Quickest here:T4 1:58.339 Oscar Jackson, Cal Club 2025 qualifying · FA 1:14.588 Greg Labadie, Cal Club 2023 qualifying · P2 1:12.573 Kevin Mitz, Cal Club 2023 qualifying
T4FAP2solid race · dashed qualifying · slower is lower
T4FAP2solid race · dashed qualifying · each class's best lap as a share of T4's at the same event (the reference class, changeable above); 100% is level, higher is quicker
Event
T4
FA
P2
Qual best
Race best
Trap
Qual best
Race best
Trap
vs T4
% of T4
Qual best
Race best
Trap
vs T4
% of T4
Cal Club 2026 CALCL262026-02-21
2:01.678Izzy Sanchez · fastest of 5 · top 5 within 5.9s+3.339s (+2.82%)
2:01.157Izzy Sanchez · fastest of 5 · top 5 within 7.2s+1.235s (+1.03%)
135.5Izzy Sanchez+27.2 mph (+25.1%)
1:35.792Greg Labadie · only car-3.750s (-3.77%)
1:37.275Greg Labadie · only car-2.623s (-2.63%)
163.8Greg Labadie+36.4 mph (+28.6%)
-23.882squal -25.886s
80.3%qual 78.7%
1:37.278Tim Day Jr · only car+24.705s (+34.04%)
1:39.758Tim Day Jr · only car
155.4Tim Day Jr
-21.399squal -24.400s
82.3%qual 79.9%
26 rule changes (T4: 19, FA: 7)4 cars added · 4 tyres & wheels · 3 induction · 2 aero · 2 suspension & brakes · 1 engine · 1 removed · 1 weight · 8 wording · FA Pro Mazda: lower intake manifold now unrestricted, throttle body raised to 80mm, wing height must not exceed 99cm, bodywork width must not exceed 132cm. · Ford Mustang V6 (05-14) removed from T4 Spec Lines. · T4 Mustang 4.0 V6 tire size increases from 245 to 255. · T2-T4 adjustable toe links now allow performance alternative bushings and spherical bearings, previously prohibited except in specified examples. · FA MZR gains alternate Noor P/N 0088-8-00 intake manifold with AT Power runners as option to Elan or Mazda Speed Elite. · FA Formula 1000 motorcycle-based engine loses maximum compression ratio 14.5:1 limit. · FA Formula 1000 allows carbon fiber external panels, forward-facing gaps, raises floor to 125mm, adds eight 75×125mm rub blocks, expands diffuser to 110cm with 75mm radius transitions. · T2, T3, T4 cars may relocate under-dash electronics and fuse boxes for access after roll cage installation. · T4 Performance now permits 1-piece alternative rotors matching spec line sizes; alternate brake kits allowed same. · Dodge/Plymouth Neon ACR SOHC/DOHC 95-99 newly classified T4 at 2350 lbs minimum weight. · FA class adds USF Pro 2000 car eligibility for Formula Atlantic racing. · T4 Mini Cooper S R53 02-06 gear ratios changed to 12.79, 7.79, 5.65, 4.62, 3.83, 3.13 or 11.42, 7.18, 5.39, 4.40, 3.65, 2.96. · Chevrolet Cobalt SS Sport Coupe 06-10 reinstated to T4 with 2384cc engine, 2628 restrictor, 2700 lbs minimum weight. · Mercedes C230 Kompressor 2002-2005 classified in T4 at 3240 lbs with 17-inch wheels and 300/290 mm brakes. · T3 and T4 Mazda MX-5 Miata models add approved gear kit PT#-0000-02-6100 to notes. · T4 Mazda MX-5 Miata/Club 16-18 wheel size changed to 17 x 7.5 inches. · T4 Mazda MX-5 Miata/Club/RF (19-24) and (16-18) remove discontinued hardtop part #0000-07-5901; T3 MX-5 Miata (16-18) and Global Cup ND (16-21) same. · T2, T3, T4 Spec Lines table header changed from T2 to ET. · FA Ligier JS F3 front tires may be Hoosier 43363 240/580R13 MS, rear 43368 300/590R13 MS. · T4 now permits B-Spec and C-Spec cars to compete in the class. · T4 Ford Mustang V6 05-14 weight drops from 3400 to 3300 lbs. · T4 Scion FR-S and Subaru BRZ Solo Spec allow any 200TW 225/45/17 or 215/45/17 DOT tire. · T4 Ford Mustang V6 05-14 allows GT 8.8 rear axle or 7.5 axle with 3.45:1 ratio. · T4 Ford Mustang V6 05-14 now permits OEM style rear deck spoiler similar to Laguna/CS packages. · FA Formula Renault 2.0 (10-17) spec notes clarified: engine sealed, manual compliance required, tire choice unrestricted, no alterations except repairs.showhide
FA Pro Mazda Classification and Performance Enhancement Proposal #39411inductionfasterFA Pro Mazda: lower intake manifold now unrestricted, throttle body raised to 80mm, wing height must not exceed 99cm, bodywork width must not exceed 132cm.
T4 T4 and T3 Feedback #39230removedremovedFord Mustang V6 (05-14) removed from T4 Spec Lines.
T4 T4 Mustang 4.0 #39489tyres & wheelsfasterT4 Mustang 4.0 V6 tire size increases from 245 to 255.
T4 Allow Alt Bushing Material in Toe Links #39607suspension & brakesfasterT2-T4 adjustable toe links now allow performance alternative bushings and spherical bearings, previously prohibited except in specified examples.
FA Alternate Intake Manifold for MZR #38223inductionunclearFA MZR gains alternate Noor P/N 0088-8-00 intake manifold with AT Power runners as option to Elan or Mazda Speed Elite.
FA Engine Compression Rule Change Request #39302enginefasterFA Formula 1000 motorcycle-based engine loses maximum compression ratio 14.5:1 limit.
FA Change Formula 1000 allowances #39608aerofasterFA Formula 1000 allows carbon fiber external panels, forward-facing gaps, raises floor to 125mm, adds eight 75×125mm rub blocks, expands diffuser to 110cm with 75mm radius transitions.
T4 Alternate Placement of Fuse Panel and Electronics Request #39370wordingwordingT2, T3, T4 cars may relocate under-dash electronics and fuse boxes for access after roll cage installation.
T4 Clarify T4 Brake Rotor Allowance #39503suspension & brakessuspension & brakesT4 Performance now permits 1-piece alternative rotors matching spec line sizes; alternate brake kits allowed same.
FA Re-Consider USF Pro 2000 Car for Formula Atlantic Class #38783cars addedcars addedFA class adds USF Pro 2000 car eligibility for Formula Atlantic racing.
T4 02-06 Mini Cooper Gear Ratios #38966wordingunclearT4 Mini Cooper S R53 02-06 gear ratios changed to 12.79, 7.79, 5.65, 4.62, 3.83, 3.13 or 11.42, 7.18, 5.39, 4.40, 3.65, 2.96.
T4 Reinstatement of the 2005-2010 Cobalt into T4 #38987cars addedcars addedChevrolet Cobalt SS Sport Coupe 06-10 reinstated to T4 with 2384cc engine, 2628 restrictor, 2700 lbs minimum weight.
T4 Request to Classify Mercedes C230K #39080cars addedcars addedMercedes C230 Kompressor 2002-2005 classified in T4 at 3240 lbs with 17-inch wheels and 300/290 mm brakes.
T4 ND Gearset Request for T4 #39166wordingwordingT3 and T4 Mazda MX-5 Miata models add approved gear kit PT#-0000-02-6100 to notes.
T4 E&O wheel size on ND #39168tyres & wheelsunclearT4 Mazda MX-5 Miata/Club 16-18 wheel size changed to 17 x 7.5 inches.
T4 ND Spec Lines Wrong PT#'s #39170wordingwordingT4 Mazda MX-5 Miata/Club/RF (19-24) and (16-18) remove discontinued hardtop part #0000-07-5901; T3 MX-5 Miata (16-18) and Global Cup ND (16-21) same.
T4 Incorrect Touring Heading #38451wordingwordingT2, T3, T4 Spec Lines table header changed from T2 to ET.
FA Ligier JS F3 Tire Choice #38434tyres & wheelstyres & wheelsFA Ligier JS F3 front tires may be Hoosier 43363 240/580R13 MS, rear 43368 300/590R13 MS.
T4 Allow B-Spec cars to run in T4 #38439wordingwordingT4 now permits B-Spec and C-Spec cars to compete in the class.
T4 T4 Mustang #38059weight -100 lbsfasterT4 Ford Mustang V6 05-14 weight drops from 3400 to 3300 lbs.
T4 SSC tire allowance #38216tyres & wheelstyres & wheelsT4 Scion FR-S and Subaru BRZ Solo Spec allow any 200TW 225/45/17 or 215/45/17 DOT tire.
T4 Correct Ring and Pinion Ratio to T3, Sorry I Mean T4 3.7 V6 Stang #38041wordingwordingT4 Ford Mustang V6 05-14 allows GT 8.8 rear axle or 7.5 axle with 3.45:1 ratio.
T4 T4 Mustang #38058aeroaeroT4 Ford Mustang V6 05-14 now permits OEM style rear deck spoiler similar to Laguna/CS packages.
FA Update Formula Renault 2.0 spec line notes #37853wordingwordingFA Formula Renault 2.0 (10-17) spec notes clarified: engine sealed, manual compliance required, tire choice unrestricted, no alterations except repairs.
