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BoP Lab / Hallett Motor Racing Circuit

GTX vs SM vs EP pace at Hallett Motor Racing Circuit

Class · click a class to switch, + to compare alongside (up to 4)
Reference class · the others' laps as a share of this one's at the same event, so years compare despite weather; + a class above to measure against it

Quickest here: GTX 1:14.200 Eric Presbrey, AVRG Green Country Grand Prix 2026 race · SM 1:22.202 Matt Stretch, AVRG Green Country Grand Prix 2024 qualifying · EP 1:22.486 Tyler Ladd, AVRG Green Country Grand Prix 2026 race

1:141:161:181:201:221:241:261:2822 rule changes between AVRG Green Country Grand Prix 2024 and AVRG Green Country Grand Prix 202522 ▾26 rule changes between AVRG Green Country Grand Prix 2025 and AVRG Green Country Grand Prix 202626 ▾GTX race best at AVRG Green Country Grand Prix 2024: 1:19.633 (Michael Staab)GTX race best at AVRG Green Country Grand Prix 2025: 1:26.202 (Michael Young)GTX race best at AVRG Green Country Grand Prix 2026: 1:14.200 (Eric Presbrey)GTX qualifying best at AVRG Green Country Grand Prix 2024: 1:20.324 (Michael Staab)GTX qualifying best at AVRG Green Country Grand Prix 2025: 1:26.333 (Michael Young)GTX qualifying best at AVRG Green Country Grand Prix 2026: 1:15.997 (Eric Presbrey)SM race best at AVRG Green Country Grand Prix 2024: 1:27.828 (Logan Stretch)SM race best at AVRG Green Country Grand Prix 2025: 1:27.516 (Vinnie Meskelis)SM race best at AVRG Green Country Grand Prix 2026: 1:26.998 (John Salerno)SM qualifying best at AVRG Green Country Grand Prix 2024: 1:22.202 (Matt Stretch)SM qualifying best at AVRG Green Country Grand Prix 2025: 1:26.641 (Vinnie Meskelis)SM qualifying best at AVRG Green Country Grand Prix 2026: 1:27.076 (John Salerno)EP race best at AVRG Green Country Grand Prix 2024: 1:22.682 (Tyler Ladd)EP race best at AVRG Green Country Grand Prix 2025: 1:24.673 (Jake Anton)EP race best at AVRG Green Country Grand Prix 2026: 1:22.486 (Tyler Ladd)EP qualifying best at AVRG Green Country Grand Prix 2024: 1:23.444 (Tyler Ladd)EP qualifying best at AVRG Green Country Grand Prix 2025: 1:24.560 (Tyler Ladd)EP qualifying best at AVRG Green Country Grand Prix 2026: 1:22.667 (Tyler Ladd)AVRG Green Country Grand Prix 20242024AVRG Green Country Grand Prix 20252025AVRG Green Country Grand Prix 20262026
GTXSMEPsolid race · dashed qualifying · slower is lower
96%98%100%102%104%106%108%110%112%114%116%118%22 rule changes between AVRG Green Country Grand Prix 2024 and AVRG Green Country Grand Prix 202522 ▾26 rule changes between AVRG Green Country Grand Prix 2025 and AVRG Green Country Grand Prix 202626 ▾GTX race best at AVRG Green Country Grand Prix 2024: 100.0% of GTX's (Michael Staab)GTX race best at AVRG Green Country Grand Prix 2025: 100.0% of GTX's (Michael Young)GTX race best at AVRG Green Country Grand Prix 2026: 100.0% of GTX's (Eric Presbrey)GTX qualifying best at AVRG Green Country Grand Prix 2024: 100.0% of GTX's (Michael Staab)GTX qualifying best at AVRG Green Country Grand Prix 2025: 100.0% of GTX's (Michael Young)GTX qualifying best at AVRG Green Country Grand Prix 2026: 100.0% of GTX's (Eric Presbrey)SM race best at AVRG Green Country Grand Prix 2024: 110.3% of GTX's (Logan Stretch)SM race best at AVRG Green Country Grand Prix 2025: 101.5% of GTX's (Vinnie Meskelis)SM race best at AVRG Green Country Grand Prix 2026: 117.2% of GTX's (John Salerno)SM qualifying best at AVRG Green Country Grand Prix 2024: 102.3% of GTX's (Matt Stretch)SM qualifying best at AVRG Green Country Grand Prix 2025: 100.4% of GTX's (Vinnie Meskelis)SM qualifying best at AVRG Green Country Grand Prix 2026: 114.6% of GTX's (John Salerno)EP race best at AVRG Green Country Grand Prix 2024: 103.8% of GTX's (Tyler Ladd)EP race best at AVRG Green Country Grand Prix 2025: 98.2% of GTX's (Jake Anton)EP race best at AVRG Green Country Grand Prix 2026: 111.2% of GTX's (Tyler Ladd)EP qualifying best at AVRG Green Country Grand Prix 2024: 103.9% of GTX's (Tyler Ladd)EP qualifying best at AVRG Green Country Grand Prix 2025: 97.9% of GTX's (Tyler Ladd)EP qualifying best at AVRG Green Country Grand Prix 2026: 108.8% of GTX's (Tyler Ladd)AVRG Green Country Grand Prix 20242024AVRG Green Country Grand Prix 20252025AVRG Green Country Grand Prix 20262026
GTXSMEPsolid race · dashed qualifying · each class's best lap as a share of GTX's at the same event (the reference class, changeable above); 100% is level, higher is quicker
EventGTXSMEP
Qual bestRace bestTrapQual bestRace bestTrapvs GTX% of GTXQual bestRace bestTrapvs GTX% of GTX
AVRG Green Country Grand Prix 2026 AVRGGR262026-04-251:15.997Eric Presbrey · fastest of 2-10.336s (-11.97%)1:14.200Eric Presbrey · fastest of 2-12.002s (-13.92%)130.9Eric Presbrey+19.0 mph (+16.9%)1:27.076John Salerno · fastest of 22 · top 5 within 0.6s+0.435s (+0.50%)1:26.998John Salerno · fastest of 22 · top 5 within 0.3s-0.518s (-0.59%)94.9Will Robinson+0.3 mph (+0.3%)+12.798squal +11.079s117.2%qual 114.6%1:22.667Tyler Ladd · fastest of 4 · top 4 within 4.4s-1.893s (-2.24%)1:22.486Tyler Ladd · fastest of 4 · top 4 within 3.4s-2.187s (-2.58%)114.2Tyler Ladd+7.4 mph (+7.0%)+8.286squal +6.670s111.2%qual 108.8%
