STL vs SM vs FE2 vs GTL pace at Buttonwillow Raceway Park
Quickest here:STL 1:54.845 Gavin Wardle, Cal Club 2026 race · SM 2:00.831 William Wallis, Cal Club 2025 qualifying · FE2 1:39.265 Jon McClintock, Cal Club 2026 qualifying
STLSMFE2GTLsolid race · dashed qualifying · slower is lower
STLSMFE2GTLsolid race · dashed qualifying · each class's best lap as a share of STL's at the same event (the reference class, changeable above); 100% is level, higher is quicker
Event
STL
SM
FE2
GTL
Qual best
Race best
Trap
Qual best
Race best
Trap
vs STL
% of STL
Qual best
Race best
Trap
vs STL
% of STL
Qual best
Race best
Trap
vs STL
% of STL
Cal Club 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%)
2:01.392Ryan Busk · fastest of 18 · top 5 within 0.8s+0.561s (+0.46%)
2:02.486William Rasmussen · fastest of 18 · top 5 within 1.3s+0.836s (+0.69%)
127.3Sam Rezai+23.4 mph (+22.6%)
+7.641squal +3.866s
106.7%qual 103.3%
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%)
-14.592squal -18.261s
87.3%qual 84.5%
8 rule changes (STL: 3, SM: 3, FE2: 2)2 weight · 6 wording · STL minimum weights increase across all classes, 1300 cc gains 195 lbs to 1950, up to 1850 cc at 2500. · FE and FE2 Enterprises must use bubble tail P/N WM138014; FE2 allows only this configuration. · STL/STU Lotus weight reduced: Evora GT4 to 2700 lbs, Elise Cup R to 2250 lbs, Elise/Exige SC to 2450-2550 lbs. · 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. · SM cars limited to one set of Hoosier SM 7.5 P205/50/ZR17 per Super Tour event weekend for dry sessions. · STL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1 instead of 2500 lbs; spec components removed, only alternative tires allowed. · FE2 allows driver safety and comfort modifications for disabled drivers with SCCA approval, not transferable to other drivers.showhide
STL Weight adjustment for STL #39579weightslowerSTL minimum weights increase across all classes, 1300 cc gains 195 lbs to 1950, up to 1850 cc at 2500.
FE2 FE & FE2 Bubble Tail #38978wordingneutralFE and FE2 Enterprises must use bubble tail P/N WM138014; FE2 allows only this configuration.
STL Lotus Weight Reduction #38772weight -50 lbsfasterSTL/STU Lotus weight reduced: Evora GT4 to 2700 lbs, Elise Cup R to 2250 lbs, Elise/Exige SC to 2450-2550 lbs.
SM SMX Data Submission - Penalties #38248wordingneutralSMX drivers must submit data acquisition files on time or face suspension and $250 fine.
SM Committee) SMX Penaly Clarification updated language #38337wordingneutralSMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fine; level 2 and 4 may carry $500 fine.
SM Clarify Tire Marking Regs #38005wordingneutralSM cars limited to one set of Hoosier SM 7.5 P205/50/ZR17 per Super Tour event weekend for dry sessions.
STL E&O: SMX Allowance in STL #37945wordingunclearSTL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1 instead of 2500 lbs; spec components removed, only alternative tires allowed.
FE2 Driver Safety & Comfort #37965wordingneutralFE2 allows driver safety and comfort modifications for disabled drivers with SCCA approval, not transferable to other drivers.
