BoP Lab / Buttonwillow Raceway Park
T1 vs SMX vs SRF3 vs FE2 pace at Buttonwillow Raceway Park
Quickest here: T1 1:46.465 Ian Barberi, Cal Club 2025 qualifying · SMX 1:56.431 Ethan Lampe, Cal Club 2025 qualifying · SRF3 1:50.233 Caleb Shrader, Cal Club 2025 qualifying · FE2 1:39.265 Jon McClintock, Cal Club 2026 qualifying
| Event | T1 | SMX | SRF3 | FE2 | ||||||||||||||||
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| Qual best | Race best | Trap | Qual best | Race best | Trap | vs T1 | % of T1 | Qual best | Race best | Trap | vs T1 | % of T1 | Qual best | Race best | Trap | vs T1 | % of T1 | |||
| Cal Club 2026 CALCL262026-02-21 | 1:59.760Ed Gless · only car+13.295s (+12.49%) | 1:59.123Ed Gless · only car+11.689s (+10.88%) | 120.7Ed Gless-18.6 mph (-13.3%) | 1:56.503Lincoln Larson · fastest of 15 · top 5 within 0.7s+0.072s (+0.06%) | 1:57.973William Wallis · fastest of 15 · top 5 within 0.8s+0.556s (+0.47%) | 141.6Joey Andrews+28.0 mph (+24.6%) | -1.150squal -3.257s | 99.0%qual 97.3% | 1:50.913Asad Nikadambaev · fastest of 27 · top 5 within 1.1s+0.680s (+0.62%) | 1:52.070Asad Nikadambaev · fastest of 27 · top 5 within 0.8s+1.245s (+1.12%) | 138.9Paul Marino+20.7 mph (+17.5%) | -7.053squal -8.847s | 94.1%qual 92.6% | 1:39.265Jon McClintock · fastest of 3 · top 3 within 1.5s-0.093s (-0.09%) | 1:40.253Jon McClintock · fastest of 3 · top 3 within 2.2s+0.541s (+0.54%) | 156.6Paul Marino+29.4 mph (+23.1%) | -18.870squal -20.495s | 84.2%qual 82.9% | ||
23 rule changes (T1: 13, SMX: 4, SRF3: 4, FE2: 2)4 weight · 3 cars added · 2 induction · 1 removed · 1 tyres & wheels · 11 wording · 1 other · T1 Corvette C6 LS1/LS6 Spec Line reinstated: 3200 lbs minimum weight, 70mm restrictor required. · T1 Spec Line restrictor changes from 70mm flat plate to unspecified new specification. · Unable to summarize: letter states intent but provides no actual rule changes to S2000 specification. · T1 non-GT4 cars: multiple restrictors enlarged (70mm to 73mm, 75mm to 78mm, 55mm to 60mm, 61mm to 70mm); one weight increased to 3600. · T1 BMW M3 E92 (08-13) Spec Line 1090 removed entirely. · FE and FE2 Enterprises must use bubble tail P/N WM138014; FE2 allows only this configuration. · SRF3 adds HD Oil Cooler P/N G1148500 as alternative to standard cooler P/N G480503. · SRF3 brakes restructured: Hawk Blue 801993 pads, Wilwood 800065 rotors only; adds Girling 880358, Wilwood 880357, Tilton 880360 master cylinders. · SMX drivers must submit data acquisition files on time or face suspension and $250 fine. · SMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fine; level 2 and 4 may carry $500 fine. · SMX Toyo RR P235/40/ZR17 tire rules clarified: one set per weekend, marking after first session, damage replacement procedures revised. · SMX data submission deadline extended from 30 to 60 minutes after each timed session. · Porsche 981 GT4 Clubsport added to T1 as spec line 4085, minimum weight 3100 lbs with driver. · T1 Honda S2000 minimum weight reduced from 2950 lbs to 2900 lbs. · T1 BMW E46 M3 permits BMW #GS7D36SG aftermarket sequential transmission in SL# 1060 and 1070. · T1 BMW M3 E92 minimum weight reduced to 3300 lbs. · T1 Mustang Darkhorse R gets 315 front and rear tyres, loses 500 lbs minimum weight to 3600. · FE2 allows driver safety and comfort modifications