26 rule changes (GTX: 5, SM: 4, EP: 17)5 weight · 4 cars added · 3 engine · 2 induction · 12 wording · GTX adds Ferrari 296 GT3 with restrictor and weight, effective 2026-04-01. · SM and SMX part number 0000-10-6900 replaced with 0000-06-5016-KT. · GT3U class removed from GCR; GT3U cars now run in STU with 3.0" main frame and 2" front spoiler minimum ride height. · EP BMW 325i/is E30 throttle body specified as 60mm in fuel injection notes. · GTX Misc Table 4 adds RCR T70 Coupe with 2200 lbs minimum weight, no restrictor specified. · EP Triumph TR2-TR4A allows 5-speed gearbox without overdrive; removes Weber carb and weight specification. · EP BMW Z3 2.5L restrictor reduced 52mm to 50mm, weight increased to 2550 lbs base; five other BMW models get smaller restrictors. · EP Nissan 280Z minimum weight reduced from 2560 to 2400 lbs. · EP Mazda MX-5 1.8L 90-97 weight reduced to 2125 lbs from 2150 lbs. · HP Austin-Healey Sprite/Midget 1098cc minimum weight drops 80 lbs to 1550. · HP Volvo 142/142E gains compression ratio limit 12.0:1 and valve lift limit .425". · HP Mini Cooper 07-15 valve lift reduced to .390", from .450". · FP and HP Volkswagen Rabbit descriptions updated: Convertible changed to Cabriolet in FP; Cabriolet added to three HP engine variants. · EP, FP, HP: rear drum brake to disc conversion clarified; rotors solid, diameter limited to largest front rotor permitted. · EP Ford Mustang (94-98) fuel injected throttle body inside diameter specified at 60. · HP Plymouth Arrow transmission max speeds clarified to 4 or 5. · EP, FP, HP wheel diameter added to Appendix G as absolute maximum specification. · EP, FP, HP throttle body inside dimensions must remain stock with +/-.25mm tolerance; butterfly dimensions stock in FP, HP only. · EP BMW Z4 03-05 restricted to 52mm flat plate intake restrictor. · EP Fiat 124 Spider 1600 & 2000 weight drops 50 lbs to 2000; carburetors gain 2mm chokes to 36mm. · HP Fiat X-1/9 base weights reduced 50–53 lbs across 1300 and 1500 spec lines. · GTX Ligier LMP3 now allows any normally aspirated LS Chevrolet engine. · 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. · GTX Porsche GT2 RS Clubsport classified with factory specifications required at all race events. · SM cars limited to one set of Hoosier SM 7.5 P205/50/ZR17 per Super Tour event weekend for dry sessions.showhide
  • GTX Ferrari 296 GT3 Classification Request #39873cars addedneutralGTX adds Ferrari 296 GT3 with restrictor and weight, effective 2026-04-01.
  • SM Part Number Change Request #39914wordingunclearSM and SMX part number 0000-10-6900 replaced with 0000-06-5016-KT.
  • GTX Remove GT3U from GCR as it is now in STU #39862cars addedneutralGT3U class removed from GCR; GT3U cars now run in STU with 3.0" main frame and 2" front spoiler minimum ride height.
  • EP Request to Update E30 BMW Throttle Body Diameter Verbiage #39363wordingneutralEP BMW 325i/is E30 throttle body specified as 60mm in fuel injection notes.
  • GTX Please Consider Adding a Spec Line to GTX Table 4 for the RCR T70 #39470cars addedneutralGTX Misc Table 4 adds RCR T70 Coupe with 2200 lbs minimum weight, no restrictor specified.
  • EP TR2 Notes E&O #39180wordingunclearEP Triumph TR2-TR4A allows 5-speed gearbox without overdrive; removes Weber carb and weight specification.
  • EP Balance of Power #39187induction +50 lbsslowerEP BMW Z3 2.5L restrictor reduced 52mm to 50mm, weight increased to 2550 lbs base; five other BMW models get smaller restrictors.
  • EP Please Lower Weight of 280Z #38871weight -160 lbsfasterEP Nissan 280Z minimum weight reduced from 2560 to 2400 lbs.
  • EP Miata Weight Adjustment Follow Up #38949weight -25 lbsfasterEP Mazda MX-5 1.8L 90-97 weight reduced to 2125 lbs from 2150 lbs.
  • EP Weight Break for 1098 Midget / Sprite #38970weight -80 lbsfasterHP Austin-Healey Sprite/Midget 1098cc minimum weight drops 80 lbs to 1550.
  • EP HP Volvo 142 spec omission #38994engineslowerHP Volvo 142/142E gains compression ratio limit 12.0:1 and valve lift limit .425".
  • EP HP Mini DOHC 1.6 #38996engineslowerHP Mini Cooper 07-15 valve lift reduced to .390", from .450".
  • EP Add to Rabbit description #39019wordingneutralFP and HP Volkswagen Rabbit descriptions updated: Convertible changed to Cabriolet in FP; Cabriolet added to three HP engine variants.
  • EP Clean-up 9.1.5.E.7e #39025wordingneutralEP, FP, HP: rear drum brake to disc conversion clarified; rotors solid, diameter limited to largest front rotor permitted.
  • EP Add TB size to Ford Mustang (94-98) Spec Line #39130wordingneutralEP Ford Mustang (94-98) fuel injected throttle body inside diameter specified at 60.
  • EP HP Plymouth Arrow spec omission #38995wordingneutralHP Plymouth Arrow transmission max speeds clarified to 4 or 5.