Cal Club 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
2:00.831William Wallis · fastest of 16 · top 5 within 0.9s
2:01.650Nick Leverone · fastest of 16 · top 5 within 0.3s
103.9Evan Jacobs
+5.968squal +5.868s
105.2%qual 105.1%
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
-15.970squal -15.605s
86.2%qual 86.4%
31 rule changes (STL: 6, SM: 5, GTL: 20)6 cars added · 4 induction · 4 weight · 2 engine · 1 aero · 14 wording · TA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement. · SMX allows OE instrument cluster relocation for aftermarket dash mounting, with wiring re-routed only; alternate gauges now permitted. · STL/STU: 90-05 Mazda Miata alternate front wheel hubs moved from General to specific part approval. · GTL Toyota G16E-GTS removes direct injection ban wording, effective 11/1/2024. · GTL Nissan L16 limited prep gains alternate 32mm choke option at 1910 lbs minimum weight. · GTL adds Toyota GR86 2021-2023, 2dr RWD, 101.3 in wheelbase. · GTL adds Spec Miata 1990-2005 with legal Spec Miata engine and intake system. · Mazda MX5 RF 2017- added to GTL with 91.0 inch wheelbase. · 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. · GTL added to GT3 choke option line for induction control. · GT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR. · GTL Datsun 510 L16 Limited Prep allows 34 mm chokes, minimum weight rises to 2000 lbs. · 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. · STL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems. · STL Acura/Honda B-series and Mazda MZR restrictors reduced 2mm; minimum weights down 25–75 lbs for 1900–2000cc engines. · STL Mazda 12A must keep 5th and 6th intake port actuators and valves, no longer allowed removal or disabling. · GTL Mazda 12A rotary engines may machine and use 13B housing to O.E. 12A specifications. · GTL Toyota GR86 (DR86, 2021-2024, 2-door RWD, 101.3-inch wheelbase) newly classified. · GTL BMW Mini years corrected to 2002-2013. · STL Mazda RX-7 12A (79-85) now allows auto-type 2 bbl with 42mm choke(s) on dual-y manifold as alternate to stock Nikki 4 bbl. · GTL small unrestricted engines under 1399cc lose 40-50 lbs across Alfa, AMC, Triumph, Mini, Sprite, Fiat, Ford, Honda, Mazda, Nissan, Subaru, Toyota, Volkswagen. · GTL Honda Fit 2009-13 2-door FWD classified with wheelbase options 94.0, 97.0, or 99.0 inches. · GTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL. · GTL Nissan Sentra/200SX A14 engine weight reduced from 1850 lbs to 1800 lbs. · STL ITA/ITS RX7 and 1985+ ITA/ITS/ITB/ITC vehicles clarified to conform to section 9.1.4.2 tire specifications. · Fields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight.showhide
GTL Correct language regarding OEM Areo Devices #37137wordingneutralTA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement.
SM E&O SMX Regs 9.1.7.1.D.5.u-.w #37070wordingneutralSMX allows OE instrument cluster relocation for aftermarket dash mounting, with wiring re-routed only; alternate gauges now permitted.
STL Request to Remove Miata Hubs from General category #37138wordingneutralSTL/STU: 90-05 Mazda Miata alternate front wheel hubs moved from General to specific part approval.
GTL G16E-GTS Fuel Injection Spec Line Change #36588wordingunclearGTL Toyota G16E-GTS removes direct injection ban wording, effective 11/1/2024.
GTL GTL Alternate Weight and Choke Option for L16 engine #36653inductionfasterGTL Nissan L16 limited prep gains alternate 32mm choke option at 1910 lbs minimum weight.
GTL Request to Include Toyota GR86 in GTL #36324cars addedneutralGTL adds Toyota GR86 2021-2023, 2dr RWD, 101.3 in wheelbase.
GTL Inclusion of Modified Spec Miata for GTL competition #36325cars addedneutralGTL adds Spec Miata 1990-2005 with legal Spec Miata engine and intake system.
GTL Include Mazda MX5 RF 2017- in GTL #36428cars addedneutralMazda MX5 RF 2017- added to GTL with 91.0 inch wheelbase.
SM SMX Camera Rule Correction #36496wordingneutralSMX Spec MX-5 camera requirement wording changed; non-functioning recorder now grounds for penalty or disqualification.
SM Committee) AIM ECU Protocol #36556wordingneutralSMX Spec MX-5 must run latest AIM Data Logger Spec MX-5 ECU Protocol; wording clarification for technical compliance.
SM Committee) OE versus OEM Definitons #36608wordingneutralSMX Mazda Miata OE versus OEM definitions clarified in GCR Section 9.1.7.1.
SM Committee) Shifter Bushing #36611wordingneutralSM and SMX shifter bushing rules clarified: alternate bushing at shift lever bottom now allowed.
GTL Add GTL to GT3 choke option line. #36236wordingunclearGTL added to GT3 choke option line for induction control.
GTL Request for Spec Line 1010 Reconsideration #35009weight +300 lbsslowerGT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR.
GTL Allow 34 mm chokes for the Datsun 510 #35661weight +50 lbsslowerGTL Datsun 510 L16 Limited Prep allows 34 mm chokes, minimum weight rises to 2000 lbs.
GTL Rear Blade Spoiler Clarification #35261aerofasterGT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed.
GTL GT Direct Injection allowance and rules #35437enginefasterGT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors.