for disabled drivers with SCCA approval, not transferable to other drivers. · SRF drivers with disabilities may modify seat and controls for safety and comfort with approval and logbook notation. · SRF SADEV-SRF3 6-speed sequential transmission gear ratios wording clarified, effective 2025-04-01. · Cadillac CT4-V Blackwing added to T1 Spec Line 1115, 3564cc, 3750 lbs minimum weight. · T1 Mustang Spec 1430 restrictor opens 60mm to 65mm; Spec 1460 weight rises to 3500 lbs, restrictor 70mm; Corvette 1190 restrictor opens 67mm to 70mm; BMW 1090 restrictor narrows 40mm to 35mm; BMW 1100 weight rises to 3350 lbs.show
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| Cal Club 2025 CALCL252025-02-22 | 1:46.465Ian Barberi · fastest of 2 | 1:47.434Ian Barberi · fastest of 3 · top 3 within 11.8s | 139.3Drew Delmonico | 1:56.431Ethan Lampe · fastest of 15 · top 5 within 1.5s | 1:57.417Ethan Lampe · fastest of 15 · top 5 within 1.6s | 113.6Ryan Gutile | +9.983squal +9.966s | 109.3%qual 109.4% | 1:50.233Caleb Shrader · fastest of 33 · top 5 within 0.4s | 1:50.825Caleb Shrader · fastest of 32 · top 5 within 0.8s | 118.2John Black | +3.391squal +3.768s | 103.2%qual 103.5% | 1:39.358Paul Marino · fastest of 4 · top 4 within 1.5s | 1:39.712Paul Marino · fastest of 4 · top 4 within 1.7s | 127.2Tom Hope | -7.722squal -7.107s | 92.8%qual 93.3% | ||
145 earlier rule changes on record, in force before Cal Club 2025 (from 2019)26 cars added · 22 weight · 12 tyres & wheels · 11 induction · 8 suspension & brakes · 5 engine · 4 aero · 1 removed · 54 wording · 2 other · T1 Mustang gains 125 lbs to 3600, restrictor shrinks 65mm to 60mm. Corvette gains 50 lbs to 3500, restrictor shrinks 70mm to 67mm. BMW deleted. · T1 E46 M3 Spec Line 1050 allows VAC Motorsports throttle body VAC-TB-S54 on 3.250L engine instead of Dinan. · T1 Chevrolet Corvette C8 (2023-23) minimum weight reduced from 3600 lbs to 3500 lbs. · T1 Chevrolet Camaro Gen 5 restrictor increases from 75mm to 80mm flat plate. · T1 Audi R8 GT4 Spec Line #4020 maximum tyre size changes to 315 DOT, 305/645, or 30/65-18 (f), 33/68-18 (r) Non-DOT. · SMX allows OE instrument cluster relocation for aftermarket dash mounting, with wiring re-routed only; alternate gauges now permitted. · T1 GT4 tire sizes adjusted across ten cars: most non-DOT rear to 305/660, Audi and McLaren 305/645, Camaro and Mustang 305/680. · BMW M4 GT4 (G82) added to T1 GT4 at 3525 lbs minimum weight with Red power stick control. · T1 Spec Lines now permits 5.5 inch clutch in Engine Notes. · T1 GT4 Spec Line 4020 restrictor opens from 44mm to 45mm, minimum weight drops to 3400 lbs. · Mustang Darkhorse R added to T1 homologated cars at 3,250 lbs minimum with 305/315 tires, ineligible for Runoffs until 3 Super Tour events. · T1 Corvette may roll or flatten wheel opening lips for tire clearance; plastic fenders may remove lips if edge thickness matches basic material. · T1 E46 M3 S54 can now use Dinan Throttle Body #D760-3400 on 3.250L engine. · SRF3 air filter rule removes K&N RC-9160 option, leaving only P/N WM301020 allowed. · SRF brake rotor minimum thickness increases from 12.20mm to 13.25mm, Wilwood vented rotor P/N 800065. · SRF3 Hoosier logo placement changes from four decals to three decals in different locations. · SMX Spec MX-5 