  • EP Add Wheel Diameter to Appendix G #39008wordingneutralEP, FP, HP wheel diameter added to Appendix G as absolute maximum specification.
  • EP Add TB ID tolerance to general Prod rules #39009wordingneutralEP, FP, HP throttle body inside dimensions must remain stock with +/-.25mm tolerance; butterfly dimensions stock in FP, HP only.
  • EP BMW Z4 update #38490inductionslowerEP BMW Z4 03-05 restricted to 52mm flat plate intake restrictor.
  • EP EP Fiat 124 Spider Competition Adjustment Request #38498weight -50 lbsfasterEP Fiat 124 Spider 1600 & 2000 weight drops 50 lbs to 2000; carburetors gain 2mm chokes to 36mm.
  • EP Base Weight Adjustment for H-Production X1/9 Spec Lines #38255weight -50 lbsfasterHP Fiat X-1/9 base weights reduced 50–53 lbs across 1300 and 1500 spec lines.
  • GTX Ligier P3 LS Swap #38164engineunclearGTX Ligier LMP3 now allows any normally aspirated LS Chevrolet engine.
  • 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.
  • GTX Request to Classify Porsche GT2 RS Clubsport #37972cars addedneutralGTX Porsche GT2 RS Clubsport classified with factory specifications required at all race events.
  • 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.
AVRG Green Country Grand Prix 2025 AVRGGR252025-04-261:26.333Michael Young · only car+6.009s (+7.48%)1:26.202Michael Young · only car+6.569s (+8.25%)112.0Michael Young-10.3 mph (-8.4%)1:26.641Vinnie Meskelis · fastest of 15 · top 5 within 0.7s+4.439s (+5.40%)1:27.516Vinnie Meskelis · fastest of 15 · top 5 within 0.6s-0.312s (-0.36%)94.6Matt Stretch-10.6 mph (-10.1%)+1.314squal +0.308s101.5%qual 100.4%1:24.560Tyler Ladd · fastest of 6 · top 5 within 14.4s+1.116s (+1.34%)1:24.673Jake Anton · fastest of 5 · top 5 within 48.2s+1.991s (+2.41%)106.7Tyler Ladd-2.2 mph (-2.1%)-1.529squal -1.773s98.2%qual 97.9%
22 rule changes (GTX: 2, SM: 5, EP: 15)5 weight · 3 cars added · 3 induction · 1 engine · 10 wording · Chevrolet Spark 16-22 classified HP Pre at 1850 lbs minimum weight, fuel injected, 1399 cc. · HP Ford Festiva 88-93 minimum weight drops to 1600 lbs, variants to 1640 and 1680 lbs; compression ratio raised to 11.0:1. · EP BMW Z3 and 3-series models get smaller intake restrictors: Z3 2.5L to 52mm, Z3 2.8L to 55mm, 328i to 58mm, 325i to 56mm. · EP, FP, HP: interior or exterior mirrors meeting rule 9.3.36 now permitted. · EP Honda S2000 1997cc base loses 75 lbs to 2375; 2157cc base loses 60 lbs to 2450. · EP Mazda MX-5/Miata 99-05 minimum weight drops to 2100 lbs, 2153 lbs with power adder, 2205 lbs with two adders. · EP BMW Z3 2.5L requires 52mm flat plate intake restrictor; Z3 2.8L 55mm; 328i/is E36 58mm; 328i/ci E46 58mm; 325i/is E46 56mm; 325i/is E36 56mm; 325is M-Technic 56mm. · EP BMW 325i/is E30 (84-91) weight reduced 50–52 lbs across three spec lines to 2150, 2204, 2258. · TA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement. · EP Triumph GT6 switches to three Weber 40 DCOE carbs with 28mm chokes, weight rises 50 lbs to 1990. · SMX allows OE instrument cluster relocation for aftermarket dash mounting, with wiring re-routed only; alternate gauges now permitted. · HP Sprite and Midget 1275cc and 1098cc Level 2 compression ratio raised to 12.0:1. · EP Mazda Miata front and rear track widths increased to 1516/1534 mm (59.7/60.4 in.) across all generations. · 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. · HP Volkswagen Golf and Jetta 85-92 track correction: front 1537mm (60.5in), rear 1529mm (60.2in). · Nissan 300ZX 84-89 classified to EP at 2550 lbs minimum, 2960cc 6-cyl SOHC, fuel injection, 12.0:1 compression limit, 0.500" valve lift limit. · Mazda RX-7 92-97 newly classified EP Prep Level 2 at 2200–2310 lbs with 13B 6-port rotary engine. · EP Mazda RX-8 (04-11) alternate spec line removed; one primary line remains. · GT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR.showhide
  • EP Request for Classification of Chevrolet Spark #37755cars addedneutralChevrolet Spark 16-22 classified HP Pre at 1850 lbs minimum weight, fuel injected, 1399 cc.
  • EP Request to Lower Ford Festiva Minimum Weight to 1600 LBS #37939weight -100 lbsfasterHP Ford Festiva 88-93 minimum weight drops to 1600 lbs, variants to 1640 and 1680 lbs; compression ratio raised to 11.0:1.
  • EP Request Competition Adjustment to BMW Z3 2.5L #37120inductionslowerEP BMW Z3 and 3-series models get smaller intake restrictors: Z3 2.5L to 52mm, Z3 2.8L to 55mm, 328i to 58mm, 325i to 56mm.
  • EP Interpretation of Production Rules on Mirrors #37235wordingneutralEP, FP, HP: interior or exterior mirrors meeting rule 9.3.36 now permitted.
  • EP Weight Reduction for Honda S2000 #37466weightfasterEP Honda S2000 1997cc base loses 75 lbs to 2375; 2157cc base loses 60 lbs to 2450.
  • EP Mazda 1999 Miata 1.8L #37488weight -50 lbsfasterEP Mazda MX-5/Miata 99-05 minimum weight drops to 2100 lbs, 2153 lbs with power adder, 2205 lbs with two adders.