GTL GT2/3 remove Direction Injection not allowed in Spec line notes #35439inductionfasterGT2/3 Nissan, Mazda, Mitsubishi 4G93, QR25DE/DD, QE25DE/DD Direct Injection now permitted per 9.1.2.F.7.5.E.
STL ST Electric-Assisted Steering Systems #35066wordingneutralSTL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems.
STL BOP Adjustments #35112inductionfasterSTL Acura/Honda B-series and Mazda MZR restrictors reduced 2mm; minimum weights down 25–75 lbs for 1900–2000cc engines.
STL Mazda 12A #35320engineslowerSTL Mazda 12A must keep 5th and 6th intake port actuators and valves, no longer allowed removal or disabling.
GTL Rotary Engine 12A Rotor Housings #35131wordingneutralGTL Mazda 12A rotary engines may machine and use 13B housing to O.E. 12A specifications.
GTL Request to Include Toyota GR86 in GTL #35198cars addedneutralGTL Toyota GR86 (DR86, 2021-2024, 2-door RWD, 101.3-inch wheelbase) newly classified.
GTL Errors and Omissions, GTL engines & Cars #35226wordingneutralGTL BMW Mini years corrected to 2002-2013.
STL Alternate Carburetor Request for 79-85 RX7 12a #35181inductionunclearSTL Mazda RX-7 12A (79-85) now allows auto-type 2 bbl with 42mm choke(s) on dual-y manifold as alternate to stock Nikki 4 bbl.
GTL Small Engines in GT Lite #34842weightfasterGTL small unrestricted engines under 1399cc lose 40-50 lbs across Alfa, AMC, Triumph, Mini, Sprite, Fiat, Ford, Honda, Mazda, Nissan, Subaru, Toyota, Volkswagen.
GTL Request to Classify Honda Fit body in GTL #35020cars addedneutralGTL Honda Fit 2009-13 2-door FWD classified with wheelbase options 94.0, 97.0, or 99.0 inches.
GTL Errors in GTCS Headings and Use of the Terms Category and ClassChange existing GTL and GTA Rules #34453wordingneutralGTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL.
GTL Weight for Nissan Sentra/200SX A 1400's #34918weight -50 lbsfasterGTL Nissan Sentra/200SX A14 engine weight reduced from 1850 lbs to 1800 lbs.
STL Clarify STL table B - IT spec notes on Tires #34187wordingneutralSTL ITA/ITS RX7 and 1985+ ITA/ITS/ITB/ITC vehicles clarified to conform to section 9.1.4.2 tire specifications.
GTL Please classify Fields Cardinal V8 #33784cars addedneutralFields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight.
Cal Club 2023 CALCL232023-02-24
101 earlier rule changes on record, in force before Cal Club 2023 (from 2019)20 cars added · 15 induction · 9 weight · 7 aero · 4 engine · 1 removed · 1 suspension & brakes · 1 tyres & wheels · 43 wording · GTL Toyota 3K, 4K, 5K engines now permitted to use 4Y block only. · GT2 Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines newly classified in spec line. · SM Mazda MX-5 Miata 01-05 weight increases to 2450 lbs, or 2465 with alternate bore. · STL Spec MX5 clutch, wheels, and tyres specified: ACT 0000-02-5004-G6, 17x8 wheels, Toyo RR and RA1 235-40-17. · GTL Fiat 1500 Limited Prep X1/9 weight increases to 2000 lbs. · GT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870. · Ford Festiva 1988-1993 added to GTL with Mazda B3 1324cc engine. · GTL Toyota G16E-GTS 3-cylinder engine added: 1618cc, 1945 lbs, naturally aspirated with SIR fuel induction. · GT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only. · SM Majors must run authorized Penske shock and mount; Regional competitors' requirement eligibility clarified. · Ginetta G40 classified in GTL with Ford Zetec 1796cc engine at 2050 lbs, plus 51 lbs for IRS or 26 lbs for sequential. · STU normally aspirated engines: minimum weights reduced up to 310 lbs; single throttle body weight reduction removed. · STL and STU Improved Touring vehicles must conform to 9.1.4 Tires & Wheels requirements. · STL and STU piston engines clarified: intake manifold and cylinder head porting remains free. · STL Mazda Renesis flat plate restrictor increases from 55mm to 60mm. · STL Mazda RX-7 12A 79-85 clarifies carburetor, emissions, and water jacket modification rules. · GT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight. · STL Spec MX-5 removes redundant specification line; no performance change. · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix. · GTL Honda B18a,b vs B18c: new split classifies