camera requirement wording changed; non-functioning recorder now grounds for penalty or disqualification. · SMX Spec MX-5 must run latest AIM Data Logger Spec MX-5 ECU Protocol; wording clarification for technical compliance. · SMX Mazda Miata OE versus OEM definitions clarified in GCR Section 9.1.7.1. · SM and SMX shifter bushing rules clarified: alternate bushing at shift lever bottom now allowed. · SRF Hoosier decal requirement reduced from four decals in specific locations to three decals with simpler placement rules. · SRF wet tires: P185/60R13 H20/W2 option removed; P185/65R13 W2 front now required with P205/60R13 W2 rear. · SRF3 alternator pulley minimum weight reduced from 12 oz to 11 oz. · Mercedes AMG-C63 S (2023) classified in T1 with 4000 lbs minimum weight and 3700 restrictor. · T1 Honda S2000 classified with 2400 lb minimum weight, 2950 cc displacement, 4.75" supercharger pulley. · Pontiac GTO 2006-2009 LS1 added to T1 as Spec Line 1590, 5700 cc, 3400 lbs minimum. · C8 Corvette T1 restrictor plate increases from 70mm to 72mm flat plate. · T1 NEW class removes 23 spec lines including Acura NSX, Ferrari, Porsche 996, Nissan Z cars, and others; Porsche 997 spec line 1680 expiration removed. · SRF rain/brake light now requires Super Bright LEDs Inc. P/N PT-STRB-R24 with specific connector and rain light switch. · SRF requires Super Bright LEDs P/N PT-STRB-R24 rain/brake light with strobing capability and specific wiring. · SRF adds brake duct and pedal extension rules, rear shift cable clamp option, camber limit to 5.0°, radiator opening height 3.5" ±0.5", and P2 engine restrictor changes. · T1-GT4 batch adjustments: five cars lighter, two heavier, restrictors and ECU maps changed, five models now eligible for Runoffs. · T1 spec lines 1000, 1010, 1020, 1040, 1360, 1400–1410, 1520–1680, 1700–1720 deleted entirely. · T1 Chevrolet Corvette C5 LS2 added with 6000cc displacement, 3300 lbs minimum weight, 72mm flat plate restrictor. · T1 Chevrolet Corvette C7 (14-19) including Z51, Grandsport newly classified as homologated car. · T1 Gen 5 Camaro minimum weight drops 75 lbs to 3475; restrictor increases 70mm to 75mm. · T1 Aston Martin Vantage permitted to use OEM Sportshift II transmission. · Pontiac GTO 2006-2009 re-integrated into T1 with LS2 at 3400 lbs, 72mm restrictor, and LS3 at 3500 lbs, 61mm restrictor. · T1 Porsche 997-1 GT3 Cup added at spec line 4210, minimum weight 3050 lbs. · SRF radiator rule clarified: P/N 480466 replaceable with Automotive P/N 1R698, CU698 or manufacturer equivalent with documentation. · Chevrolet Camaro GT4-R classified in T1 GT4 Spec Line 4035, minimum weight 3375 lbs, 315 max tire, 63mm restrictor, ineligible for Runoffs. · T1 Dodge Viper ACR / SRT RT-10 and ACR/ACR-X spec lines 1350 and 1370 remove 12/23 expiration. · T1 GT4 McLaren 570S, Mercedes AMG GT4, and Porsche 718 Cayman GT4 CS MR now eligible for Runoffs competition. · T1 GT4 BMW M4 Spec Line Number changed from 4050 to 4030. · T1 Corvette C5 gains approved aero parts: carbon rear spoiler, vented front splitter, side skirts, with 50 lb weight reduction allowed. · T1 Dodge Viper ACR/ACR-X restrictor increases from 50mm to 60mm flat plate. · T1 Dodge Viper ACR/ACR-X: Spec Line 1370 restrictor increases to 55mm, Line 1390 decreases to 55mm. · T1 Ford