  • EP Effective date for Jan 2025 GCR updates #37654inductionslowerEP BMW Z3 2.5L requires 52mm flat plate intake restrictor; Z3 2.8L 55mm; 328i/is E36 58mm; 328i/ci E46 58mm; 325i/is E46 56mm; 325i/is E36 56mm; 325is M-Technic 56mm.
  • EP Request to Reduce Weight of BMW 325i/is E30 (84-91) Spec Line #37119weight -50 lbsfasterEP BMW 325i/is E30 (84-91) weight reduced 50–52 lbs across three spec lines to 2150, 2204, 2258.
  • GTX Correct language regarding OEM Areo Devices #37137wordingneutralTA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement.
  • EP Triumph GT6 Adjustments #37112inductionslowerEP Triumph GT6 switches to three Weber 40 DCOE carbs with 28mm chokes, weight rises 50 lbs to 1990.
  • 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.
  • EP 1275 HP Spridget Level 2 Only #36518enginefasterHP Sprite and Midget 1275cc and 1098cc Level 2 compression ratio raised to 12.0:1.
  • EP NA Miata Track Width Correction #36902wordingneutralEP Mazda Miata front and rear track widths increased to 1516/1534 mm (59.7/60.4 in.) across all generations.
  • 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.
  • EP Errant entry in HP production line item #36231wordingneutralHP Volkswagen Golf and Jetta 85-92 track correction: front 1537mm (60.5in), rear 1529mm (60.2in).
  • EP NIssan 300ZX Z31 to EP #35830cars addedneutralNissan 300ZX 84-89 classified to EP at 2550 lbs minimum, 2960cc 6-cyl SOHC, fuel injection, 12.0:1 compression limit, 0.500" valve lift limit.
  • EP RX7 1993 and Up Request In EP Spec Lines, classify #36031cars addedneutralMazda RX-7 92-97 newly classified EP Prep Level 2 at 2200–2310 lbs with 13B 6-port rotary engine.
  • EP Clean-up Multiple EP RX-8 Spec Lines In EP #36156wordingneutralEP Mazda RX-8 (04-11) alternate spec line removed; one primary line remains.
  • GTX Request for Spec Line 1010 Reconsideration #35009weight +300 lbsslowerGT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR.
AVRG Green Country Grand Prix 2024 AVRGGR242024-04-201:20.324Michael Staab · fastest of 21:19.633Michael Staab · fastest of 2122.3Michael Staab1:22.202Matt Stretch · fastest of 24 · top 5 within 5.6s1:27.828Logan Stretch · fastest of 23 · top 5 within 0.7s105.2Matt Stretch+8.195squal +1.878s110.3%qual 102.3%1:23.444Tyler Ladd · fastest of 8 · top 5 within 2.4s1:22.682Tyler Ladd · fastest of 8 · top 5 within 4.1s109.0Tyler Ladd+3.049squal +3.120s103.8%qual 103.9%
127 earlier rule changes on record, in force before AVRG Green Country Grand Prix 2024 (from 2019)32 cars added · 17 weight · 12 induction · 6 engine · 4 suspension & brakes · 2 aero · 2 tyres & wheels · 51 wording · 1 other · HP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve, Scirocco 1588. · HP Honda Civic 1.5 (88-91) weight reduced to 2175 lbs base, 2229 lbs with power adder, 2284 lbs with two. · 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. · EP BMW Z3 2.5L weight increases to 2500 lbs, 2563 lbs with turbo, 2625 lbs with supercharger. · EP Mazda MX-5 1.8L 1990-97 minimum weight drops to 2150 lbs; 1994-97 variants to 2000, 2050, 2100 lbs respectively. · EP Triumph GT6 dual 1.75" carbs weight drops to 1940 lbs; triple Weber 40 DCOE options consolidated. · EP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm. · EP Triumph TR8 dry sump allowance moved from carburetor line to notes section. · EP Porsche 944/924S 2.5L and 2.7L weight minimums corrected: 2479cc to 2306/2363 lbs, 2681cc to 2358/2415 lbs. · GTX adds KTM X-Bow classification with restrictor and weight specifications effective 2024-01-01. · EP Porsche 944/924S combines 2.5L and 2.7L variants with new weights: 2250–2415 lbs depending on engine and year. · EP Triumph GT6 minimum weight reduced to 1800 lbs. · GTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL. · EP Triumph TR8 78-81 removes alternate front hub allowance note; stock hubs now required. · EP Triumph GT6 carburetors change from SU or Stromberg to 1.5" Auto-type. · EP Triumph GT6 brakes may now use TR-6 standard or alternate calipers and discs. · FP and HP Sprite, Midget, and Spitfire 1500 intake valve size corrected to 36.6/(1.44). · GTX Ligier LMP3 3.7L NA classified at 2203 lbs with 22 mm restrictor. · GTX Ligier JSP4 newly classified as GTX Misc with restrictor and weight specified. · EP Porsche 914-6 2.0L intake valves increase to 2.0 mm, exhaust valves corrected to 38.0 mm. · Fields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight. · EP BMW Z3 2.5L intake restrictor reduced from 58mm to 56mm flat plate. · EP 79-85 RX-7 12A/13B brake spec simplification removes hub/rotor weight minimum allowance. · EP 280Z carburetor option adds Hitachi-SU 1bbl 46mm throttle bores alongside fuel injection. · EP Mazda RX-2, RX-3, RX-4, and 12A RX-7 now allow 2 bbl fuel injected throttle body w/ 42mm chokes on dual-y manifold. · EP Mazda RX-2, RX-3, RX-3SP, and RX-4 minimum weights reduced 50–52 lbs across all spec lines. · EP Triumph TR8 78-81 now allowed to run dry sump. · EP, FP, HP cylinder head ports limited to 1 inch maximum depth matching from mating surface. · EP Prep 280ZX (79-83) added to spec lines with 2425–2546 lbs, 2760cc SOHC 6-cyl, fuel injection, 12.0:1 compression limit, .500" valve lift limit. · SM Mazda MX-5 Miata 01-05 weight increases to 2450 lbs, or 2465 with alternate bore. · GT2 TA2 and GTA throttle body part numbers updated to GM 90mm electronic #12570790 or Edelbrock 90mm mechanical #33869 or #3870. · VW New Beetle 2.5L 5-cyl added to EP at 2400–2520 lbs, 2480 cc, fuel