B18a,b at 2050 lbs, B18c at 2065 lbs. · GTL Nissan B13 Sentra allowed hood bulge maximum 1.5 inches high, 10.0 inches long, 6.0 inches wide. · GTL BMW E21 added to GT Cars - BMW classification. · STL Volkswagen 2.0L TFSI 1984cc classified with turbocharger removal required, meeting all other STL specs. · STL Pontiac Solstice/Saturn Sky allowed 4" ride height. · STL Mazda B5 DOHC added to classification with standard STL regulations. · STL Honda B16A JDM restrictor reduced from 54mm to 53mm. · SM adds procedures for testing obsolete part replacements and BOP updates in sanctioned events with CRB approval. · ST oil coolers and filters now explicitly allowed to be added or substituted; wording clarifies existing permissions. · GTL Mazda 12A SIR increases to 29mm, minimum weight rises to 2000 lbs. · STL GM Ecotec engines now permit any combination within the family, must use 55mm flat plate restrictor. · STL/STU 90-05 Mazda Miata gains approval for Mazda Motorsports Development alternate front wheel hubs. · Fiat X-1/9 Bertone 1500 added to GTL with 2000 lbs minimum weight, SOHC, fuel induction options, Level 2 prep. · ST cars may relocate ABS actuation hardware and wiring anywhere in engine compartment. · STL rear wing trailing edge, including end plates and gurney flap, maximum rearward mounting clarified to center of rearmost bodywork. · STL allows OEM gear sets from same manufacturer transmissions with input shaft modifications for fitment. · GTL Nissan MRA8DE 1797cc engine classified with 2050 lbs minimum weight and 22.5mm restrictor. · GTL Mazda 13B SIR increases from 26mm to 28mm; 27mm plus 175 lbs option removed. · STL RWD strut suspension weight penalty cut to 0.5%, other RWD cut to 2.5%. · STL Honda F20C loses 2% weight penalty, minimum weight reduced by approximately 35 lbs. · STL Honda B16/B17/B18C1 restrictor tightened to 53mm; B18C variants and Mazda MZR to 52mm. · ST aero devices and reference areas now include end plates but exclude fasteners protruding over 1/2 inch. · SM aftermarket radiators must mount in original location, maintain core plane, require no body modifications, block openings, keep one OEM fan in stock location; 1990-1997 cars may install upper radiator seal NA75-50-OK7A. · 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. · GT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line. · GTL Mazda 13B restrictor increases to 26mm SIR, minimum weight rises to 2125 lbs. · SM rear brake calipers may use single bracket under upper retaining bolt to prevent pin failure. · STL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis adjustments. · STL and STU rear wing rules clarify that wicker is a Gurney flap; no performance change. · GTL Toyota MR2 Spyder 1999-2007 newly classified. · 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. · GTL Mazda 13B restrictor size clarification issued; refer to letter 28518 for details. · GT3 and STU add Borg-Warner EFR6258 to approved turbocharger list. · GTL stall test procedure clarified: intake system must pass SIR test as raced, no air bypass allowed. · STL adds 2016-2019 Mazda MX-5 Global Cup at 2000cc, 2450-2550 lbs minimum weight. · STL Mazda MX-5 Club Model 06-15 allows Mazda header part number 0000-06-5407-NC. · STL Honda/Acura B18 non-C gets 54mm restrictor; B18C variants drop B18C1, get 53mm restrictor. · GTL wing mount openings excluded from square inch limit. · STL Honda B18 restrictor reduced from 54mm to 53mm flat plate; B18C1 added with 54mm restrictor. · STU GM Ecotech LNF now allowed with turbo removed or with LE5 head and intake manifold, meeting STL specs. · STL Mazda MZR restrictor reduced from 54 mm to 53 mm. · STL Mazda MZR restrictor reduced from 55 mm to 53 mm. · GTL wing mounting posts limited to 85 square inches exposed area each, measured flat from side view. · GTL wing mounting posts limited to 85 square inches exposed area each, measured flat from side. · GTL wing endplates change from 8.5×3.0 inch rectangle to maximum 64 square inches. · GTL Mazda 12A Street Port minimum weight reduced to 1950 lbs from 2000 