BoP Lab / Buttonwillow Raceway Park
FF vs GTX vs GT3U vs FV pace at Buttonwillow Raceway Park
Quickest here: FF 1:51.118 Eric Poulsen, Cal Club 2025 race · GTX 1:49.596 Rob Scholl, Cal Club 2025 race · GT3U 1:55.650 Michael Lewis, Cal Club 2025 race · FV 1:58.898 Mace Gjerman, Cal Club 2026 race
| Event | FF | GTX | GT3U | FV | ||||||||||||||||
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| Qual best | Race best | Trap | Qual best | Race best | Trap | vs FF | % of FF | Qual best | Race best | Trap | vs FF | % of FF | Qual best | Race best | Trap | vs FF | % of FF | |||
| Cal Club 2026 CALCL262026-02-21 | 1:53.098Edward Erlandson · fastest of 2+1.054s (+0.94%) | 1:54.741Edward Erlandson · fastest of 2+3.623s (+3.26%) | 133.7Edward Erlandson+19.0 mph (+16.5%) | 1:54.892Moze Cowper · only car | 1:55.330Moze Cowper · only car+5.734s (+5.23%) | 146.0Moze Cowper+29.6 mph (+25.4%) | +0.589squal +1.794s | 100.5%qual 101.6% | 2:02.562Gavin Sweeney · fastest of 7 · top 5 within 3.3s+0.208s (+0.17%) | 1:58.898Mace Gjerman · fastest of 7 · top 5 within 6.0s-2.299s (-1.90%) | 124.6Gavin Sweeney+21.2 mph (+20.5%) | +4.157squal +9.464s | 103.6%qual 108.4% | |||||||
9 rule changes (FF: 3, GTX: 3, GT3U: 3)3 weight · 2 cars added · 2 tyres & wheels · 1 engine · 1 wording · FF clarifies alternative tire eligibility for cars homologated 1989 or earlier with rocker arm or outboard suspension on all four corners. · GTX Misc Table 4 adds RCR T70 Coupe with 2200 lbs minimum weight, no restrictor specified. · GTX Ligier LMP3 now allows any normally aspirated LS Chevrolet engine. · FF adds rocker arm and outboard suspension cars optional bias ply and VFF tires; removes front-as-rear rule, adds mixing restrictions. · STU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments. · GTX Porsche GT2 RS Clubsport classified with factory specifications required at all race events. · STU-GT3U non-TCR cars may reduce weight by 4% after all other modifiers. · FF allows older cars with rocker arm or outboard suspension to use bias ply slicks or VFF tires instead of radials. · STU GT3U minimum weight increases 150 to 250 pounds.show
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| Cal Club 2025 CALCL252025-02-22 | 1:52.044Eric Poulsen · only car | 1:51.118Eric Poulsen · only car | 114.7Eric Poulsen | 1:49.596Rob Scholl · only car | 116.4Rob Scholl | -1.522s | 98.6% | 2:00.536Michael Lewis · fastest of 2 | 1:55.650Michael Lewis · fastest of 2 | 108.8Michael Lewis | +4.532squal +8.492s | 104.1%qual 107.6% | 2:02.354Gavin Sweeney · fastest of 5 · top 5 within 10.3s | 2:01.197Gavin Sweeney · fastest of 5 · top 5 within 9.6s | 103.5Gavin Sweeney | +10.079squal +10.310s | 109.1%qual 109.2% | |||
71 earlier rule changes on record, in force before Cal Club 2025 (from 2019)20 cars added · 6 tyres & wheels · 3 engine · 3 induction · 3 weight · 2 aero · 1 suspension & brakes · 33 wording · TA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement. · FF and FC cars with sequential gearbox must add 10 lbs. to minimum weight, down from 25 lbs. · FF Honda Fit allows Fast Forward 0.25mm oversize pistons PN FF800-110 as alternative; piston diameter spec clarified to 2.8835 inches. · FF VTEC activation valve must function; EGR blanking plate rule clarified with Fast Forward part numbers. · FV ferrous rotor no longer required to be smooth; may have up to three pad cleaning grooves per side. · GT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR. · GT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed. · GT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors. · GT2/3 Nissan, Mazda, Mitsubishi 4G93, QR25DE/DD, QE25DE/DD Direct Injection now permitted per 9.1.2.F.7.5.E. · FF Honda Fit gains Fast Forward FF800-100 oversize piston ring pack option. · GTX adds KTM X-Bow classification with restrictor and weight specifications effective 2024-01-01. · FV front wheel bearings wording clarified in GCR 9.1.1.C.10.G. · GTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL. · GTX Ligier LMP3 3.7L NA classified at 2203 lbs with 22 mm restrictor. · GTX Ligier JSP4 newly classified as GTX Misc with restrictor and weight specified. · Fields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight. · FF Honda Fit engine adds Fast Forward part number alternatives for intake, exhaust, oil system, and scavenge pump components. · GT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870. · GT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only. · Porsche 992 GT3 Cup Car newly classified in GTX. · GTX Wolf GB08 F1 Ford 52XS V8 added to classification at 1725 lbs minimum weight. · C7 Corvette Grand Sport classified in GTX Misc at 3200 lbs with option to remove displacement on demand valve train. · GTX eligible prototypes expanded: IMSA GTP years changed