injection, comp ratio 12.0:1 max, valve lift 0.500" max. · EP Mazda RX-7 12A/13B gains fuel injection option on dual-y manifold with 42mm choke(s). · EP VW Corrado 92-95 stroke corrected to 90.3 mm, displacement to 2792 cc. · GT taillights may now be original style or a panel graphic with functioning red LED brake lamps; wording change only. · EP Subaru BRZ and Toyota 86/Scion FR-S model year ranges updated to 13-20. · Porsche 992 GT3 Cup Car newly classified in GTX. · EP Mazda MX-5 Global Cup 16-22 minimum weight set to 2400 lbs; sequential gearbox allowed with +150 lbs penalty. · BMW 128i (08-13) classified in EP at 2700 lbs minimum with stock throttle body, 11.0:1 compression ratio, 0.400 in. valve lift limits. · EP/FP/HP open cars may now use carbon fiber hardtops if they retain OEM appearance in all exterior profiles. · GTX Wolf GB08 F1 Ford 52XS V8 added to classification at 1725 lbs minimum weight. · C7 Corvette Grand Sport classified in GTX Misc at 3200 lbs with option to remove displacement on demand valve train. · GTX eligible prototypes expanded: IMSA GTP years changed to 1981-1993, five prototype categories added. · EP Mazda RX-8 13B carburetor rules clarified: dual 2bbl carb, fuel injected throttle body, or stock fuel injection permitted. · EP and FP Production clarifies idle control valve rules: stock devices allowed original, removed with blocked ports, or mechanical replaced with electronic stock type. · SM Majors must run authorized Penske shock and mount; Regional competitors' requirement eligibility clarified. · EP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate. · Ford Mustang 99-03 classified to EP at 2700/2768/2835 lbs; 94-98 Mustang weight reduced to 2550/2614/2678 lbs. · EP, FP, HP Improved Touring cars may use any DOT-approved tire per section 9.3.45 in Production class. · GTX McLaren 720s GT3 newly classified at 3000 lbs with 3000 mm restrictor. · EP, FP, HP classes allow stock/original idle control devices unmodified or completely removed with openings blocked. · EP Porsche 968 (92-95) now allows dry sump. · EP 1979-1985 Mazda RX-7 12A and 13B weight reduced by 50-53 lbs across all configurations. · GTX-FIA GT3 removes all intake restrictor requirements for fifteen car models; McLaren name corrected. · EP Porsche 968 intake valve size increased from 37 to 39.0 mm. · EP, FP, HP front-wheel-drive cars may alter body and suspension to install alternate transmission, transaxle, and axle shaft. · EP BMW Z3 2.5L allows alternate throttle body from 92-95 325i with Turner adapter; head casting 1738400 permitted with specific blocks. · EP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; comp ratio max 12.0:1, valve lift max 0.500". · HP Corolla GTS RWD (84-87) added at 2300 lbs; HP Corolla FX16 FWD (87-88) added at 2260 lbs; old Corolla (84-87) removed. · HP Toyota MR-2 1.6L (85-89) track corrected to 15.47 inches front and rear. · GT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight. · GTX SRO-GT4 Porsche 718 Club Sport MR GT4 classified, unrestricted, 2900 lbs minimum weight. · Honda S2000 (00-03) reclassified as EP Prep with F22c engine option: 1997cc or 2157cc, weight 2450–2636 lbs depending on displacement. · EP Nissan 240-SX S13/S14 loses 200-210 lbs minimum weight; comp ratio rises to 12.0:1, valve lift to .500. · GTA part numbers updated: 0-80541-1 to 0-80541-2 in two sections and 6010 to 6014X in TA2 Appendix. · Grullon GT with 2.0L K20 moved from GTX to GT2-ST, minimum weight 2350 lbs, unrestricted. · EP Lotus/Caterham 7 America carburetor changed from IT fuel injection prep to fuel injection. · Daimler SP 250 classified in EP at 2165 lbs with 2548 cc OHV 8-cylinder engine. · GTX Grullon GT added, unrestricted, 2350 lbs, factory spec required. · EP, FP, HP clarifies percentage weight penalties sum first, then apply to base weight, rounding to nearest pound. · 84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lbs weight, 1998cc SOHC, dual 32mm carbs. · FP Fiat X1/9 brake rotors change to 257 (10.1) x 12 (.407) solid disc. · EP Mazda MX-5 year range corrected from 06-14 to 06-15. · Mazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC, 12.0:1 compression, .500" valve lift limit. · SM adds procedures for testing obsolete part replacements and BOP updates in sanctioned events with CRB approval. · EP Austin-Healey 3000 Mk. I, II, III now allows TR-6 front calipers and discs as alternate. · FP Volkswagen Golf and Jetta 1.8 lose 50 lbs each, to 1900. HP Jetta GLI engine code removed. · EP, FP, HP Level 1 and Level 2 induction systems: clarified carburetor and fuel injection rules, jets/needles/rods unrestricted in Level 2. · EP Datsun SRL 311U Roadster minimum weight reduced to 1925 lbs from 2000 lbs. · EP Triumph TR8 78-81 weight reduced from 2600 to 2500 lbs. · HP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches. · 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. · GT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line. · EP BMW Z3 2.5L iron block casting 1738566-C designation removed, wording clarification only. · GTX Chevrolet Camaro ZL1 LT4 with factory supercharger classified at 3400 lbs minimum weight. · GTX adds KTM X-Bow GT4, turbocharged 2.5L Audi TFSI I5, 2000 lbs minimum weight. · SM rear brake calipers may use single bracket under upper retaining bolt to prevent pin failure. · Porsche 911 S 67-68 classified in EP at three weight levels: 1800, 1845, or 1890 lbs. · 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. · EP BMW 