lbs. · STL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL. · GT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications. · Factory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs. · GTL adds Jetta Mk1 two door classification effective 2020-01-01. · FE and FE2 minimum weight increased to 1270 lbs including driver; spring options and tire warmer ban added. · GTL Honda CRX 84-87 and 88-91 remove IRS option with 2.5% weight penalty. · Mazda Spec MX-5 Challenge classified in STL with 2000cc displacement and 2500 lbs minimum weight. · GTL Fun Cup Beetle engine weight specified at 1850 lbs with sealed SOHC 1780cc specification. · GTL Fun Cup Beetle removes reference to VW engine table; Fun Cup engine spec remains 1.8L at 2040 lbs. · GTL Honda CRZ 10-14, CRZ 15-16, and Insight 00-06 gain alternate wheelbase option of 90.6 in. · STU alternate intake manifolds now allowed case-by-case instead of prohibited. · STL Acura/Honda B18 except C engine restrictor increases from 53mm to 54mm flat plate. · GTL adds VW Fun Cup Beetle, all model years, 2-door RWD, 94.5-inch wheelbase. · 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. · GTL Mazda 13B may use 25mm SIR with 175 lbs weight penalty added. · STL and STU ride height measurement clarified: without driver, at rocker panel lowest point, excluding pinch weld. · 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. · GTL Mazda 12A may use 28mm SIR plus 175 lbs. · GTL Mustang 94-04 newly classified in GTL. · SM fuel pump and filter must be Mazda or OEM Equivalent part. · STL adds VW 1.8L R4 20VT 1781cc, 1 minimum weight, turbo removed permitted. · STL Mazda Renesis minimum weight reduced from 2800 to 2700 lbs. · STL Mazda MX-5 Cup brake pad compound changed to open. · STL adds Acura/Honda B18C1 GSR with 54mm flat plate restrictor and port matching limited to 1 inch. · STL Mazda 12 and 13B now permit port matching; previous ban removed. · SM 1999-2000 model year cars may use replacement Mazda ECU and injector harnesses, unmodified. · SM electrical rules reorganized and clarified; alternator external regulation now prohibited except via OEM ECU/kill switch. · SM removes tire tread protrusion beyond fender opening requirement from GCR 9.1.7.C.5. · GTL Mini 1275-1399 Iron and Aluminum Crossflow gain 75 lbs weight reduction to 125 lbs with OE common sump gearbox. · GTL BMC thru Rover Group removes long inactive Mini engines: 948, 970, 1071, 1098. · GTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified. · STL B18C Type R variants get 54mm flat plate restrictor; B17 also gets 54mm restrictor. · STL Mazda Miata removes maximum displacement limit and adjusts minimum weight.showhide
GTL Toyota 4Y Engine Classification Request #33562engineneutralGTL Toyota 3K, 4K, 5K engines now permitted to use 4Y block only.
GTL Toyota 4A-F and 4A-FE 1.6L DOHC 16V Engine Request #33415cars addedneutralGT2 Toyota 4A-F and 4A-FE 1.6L DOHC 16V engines newly classified in spec line.
SM BOP for NB1 and NB2 #32309weightslowerSM Mazda MX-5 Miata 01-05 weight increases to 2450 lbs, or 2465 with alternate bore.
STL Spec MX5 in STL #33473wordingneutralSTL Spec MX5 clutch, wheels, and tyres specified: ACT 0000-02-5004-G6, 17x8 wheels, Toyo RR and RA1 235-40-17.
GTL Fiat HP Limited Prep X1/9 Weight in GTL #33297weightslowerGTL Fiat 1500 Limited Prep X1/9 weight increases to 2000 lbs.
GTL GT2 (TA2)/GTA Part Number Update #33315wordingneutralGT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870.
GTL Request to add Ford Festiva to GTL #33335cars addedneutralFord Festiva 1988-1993 added to GTL with Mazda B3 1324cc engine.
GTL Engine Request #33064cars addedneutralGTL Toyota G16E-GTS 3-cylinder engine added: 1618cc, 1945 lbs, naturally aspirated with SIR fuel induction.
GTL Tail lights on all GT category race cars. #32799wordingneutralGT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only.
SM Update GCR Section 9.1.7.3.A.1. #32217wordingneutralSM Majors must run authorized Penske shock and mount; Regional competitors' requirement eligibility clarified.
GTL Request to Classify Ginetta G40 in GTL #31599cars addedneutralGinetta G40 classified in GTL with Ford Zetec 1796cc engine at 2050 lbs, plus 51 lbs for IRS or 26 lbs for sequential.