Mustang S197 05-14 now requires OEM 8.8 differential housing. · T1 Chevrolet Camaro Gen 5 LS7 gets two spec lines: 1131 with 70mm restrictor, 1136 with 53mm restrictor, both 3450 lbs minimum. · T1 Chevrolet Camaro Gen 5, Corvette C5 and C6: engine resleeve restricted to stock parameters only, no longer LS3 bore/stroke. · SRF Hoosier wet front tire updated to P/N 46100 P185/60R13 H20 or W2. · T1 Ford Mustang S197 (05-14) reinstated with 3550 lbs minimum weight, 75mm restrictor, Voodoo engine permitted. · SRF Hoosier front rain tyre part number changes from 46100 to 46101 P185/65R13 W2. · T1 GT4 weights clarified for nine cars, ranging from 3200 lbs Porsche 718 Cayman to 3575 lbs Aston Martin. · T1-GT4 McLaren 570S and Mercedes AMG GT4 front tires widen to 315 mm. · T1 Chevrolet Camaro Gen5 LS3-6160 adds 70mm flat plate restrictor, weight 3550 lbs. · SRF Renault Alliance solid front rotors banned; restrictor reduced 35mm to 34mm for 2011+ Kawasaki; minimum weight increased to 1100 lbs for 2009+ stock engines. · SRF3 tail sections allowed on SRFs with GEN3 airbox shimming up to 19 mm; alternate dash panel P/N 180100 or 180101 relocated in rules. · T1 cars with aftermarket sequential transmissions get 10-inch max bellhousing; non-sequential cars gain 100 lbs weight break. · T1 GT4 all nine cars lose 125 lbs minimum weight with driver, from 3200–3575 to 3075–3450. · T1 removes GCR Section 9.1.9.1.A. and T1 Spec Lines entirely, sunsetting pre-2023 Touring 1 rules. · GT4 McLaren 570S maximum tire size changes to 285 front, 315 rear. · Eight GT4 models added to T1 with weights from 3200 to 3575 lbs and restricted power per SRO 2022 rules. · T1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird, Pontiac GTO 6162 OEM minimum weight reduced to 3475 lbs. · SRF tire rule wording changed from 'Tires: must be run as delivered' to 'Tires must be run as delivered.' · SRF brake rotor minimum thickness reduced from 13.25 to 12.20mm; seal and air filter rules clarified. · T1-LP Ford Mustang FP350S restrictor increases from 70mm to 75mm. · Mercedes Benz AMG GT4 2017-2021 classified T1 Maximum at 3400 lbs minimum weight with HP-controlled SRO Power Level 2 engine. · T1 Dodge Viper ACR displacement rises to 8400 OEM, minimum weight drops to 3550 lbs. · T1 Limited T1 wording changed to clarify all T1 cars permitted specifications. · T1 Mazda RX-7 classified: 2700 lbs minimum weight, 44mm restrictor, 13B Rotary with single Garrett Turbo #3076. · T1 Cadillac CTS/CTS-V, Chevrolet Camaro, Pontiac Firebird, Pontiac GTO LS3 minimum weight reduced to 3475 lbs. · T1 Camaro maximum displacement 7011 loses 50 lbs, to 3500. · T1 removes 33mm brake rotor thickness limit; rotors now unrestricted on thickness. · SRF front wet tire changes from P185/60R13 H20 to P185/65R13 W2; SRF3 adds mandatory G301048 restrictor plate Jan. 1, 2022. · T1 Mazda MX-5 Miata MazdaSpeed minimum weight rises to 2550 lbs, restrictor increases to 42mm. · T1 Chevrolet Corvette Cadillac XLR classified for model years through 2019. · SRF wet tyres add Hoosier P185/60R13 W2 front and P205/60R13 W2 rear as alternatives to H20. · SRF adds SADEV-SRF3 6-speed sequential option with final drive 3.20 versus OEM 5-speed 3.85. · SRF seal procedures clarified: unsealed components need CSR inspection and logbook