2.8L, 328i E36/E46, and 325i E36 blocks now iron only; 325i E46 aluminum only. · GTX tube frame cars must weigh 2780 pounds; stock car bodies now permitted. · 1990-1994 Mazda Protege classified in FP Pre at 2150–2258 lbs with 1839cc DOHC engine, fuel injection. · HP Mini Cooper model year ranges for convertibles revised: 02-06 now includes 05-08, 07-13 now includes 09-15. · GTX adds Lotus Evora GTS with 3.5L 2GR-FE engine, no restrictor, 2950 lbs minimum weight. · EP Caterham 7 Spec Line removes redundant suspension note, clarifies engine prep limits and comp ratio to 10.0:1. · EP BMW Z3 2.5L compression ratio capped 12.0:1, valve lift .500, 59mm restrictor required; Z3 2.8L same limits added; 944S2 compression 12.0:1, valve lift .500, 56mm restrictor required. · EP BMW 325is M-Technic loses 100–105 lbs across three weight configurations, to 2550–2678. · HP Datsun 510 gains 40 DCOE carburetor option alongside existing 40 DCN and 36mm DCNVH choices. · EP BMW fuel injected throttle body maximum inside diameter set to 64mm. · HP Datsun 1200 carburetor choke size increases from 26mm to 30mm. · GT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications. · FP and EP Mazda Miata models standardized to 55mm throttle body diameter; brake spec clarified. · Factory Five Type 65 Coupe R with Ford 302/351 or 5.0/5.2L NA added to GTX-MISC at 2600 lbs. · EP, FP, HP cylinder head rules reorganized for clarity; no performance change. · FP and HP Austin-Healey Sprite Mk I and MG Midget variants may replace rear bodywork aft of cockpit with stock-appearing alternate material components. · EP Mazda MX-5 Global Cup classification year changes from 16-18 to 16-19. · Production suspension rule clarifies spindles, hubs, bushings, bearings, ball joints unrestricted. · Production carb rules clarified: carburetor options, fuel injection throttle body dimensions, and intake manifold restrictions reorganised and refined. · EP, FP, HP carburetors clarified: jets, needles, metering rods, needle valves unrestricted; choke parts removable; permitted optional carburetors listed. · EP Mazda MX-5/Miata eligibility years expanded from 1999-2002 to 1999-2005. · EP Mazda RX-8 firewall modification allowed for 13B engine fitment in stock location. · 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. · EP, FP, HP clarified: tapered holes in ball joints now allowed for bolt conversion; wheel bearings and hubs unrestricted at any wheel. · EP open cars may now use aftermarket hardtops if they retain OEM appearance; specific model hardtop allowances removed. · GT1 and GT2/GT3/LITE ride height requirements removed from GCR sections 9.1.2.D.5.a.1 and 9.1.2.F.7.b. · EP Mazda RX-7 12A and 13B (79-85) lose up to 80 lbs; 13B (86-91) loses up to 79 lbs. · GTX replaces all FIA GT4 references with SRO GT4. · SM fuel pump and filter must be Mazda or OEM Equivalent part. · 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. · GTX FIA GT3: Audi R8 40mm restrictor 2900 lbs, BMW Z4 70mm 2800 lbs, Ferrari 488 35mm restrictor 3025 lbs classified.showhide
  • EP GCR Correction - Redundant HP Spec Lines #35623wordingneutralHP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve, Scirocco 1588.
  • EP Update 1988-1991 Civic to Match 1988-1991 CRX #35399weightfasterHP Honda Civic 1.5 (88-91) weight reduced to 2175 lbs base, 2229 lbs with power adder, 2284 lbs with two.
  • GTX Rear Blade Spoiler Clarification #35261aerofasterGT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed.
  • GTX GT Direct Injection allowance and rules #35437enginefasterGT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors.
  • GTX 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.
  • EP Request to Review Z3 2.5 Spec Line #35073weight +50 lbsslowerEP BMW Z3 2.5L weight increases to 2500 lbs, 2563 lbs with turbo, 2625 lbs with supercharger.
  • EP Miata Alternate Head #35253weight -50 lbsfasterEP Mazda MX-5 1.8L 1990-97 minimum weight drops to 2150 lbs; 1994-97 variants to 2000, 2050, 2100 lbs respectively.
  • EP Triumph GT6 Adjustments #35255weightfasterEP Triumph GT6 dual 1.75" carbs weight drops to 1940 lbs; triple Weber 40 DCOE options consolidated.
  • EP Honda S2000 throttle body #35272inductionfasterEP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm.
  • EP Correction within Triumph TR8 Spec Line #35315wordingneutralEP Triumph TR8 dry sump allowance moved from carburetor line to notes section.
  • EP Correction to EP 924S/944 Spec Line #35317wordingneutralEP Porsche 944/924S 2.5L and 2.7L weight minimums corrected: 2479cc to 2306/2363 lbs, 2681cc to 2358/2415 lbs.
  • GTX KTM X Bow GTX #34956cars addedneutralGTX adds KTM X-Bow classification with restrictor and weight specifications effective 2024-01-01.
  • EP Porsche 944/924S Rule Change Request #35002cars addedneutralEP Porsche 944/924S combines 2.5L and 2.7L variants with new weights: 2250–2415 lbs depending on engine and year.
  • EP Triumph GT6 Adjustments #35054weight -30 lbsfasterEP Triumph GT6 minimum weight reduced to 1800 lbs.
  • GTX 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.
  • EP Hub Note Clean Up In EP TR8 Spec Line #34649wordingneutralEP Triumph TR8 78-81 removes alternate front hub allowance note; stock hubs now required.
  • EP Triumph GT6 Adjustments #34662wordingunclearEP Triumph GT6 carburetors change from SU or Stromberg to 1.5" Auto-type.
  • EP Triumph GT6 Adjustments: Brakes #34663wordingneutralEP Triumph GT6 brakes may now use TR-6 standard or alternate calipers and discs.