Cal Club 2025 CALCL252025-02-22
1:58.339Oscar Jackson · fastest of 5 · top 5 within 8.3s
1:59.922Oscar Jackson · fastest of 4 · top 4 within 7.3s
108.4Tony Kiratsous
1:39.542Greg Labadie · only car+24.954s (+33.46%)
1:39.898Greg Labadie · only car
127.4Greg Labadie
-20.024squal -18.797s
83.3%qual 84.1%
76 rule changes (T4: 62, FA: 4, P2: 10)13 weight · 12 cars added · 6 suspension & brakes · 4 engine · 4 tyres & wheels · 3 aero · 1 induction · 1 removed · 28 wording · 4 other · FA adds Tatuus F.3 T-318 or FR-19 as spec line car in Table 2 for Formula Regional European Championship. · T4 Ford Mustang V6 (05-14) final drive set to 3.45, GT/CS front bumper cover permitted with front fascia. · Ford SCCA Club Spec Mustang classified T3 at 3350 lbs with driver; Mazda SCCA Club Spec MX-5 classified T4 at 2500 lbs with driver. · T2, T3, T4 remove nine, nine, and thirty-six expired spec lines respectively, effective 2025-01-01. · T4 2016-2018 Mazda Miata MX-5 minimum weight reduced to 2575 lbs from 2650 lbs. · P2 2000cc Pinto engine car minimum weight set to 1335 lbs. · T2 and T3 Mustang spec lines remove redundant driveshaft alternate/aluminum allowance wording. · T4 Mini Cooper S R53 now allows Alta 15% Pulley #AMPENG20X. · T4 removes restriction on aftermarket wheel weight minimum of 15 lbs. · T2, T3, T4 fuel cell installations may remove charcoal canisters, emissions valves, and sensors. · Mazda 3 (19-24) newly classified in T4 at 2850 lbs with 17×8 wheels and 245 tires. · T2, T3, T4 brake component wording clarified: 2-piece rotors allowed in T2 within 5% OE diameter, T3 within 2% OEM diameter. · T2, T3, T4 fuel cell cars may remove charcoal canisters, emissions valves, and sensors. · T3 and T4 Mazda RX-8 and MX-5 permit transmission kit #0000-02-5700. · Porsche Spec Boxster moves to T4, minimum weight 2750 lbs, requires 3 Super Tour events before Runoffs eligibility. · Ford Mustang V6 (05-14) newly classified to T4 with 50mm restrictor, 3400 lbs minimum weight. · T4 BMW 320i 14-15 Spec Line expires 12/31/24 removed; Turner Motorsports intercooler #024703TMS02 allowed. · Unable to summarize: rule changes specified in letter #37281, not provided. · Cadillac CTS 02-07 3.6L classified in T3. · T4 Honda Civic Si 06-11 minimum weight drops 50 lbs to 2900, restrictor clarified. · T4 NC MX-5 06-15 removes SM5 suspension allowance, clarifies Mazda Motorsports LSD part number, adds weight penalty for other LSDs. · T4 Mazda MX-5 Miata/Club (16-18) wheel size changes to 17 x 7.5 inches. · T4 Mazda RX-8 gets 59mm restrictor and 3200 lbs; MX-5 Club drops to 2550 lbs. · T4 Mazda MX5 Miata/Club/RF 19-24 wheel size changes to 17 x 7.5. · T4 Honda Civic Si 06-11 permitted to use LSD per category rules. · T4 Chevrolet Camaro V-6 (96-02) weight reduced from 3250 lbs to 3150 lbs. · T4 Mazda MX-5 Miata/Club 16-18 drops 50 lbs to 2650; 19-24 RF drops 50 lbs to 2750. · Ford Mustang GT 5.0L and V6 now permit Track/Performance Package parts in T2 and T3. · Mercedes C300 4Matic 2008-2011 homologated to T4 at 3,725 lbs with 18x8.5 wheels, 245 max tires, 3.27 final drive. · T2-T4 Ford Mustangs: remove 25 lbs penalty for non-OEM driveshaft, clarify alternate driveshaft allowances. · T4 Mini Cooper S (02-04) deleted; (05-06) model year corrected to R53; (07-13) R56 simplified specs; (2014-2023) added with spring rates. · T4 OEM intake chambers, resonators and acoustic devices may be removed if ports sealed and before restrictor. · Audi S4 (2000-2002) moves to T3 with 3400 lbs minimum weight, 38mm turbo inlet restrictor required. · T4 Mazda MX-5 Club 06-15 now permits OEM front spoiler NF51-V4-900F. · T4 Ford Mustang V6 (05-10) weight reduced 50 lbs to 3225. · T4 Mini Cooper S 02-04 and 05-06 now allow Milltek exhaust manifold #SSXM459 and 25mm rear sway bar. · P2 Spec ECU engine modifications clarified: oil system, ECU, and exhaust unrestricted only. · P2 FIA Group CN spec notes clarified: Series changed to Challenge, documentation requirement moved to online link. · T3 and T4 Mazda RX-8 may remove or disable factory oil injection system. · T4 Mazda MX5 Miata/Club/RF year range extended to 2024, suspension package permitted with 100 lbs weight increase. · T4 Volkswagen Rabbit 2.5 (06-09) front brakes increase from 228 to 288 vented disc. · T2, T3, T4 driveshafts may use alternative materials or one-piece units; non-OEM adds 25 lbs. · T4 Mazda MX-5 Miata/Club 16-18 removes differential stock requirement, allows up to 500lb front and 300lb rear springs. · T4 Mazda RX-8 allows Mazdaspeed radiator, coil spring kit, OE rear spoiler, front air dam, springs to 700 lb front/400 lb rear, oil metering pump bypass, sway bars to 32 mm front/19 mm rear. · T2-T4 Spec Lines remove wheelbase requirement, replace with Required Restrictor specification. · T4 Mazda RX-8 rear spring opens to any 400lb, was specific part numbers only. · T2 and T3 Nissan 370Z brake rotors enlarged: front 320x28 to 355x32mm, rear 320x16 to 350x20mm vented. · T2, T3, T4 battery replacement wording simplified; OEM weight tolerance requirement removed. · T4 Mazda MX-5 Miata/Club (16-18) and (19-21) permitted to replace 3rd and 4th gears with specific parts. · T4 now permits C-Spec cars to compete alongside B-Spec cars. · T2-T4 spec lines for 46 cars expire 12/31/24; appeal required to continue. · P2 AMAC modified engine range clarified to 2008 and older stock engines only, restrictor 38mm, weight 1025 lbs. · P2 Suzuki GSX-R1000 07/08 engine crankcase may swap to GSX-S1000 16/19 part #11301-04840. · T4 Mazda MX-5 ND1 minimum weight increases 50 lbs to 2700; suspension springs now allow up to 500 lb front, 300 lb rear. · T4 BRZ/FRS/86 spring allowance clarified: 225 lb front and 300 lb rear springs permitted; non-OEM LSD allowed with +50 lbs penalty. · T4 Acura TSX 2004-2008 now allows header. · T3 Nissan 370Z model years expanded to include NISMO Edition through 2022. · P2 Table 1 corrects engine date ranges and brand specifications for Stock and Modified engines across multiple car models. · T4 Mercedes Benz CLK 320 Coupe model years expand to 2000-2007, C320 Sedan added. · T3 Mazda RX-8 removes transmission/final drive pairing requirement; T4 removes same requirement, adds Mazdaspeed radiator and coil spring kit. · T3 BMW 320i (14-15) gains aftermarket intercooler permission; T4 loses it. · T3 Pontiac Solstice GXP minimum ride height set to 3 inches. · T4 Mini Cooper S R53 loses 50 lbs, to 2700 for both 02-04 and 05-06 model years. · FA Pro Formula Mazda front wheels widen to 10 in. max; rear wheels narrow to 14 in. min. · T4 Mini Cooper S all years now run 17-inch wheels, up from 16, with wider rims to 8 inches. · T4 Volkswagen Rabbit 2.5 (06-09) consolidates 06-07 and 08-09 models; Integrated Engineering intake allowed with 25lb penalty. · T4 Audi A4 2.8 V6 wheels grow to 17x8, tyres to 245, springs now 800lb with 32mm sway bars. · FA Pro Formula Mazda maximum bodywork width behind front wheels increases to 51.97 inches. · FA MSR Formula Mazda FMzR added to Table 2 classification. · P2 side body height requirement clarified: outermost surface between wheel openings must equal front axle centerline height. · P2 closed cockpit single seat cars now prohibited unless specifically allowed in Table 1. · P2 engine table wording updated; redundant effective date language removed. · P2 motorcycle engines: 2011+ Kawasaki restrictor reduced to 34mm, minimum weight raised to 1100 lbs; 2009+ other brands weight raised to 1100 lbs. · Acura TSX 2004-2008 newly classified in T4 at 3000 lbs minimum weight with 2354cc engine. · T4 Mustang rear sway bar increases from 22mm to 28mm permitted. · T3 BMW 320I now permitted to use aftermarket intercooler.showhide
FA Classify FR European Championship car as spec line car in Table 2 #37658cars addedcars addedFA adds Tatuus F.3 T-318 or FR-19 as spec line car in Table 2 for Formula Regional European Championship.
T4 Ford Mustang V6 (05-14) #37516wordingwordingT4 Ford Mustang V6 (05-14) final drive set to 3.45, GT/CS front bumper cover permitted with front fascia.
T4 Request to Classify Club Spec in Appropriate Touring Classes #37523cars addedcars addedFord SCCA Club Spec Mustang classified T3 at 3350 lbs with driver; Mazda SCCA Club Spec MX-5 classified T4 at 2500 lbs with driver.
T4 Remove spec lines that have expired #37269removedremovedT2, T3, T4 remove nine, nine, and thirty-six expired spec lines respectively, effective 2025-01-01.
P2 2000 cc Pinto Engine Car Weight #37187weightslowerP2 2000cc Pinto engine car minimum weight set to 1335 lbs.
T4 Redundant Verbiage Regarding Mustang Spec Lines for Driveshaft #36484wordingwordingT2 and T3 Mustang spec lines remove redundant driveshaft alternate/aluminum allowance wording.
T4 R53 Mini Cooper S Weight Reduction Request #36612enginefasterT4 Mini Cooper S R53 now allows Alta 15% Pulley #AMPENG20X.
T4 Allowable Wheel Offset #36855wordingwordingT4 removes restriction on aftermarket wheel weight minimum of 15 lbs.
T4 Fuel Emissions Components #37076wordingwordingT2, T3, T4 fuel cell installations may remove charcoal canisters, emissions valves, and sensors.
T4 2019-2024 Mazda 3 for T4 #37077cars addedcars addedMazda 3 (19-24) newly classified in T4 at 2850 lbs with 17×8 wheels and 245 tires.
T4 fix brake wording #37129wordingwordingT2, T3, T4 brake component wording clarified: 2-piece rotors allowed in T2 within 5% OE diameter, T3 within 2% OEM diameter.
T4 Evaporative emissions systems #37130wordingwordingT2, T3, T4 fuel cell cars may remove charcoal canisters, emissions valves, and sensors.
T4 Allow Spec MX5 upgrade kit for 2009-11 RX8 S2 Transmision #37140wordingwordingT3 and T4 Mazda RX-8 and MX-5 permit transmission kit #0000-02-5700.
T4 Move Spec Boxster to T4 #37158cars addedcars addedPorsche Spec Boxster moves to T4, minimum weight 2750 lbs, requires 3 Super Tour events before Runoffs eligibility.
T4 3.7 Mustangs to T4 #37188cars addedcars addedFord Mustang V6 (05-14) newly classified to T4 with 50mm restrictor, 3400 lbs minimum weight.
T4 BMW 320i Spec Line #37204wordingwordingT4 BMW 320i 14-15 Spec Line expires 12/31/24 removed; Turner Motorsports intercooler #024703TMS02 allowed.
T4 MX5 2006-2015 NC Help #37221otherunclearUnable to summarize: rule changes specified in letter #37281, not provided.
T4 Classification for a 2005 Cadillac CTS 3.6 liter 6 speed manual #37224cars addedcars addedCadillac CTS 02-07 3.6L classified in T3.
T4 Civic SI in T4 #37248weight -50 lbsfasterT4 Honda Civic Si 06-11 minimum weight drops 50 lbs to 2900, restrictor clarified.
T4 2006-2015 T4 NC Mx5 spec line #37278wordingwordingT4 NC MX-5 06-15 removes SM5 suspension allowance, clarifies Mazda Motorsports LSD part number, adds weight penalty for other LSDs.
T4 ND MX-5 wheel allowance #37279tyres & wheelsunclearT4 Mazda MX-5 Miata/Club (16-18) wheel size changes to 17 x 7.5 inches.
T4 T4 BOP #37281weight +75 lbsslowerT4 Mazda RX-8 gets 59mm restrictor and 3200 lbs; MX-5 Club drops to 2550 lbs.