STL Single TB Weight Modifiers #31449weightfasterSTU normally aspirated engines: minimum weights reduced up to 310 lbs; single throttle body weight reduction removed.
STL Improved Touring Tires #32063tyres & wheelsneutralSTL and STU Improved Touring vehicles must conform to 9.1.4 Tires & Wheels requirements.
STL Throttling Device Clarification #31323wordingneutralSTL and STU piston engines clarified: intake manifold and cylinder head porting remains free.
STL Mazda Renesis Restriction #31467inductionfasterSTL Mazda Renesis flat plate restrictor increases from 55mm to 60mm.
STL Clarification of 79-85 RX7 Spec line #31621wordingneutralSTL Mazda RX-7 12A 79-85 clarifies carburetor, emissions, and water jacket modification rules.
GTL Request car classification #31032cars addedneutralGT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight.
STL Request to clean up Spec MX-5 Redundancy #31069wordingneutralSTL Spec MX-5 removes redundant specification line; no performance change.
GTL Request to Update GTA Obsolete Part Numbers #30615wordingneutralGTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix.
GTL Request clarification for the Honda B18a,bVS B18c #30482wordingneutralGTL Honda B18a,b vs B18c: new split classifies B18a,b at 2050 lbs, B18c at 2065 lbs.
GTL Request to Allow Hood Bulge on Nissan B13 Sentra #30504aeroneutralGTL Nissan B13 Sentra allowed hood bulge maximum 1.5 inches high, 10.0 inches long, 6.0 inches wide.
GTL Request BMW E21 Classing #30582cars addedneutralGTL BMW E21 added to GT Cars - BMW classification.
STL VW Engine Request #30625engineslowerSTL Volkswagen 2.0L TFSI 1984cc classified with turbocharger removal required, meeting all other STL specs.
STL Request Mazda B5 DOHC #30420cars addedneutralSTL Mazda B5 DOHC added to classification with standard STL regulations.
STL Honda B16A (JDM) Restrictor change #30531inductionslowerSTL Honda B16A JDM restrictor reduced from 54mm to 53mm.
SM Updates - Obsolete Parts & BOP Parts #30438wordingneutralSM adds procedures for testing obsolete part replacements and BOP updates in sanctioned events with CRB approval.
STL ST Oil Coolers E&O Correction to 9.1.4.2.H #30388wordingneutralST oil coolers and filters now explicitly allowed to be added or substituted; wording clarifies existing permissions.
GTL Request for Help for Mazda 12A #29754induction +50 lbsslowerGTL Mazda 12A SIR increases to 29mm, minimum weight rises to 2000 lbs.
STL GM Ecotec engines in STL #30247wordingneutralSTL GM Ecotec engines now permit any combination within the family, must use 55mm flat plate restrictor.
STL Super Touring Alternate Miata Hubs #30345wordingneutralSTL/STU 90-05 Mazda Miata gains approval for Mazda Motorsports Development alternate front wheel hubs.
GTL Request LP HP Fiat X1/9 & Bertone 1500 to GTL #30058cars addedneutralFiat X-1/9 Bertone 1500 added to GTL with 2000 lbs minimum weight, SOHC, fuel induction options, Level 2 prep.
STL Brake Component Relocation #29990wordingneutralST cars may relocate ABS actuation hardware and wiring anywhere in engine compartment.
STL Super Touring Wing Clarification #30111aeroneutralSTL rear wing trailing edge, including end plates and gurney flap, maximum rearward mounting clarified to center of rearmost bodywork.
STL Transmission Options #30118wordingneutralSTL allows OEM gear sets from same manufacturer transmissions with input shaft modifications for fitment.
GTL Increase 13b SIR size #29867inductionfasterGTL Mazda 13B SIR increases from 26mm to 28mm; 27mm plus 175 lbs option removed.
STL Request for FWD and RWD Parity #29728weightfasterSTL RWD strut suspension weight penalty cut to 0.5%, other RWD cut to 2.5%.
STL Request to Remove Honda F20C 2% Weight Penalty #29815weightfasterSTL Honda F20C loses 2% weight penalty, minimum weight reduced by approximately 35 lbs.
STL Request for FWD and RWD Parity #30023inductionslowerSTL Honda B16/B17/B18C1 restrictor tightened to 53mm; B18C variants and Mazda MZR to 52mm.
STL Request clarification on wing measurement #29640aeroneutralST aero devices and reference areas now include end plates but exclude fasteners protruding over 1/2 inch.