  • EP Correct Intake Valve Size on 1500cc Midget/Spitfire #34419wordingneutralFP and HP Sprite, Midget, and Spitfire 1500 intake valve size corrected to 36.6/(1.44).
  • GTX Request Ligier LMP3 Classification #34043cars addedneutralGTX Ligier LMP3 3.7L NA classified at 2203 lbs with 22 mm restrictor.
  • GTX Ligier JSP4 Request #34173cars addedneutralGTX Ligier JSP4 newly classified as GTX Misc with restrictor and weight specified.
  • EP 914-6 Valve Size Correction #34185enginefasterEP Porsche 914-6 2.0L intake valves increase to 2.0 mm, exhaust valves corrected to 38.0 mm.
  • GTX Please classify Fields Cardinal V8 #33784cars addedneutralFields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight.
  • EP Investigate Parity of Z3 #33343inductionslowerEP BMW Z3 2.5L intake restrictor reduced from 58mm to 56mm flat plate.
  • EP Revise 79-85 RX7 Brake Spec Line Allowance #33293wordingunclearEP 79-85 RX-7 12A/13B brake spec simplification removes hub/rotor weight minimum allowance.
  • EP Request alternate carburetors for EP 280z #33405wordingneutralEP 280Z carburetor option adds Hitachi-SU 1bbl 46mm throttle bores alongside fuel injection.
  • EP Fuel Injection 12a Mazda RX3 #33434inductionneutralEP Mazda RX-2, RX-3, RX-4, and 12A RX-7 now allow 2 bbl fuel injected throttle body w/ 42mm chokes on dual-y manifold.
  • EP Mazda RX3 - Weight Reduction #33436weight -50 lbsfasterEP Mazda RX-2, RX-3, RX-3SP, and RX-4 minimum weights reduced 50–52 lbs across all spec lines.
  • EP Request TR8 Dry Sump Allowance #33460enginefasterEP Triumph TR8 78-81 now allowed to run dry sump.
  • EP Review Limited Prep Port Matching Rules #33600wordingneutralEP, FP, HP cylinder head ports limited to 1 inch maximum depth matching from mating surface.
  • EP 280ZX Classification Request #33611cars addedneutralEP Prep 280ZX (79-83) added to spec lines with 2425–2546 lbs, 2760cc SOHC 6-cyl, fuel injection, 12.0:1 compression limit, .500" valve lift limit.
  • SM BOP for NB1 and NB2 #32309weightslowerSM Mazda MX-5 Miata 01-05 weight increases to 2450 lbs, or 2465 with alternate bore.
  • GTX 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.
  • EP Request to classify VW New Beetle 2.5L in EP #32725cars addedneutralVW New Beetle 2.5L 5-cyl added to EP at 2400–2520 lbs, 2480 cc, fuel injection, comp ratio 12.0:1 max, valve lift 0.500" max.
  • EP Request Rotary Injection on Dual Y manifold #32775inductionunclearEP Mazda RX-7 12A/13B gains fuel injection option on dual-y manifold with 42mm choke(s).
  • EP Request for Corrado Stroke & Displacement Correction #32985wordingneutralEP VW Corrado 92-95 stroke corrected to 90.3 mm, displacement to 2792 cc.
  • GTX 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.
  • EP Subaru BRZ Model Years #32500wordingneutralEP Subaru BRZ and Toyota 86/Scion FR-S model year ranges updated to 13-20.
  • GTX Classify 992 GT3 Cup #32649cars addedneutralPorsche 992 GT3 Cup Car newly classified in GTX.
  • EP EP MX-5 Global Cup Car #32218weightslowerEP Mazda MX-5 Global Cup 16-22 minimum weight set to 2400 lbs; sequential gearbox allowed with +150 lbs penalty.
  • EP Please Class BMW 128i in EP #32370cars addedneutralBMW 128i (08-13) classified in EP at 2700 lbs minimum with stock throttle body, 11.0:1 compression ratio, 0.400 in. valve lift limits.
  • EP Inconsistency in Body Work Descriptions #32396aerofasterEP/FP/HP open cars may now use carbon fiber hardtops if they retain OEM appearance in all exterior profiles.
  • GTX Add Classification to the accepted Model Table #31981cars addedneutralGTX Wolf GB08 F1 Ford 52XS V8 added to classification at 1725 lbs minimum weight.
  • GTX Request to classify C7 Corvette Grand Sport IN GTX Misc #32254cars addedneutralC7 Corvette Grand Sport classified in GTX Misc at 3200 lbs with option to remove displacement on demand valve train.
  • GTX E&O list of eligible prototypes #32511cars addedneutralGTX eligible prototypes expanded: IMSA GTP years changed to 1981-1993, five prototype categories added.
  • EP Mazda RX8 with 13b Rotary #32170wordingneutralEP Mazda RX-8 13B carburetor rules clarified: dual 2bbl carb, fuel injected throttle body, or stock fuel injection permitted.
  • EP Request Idle control valve clarification #32178wordingneutralEP and FP Production clarifies idle control valve rules: stock devices allowed original, removed with blocked ports, or mechanical replaced with electronic stock type.
  • SM Update GCR Section 9.1.7.3.A.1. #32217wordingneutralSM Majors must run authorized Penske shock and mount; Regional competitors' requirement eligibility clarified.
  • EP EP Adjustments #31858inductionslowerEP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate.
  • EP 1999 3.8L Ford Mustang to EP? #31635weightfasterFord Mustang 99-03 classified to EP at 2700/2768/2835 lbs; 94-98 Mustang weight reduced to 2550/2614/2678 lbs.
  • EP Improved Touring Tires #32064tyres & wheelsneutralEP, FP, HP Improved Touring cars may use any DOT-approved tire per section 9.3.45 in Production class.
  • GTX McLaren 720s GT3 #31955cars addedneutralGTX McLaren 720s GT3 newly classified at 3000 lbs with 3000 mm restrictor.
  • EP Throttle Body and Idle Air #31800wordingneutralEP, FP, HP classes allow stock/original idle control devices unmodified or completely removed with openings blocked.