T4 Allow 7.5 #37286tyres & wheelstyres & wheelsT4 Mazda MX5 Miata/Club/RF 19-24 wheel size changes to 17 x 7.5.
T4 Bop Request 06-11 Honda Civic Si #37013wordingwordingT4 Honda Civic Si 06-11 permitted to use LSD per category rules.
T4 T4 Camaro V6 weight reduction #36232weightfasterT4 Chevrolet Camaro V-6 (96-02) weight reduced from 3250 lbs to 3150 lbs.
T4 BOP adjustment for ND MX5s #36345weight -50 lbsfasterT4 Mazda MX-5 Miata/Club 16-18 drops 50 lbs to 2650; 19-24 RF drops 50 lbs to 2750.
T4 Mustang T2/T3 #35877wordingunclearFord Mustang GT 5.0L and V6 now permit Track/Performance Package parts in T2 and T3.
T4 Homologation of car to T4 #36030cars addedcars addedMercedes C300 4Matic 2008-2011 homologated to T4 at 3,725 lbs with 18x8.5 wheels, 245 max tires, 3.27 final drive.
T4 T2-T4 Driveshaft Mistake...? #36050weightfasterT2-T4 Ford Mustangs: remove 25 lbs penalty for non-OEM driveshaft, clarify alternate driveshaft allowances.
T4 MINI Cooper S Spec Lines Corrections. #36086wordingwordingT4 Mini Cooper S (02-04) deleted; (05-06) model year corrected to R53; (07-13) R56 simplified specs; (2014-2023) added with spring rates.
T4 Allow Removal of Sound Tubes #36130inductionfasterT4 OEM intake chambers, resonators and acoustic devices may be removed if ports sealed and before restrictor.
T4 B8/8.5 Audi S4 T3 and T2 #36195cars addedcars addedAudi S4 (2000-2002) moves to T3 with 3400 lbs minimum weight, 38mm turbo inlet restrictor required.
T4 Allow OEM Front Spoiler 06-08 Miata in T4 #35941aerofasterT4 Mazda MX-5 Club 06-15 now permits OEM front spoiler NF51-V4-900F.
T4 T4 Mustang Weight Reduction In T4 Spec #36051weight -50 lbsfasterT4 Ford Mustang V6 (05-10) weight reduced 50 lbs to 3225.
T4 R53 Mini Cooper S spec line request In #36056otherfasterT4 Mini Cooper S 02-04 and 05-06 now allow Milltek exhaust manifold #SSXM459 and 25mm rear sway bar.
P2 E&O - Correct FIA Group CN spec line notes #35900wordingwordingP2 FIA Group CN spec notes clarified: Series changed to Challenge, documentation requirement moved to online link.
T4 Allow T4 and T3 RX8 to Disable/Remove Factory Oil Inj. #35761engineunclearT3 and T4 Mazda RX-8 may remove or disable factory oil injection system.
T4 2023 ND2 Miata Classification and Allowances #35837weightslowerT4 Mazda MX5 Miata/Club/RF year range extended to 2024, suspension package permitted with 100 lbs weight increase.
T4 Errors and Omissions for 06-09 VW Rabbit Rotor #35851suspension & brakesfasterT4 Volkswagen Rabbit 2.5 (06-09) front brakes increase from 228 to 288 vented disc.
T4 Driveshafts #35916weightslowerT2, T3, T4 driveshafts may use alternative materials or one-piece units; non-OEM adds 25 lbs.
T4 GCR ERROR - letter not properly applied to GCR #35999suspension & brakesfasterT4 Mazda MX-5 Miata/Club 16-18 removes differential stock requirement, allows up to 500lb front and 300lb rear springs.
T4 Corrections to T4 RX8 Spec line #35767wordingwordingT4 Mazda RX-8 allows Mazdaspeed radiator, coil spring kit, OE rear spoiler, front air dam, springs to 700 lb front/400 lb rear, oil metering pump bypass, sway bars to 32 mm front/19 mm rear.
T4 Allow any 400lb rear spring in the RX8 #35433suspension & brakessuspension & brakesT4 Mazda RX-8 rear spring opens to any 400lb, was specific part numbers only.
T4 370Z Brake Rotor Size Correction #35487suspension & brakessuspension & brakesT2 and T3 Nissan 370Z brake rotors enlarged: front 320x28 to 355x32mm, rear 320x16 to 350x20mm vented.
T4 More Car Lightening Stuff #35319weightfasterT2, T3, T4 battery replacement wording simplified; OEM weight tolerance requirement removed.
T4 ND Missed Items #35352wordingwordingT4 Mazda MX-5 Miata/Club (16-18) and (19-21) permitted to replace 3rd and 4th gears with specific parts.
T4 Inclusion of B-C spec cars in T4 #35374cars addedcars addedT4 now permits C-Spec cars to compete alongside B-Spec cars.
T4 T2-T4 Set expiration dates on spec lines #35378wordingwordingT2-T4 spec lines for 46 cars expire 12/31/24; appeal required to continue.
P2 E&O - Clarify B.1 modified engine range in AMAC spec lines #35225wordingwordingP2 AMAC modified engine range clarified to 2008 and older stock engines only, restrictor 38mm, weight 1025 lbs.
P2 Replacement Engine Crankcase for 07/08 Suzuki GSX-R1000 Engines #35340engineunclearP2 Suzuki GSX-R1000 07/08 engine crankcase may swap to GSX-S1000 16/19 part #11301-04840.
T4 Mazda MX-5 ND1 Spec Line Request #34232weight +50 lbsslowerT4 Mazda MX-5 ND1 minimum weight increases 50 lbs to 2700; suspension springs now allow up to 500 lb front, 300 lb rear.
T4 BRZ/FRS/86 Spring Allowance #35038wordingwordingT4 BRZ/FRS/86 spring allowance clarified: 225 lb front and 300 lb rear springs permitted; non-OEM LSD allowed with +50 lbs penalty.
T4 TSX Allowance #35219aerofasterT4 Acura TSX 2004-2008 now allows header.
T4 Requested Update of Model Years of 370Z #35231wordingwordingT3 Nissan 370Z model years expanded to include NISMO Edition through 2022.
P2 Correct Table 1 for Engine Date Range Specifications #35182wordingwordingP2 Table 1 corrects engine date ranges and brand specifications for Stock and Modified engines across multiple car models.
T4 Inclusion of similar car. (CLK 320) #34626cars addedcars addedT4 Mercedes Benz CLK 320 Coupe model years expand to 2000-2007, C320 Sedan added.
T4 Rules Clarification for Mazda RX8 Spec Line #34395wordingwordingT3 Mazda RX-8 removes transmission/final drive pairing requirement; T4 removes same requirement, adds Mazdaspeed radiator and coil spring kit.
T4 rule book corrections #34437otherfasterT3 BMW 320i (14-15) gains aftermarket intercooler permission; T4 loses it.
T4 Ride Height Correction for the T3 Solstice. #34615wordingwordingT3 Pontiac Solstice GXP minimum ride height set to 3 inches.
T4 2002-2006 Mini Cooper S R53 Spec Line Request #34336weight -50 lbsfasterT4 Mini Cooper S R53 loses 50 lbs, to 2700 for both 02-04 and 05-06 model years.
FA Simplify Pro Formula Mazda wheel allowance #34190tyres & wheelsunclearFA Pro Formula Mazda front wheels widen to 10 in. max; rear wheels narrow to 14 in. min.
T4 05-06 Mini Wheel Weight #34112tyres & wheelsfasterT4 Mini Cooper S all years now run 17-inch wheels, up from 16, with wider rims to 8 inches.
T4 96-01 Audi a4 2.8 Spring Rate #34217suspension & brakesfasterT4 Audi A4 2.8 V6 wheels grow to 17x8, tyres to 245, springs now 800lb with 32mm sway bars.
FA E&O - Correct Pro Formula Mazda spec line dimensional equivalent #34085aerofasterFA Pro Formula Mazda maximum bodywork width behind front wheels increases to 51.97 inches.
FA Add new spec line for MSR Formula Mazda FMzR to Table 2 #34139cars addedcars addedFA MSR Formula Mazda FMzR added to Table 2 classification.
P2 Clarify minimum side body height requirement #34143wordingwordingP2 side body height requirement clarified: outermost surface between wheel openings must equal front axle centerline height.
P2 Clarify closed cockpit single seat car allowance #34144wordingwordingP2 closed cockpit single seat cars now prohibited unless specifically allowed in Table 1.
P2 Remove redundant effective date language and update engine table #34012wordingwordingP2 engine table wording updated; redundant effective date language removed.
P2 E&O - Correct dimensional equivalents #34038engineslowerP2 motorcycle engines: 2011+ Kawasaki restrictor reduced to 34mm, minimum weight raised to 1100 lbs; 2009+ other brands weight raised to 1100 lbs.
T4 Request to Classify 2004-2008 Acura TSX in T4 #33590cars addedcars addedAcura TSX 2004-2008 newly classified in T4 at 3000 lbs minimum weight with 2354cc engine.
T4 T4 Mustang Brakes/Swaybar #34036suspension & brakesfasterT4 Mustang rear sway bar increases from 22mm to 28mm permitted.
T4 BMW 320I intercooler #33762otherfasterT3 BMW 320I now permitted to use aftermarket intercooler.