to 1981-1993, five prototype categories added. · FV connecting rod rules add Brian Crower part #BC6417 and Newland Group #4M113077 as allowed replacements. · FV connecting rods minimum weight 425.0 grams, center-to-center length 130 ± 0.10/-0.25 mm specified. · GTX McLaren 720s GT3 newly classified at 3000 lbs with 3000 mm restrictor. · GTX-FIA GT3 removes all intake restrictor requirements for fifteen car models; McLaren name corrected. · FV connecting rod suppliers clarified: Crower SP93280B and BrianCrower BC6417 allowed as direct replacements. · FV allows Crower SP93280B and Brian Crower Racing Rods as direct replacement connecting rods, must meet OEM minimum weight. · GT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight. · GTX SRO-GT4 Porsche 718 Club Sport MR GT4 classified, unrestricted, 2900 lbs minimum weight. · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix. · Grullon GT with 2.0L K20 moved from GTX to GT2-ST, minimum weight 2350 lbs, unrestricted. · GTX Grullon GT added, unrestricted, 2350 lbs, factory spec required. · FF block relief permitted only as needed to fit allowed crankshaft. · FF class cylinder head may now have optional coolant bleed line fitting to top of head for air release. · FF Honda LC1 ECU by HPD permitted effective 12/1/2020, must use HPD lambda sensor. · GT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line. · FF Honda LC1 ECU implementation date changed from 3/1/2020 to pending availability of support materials. · GTX Chevrolet Camaro ZL1 LT4 with factory supercharger classified at 3400 lbs minimum weight. · GTX adds KTM X-Bow GT4, turbocharged 2.5L Audi TFSI I5, 2000 lbs minimum weight. · FV now allows 4 bolt wheels, previously restricted to 5 bolt wheels. · FV now supports 4-bolt pattern wheels in addition to existing wheel specifications. · TA2 Gurney flap wording clarified: terminology standardized to 'Gurney flap', height limits and thickness specifications remain 0.50 inch / 0.625 inch or 0.375 inch / 0.0625 inch depending on configuration. · STO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules. · GT classes clarify Gurney flap wording, replacing wickerbill/tab terminology with flap; specifications unchanged. · GTX tube frame cars must weigh 2780 pounds; stock car bodies now permitted. · GTX adds Lotus Evora GTS with 3.5L 2GR-FE engine, no restrictor, 2950 lbs minimum weight. · FF alternator changes from not required to optional. · FF allows Honda HPD LC1 low-cost ECU with lambda sensor; E1 ECU no longer supported but existing units permitted if sealed. · FF rain tyres now allow Hoosier W3 Radial in addition to existing Hoosier Wet option. · FV rain tire requirement changed to Hoosier #44266 22.5 x 5.0 x 15 WET or W3. · GT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications. · FV allows non-spec Hoosier tires in Regional races until 2020-01-01, when spec tires become required. · FV allows rear tires on front of car; mandates Hoosier #43337 fronts and #43353 rears, plus #44266 rain tire from 2020-01-01. · Factory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs. · FV wheels clarified: 15" x 4J standard or 15" x 4.5J steel VW, 5-bolt pattern, same track dimensions. · FV exhaust outlet location tightened to 1–4 inches behind rearmost body part. · FV wheels now permit 15-inch 4.5J steel wheels within C.2 track dimensions, adding to standard 4J options. · FV exhaust opening can now extend to 4 inches behind body rear, previously 3 inches maximum. · FV front track maximum 52.500" and rear track 49.125"-50.750" no longer prohibits spacers. · GTX tube frame cars gain fuel injection with 90mm maximum throttle body size. · Ligier JS2 R classified in GTX, no performance parameters specified in filing. · FV disc brake assembly minimum weight clarified to 16.5 lbs total; caliper minimum weight requirement removed. · GT1 and GT2/GT3/LITE ride height requirements removed from GCR sections 9.1.2.D.5.a.1 and 9.1.2.F.7.b. · GTX replaces all FIA GT4 references with SRO GT4. · FF Honda Fit permitted to use 0.25mm oversize pistons, cylinder honing increased to 73.315mm maximum. · FF heat shield rule clarified: thermal wrap allowed on manifold exterior if easily removable for inspection. · FF catch tank minimum capacity rules clarified: coolant catch tank now one U.S. pint minimum, oil catch tank one U.S. quart minimum. · FV intake manifold horizontal tube measurement locations clarified between 1.500" and 8.000" on short side. · GTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified.show
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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 FF" is the class's best as a share of FF'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 FF'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.