SM Radiator E&O Clarifications #29294wordingneutralSM aftermarket radiators must mount in original location, maintain core plane, require no body modifications, block openings, keep one OEM fan in stock location; 1990-1997 cars may install upper radiator seal NA75-50-OK7A.
FE2 FE/FE2 Oil Cooler #29293wordingneutralFE2 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.
GTL GT Category Wording #29193wordingunclearGT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line.
GTL Request to change the Mazda 13b restrictor size #28518induction +175 lbsfasterGTL Mazda 13B restrictor increases to 26mm SIR, minimum weight rises to 2125 lbs.
SM Modifications to prevent failures of Rear Brake Caliper Pin #28953suspension & brakesneutralSM rear brake calipers may use single bracket under upper retaining bolt to prevent pin failure.
STL Minimum Weight Determination #27695wordingneutralSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis adjustments.
STL ST Gurney flap Wicker clarification #29012wordingneutralSTL and STU rear wing rules clarify that wicker is a Gurney flap; no performance change.
GTL Request to classify 1999-2007 Toyota MR2 Spyder body #28870cars addedneutralGTL Toyota MR2 Spyder 1999-2007 newly classified.
GTL TA2 Gurney flap wicker clarification #28874wordingneutralTA2 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.
GTL STO Gurney flap wicker clarification #28883wordingneutralSTO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules.
GTL Mazda 13b Restrictor Size Follow up to Letter 28518 #29015wordingunclearGTL Mazda 13B restrictor size clarification issued; refer to letter 28518 for details.
STL Request for Addition to GT3 Approved Turbo List #27576wordingneutralGT3 and STU add Borg-Warner EFR6258 to approved turbocharger list.
GTL Stall Test #28709wordingneutralGTL stall test procedure clarified: intake system must pass SIR test as raced, no air bypass allowed.
STL Request to add 2016-2019 GMX-5 Spec line #28604cars addedneutralSTL adds 2016-2019 Mazda MX-5 Global Cup at 2000cc, 2450-2550 lbs minimum weight.
STL Request to update PN for MX-5 #28622wordingunclearSTL Mazda MX-5 Club Model 06-15 allows Mazda header part number 0000-06-5407-NC.
STL Correction - Clarification Honda/Acura B18B engine Letter # 26209 #28873inductionunclearSTL Honda/Acura B18 non-C gets 54mm restrictor; B18C variants drop B18C1, get 53mm restrictor.
GTL GTL Wing Rule #28754aeroneutralGTL wing mount openings excluded from square inch limit.
STL STL Honda B18 restrictor changes #28794inductionfasterSTL Honda B18 restrictor reduced from 54mm to 53mm flat plate; B18C1 added with 54mm restrictor.
STL Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0 #27884engineslowerSTU GM Ecotech LNF now allowed with turbo removed or with LE5 head and intake manifold, meeting STL specs.
STL Acura/Honda B18C engine chart. Reduce the current 54 mm flat plat #28663inductionslowerSTL Mazda MZR restrictor reduced from 54 mm to 53 mm.
STL Mazda MZR engine chart. Reduce the current 55 mm flat plate to 53 #28664inductionslowerSTL Mazda MZR restrictor reduced from 55 mm to 53 mm.
GTL Wing Mounting Upright Size #27641aeroneutralGTL wing mounting posts limited to 85 square inches exposed area each, measured flat from side view.
GTL Wing Mounting Upright Size #27641aeroneutralGTL wing mounting posts limited to 85 square inches exposed area each, measured flat from side.
GTL GTL wing end plates addition #28243aerofasterGTL wing endplates change from 8.5×3.0 inch rectangle to maximum 64 square inches.
GTL Clarification to letter #27406 #28309weight -50 lbsfasterGTL Mazda 12A Street Port minimum weight reduced to 1950 lbs from 2000 lbs.
STL Request to add wheel part numbers #28342wordingneutralSTL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL.
GTL Windshield Clips #27323wordingneutralGT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications.
GTL Request Factory Five Daytona coupe classification #26308cars addedneutralFactory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs.
GTL Request to Classify the MK1 two door Jetta #27648cars addedneutralGTL adds Jetta Mk1 two door classification effective 2020-01-01.
FE2 FE / FE2 Update Rules #27624weightslowerFE and FE2 minimum weight increased to 1270 lbs including driver; spring options and tire warmer ban added.
GTL 88-91 Honda CRX Spec Line Correction #27233wordingneutralGTL Honda CRX 84-87 and 88-91 remove IRS option with 2.5% weight penalty.