Cal Club 2023 CALCL232023-02-24
1:14.588Greg Labadie · only car
1:12.573Kevin Mitz · only car
190 earlier rule changes on record, in force before Cal Club 2023 (from 2019)27 cars added · 18 weight · 15 suspension & brakes · 14 induction · 11 engine · 7 aero · 7 tyres & wheels · 1 removed · 85 wording · 5 other · T4 Mazda MX-5 ND2 (19-21) classified: 1998cc, 2309mm wheelbase, 225 max tires, 2800 lbs. · T2/T3 Mustang GT 5.0L and V6 (11-14) may remove upper grille fog lights, replace with mesh or screen. · T4 Mazda MX-5 Club Model 06-15 Mazda Motorsports LSD part number corrected from 32655 to 0000-02-5564. · FA BDA engine displacement specification line added to Table 1, effective 2023-01-01. · Sebeco NP01-EVO and Elan NP01 Mazda 2.0L MZR added to P2, 1600 lb minimum, no restrictor required. · P2 Radical SR3/SR4/Cup/Club Sport/Pro-Sport/PR6 removes assisted shifting requirement across all spec lines. · P2 chassis rules clarified to allow composite materials in non-fully-composite construction; anti-intrusion panel attachment standardized; Stohr and converted F600 cars added with specific allowances. · Unable to summarize: the change to P2 Engine Table Spec Line B.1 is not detailed in the provided text. · T4 Honda Civic Si 06-11 now permits 32mm sway bars front and rear and 700 pound springs. · T5 class added as regional-only; T5 tyres maximum width 225, minimum aspect ratio 45. · T2-T5 Touring front and rear suspension maximum negative camber changed to 3.5 degrees. · Formula Renault 2.0 (10-17) reclassified from FX to FA; weight reduced to 1280 lbs, restrictor removed. · FA Swift 016 2.3L restrictor increases from 31mm to 32mm SIR; minimum weight drops 30 lbs to 1420. · T4 Ford Mustang V6 (05-10) wheels widen to 18x9, front brakes grow to 314mm vented, weight drops to 3275 lbs. · T4 Mazda MX-5 Club (06-15) minimum weight drops 25 lbs to 2600; Mazda LSD #32655 now permitted without penalty. · Pro Formula Mazda allows street or bridge port, unrestricted apex seals, 70mm throttle body, 99cm wing height max, 132cm bodywork width max. · T3 Subaru BRZ 2022- minimum weight up to 2975 lbs; spring rate to 1000 F/R, brake parts allowed without penalty. · T4 Mazda3 04-09 now permits Corksport balance shaft delete kit GEN-6-504-10. · T4 Hyundai Tiburon V-6 wheel width increases from 7 to 8 inches at 17-inch diameter. · FA Ligier JS F3 must comply with Formula Regional Americas rules instead of FIA Formula 3 Regional Technical Regulations. · FA sealed engines must undergo full inspection; competitor pays reassembly and resealing costs. · FA Formula Lites FL15 and FR Americas Ligier JS F3 engine sealing requirements clarified to reference respective series technical regulations. · P2 chassis construction rules clarified: fully composite or partially composite requiring composite for mobility allowed; partial composite must roll without composite parts. · P2 classification wording cleaned up in GCR section 9.1.8.C and Contents. · T4 Mazda3 i 2.0L added as spec line with 1999cc displacement and 2425 lbs minimum weight. · T2-T4 Touring cars with alternative springs may use performance top hats with spherical bearings on shocks and struts. · FA transmission rule clarified: transverse shafts prohibited except final drive and motorcycle gearbox in Formula 1000. · FA Swift 016 2.5 liter aero spec now references 2.3 liter notes instead of N notes. · P2 Oldsmobile cam rules clarify aftermarket manufacturer requirements; wording only. · T2-T4 cars model year 2018+ may use non-OEM ECU with 75 lb weight penalty via spec line adjustment. · T4 Nissan Sentra SE-R Spec V 02-06 now permits balance shaft removal kit OQR25-NOBAL. · T4 BMW 323 (98-00) wheelbase increases to 2725 mm, final drive ratio changes to 3.07. · T4 Mazda RX-8 04-12 gains Eibach spring alternatives to Mazda Motorsports springs front and rear. · T4 Mazda3 04-09 tire size increases from 235 to 245. · T4 Ford Mustang V6 05-10 shock part numbers corrected to 8741-1494SPORT front and 8241-1240SPORT rear. · T4 Scion FR-S and Subaru BRZ Solo Spec Coupes updated to 2020 specifications Rev 7/20. · T4 2016–18 Mazda MX-5 Miata/Club gains 100 lbs. for approved suspension package with specific springs. · FA Pro Formula Mazda now allows street port or bridge port, previously porting was prohibited. · P2 adds Beasley B2 spec line with 1350 lbs, Mazda 12A, 40.5mm venturi, 16.5in wing. · P2 wing specs correct terminology from 'cord' to 'chord' for 16.5in single or dual element wings. · P2 Converted F5 cars reclassified as Converted F500 cars; suspension must comply with F500 requirements, minimum width 55 inches. · T2-T4 grill openings may remove non-metallic webbed false sections; 16 square inch limit removed. · T3 Spec Lines Subaru BRZ TS (13-21) added to class specification wording. · FA adds Honda K20Z3 2.0L engine spec at 1350 lbs minimum and Mazda MZR 2.0L spec at 1300 lbs minimum to Table 1. · P2 motorcycle engines increase to 1505cc max, two-stroke to 1205cc max; automotive engines gain 50 lbs minimum weight to 1350. · T4 Mazda MX-5 Club 06-15 allows non-OEM LSD with +50 lbs penalty; removes stock transmission and differential requirements. · T4 2005-2010 Ford Mustang V6 now specifies Koni damper part numbers 8741.1494 front and 8741.1240 rear. · P2 Control Area definition narrowed; aerodynamic attachments and vertical structures like turning vanes now prohibited. · T2-T4 clarified: grill opening area may increase max 16 sq in for radiator cooling only, retaining factory mesh shape. · T4 BMW 323 98-00 minimum weight drops to 3250 lbs, 50mm restrictor removed. · T4 Honda Civic Si consolidates 12-13 and 14-15 into single 12-15 spec line with updated suspension allowances. · T2, T3, T4 radiator and coolant hoses may be replaced with aftermarket options; coolant temp sensor modification permitted. · T2, T3, T4 clarify that spec lines listing permitted or allowed parts are alternatives to category rules, not replacements. · T4 Acura RSX/RSX Type-S 02-06 removes requirement that original wheels must remain stock. · T4 Chevrolet Camaro V-6 (96-02) removes requirement that shock/struts, mounts, and transmission differential remain stock. · P2 Engine Table Spec Line B.1 changed effective 1-1-22, details not provided in excerpt. · P2 Control Area definition clarified: floor extensions and aerodynamic attachments on bottom or top side now explicitly included. · Nissan Sentra SE-R Spec V (2007–2012) newly classified in T4 at 3000 lbs minimum weight. · T4 Mazda RX-8 04-12 allows alternate sway bars max 32mm front, 19mm rear; removes 60mm restrictor requirement. · T4 BMW 320i (14-15) now allows GFB T9357 aluminum diverter valve. · T4 Honda Civic FWD gets wider 8-inch wheels, 245 tyres max, and sway bar allowances to 29mm front, 22mm rear. · T4 multiple cars: Volkswagen Rabbit 2.5 (08-09) to 2675 lbs; Mazda MX-5/Club (06-15) to 2625 lbs; RX-8 to 3125 lbs; Honda/Acura/Chevy/Mazda wheel widths 7 to 8 inches. · T4 Volkswagen Passat, Jetta 1.8T adds 2014 model year to eligible years. · FA Mazda MZR 2.0 spec line removes redundant '2.0' designation; Honda Civic K20Z3 spec line unchanged. · P2 CN Honda K20A-FD2 engine rebuild rules clarified: machining prohibition replaced with specific restrictions on balancing, porting, polishing, valve jobs, cylinder honing. · FA Toyota 1800 moves from Table 1 to Table 2 (Spec Line Cars). · FA Swift 016 Mazda MZR/Ford Duratec wheel width specification clarified: front 10, rear 14 minimum and 15 maximum. · Converted F5 cars in P2 minimum width reduced to 55 inches from F5 spec. · P2 clarifies minimum body width requirement between front and rear wheels for Ralt RT40, RT41, Swift 008, 014. · FA rule wording clarified: Table 1 for purpose-built and ex-pro cars, Table 2 for spec line cars with exceptions noted. · FA Mazda MZR/Ford Duratec 2296cc and 2500cc moved from Table 1 to Table 2. · FA Mazda MZR 2.0 and Honda Civic K20Z3 remove sequential designation from 5-speed transmission spec. · T4 BMW 320i 14-15 part number corrected from 20121.140 to E10-20-031-01-22. · FA Mazda MZR 2.0 limited to Ralt RT40, RT41, Swift 008, 014 chassis; Honda Civic K20Z3 removes Swift 016 chassis. · T3 Honda Civic Type-R 2020+ allows brake rotor 45251-TGH-A01 with 25 lb penalty. · FA Swift 016 2.3 liter engine name corrected to Mazda MZR/Ford Duratec. · FA Swift 016 2.5 liter engine name corrected to Mazda MZR/Ford Duratec. · FA removes four spec lines and replaces Ford Duratec/Mazda MZR with Honda B16 at 1615cc, 1175 lbs minimum. · P2 tonneau covers now allowed to meet minimum dimensions; equipment attachment requirements clarified. · P2 multiple chassis models remove effective dates from Table 1 specifications. · P2 engines limited to 4 valves per cylinder maximum across all three spec lines. · T4 Mini Cooper S (02-04, 05-06) suspension/wheel rules simplified; (07-13) gear ratios changed to 3.31, 2.13, 1.48, 1.14, 0.95, 0.82, final drive to 3.65, brakes to 280 mm. · T4 Ford Mustang V6 05-10 now allows cold air intake. · FA Spec Line C loses 25 lbs to 1175; Line I loses 75 lbs to 1175; Line K gains 15 lbs to 1175. · FA purpose built and ex-Pro Atlantic cars lose 25 lb sequential transmission penalty wording. · FA Ligier JS F3 car name corrected in FR Americas spec line. · FA Ford Duratec/Mazda MZR 2500 spec line D wording cleanup: 4-valve becomes 4 valves per cylinder. · FA Honda Civic K20Z3 intake manifold and throttle body assembly now allows AT Power Direct-To-Head 45mm individual throttle bodies as alternative to HPD parts. · T2-T4 clutch disc and pressure plate must be at least 95% of factory OEM weight. · FA Ford Duratec/Mazda MZR intake restrictor reduced from 32mm to 30mm SIR; Swift 016 2.5 Mazda restrictor reduced from 35mm to 33mm SIR. · FA Toyota 4A-GE engines cleaned up, spec lines A and B engine designations corrected. · FA Ford BD Series max displacement increases from 1600 to 1615 cc, minimum weight stays 1200 lbs. · FA Ford Duratec/Mazda MZR and Honda B16 both now 1615cc max displacement; Honda B16 removes NA requirement. · FA Pro Formula Mazda engine specs moved from Table 1 to Table 2 notes; Renesis Rotary details consolidated. · FA F3 Americas spec line updated effective 2021-03-01; specific changes not legible in provided text. · P2 adds new spec line for 2-cycle 3-cylinder engine up to 820cc with 10 front and 14-15 rear wheel width. · T4 Ford Mustang V6 05-10 wheels increase from 17 to 18 inches. · Toyota Supra 2020- newly classified in T2 at 3450 lbs minimum weight with 295 tire and 19-inch wheels. · T4 Mazda MX-5 durability rule now applies to T2-T4 instead of T2-T3 only. · T4 Chevrolet Sonic (2011-) spec clarified: 28mm TIR restrictor placement, PCV plug requirement, and allowed suspension