notation instead of engine removal. · T1 BMW E46/E36/Z3 minimum weight increases to 2700 lbs, 3.4L engine car to 2750 lbs. · T1 Dodge Viper SRT-10 restrictor increases from 45mm to 57mm. · T1 Chevrolet Corvette Cadillac XLR LS6 engine now permits Casting #799 heads with no other head modifications. · SRF3 alternator pulley restricted to P/N G902130 or G902130A, 12oz minimum weight. · T1 Ford Mustang Shelby/GT350/GT500 5.0L Coyote restrictor opens from 65mm to 70mm flat plate. · T1 Dodge Viper SRT-10 restrictor increases from 45mm to 57mm. · T1-LP Chevrolet Corvette C7 restrictor increases from 70 to 73 mm. · T1-LP Corvette Z06 06-13 now allows aluminum chassis replacement with equivalent OE steel chassis. · T1 Chevrolet Camaro with 6162 displacement minimum weight reduced to 3500 lbs. · T1-LP Chevrolet Corvettes C5 Z06, C6 Grand Sport, and Z06 dry sump kit notes clarified to remove contradictions. · SRF and SRF3 mandatory identification simplified: removed Ford Performance and Blue Oval decals, kept Hoosier logo placement. · T1 LP removes 50 lbs weight allowance for stock headers, adds aero device allowance up to 100 lbs, permits headers. · T1 Ford Mustang Challenge 3-valve maximum displacement changes to 4600/5000. · T1 BMW E46 now allows carbon or fiberglass OEM-style dashboards with 25 pound penalty. · T1 Ford Mustang/Thunderbird limited to Shelby/Shelby GT350/GT500 models through 2018. · Dodge Viper ACR classified in T1 with 8400cc displacement, 3600 lbs minimum weight, 55mm restrictor. · BMW M2CS Club Sport classified in T1-LP Spec Lines effective 2021-02-01. · Porsche 997.1 GT3 Cup (2006-2011) classified in T1 at 3600cc, 3150 lbs minimum weight. · T1 Chevrolet Corvette Z06 years extended from 06-12 to 06-13. · SRF shocks, springs, bump stops sealed; rear springs 412-429 lbs/in P/N 280390 only; previous parts no longer allowed. · T1 Corvette C8 Z51 gets wider wheels and tyres, weight drops 100 lbs to 3550. · FE2 oil cooler wording clarified: optional air-to-oil cooler allowed, Setrab 50-625-7612 or equivalent max 13 inches wide by 6.5 inches high. · T1 rear wing Gurney flap wording clarified: Gurney flap in chord length and mounting height rules. · SRF3 shock absorber brand restriction removed; all shocks must be sealed by Enterprises. · T1 and T2 Corvettes may convert leaf spring suspension to coilover with 800 lb max spring rate allowed. · SRF3 bump stop now must be SCCA P/N 280407 only, no modifications, optional, max one per shock. · SRF shock absorber bump stop clarified: only SCCA P/N 280407 allowed as delivered, maximum one per shock, effective 05/01/2020. · T1 Porsche 996 GT3 Cup eligible model years changed from 2002-2005 to 1998-2004. · T1 Corvette and Cadillac XLR permitted to install SCRSPLR-001 rear spoiler with OE bodywork. · T1 Gen 5 Camaro allowed 366mm OEM rear rotor and caliper without weight penalty. · T1 Porsche 996 Spec Lines now allows 996 Cup Replica Rear deck lid. · T1 Acura NSX Turbo World Challenge and Audi TTRS GTS 2011 now require DOT tires per GCR section 9.3. · T1 BMW E46 wagon with S54 engine allowed; displacement corrected from 3200 to 3250cc. · T1 adds Subaru WRX/WRX STI 2005-2020 at 3000 lbs minimum weight with 46 mm restrictor. · T1 Ford Mustang GT (15-17) and GT5.0L (2018-) weight raised to 3500 