honda CBR600RR, Suzuki GSXR600, Yamaha R6 restrictor reduced to 28mm from 29mm. · FE2 Mazda 2.0L MZR engine now permitted in all SCCA events at 1250 lbs minimum; FE 2.3L becomes Regional Only through 2019 Runoffs. · FE minimum weight rises to 1270 lbs; FE2 minimum weight rises to 1270 lbs; new spring options added; tire warmers prohibited. · FE Hoosier wet rear tire width increases from 7.5 to 8.0 inches, part number 44196 W3. · STL adds Mazda Spec MX-5 Challenge, 2000cc displacement, 2500 lb minimum weight, with mandatory Roush, Penske, Eibach, and other specified components. · F500 Honda CBR600RR, Suzuki GSXR600, and Yamaha R6 minimum weights increase to 900 lbs. · FE removes American Racer tires, mandates Hoosier dry tires 22.0 X 8.0-13 and 22.0 X 10.0-13, wet tires 22.0 X 7.5-13 and 22.0 X 9.0-13. · STU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required. · FE anti-roll bar links may be removed one per end for safety, but bars must stay connected. · FE and FE2 Enterprise bubble tail P/N WM138014 newly allowed for both classes. · STL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate. · STL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld.show
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| Super Tour Apr 2019 ST19APR262019-04-26 | ||||||||||||||||||||
8 earlier rule changes on record, in force before Super Tour Apr 2019 (from 2019)2 cars added · 2 engine · 1 tyres & wheels · 1 weight · 2 other · FE Hoosier rain tyre part numbers updated: front 44195 W3, rear 44217 W3. · STL adds VW 1.8L R4 20VT 1781 cc, 1781 minimum weight, naturally aspirated only. · STL Mazda Renesis minimum weight reduced to 2700 lbs. · STL Mazda MX-5 Cup brake pad compound now open. · STL adds Acura/Honda B18C1 GSR with 1797cc displacement, 54mm flat plate restrictor required, porting outside 1" allowance prohibited. · STL Mazda 12 and 13B now permit port matching; porting ban removed. · STL B17 now requires 54mm flat plate restrictor; B18C Type R variants move to 54mm restrictor, weight chart baseline. · STL Mazda Miata removes maximum displacement limit; minimum weight corrected to unspecified figure.show
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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 FE" is the class's best as a share of FE'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 FE'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.