parts listed. · T4 Mazda MX-5 06-15 removes front and rear end links from suspension package spec. · T4 BMW Z4 2.5L (03-05) minimum weight reduced from 3100 to 3050 lbs. · T4 2016+ Mazda MX-5 Miata gains allowance for 29mm front and 16mm rear sway bars. · T4 Scion FR-S, Subaru BRZ, and Toyota 86 replace Eibach part 4.10582.880 with 82105.320, 4.10582 and SPC 67660. · T4 Ford Mustang V6 05-10 allows GT 8.8 rear axle with 3.45 or 3.55 ratio at +25 lb penalty. · Formula Lites Crawford FL15 newly classified in FA. · BMW M2 CS Cup 2020+ classified in T2 at 3625 lbs with 2979cc engine, 10.5x18 wheels, 295 tires. · T3 and T4 Mazda MX-5 06-15 now allow Mazda Transmission kit part # 0000-02-5700. · T4 Ford Mustang V6 05-10 allows GT 8.8 rear axle with 3.55 final drive, adds 25 lb penalty. · T3 and T4 FR-S, 86, and BRZ year ranges capped: T3 at 2021, T4 at 2017-2021. · P2 Honda K20A-FD2 intake restrictor reduced from 55mm to 50mm, making cars faster. · T3 Alfa Romeo 4C Launch Edition now allowed in Spec Lines. · P2 rear wing requirements clarified: standard wing 6×12 inches, end plates 14-inch square; alternate 110cm width wing 9×18 inches, end plates 14×18 inches. · T4 Scion FRS and Subaru BRZ Solo Spec Coupe final drive ratio changed from 4.30 to 4.10. · FA stock engines not given weight adjustment; modified engines now allowed in class. · T4 Mazda RX-8 04-12 now allows OE rear spoiler #F151-V4-920F and OE front air dam #F151-V4-900f-BB. · T4 2006-2015 Mazda MX-5 Club Model now allows non-stock wheels; transmission, differential, LSD remain stock. · Cannot read: letter references external document #27663 not provided. · FA engine modifications wording clarified: bore/crankshaft/stroke/flywheel unrestricted if displacement limit met, distributor/transistor ignition allowed without engine modification, compression ratio increasable by machining/gasket chang… · FA transmission rules clarified: no more than five forward speeds and operational reverse gear unless Table 2 notes otherwise. · FA Swift 016 Mazda Duratec Gurney flap wording clarified; terminology and mounting rules unchanged. · Elan NP01 classified in P2 Table 1 as Spec Line car with 2000cc displacement and P2 Engine Table restrictor. · 2004 Mercedes Benz CLK 320 Coupe classified in T4 at 3200 lbs with 3299cc engine and Eibach PN# 2563.140 springs allowed. · FA Volkswagen 1835cc SOHC removed from Table 1. · FA engine rules clarified: blocks and heads must be OEM unless Tables note exceptions. · P2 Enterprises Sports Racer adds 55mm flat plate intake restrictor Part # WM303013 as alternative to SIR. · T4 06-15 Mazda MX-5 now allows header part numbers 0000-06-5407 or 0000-06-5407-NC. · T3 BMW Z3 M & Coupe 1998-1999 weight reduced from 3350 to 3150 lbs. · FA Formula 1000 motorcycle-based engine compression ratio raised to 14.5:1 from 13.5:1. · FA removes Ex-FSV front wheel width 6–8 inches and rear 8–10 inches provisions; all cars use front 10 inches, rear 14–15 inches. · FA Formula 3 engines now allowed through 2017, previously 2008, with 30mm restrictor required. · P2 Enterprise Sports Racer 2.3L engine now requires SIR or Flat Plate restrictor sized in 0.5mm increments. · FA engine note clarification removes Table E reference, Pro Formula Mazda directed to Table 1. · P2 fly-by-wire throttle control wording clarified: stock ECUs with drive-by-wire must activate original throttle shaft mechanism. · T4 Honda Civic Si 12-13 and 14-15 now allow H&R and HPD springs up to 700 pounds with 47mm restrictor. · T4 Ford Mustang V6 05-10 springs now permitted max 500 lbs front and 400 lbs rear. · T4 Ford Mustang V6 05-10 allowed aluminum driveshaft, any LSD, and Ford brake kit M-2300-D. · Pontiac Solstice GXP and Saturn Sky move from T2 to T3; wheels widen to 18 x 9.5 inches, Sky weight drops to 3200 lbs. · Mazda RX-8 Base/R3/Sport/GT (04-12) classified in T3 effective 2020-02-01. · T4 Mazda3 14-18 gains permitted modifications: springs to 800/1000 lbs, 15 lb wheels, cold air intake, camber plates, 25mm rear bar, mirrors, CorkSport arms, header, specific calipers and rotor. · T4 allows aftermarket OEM coolant expansion tanks with no other functional purpose. · T4 Mazda MX-5 Club Model 06-15 now allows aftermarket power steering reservoir. · T4 Subaru BRZ and Scion FR-S allowed factory installed wings. · T4 now permitted to use any OEM diameter clutch disc and pressure plate, previously T2-T3 only. · Chevrolet Sonic 2011+ added to T4 at 2800 lbs with 1364 cc engine and 225 max tire size. · T4 Mazda MX-5/Miata 1999-2005 minimum weight reduced 50 lbs to 2400. · Formula 1000 motorcycle-based engine classified into FA, throttle bodies and ECUs unrestricted. · F1000 reclassified into FA with specification changes effective 2020-01-01. · FA Swift 016 2.3L Mazda Duratec restrictor reduced from 33mm to 31mm SIR, making it slower. · P2 adds BMW to motorcycle-based engine options in 4-cycle line alongside Kawasaki, Suzuki, Yamaha, Honda. · T2 requires onboard fire system; T3 and T4 may have one per GCR 9.3. · T3 Ford Mustang EcoBoost 2015- gains three transmission gear ratio options. · T4 BRZ, FR-S, and 86 maximum tire size reduced from 245 to 225. · T4 Mazda MX-5 Club Model 06-15 minimum weight cut from 2625 to 2550 lbs. · Mazda RX-8 Base/R3 (04-12) reclassified in T3 and T4 to include Sport and GT variants. · Toyota 86 GT (2017-) added to T3 and T4 Spec Line. · FA wheel dimension rules moved from Bodywork subsection to General section; no specification changes. · FA Mazda MZR 2.0 now limited to Ralt RT40, Ralt RT41, and Swift 014 chassis only. · FA Honda Civic K20Z3 engines consolidated: three separate base/uprated specs removed, replaced with single unified 1350 lb minimum weight spec for Swift 014/016. · P2 Honda K20A-FD2 non-composite chassis must use 55mm flat plate intake restrictor at 1500 lbs minimum weight. · FA Swift 014 Mazda MZR 2.0 piston minimum weight reduced from 320g to 280g. · P2 motorcycle engines: Stock restrictor 36.5mm to 35mm, modified 37.5mm to 34mm; B.5 restrictor 37.5mm to 33mm. All weights increase 25 lbs. · T2-T4 spare tire/wheel rules clarified: removable covers can be removed with hardware and bracketry. · T4 Mazda MX-5 Club (06-15) gains suspension package with 100 lbs weight increase, allows RX8 hubs and SM5 suspension, permits non-OEM LSD with 50 lbs penalty. · P2 cars limited to power application on maximum two wheels, effective 2019-07-01. · T4 Toyota MR-2 Spyder 16V DOHC years corrected from 01-05 to 00-07. · P2 Enterprise minimum weight increases to 1375 lbs; peak horsepower of sealed ESR engine reduced per CRB specification. · FA Line N minimum weight increases to 1375 lbs. · T4 Mazda Protégé ES 2000 now allows piggyback ECU tuning device; OBD2 requirement waived. · T4 Mazda MX5 Club Model 06-15 allows suspension package with 100 lbs weight increase including helper springs. · FA cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs. · T4 BMW 323 (98-00) newly classified at 3450 lbs with 50mm flat plate restrictor and M52TUB25 engine required. · FA Formula 3 car sequential gearbox weight penalty of 25 lbs removed; minimum weight now 1215 lbs. · P2 stock engine restrictor shrinks to 35.0mm and weight rises to 1025 lbs; modified engine restrictor to 34.0mm, weight to 1125 lbs; line B.5 restrictor to 33.0mm, weight to 1185 lbs. · P2 Line A.1 restrictor reduced from 40mm to 38mm. · T4 Mazda MX-5 Club (06-15) and (2016-), T3 MX-5 Cup and Miata (2016-) hardtop rules clarified; wording changes to permitted parts and specifications. · T2, T3, T4 now allow any thermostat serving only OE intent, previously restricted. · T3 and T4 Mazda MX-5 Miata eligibility capped at 2018 model year, effective 2019-03-01. · FA Swift 014-Mazda MZR 2.0 engine now requires OE block casting #LF95 and specific OE components instead of sealed Elite Engines sourcing. · FA Swift 016 Mazda Duratec 2.3L and 2.5L minimum weight increases from 1420 to 1450 lbs. · T4 Honda Civic Si 2012-2015 permitted sway bars increased to 32mm front and rear. · P2 Spec Line cars now allow 1345cc Hayabusa stock engines at 1050 lbs with 30mm restrictor. · P2 Group CN Honda K20A-FD2 55mm restrictor implementation delayed from 1/1/2019 to 3/1/2019. · P2 Honda K20A-FD2 in CN chassis must use stock intake manifold with 64mm throttle body and 55mm restrictor at 1500 lbs minimum weight. · T4 Ford Fiesta ST years corrected to 14-; T4 Fiat 124/Abarth Edition years added 16-18; battery rule clarified. · T4 Fiat 124 Abarth Edition restrictor changes from 29mm flat plate to 30mm TIR. · T1-T3 spec cars receive clarifications on permitted modifications, documentation requirements, and rule conformance; no performance changes. · T2-T4 subframe bushings may now be replaced with non-spherical bushings of any material. · Scion FR-S and Subaru BRZ 13-16 Solo Spec Coupes added to T4, both 1998cc, 2570 lbs, 225/45/17 tires.showhide
T4 Mustang OEM Grill Request #33333aeroaeroT2/T3 Mustang GT 5.0L and V6 (11-14) may remove upper grille fog lights, replace with mesh or screen.
T4 Mazda OEM LSD was letter 32655 typo #33666wordingwordingT4 Mazda MX-5 Club Model 06-15 Mazda Motorsports LSD part number corrected from 32655 to 0000-02-5564.
FA BDA Displacement #33431wordingwordingFA BDA engine displacement specification line added to Table 1, effective 2023-01-01.
P2 Request to Classify Sebeco NP01 #33378cars addedcars addedSebeco NP01-EVO and Elan NP01 Mazda 2.0L MZR added to P2, 1600 lb minimum, no restrictor required.
P2 Radical spec line clarifications #33485wordingwordingP2 Radical SR3/SR4/Cup/Club Sport/Pro-Sport/PR6 removes assisted shifting requirement across all spec lines.
P2 E&O original class intent #33519wordingwordingP2 chassis rules clarified to allow composite materials in non-fully-composite construction; anti-intrusion panel attachment standardized; Stohr and converted F600 cars added with specific allowances.
P2 Update Engine Table Spec Line B.1 #33608engineunclearUnable to summarize: the change to P2 Engine Table Spec Line B.1 is not detailed in the provided text.
T4 Allowable Springs and Sway Bars for 06-11 Civic si Spec Line #33294suspension & brakesfasterT4 Honda Civic Si 06-11 now permits 32mm sway bars front and rear and 700 pound springs.
T4 Touring (T2-T5) Category #33617cars addedcars addedT5 class added as regional-only; T5 tyres maximum width 225, minimum aspect ratio 45.
T4 ENO 9.1.9.2.D.1.e.1.a. #33651suspension & brakessuspension & brakesT2-T5 Touring front and rear suspension maximum negative camber changed to 3.5 degrees.
FA Reclassify 2010-2017 Formula Renault 2.0 as a spec line car in FA #33395cars addedfasterFormula Renault 2.0 (10-17) reclassified from FX to FA; weight reduced to 1280 lbs, restrictor removed.