STL Request to Classify Spec MX-5 Challenge in STL #27399cars addedneutralMazda Spec MX-5 Challenge classified in STL with 2000cc displacement and 2500 lbs minimum weight.
GTL Fun Cup Beetle #27334wordingneutralGTL Fun Cup Beetle engine weight specified at 1850 lbs with sealed SOHC 1780cc specification.
GTL GTL #26960wordingneutralGTL Fun Cup Beetle removes reference to VW engine table; Fun Cup engine spec remains 1.8L at 2040 lbs.
GTL Request CRZ wheelbase change #26896wordingunclearGTL Honda CRZ 10-14, CRZ 15-16, and Insight 00-06 gain alternate wheelbase option of 90.6 in.
STL Request clarification for manifold and throttle in STU #27004inductionfasterSTU alternate intake manifolds now allowed case-by-case instead of prohibited.
STL Request Restrictor Plate correction #26779inductionfasterSTL Acura/Honda B18 except C engine restrictor increases from 53mm to 54mm flat plate.
GTL Request to Classify VW Fun Cup Beetle #25986cars addedneutralGTL adds VW Fun Cup Beetle, all model years, 2-door RWD, 94.5-inch wheelbase.
GTL Request GTX Fuel injection for previous GT-1 tube frame cars #26141inductionfasterGTX tube frame cars gain fuel injection with 90mm maximum throttle body size.
GTL Request to Classify Ligier JS2 R #26535cars addedneutralLigier JS2 R classified in GTX, no performance parameters specified in filing.
GTL Request for GTL Mazda 13B SIR Increase with Penalty #26572engineslowerGTL Mazda 13B may use 25mm SIR with 175 lbs weight penalty added.
STL Request Ride Height Clarification #26597wordingneutralSTL and STU ride height measurement clarified: without driver, at rocker panel lowest point, excluding pinch weld.
GTL Request Ride Height Clarification #26600wordingneutralGT1 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.
GTL Request Mazda 12a Rotary SIR Increase #26081inductionfasterGTL Mazda 12A may use 28mm SIR plus 175 lbs.
GTL Request to Classify Mustang 2 Body in GTL #26222cars addedneutralGTL Mustang 94-04 newly classified in GTL.
SM Request to allow aftermarket fuel filters. #26370wordingneutralSM fuel pump and filter must be Mazda or OEM Equivalent part.
STL Request to reduce weight of RX8 with Renesis rotary #25781weight -100 lbsfasterSTL Mazda Renesis minimum weight reduced from 2800 to 2700 lbs.
STL Request for Open Brake Pads On Mazda MX-5 Cup NC #25821wordingneutralSTL Mazda MX-5 Cup brake pad compound changed to open.
STL Request to clarify B18C1 GSR Honda B motor table #26209cars addedneutralSTL adds Acura/Honda B18C1 GSR with 54mm flat plate restrictor and port matching limited to 1 inch.
STL Port Matching #26415wordingfasterSTL Mazda 12 and 13B now permit port matching; previous ban removed.
SM Request 99-00 replacement Wire harnesses #25602wordingneutralSM 1999-2000 model year cars may use replacement Mazda ECU and injector harnesses, unmodified.
SM Organize and Clarify 9.1.7.C.1.o. #25913wordingneutralSM electrical rules reorganized and clarified; alternator external regulation now prohibited except via OEM ECU/kill switch.
SM Strike Tire Tread Language #26123wordingneutralSM removes tire tread protrusion beyond fender opening requirement from GCR 9.1.7.C.5.
GTL Request for GTL Mini Adjustments #25754weightfasterGTL Mini 1275-1399 Iron and Aluminum Crossflow gain 75 lbs weight reduction to 125 lbs with OE common sump gearbox.
GTL BMC thru Rover Group remove long inactive mini #25771removedneutralGTL BMC thru Rover Group removes long inactive Mini engines: 948, 970, 1071, 1098.
GTL GTX Homologation table update #26034cars addedneutralGTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified.
STL Request to equalize FPR Reduction on all B-Series Vtec Engines #24746inductionslowerSTL B18C Type R variants get 54mm flat plate restrictor; B17 also gets 54mm restrictor.
STL Request E&O for Mazda Miata Spec Line #25955wordingunclearSTL Mazda Miata removes maximum displacement limit and adjusts minimum weight.
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 STL" is the class's best as a share of STL'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 STL'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.