lbs; Brembo BBK 380mm now at no penalty; restrictors removed from notes. · T1 Ford Mustang/Thunderbird 5000 Coyote OEM reclassified to include 2015–2017 and 2018+ model years with 65mm restrictor for 18+. · T1 BMW M3 E92 carbon dash allowed with 25 lb penalty. · T1 Corvette C5 Z06, C6 coupe, C6 Grand Sport, and Z06 may convert leaf springs to conventional coilover suspension. · SRF rain and brake rule wording updated; supersedes GCR 9.3.32.B.2 effective 1/1/202 through 12/31/2024. · FE and FE2 minimum weight increased to 1270 lbs including driver; spring options and tire warmer ban added. · SRF bans tire warmers and cooling methods other than natural air convection or conduction. · SRF front nose weight minimum reduced from 35 to 32 lbs. · SRF3 reclassified as Spec Racer Ford 3 with 1.6L conversion; SRF2 becomes Regional Only Class. · T1-LP Chevrolet Camaro 1LE 2016- weight drops to 3500 lbs, restrictor increases to 70mm flat plate. · Ford Mustang Challenge returns to T1 as E&O, 4600 cc, 3300 lbs minimum, no restrictor. · T1 Chevrolet Corvette Cadillac XLR year range corrected from 04-09. · SRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102. · T1 Camaro, CTS, Firebird, GTO restrictor increases from 67mm to 70mm flat plate. · SRF3 nose assembly must use approved multi-piece design; no modifications allowed except as specified. · T2-T4 clarifies DOT tire requirements; must have minimum U speed rating and be DOT certified; touring spec line supersedes other rules. · SRF3 brakes now allow Hawk Blue 9012 pads P/N 801993 only; shocks simplified to Penske P/N 280396 sealed assembly only, with optional SCCA Enterprises bump rubber P/N 280407 from 05/01/2020. · Ford Mustang EcoBoost 3.5L classified in T1 at 3300 lbs minimum weight with 31mm restrictor. · T1 Corvette C5 body allowed C7 carbon aero parts, plus 50 lbs. · T1 Audi TTRS must conform to July 24th, 2015 revision 7 GTS rules instead of December 14th, 2011 revision 3. · T1 minimum ride height established at 3.5 inches, measured at rocker panel without driver. · T1 Porsche 928 S4/GTS-R minimum weight reduced to 3200 lbs, throttle restrictor removed. · Porsche 928 S4/928 GTS-R newly classified in T1 at 3500 lbs minimum with 60mm flat plate restrictor. · T1-LP Ford Mustang GT 5.0L 2018+ classified at 3400 lbs with 65mm flat plate restrictor. · T1-LP Mustang GT350(R) spec line replaced with 2015+ model parameters including 5163cc engine, 3650 lbs curb weight, 315 tire size. · Ford Mustang FP350S (2018) classified in T1-LP at 3600 lbs with 18×11 wheels and 315 tires. · T1 suspension rules clarified: spherical bearings and bushings now explicitly permitted, alternate control arms allowed. · T1 Porsche 996 drops 200 lbs to 3000; 996 GT3 Cup drops 150 lbs to 3000; 997 drops 50 lbs to 3100. · Porsche 997 T1 Maximum now allows OEM PDK transmission alongside existing drivetrain options. · T1 Acura NSX Turbo World Challenge weight to 3100 lbs, restrictor to 44mm. · T1-T3 spec cars receive clarifications on permitted modifications, documentation requirements, and rule conformance; no performance changes.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 T1" is the class's best as a share of T1'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 T1'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.