FA Change Swift 016 2.3L restrictor size and minimum weight #33472induction -30 lbsfasterFA Swift 016 2.3L restrictor increases from 31mm to 32mm SIR; minimum weight drops 30 lbs to 1420.
T4 T4 mustang #32789tyres & wheels -25 lbsfasterT4 Ford Mustang V6 (05-10) wheels widen to 18x9, front brakes grow to 314mm vented, weight drops to 3275 lbs.
T4 Mazda OEM LSD was letter 32655 #32933weight -25 lbsfasterT4 Mazda MX-5 Club (06-15) minimum weight drops 25 lbs to 2600; Mazda LSD #32655 now permitted without penalty.
FA Pro Formula Mazda Dimension E&O #33160wordingwordingPro Formula Mazda allows street or bridge port, unrestricted apex seals, 70mm throttle body, 99cm wing height max, 132cm bodywork width max.
T4 Another 2022 BRZ/86 T3 request #32945weight +225 lbsslowerT3 Subaru BRZ 2022- minimum weight up to 2975 lbs; spring rate to 1000 F/R, brake parts allowed without penalty.
T4 Request Wider Wheels for Hyundai Tiburon #32536tyres & wheelsfasterT4 Hyundai Tiburon V-6 wheel width increases from 7 to 8 inches at 17-inch diameter.
FA Update FR Americas rulebook requirement #32491wordingwordingFA Ligier JS F3 must comply with Formula Regional Americas rules instead of FIA Formula 3 Regional Technical Regulations.
FA Clarify verification of sealed engine compliance #32522wordingwordingFA sealed engines must undergo full inspection; competitor pays reassembly and resealing costs.
FA Clarify Formula Lites and FR Americas sealed engine requirement #32523wordingwordingFA Formula Lites FL15 and FR Americas Ligier JS F3 engine sealing requirements clarified to reference respective series technical regulations.
P2 E&O Clarification of Chassis Construction Requirements #32469wordingwordingP2 chassis construction rules clarified: fully composite or partially composite requiring composite for mobility allowed; partial composite must roll without composite parts.
P2 Clean up P2 wording #32525wordingwordingP2 classification wording cleaned up in GCR section 9.1.8.C and Contents.
T4 Request to Add Spec Line for 2004-2009 Mazda3 i 2.0 #32395cars addedcars addedT4 Mazda3 i 2.0L added as spec line with 1999cc displacement and 2425 lbs minimum weight.
T4 Request Alternate Front & Rear Strut/Shock Top Hats #32452suspension & brakessuspension & brakesT2-T4 Touring cars with alternative springs may use performance top hats with spherical bearings on shocks and struts.
FA E&O FA Transmission section #32251wordingwordingFA transmission rule clarified: transverse shafts prohibited except final drive and motorcycle gearbox in Formula 1000.
FA E&O Swift 016 2.5 liter Aero column #32363wordingunclearFA Swift 016 2.5 liter aero spec now references 2.3 liter notes instead of N notes.
P2 After Market to Aftermarket #32373wordingwordingP2 Oldsmobile cam rules clarify aftermarket manufacturer requirements; wording only.
T4 Request to Allow the Use of Aftermarket ECU's in Touring #31067weightslowerT2-T4 cars model year 2018+ may use non-OEM ECU with 75 lb weight penalty via spec line adjustment.
T4 Request JWT BSR Kit for 02-06 Nissan Sentra SE-R/Spec V #31685enginefasterT4 Nissan Sentra SE-R Spec V 02-06 now permits balance shaft removal kit OQR25-NOBAL.
T4 Please Confirm Touring 4 (98-00) BMW 323 is E46 generation #31972wordingunclearT4 BMW 323 (98-00) wheelbase increases to 2725 mm, final drive ratio changes to 3.07.
T4 RX-8 Spring Part Numbers (E&O) #32151suspension & brakessuspension & brakesT4 Mazda RX-8 04-12 gains Eibach spring alternatives to Mazda Motorsports springs front and rear.
T4 04-09 Mazda3 Tire Limit Clarification #32249tyres & wheelsfasterT4 Mazda3 04-09 tire size increases from 235 to 245.
T4 Shock Part Number Errors & Omissions #32252wordingwordingT4 Ford Mustang V6 05-10 shock part numbers corrected to 8741-1494SPORT front and 8241-1240SPORT rear.
T4 Update Solo Spec Coupe to latest '20 specs for Road Racing #32262wordingunclearT4 Scion FR-S and Subaru BRZ Solo Spec Coupes updated to 2020 specifications Rev 7/20.
T4 Request 2016 Mazda MX5 springs #32265suspension & brakesslowerT4 2016–18 Mazda MX-5 Miata/Club gains 100 lbs. for approved suspension package with specific springs.
FA Closing the Gap #31934inductionfasterFA Pro Formula Mazda now allows street port or bridge port, previously porting was prohibited.
P2 Add spec line for Beasley B2 #32147cars addedcars addedP2 adds Beasley B2 spec line with 1350 lbs, Mazda 12A, 40.5mm venturi, 16.5in wing.
P2 E&O Table 1 spec line wing terminology #32148wordingwordingP2 wing specs correct terminology from 'cord' to 'chord' for 16.5in single or dual element wings.
P2 E&O class name #32196wordingwordingP2 Converted F5 cars reclassified as Converted F500 cars; suspension must comply with F500 requirements, minimum width 55 inches.
T4 Reply to letter #31486/29879 T2-T4 Grill openings #31935aerofasterT2-T4 grill openings may remove non-metallic webbed false sections; 16 square inch limit removed.
T4 BRZ vs BRZ TS #32022wordingwordingT3 Spec Lines Subaru BRZ TS (13-21) added to class specification wording.
FA Reorganize Tables 1 and 2 #31985cars addedcars addedFA adds Honda K20Z3 2.0L engine spec at 1350 lbs minimum and Mazda MZR 2.0L spec at 1300 lbs minimum to Table 1.
P2 E&O Engine section #31969enginefasterP2 motorcycle engines increase to 1505cc max, two-stroke to 1205cc max; automotive engines gain 50 lbs minimum weight to 1350.
T4 MX-5 Durability Detailed #31102weightslowerT4 Mazda MX-5 Club 06-15 allows non-OEM LSD with +50 lbs penalty; removes stock transmission and differential requirements.
T4 Request Allowances for 2005 - 2010 Mustang #31624suspension & brakessuspension & brakesT4 2005-2010 Ford Mustang V6 now specifies Koni damper part numbers 8741.1494 front and 8741.1240 rear.
P2 E&O letter #31539 – Control Area definition #31783aeroslowerP2 Control Area definition narrowed; aerodynamic attachments and vertical structures like turning vanes now prohibited.
T4 Reply to letter 29879 T2-T4 Grill Openings #31486aerofasterT2-T4 clarified: grill opening area may increase max 16 sq in for radiator cooling only, retaining factory mesh shape.
T4 Please Adjust 98-00 BMW 323 Min Weight to Reflect Current Class #31595weight -200 lbsfasterT4 BMW 323 98-00 minimum weight drops to 3250 lbs, 50mm restrictor removed.
T4 Consolidate 12-13 and 14-15 Honda Civic Si spec lines for T4 #31596wordingwordingT4 Honda Civic Si consolidates 12-13 and 14-15 into single 12-15 spec line with updated suspension allowances.
T4 Request to clarify radiator hoses #31682wordingwordingT2, T3, T4 radiator and coolant hoses may be replaced with aftermarket options; coolant temp sensor modification permitted.
T4 Clarify Permitted/Allowed #31743wordingwordingT2, T3, T4 clarify that spec lines listing permitted or allowed parts are alternatives to category rules, not replacements.
T4 Correct RSX wording #31746wordingfasterT4 Acura RSX/RSX Type-S 02-06 removes requirement that original wheels must remain stock.
T4 Camaro #31751suspension & brakesfasterT4 Chevrolet Camaro V-6 (96-02) removes requirement that shock/struts, mounts, and transmission differential remain stock.
P2 BoP adjustment effective 1-1-22 #31538wordingunclearP2 Engine Table Spec Line B.1 changed effective 1-1-22, details not provided in excerpt.
P2 E&O clarification of "Control Area" definition #31539wordingwordingP2 Control Area definition clarified: floor extensions and aerodynamic attachments on bottom or top side now explicitly included.
T4 Nissan Sentra SE-R Spec. V #30958cars addedcars addedNissan Sentra SE-R Spec V (2007–2012) newly classified in T4 at 3000 lbs minimum weight.
T4 Mazda RX-8 Spec Line Suspension Parts #31113suspension & brakesfasterT4 Mazda RX-8 04-12 allows alternate sway bars max 32mm front, 19mm rear; removes 60mm restrictor requirement.
T4 Diverter Valve Plunger Upgrade #31307wordingwordingT4 BMW 320i (14-15) now allows GFB T9357 aluminum diverter valve.
T4 Adjust Honda FWD in T4 to encourage more Drivetrain Diversity #31472tyres & wheelsfasterT4 Honda Civic FWD gets wider 8-inch wheels, 245 tyres max, and sway bar allowances to 29mm front, 22mm rear.
T4 Touring 4 BOP adjustments for 2022 #31482weight -175 lbsslowerT4 multiple cars: Volkswagen Rabbit 2.5 (08-09) to 2675 lbs; Mazda MX-5/Club (06-15) to 2625 lbs; RX-8 to 3125 lbs; Honda/Acura/Chevy/Mazda wheel widths 7 to 8 inches.
T4 Request to Classify 2014 VW Jetta 1.8t TSI #30436cars addedcars addedT4 Volkswagen Passat, Jetta 1.8T adds 2014 model year to eligible years.
FA E&O Table 2 engine names #31085wordingwordingFA Mazda MZR 2.0 spec line removes redundant '2.0' designation; Honda Civic K20Z3 spec line unchanged.
P2 P2 CN Engine Rebuild Clarification #31000wordingwordingP2 CN Honda K20A-FD2 engine rebuild rules clarified: machining prohibition replaced with specific restrictions on balancing, porting, polishing, valve jobs, cylinder honing.
FA Move Toyota 1800 to Table 2 #30822cars addedcars addedFA Toyota 1800 moves from Table 1 to Table 2 (Spec Line Cars).
FA E&O Swift 016 wheel width reference #30939wordingwordingFA Swift 016 Mazda MZR/Ford Duratec wheel width specification clarified: front 10, rear 14 minimum and 15 maximum.
P2 F5 P2 Conversion #30856aerofasterConverted F5 cars in P2 minimum width reduced to 55 inches from F5 spec.
P2 Clarify minimum body width requirement #30859wordingwordingP2 clarifies minimum body width requirement between front and rear wheels for Ralt RT40, RT41, Swift 008, 014.
FA Update FA rules package #30717wordingwordingFA rule wording clarified: Table 1 for purpose-built and ex-pro cars, Table 2 for spec line cars with exceptions noted.
FA Move Mazda MZR/Ford Duratec 2296cc and 2500cc to Table 2 #30718wordingwordingFA Mazda MZR/Ford Duratec 2296cc and 2500cc moved from Table 1 to Table 2.
FA Clean up Table 2 Mazda MZR 2.0L and Honda Civic K20Z3 spec lines #30719wordingwordingFA Mazda MZR 2.0 and Honda Civic K20Z3 remove sequential designation from 5-speed transmission spec.
T4 Wrong Part Number on 320i Spec Line #30645wordingwordingT4 BMW 320i 14-15 part number corrected from 20121.140 to E10-20-031-01-22.
FA E&O Mazda MZR 2.0 and Honda Civic K20Z3 chassis eligibility #30632wordingwordingFA Mazda MZR 2.0 limited to Ralt RT40, RT41, Swift 008, 014 chassis; Honda Civic K20Z3 removes Swift 016 chassis.
T4 Civic Type R Brake Rotors #29817weightslowerT3 Honda Civic Type-R 2020+ allows brake rotor 45251-TGH-A01 with 25 lb penalty.
FA Correct engine name in Swift 016 2.3 liter spec line #30447wordingwordingFA Swift 016 2.3 liter engine name corrected to Mazda MZR/Ford Duratec.
FA Correct engine name in Swift 016 2.5 liter spec line #30448wordingwordingFA Swift 016 2.5 liter engine name corrected to Mazda MZR/Ford Duratec.
FA Revise Table 1 Spec Lines and clarify application of Engine Notes #30456cars addedunclearFA removes four spec lines and replaces Ford Duratec/Mazda MZR with Honda B16 at 1615cc, 1175 lbs minimum.
P2 E&O tonneau cover provision in cockpit opening section #30459wordingwordingP2 tonneau covers now allowed to meet minimum dimensions; equipment attachment requirements clarified.
P2 Remove effective dates in Table 1 #30468wordingwordingP2 multiple chassis models remove effective dates from Table 1 specifications.
P2 E&O Maximum Valves Per Cylinder #30560engineengineP2 engines limited to 4 valves per cylinder maximum across all three spec lines.
T4 Mini Cooper Spec Line Anomalies #30478suspension & brakesunclearT4 Mini Cooper S (02-04, 05-06) suspension/wheel rules simplified; (07-13) gear ratios changed to 3.31, 2.13, 1.48, 1.14, 0.95, 0.82, final drive to 3.65, brakes to 280 mm.
T4 Request CAI Mustang in T4 #30562inductionfasterT4 Ford Mustang V6 05-10 now allows cold air intake.
FA Update Table 1 Weights for Spec Lines C, I, and K #30355weight -25 lbsfasterFA Spec Line C loses 25 lbs to 1175; Line I loses 75 lbs to 1175; Line K gains 15 lbs to 1175.
FA Remove redundant reference in Table 2 spec line #30366wordingfasterFA purpose built and ex-Pro Atlantic cars lose 25 lb sequential transmission penalty wording.
FA Correct the name of the FR Americas car #30369wordingwordingFA Ligier JS F3 car name corrected in FR Americas spec line.
FA Clean up Spec Line D in Table 1 #30372wordingwordingFA Ford Duratec/Mazda MZR 2500 spec line D wording cleanup: 4-valve becomes 4 valves per cylinder.
FA Table 2 Honda K20Z3 request #30386inductionfasterFA Honda Civic K20Z3 intake manifold and throttle body assembly now allows AT Power Direct-To-Head 45mm individual throttle bodies as alternative to HPD parts.
T4 Request consistency review in GCR #30263wordingslowerT2-T4 clutch disc and pressure plate must be at least 95% of factory OEM weight.
FA E&O FA Intake Restrictors #30273inductionslowerFA Ford Duratec/Mazda MZR intake restrictor reduced from 32mm to 30mm SIR; Swift 016 2.5 Mazda restrictor reduced from 35mm to 33mm SIR.
FA Clean up Spec Lines A and B in Table 1 #30274wordingwordingFA Toyota 4A-GE engines cleaned up, spec lines A and B engine designations corrected.
FA Clean up Spec Line C in Table 1 #30275enginefasterFA Ford BD Series max displacement increases from 1600 to 1615 cc, minimum weight stays 1200 lbs.
FA Clean up Spec Lines J and L in Table 1 #30276wordingwordingFA Ford Duratec/Mazda MZR and Honda B16 both now 1615cc max displacement; Honda B16 removes NA requirement.
FA Move engine specifications to Pro Formula Mazda spec line notes #30278wordingwordingFA Pro Formula Mazda engine specs moved from Table 1 to Table 2 notes; Renesis Rotary details consolidated.
FA Update F3 Americas spec line #30280wordingunclearFA F3 Americas spec line updated effective 2021-03-01; specific changes not legible in provided text.
P2 Add a new spec line for a 2-cycle, 3-cylinder engine up to 820cc #30272cars addedcars addedP2 adds new spec line for 2-cycle 3-cylinder engine up to 820cc with 10 front and 14-15 rear wheel width.
T4 E & O T4 Mustang Wheels #30245tyres & wheelsfasterT4 Ford Mustang V6 05-10 wheels increase from 17 to 18 inches.
T4 2021 Toyota Supra #29567cars addedcars addedToyota Supra 2020- newly classified in T2 at 3450 lbs minimum weight with 295 tire and 19-inch wheels.
T4 06-15 MX-5 Durability #29781wordingwordingT4 Mazda MX-5 durability rule now applies to T2-T4 instead of T2-T3 only.
T4 Request for Update to T4 Spec Line for Chevrolet Sonic (2011-) #29838wordingwordingT4 Chevrolet Sonic (2011-) spec clarified: 28mm TIR restrictor placement, PCV plug requirement, and allowed suspension parts listed.
T4 NC MX-5 06-15 Part Number updates for 2021 #29921wordingwordingT4 Mazda MX-5 06-15 removes front and rear end links from suspension package spec.
T4 BMW Z4 2.5L (03-05) Spec Line #30037weight -50 lbsfasterT4 BMW Z4 2.5L (03-05) minimum weight reduced from 3100 to 3050 lbs.
T4 Sway Bars for T4 2016+ MX5 Mazda #30063suspension & brakessuspension & brakesT4 2016+ Mazda MX-5 Miata gains allowance for 29mm front and 16mm rear sway bars.
T4 Change part numbers on BRZ, FRS lines in T4 #30104wordingwordingT4 Scion FR-S, Subaru BRZ, and Toyota 86 replace Eibach part 4.10582.880 with 82105.320, 4.10582 and SPC 67660.
T4 T4 Mustang Axle Ratio and Wheels #30149weightslowerT4 Ford Mustang V6 05-10 allows GT 8.8 rear axle with 3.45 or 3.55 ratio at +25 lb penalty.
FA Request to classify Formula Lites Crawford FL15 #29702cars addedcars addedFormula Lites Crawford FL15 newly classified in FA.
T4 Request to Classify BMW M2 CS #29523cars addedcars addedBMW M2 CS Cup 2020+ classified in T2 at 3625 lbs with 2979cc engine, 10.5x18 wheels, 295 tires.
T4 Allow the SpecMX-5 Update Kit Into Touring 4 for the MX-5 #29681wordingunclearT3 and T4 Mazda MX-5 06-15 now allow Mazda Transmission kit part # 0000-02-5700.
T4 Request Mustang 8.8†rear axle replacement #29860weightslowerT4 Ford Mustang V6 05-10 allows GT 8.8 rear axle with 3.55 final drive, adds 25 lb penalty.
T4 Cap year range on all 86s #29908wordingwordingT3 and T4 FR-S, 86, and BRZ year ranges capped: T3 at 2021, T4 at 2017-2021.
P2 Balance of Performance adjustments effective 01-01-2021 #29822inductionfasterP2 Honda K20A-FD2 intake restrictor reduced from 55mm to 50mm, making cars faster.
T4 Alfa Romeo 4C Launch Edition #29531wordingwordingT3 Alfa Romeo 4C Launch Edition now allowed in Spec Lines.
T4 Post Runoffs Feedback for T4 #29752tyres & wheels -50 lbs
P2 E&O clarification of P2 rear wing requirements #29205aeroaeroP2 rear wing requirements clarified: standard wing 6×12 inches, end plates 14-inch square; alternate 110cm width wing 9×18 inches, end plates 14×18 inches.
T4 Scion FRS Solo Spec Coupe Gear Ratio #29021otherfasterT4 Scion FRS and Subaru BRZ Solo Spec Coupe final drive ratio changed from 4.30 to 4.10.
FA Request to Adjust FB Weight for Stock Engines #29005wordingwordingFA stock engines not given weight adjustment; modified engines now allowed in class.
T4 T4 RX8 bodywork clarification #28941aeroaeroT4 Mazda RX-8 04-12 now allows OE rear spoiler #F151-V4-920F and OE front air dam #F151-V4-900f-BB.
T4 2006-2015 MX-5 Clarification #28942otherfasterT4 2006-2015 Mazda MX-5 Club Model now allows non-stock wheels; transmission, differential, LSD remain stock.
T4 Request to Add a Vehicle to the Roster (contd.) #27698cars addedunclearCannot read: letter references external document #27663 not provided.
FA E&O permitted engine modifications #28831wordingwordingFA engine modifications wording clarified: bore/crankshaft/stroke/flywheel unrestricted if displacement limit met, distributor/transistor ignition allowed without engine modification, compression ratio increasable by machining/gasket chang…
FA E&O Transmissions #28832wordingwordingFA transmission rules clarified: no more than five forward speeds and operational reverse gear unless Table 2 notes otherwise.
FA Swift 016 Gurney flap wicker clarification #28884wordingwordingFA Swift 016 Mazda Duratec Gurney flap wording clarified; terminology and mounting rules unchanged.
P2 Classify Elan NP01 in P2 Table 1 #28812cars addedcars addedElan NP01 classified in P2 Table 1 as Spec Line car with 2000cc displacement and P2 Engine Table restrictor.
T4 Request to Classify 2004 Mercedes Benz 320 CLK #27663cars addedcars added2004 Mercedes Benz CLK 320 Coupe classified in T4 at 3200 lbs with 3299cc engine and Eibach PN# 2563.140 springs allowed.
FA Remove redundant spec line in Table 1 #28720removedremovedFA Volkswagen 1835cc SOHC removed from Table 1.
FA E&O general engine rules #28772wordingwordingFA engine rules clarified: blocks and heads must be OEM unless Tables note exceptions.
P2 SCCA Enterprises ESR / P2 engine restrictor testing #28669engineengineP2 Enterprises Sports Racer adds 55mm flat plate intake restrictor Part # WM303013 as alternative to SIR.
T4 Request to change allowed header part # for T4 06-15 Miata #28223wordingwordingT4 06-15 Mazda MX-5 now allows header part numbers 0000-06-5407 or 0000-06-5407-NC.
T4 Z3M Roadster Weight #28437weightfasterT3 BMW Z3 M & Coupe 1998-1999 weight reduced from 3350 to 3150 lbs.
FA Request higher compression ratio and prior weights for F1000 cars #28162enginefasterFA Formula 1000 motorcycle-based engine compression ratio raised to 14.5:1 from 13.5:1.
FA Remove redundant wheel dimension provisions #28554wordingwordingFA removes Ex-FSV front wheel width 6–8 inches and rear 8–10 inches provisions; all cars use front 10 inches, rear 14–15 inches.
FA E&O Formula 3 spec line #28596enginefasterFA Formula 3 engines now allowed through 2017, previously 2008, with 30mm restrictor required.
P2 Add ESR inlet restrictor #27869inductionslowerP2 Enterprise Sports Racer 2.3L engine now requires SIR or Flat Plate restrictor sized in 0.5mm increments.
FA FA weight correction/clarification #28430wordingwordingFA engine note clarification removes Table E reference, Pro Formula Mazda directed to Table 1.
P2 Request for Fly by Wire Rule Wording Change #28247wordingwordingP2 fly-by-wire throttle control wording clarified: stock ECUs with drive-by-wire must activate original throttle shaft mechanism.
T4 Request for 12-13 and 14-15 Honda Civic Springs #27848wordingwordingT4 Honda Civic Si 12-13 and 14-15 now allow H&R and HPD springs up to 700 pounds with 47mm restrictor.
T4 Request to Clarify T4 05-10 Mustang Spring Allowance #27899suspension & brakessuspension & brakesT4 Ford Mustang V6 05-10 springs now permitted max 500 lbs front and 400 lbs rear.
T4 Request to Allow Brake Upgrade on T4 Mustang #27329otherotherT4 Ford Mustang V6 05-10 allowed aluminum driveshaft, any LSD, and Ford brake kit M-2300-D.
T4 Please Switch the Solstice GXP as Specified in T2, to T3 #27413cars added -50 lbsfasterPontiac Solstice GXP and Saturn Sky move from T2 to T3; wheels widen to 18 x 9.5 inches, Sky weight drops to 3200 lbs.
T4 Request to Classify all Mazda RX8 Models in T3/T4 #27606cars addedcars addedMazda RX-8 Base/R3/Sport/GT (04-12) classified in T3 effective 2020-02-01.
T4 Request for 2014-2018 Mazda 3 GT Brakes #27659suspension & brakesfasterT4 Mazda3 14-18 gains permitted modifications: springs to 800/1000 lbs, 15 lb wheels, cold air intake, camber plates, 25mm rear bar, mirrors, CorkSport arms, header, specific calipers and rotor.
T4 Request to allow aftermarket OEM coolant expansion tank #27763wordingwordingT4 allows aftermarket OEM coolant expansion tanks with no other functional purpose.
T4 Request to allow aftermarket OEM power steering reservoir #27764wordingwordingT4 Mazda MX-5 Club Model 06-15 now allows aftermarket power steering reservoir.
T4 Request for Factory Installed Wings on Subaru BRZ #27831wordingwordingT4 Subaru BRZ and Scion FR-S allowed factory installed wings.
T4 Request for Replacement Clutches #27892wordingwordingT4 now permitted to use any OEM diameter clutch disc and pressure plate, previously T2-T3 only.
T4 Request to Classify Chevy Sonic 1.4 In T4 #27906cars addedcars addedChevrolet Sonic 2011+ added to T4 at 2800 lbs with 1364 cc engine and 225 max tire size.
FA Request to merge FB into FA #25611cars addedfasterFormula 1000 motorcycle-based engine classified into FA, throttle bodies and ECUs unrestricted.
FA Suggestions for FB/F1000 into FA #27319cars addedunclearF1000 reclassified into FA with specification changes effective 2020-01-01.
FA Change Swift 016 - 2.3 liter Mazda Duratec restrictor size #27880inductionslowerFA Swift 016 2.3L Mazda Duratec restrictor reduced from 33mm to 31mm SIR, making it slower.
P2 Request for addition of BMW Engine in P2 Engine Table #27821cars addedcars addedP2 adds BMW to motorcycle-based engine options in 4-cycle line alongside Kawasaki, Suzuki, Yamaha, Honda.
T4 Clarification of On-Board Fire System for T2 #27183wordingwordingT2 requires onboard fire system; T3 and T4 may have one per GCR 9.3.
T4 Mustang Ecoboost and GT Transmission #27439otherunclearT3 Ford Mustang EcoBoost 2015- gains three transmission gear ratio options.
T4 BRZ/FRS/86 Tire Size in T4 #27660tyres & wheelsslowerT4 BRZ, FR-S, and 86 maximum tire size reduced from 245 to 225.
T4 NC MX5 2006-2015 Spec Adjustment Request #27739weight -75 lbsfasterT4 Mazda MX-5 Club Model 06-15 minimum weight cut from 2625 to 2550 lbs.
T4 T4 RX8 Classification Error #27902wordingwordingMazda RX-8 Base/R3 (04-12) reclassified in T3 and T4 to include Sport and GT variants.
T4 Request to add Toyota 86 GT to Spec Line #27910cars addedcars addedToyota 86 GT (2017-) added to T3 and T4 Spec Line.
FA Move wheel dimensions from Bodywork subsection to #27493wordingwordingFA wheel dimension rules moved from Bodywork subsection to General section; no specification changes.
FA Table 2 Mazda MZR 2.0 E&O #27640wordingwordingFA Mazda MZR 2.0 now limited to Ralt RT40, Ralt RT41, and Swift 014 chassis only.
FA Follow up to Letter #27344 on Honda Powered FA Rules #27363wordingwordingFA Honda Civic K20Z3 engines consolidated: three separate base/uprated specs removed, replaced with single unified 1350 lb minimum weight spec for Swift 014/016.
P2 Update Engine Table Line E notes #27414inductionslowerP2 Honda K20A-FD2 non-composite chassis must use 55mm flat plate intake restrictor at 1500 lbs minimum weight.
FA Swift 014 Mazda MZR 2.0 E&O #27305enginefasterFA Swift 014 Mazda MZR 2.0 piston minimum weight reduced from 320g to 280g.
P2 Update P2 Engine Table spec lines to reflect 3/1/2019 #27254inductionslowerP2 motorcycle engines: Stock restrictor 36.5mm to 35mm, modified 37.5mm to 34mm; B.5 restrictor 37.5mm to 33mm. All weights increase 25 lbs.
T4 Request spare tire/wheel clarification #27012wordingwordingT2-T4 spare tire/wheel rules clarified: removable covers can be removed with hardware and bracketry.
T4 Research E&O Mazda MX5 #27112suspension & brakesslowerT4 Mazda MX-5 Club (06-15) gains suspension package with 100 lbs weight increase, allows RX8 hubs and SM5 suspension, permits non-OEM LSD with 50 lbs penalty.
P2 E&O Transmissions #27006otherslowerP2 cars limited to power application on maximum two wheels, effective 2019-07-01.
T4 MR2 Spyder Year Correction #26936wordingwordingT4 Toyota MR-2 Spyder 16V DOHC years corrected from 01-05 to 00-07.
P2 Request to restrict all cars #26246weightslowerP2 Enterprise minimum weight increases to 1375 lbs; peak horsepower of sealed ESR engine reduced per CRB specification.
FA Adjust Line N restrictor size and minimum weight #26691weight +30 lbsslowerFA Line N minimum weight increases to 1375 lbs.
T4 Request to allow piggy back ECU on 2000 Mazda Protégé #26085enginefasterT4 Mazda Protégé ES 2000 now allows piggyback ECU tuning device; OBD2 requirement waived.
T4 Request helper spring as optional #26678suspension & brakesslowerT4 Mazda MX5 Club Model 06-15 allows suspension package with 100 lbs weight increase including helper springs.
FA Add data plate requirement #26707wordingwordingFA cars must install AIM part #X47KPFSOLO2R0 data box mount for Majors and Runoffs.
T4 Request to classify 2000 - 2001 BMW 323 #25096cars addedcars addedT4 BMW 323 (98-00) newly classified at 3450 lbs with 50mm flat plate restrictor and M52TUB25 engine required.
FA Request to add FA engine spec lines #26183weightfasterFA Formula 3 car sequential gearbox weight penalty of 25 lbs removed; minimum weight now 1215 lbs.
P2 Change Engine Table Lines B.1 & B.5 #25777inductionslowerP2 stock engine restrictor shrinks to 35.0mm and weight rises to 1025 lbs; modified engine restrictor to 34.0mm, weight to 1125 lbs; line B.5 restrictor to 33.0mm, weight to 1185 lbs.
P2 Change Line A.1 restrictor size #26429inductionslowerP2 Line A.1 restrictor reduced from 40mm to 38mm.
T4 Correct Mazda MX-5 Hard Top Notes #26137wordingwordingT4 Mazda MX-5 Club (06-15) and (2016-), T3 MX-5 Cup and Miata (2016-) hardtop rules clarified; wording changes to permitted parts and specifications.
T4 Consider opening class rules to allow any thermostat #26187wordingwordingT2, T3, T4 now allow any thermostat serving only OE intent, previously restricted.
T4 Cap 2016 Mazda Miata year at 2018 #26388wordingwordingT3 and T4 Mazda MX-5 Miata eligibility capped at 2018 model year, effective 2019-03-01.
FA FA MZR 2.0 Engine Specification #25814wordingwordingFA Swift 014-Mazda MZR 2.0 engine now requires OE block casting #LF95 and specific OE components instead of sealed Elite Engines sourcing.
FA FA 016 weight increase #26063weightslowerFA Swift 016 Mazda Duratec 2.3L and 2.5L minimum weight increases from 1420 to 1450 lbs.
T4 2012-2015 Honda Civic Si Performance Request #26129suspension & brakesfasterT4 Honda Civic Si 2012-2015 permitted sway bars increased to 32mm front and rear.
P2 Request to Allow 1345cc Hayabusa Engines for Spec Line P2 Cars #25595enginefasterP2 Spec Line cars now allow 1345cc Hayabusa stock engines at 1050 lbs with 30mm restrictor.
P2 Change CN inlet restrictor implementation date #25816wordingwordingP2 Group CN Honda K20A-FD2 55mm restrictor implementation delayed from 1/1/2019 to 3/1/2019.
P2 Clarify Honda K20A-FD2 parts requirement #25950inductionslowerP2 Honda K20A-FD2 in CN chassis must use stock intake manifold with 64mm throttle body and 55mm restrictor at 1500 lbs minimum weight.
T4 Errors, Omissions, and Updates (Various) #22414wordingwordingT4 Ford Fiesta ST years corrected to 14-; T4 Fiat 124/Abarth Edition years added 16-18; battery rule clarified.
T4 Request for Adjustments to fiat 124 specline #25371inductionfasterT4 Fiat 124 Abarth Edition restrictor changes from 29mm flat plate to 30mm TIR.
T4 Add Clarification to Spec Car Classifications Vehicle Spec #25774wordingwordingT1-T3 spec cars receive clarifications on permitted modifications, documentation requirements, and rule conformance; no performance changes.
T4 Clarify Subframe Bushings Permitted for T2-T4 #25800wordingwordingT2-T4 subframe bushings may now be replaced with non-spherical bushings of any material.
T4 Consider Solo SSC cross over classification into T4 #25802cars addedcars addedScion FR-S and Subaru BRZ 13-16 Solo Spec Coupes added to T4, both 1998cc, 2570 lbs, 225/45/17 tires.
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 T4" is the class's best as a share of T4'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 T4'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.