  • EP Porsche 968 Engine Questions #31831otherneutralEP Porsche 968 (92-95) now allows dry sump.
  • EP Request weight reduction for 1979-1985 Mazda RX-7 #31833weightfasterEP 1979-1985 Mazda RX-7 12A and 13B weight reduced by 50-53 lbs across all configurations.
  • GTX Remove restrictions from GTX-FIA GT3 #32039inductionfasterGTX-FIA GT3 removes all intake restrictor requirements for fifteen car models; McLaren name corrected.
  • EP Porsche 968 Engine Questions #31478enginefasterEP Porsche 968 intake valve size increased from 37 to 39.0 mm.
  • EP PCS E. 2. n. 4. Add Axle Shaft to Allow FWD the Same Freedom #31592wordingneutralEP, FP, HP front-wheel-drive cars may alter body and suspension to install alternate transmission, transaxle, and axle shaft.
  • EP BMW Z3 2.5L Spec Line #31724wordingneutralEP BMW Z3 2.5L allows alternate throttle body from 92-95 325i with Turner adapter; head casting 1738400 permitted with specific blocks.
  • EP 944S2 Restrictor #31396inductionslowerEP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; comp ratio max 12.0:1, valve lift max 0.500".
  • EP Classing Clarification for 1986 Toyota Corolla FX16 #31527cars addedneutralHP Corolla GTS RWD (84-87) added at 2300 lbs; HP Corolla FX16 FWD (87-88) added at 2260 lbs; old Corolla (84-87) removed.
  • EP E&O; MR2 Track #31120wordingneutralHP Toyota MR-2 1.6L (85-89) track corrected to 15.47 inches front and rear.
  • GTX Request car classification #31032cars addedneutralGT3 Fun Cup Beetle EVO3 classified with 1984 cc sealed SOHC engine, 2060 lbs minimum weight.
  • GTX Request to classify 2020 Porsche 718 GT4 Clubsport MR #30956cars addedneutralGTX SRO-GT4 Porsche 718 Club Sport MR GT4 classified, unrestricted, 2900 lbs minimum weight.
  • EP Request to Allow F22c Engine for 2000-2003 Honda S2000 #30548cars addedunclearHonda S2000 (00-03) reclassified as EP Prep with F22c engine option: 1997cc or 2157cc, weight 2450–2636 lbs depending on displacement.
  • EP Request a review of the S14 240SX in EP. #30873weight -200 lbsfasterEP Nissan 240-SX S13/S14 loses 200-210 lbs minimum weight; comp ratio rises to 12.0:1, valve lift to .500.
  • GTX 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.
  • GTX GTX class correction to GT2/ST #30973cars addedneutralGrullon GT with 2.0L K20 moved from GTX to GT2-ST, minimum weight 2350 lbs, unrestricted.
  • EP Lotus/Caterham 7 America Request #30392wordingunclearEP Lotus/Caterham 7 America carburetor changed from IT fuel injection prep to fuel injection.
  • EP Reclassify Daimler SP 250 #30721cars addedneutralDaimler SP 250 classified in EP at 2165 lbs with 2548 cc OHV 8-cylinder engine.
  • GTX Request classification of Grullon #30481cars addedneutralGTX Grullon GT added, unrestricted, 2350 lbs, factory spec required.
  • EP Clarify Application of Percentage Based Weight Penalties #30669weightslowerEP, FP, HP clarifies percentage weight penalties sum first, then apply to base weight, rounding to nearest pound.
  • EP Change Classification of 84-87 Mazda 626 from FP to HP #30350cars addedneutral84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lbs weight, 1998cc SOHC, dual 32mm carbs.
  • EP Fiat X1/9 brake rotors #30423suspension & brakesneutralFP Fiat X1/9 brake rotors change to 257 (10.1) x 12 (.407) solid disc.
  • EP NC MX-5 year range correction E&O #30503wordingneutralEP Mazda MX-5 year range corrected from 06-14 to 06-15.
  • EP Please Classify Mazda3 in FP #30165cars addedneutralMazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC, 12.0:1 compression, .500" valve lift limit.
  • SM Updates - Obsolete Parts & BOP Parts #30438wordingneutralSM adds procedures for testing obsolete part replacements and BOP updates in sanctioned events with CRB approval.
  • EP Alternate Front Brake Rotors and Calipers for EP AH 3000 #29893suspension & brakesneutralEP Austin-Healey 3000 Mk. I, II, III now allows TR-6 front calipers and discs as alternate.
  • EP Mk2 VW Consistency and Cleanup of FP and HP Spec Lines #29195weight -50 lbsfasterFP Volkswagen Golf and Jetta 1.8 lose 50 lbs each, to 1900. HP Jetta GLI engine code removed.
  • EP Correct Wording for Level 1 and Level 2 Induction Systems #29406wordingneutralEP, FP, HP Level 1 and Level 2 induction systems: clarified carburetor and fuel injection rules, jets/needles/rods unrestricted in Level 2.
  • EP Weight Reduction for Datsun Roadster #29409weight -75 lbsfasterEP Datsun SRL 311U Roadster minimum weight reduced to 1925 lbs from 2000 lbs.
  • EP EP TR8 Adjustment #29512weight -100 lbsfasterEP Triumph TR8 78-81 weight reduced from 2600 to 2500 lbs.
  • EP 84-87 Toyota Corolla HP Wheel Diameter Allowance Proposal E&O #29458tyres & wheelsfasterHP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches.
  • 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.
  • GTX GT Category Wording #29193wordingunclearGT1, GT2, GT3, GTL, GTX now permit turbocharging/supercharging if listed on spec line.
  • EP EP BMW Z3 Rule Clarification #28998wordingneutralEP BMW Z3 2.5L iron block casting 1738566-C designation removed, wording clarification only.
  • GTX Request Car classification #28935cars addedneutralGTX Chevrolet Camaro ZL1 LT4 with factory supercharger classified at 3400 lbs minimum weight.
  • GTX X-Bow GT4 #29088cars addedneutralGTX adds KTM X-Bow GT4, turbocharged 2.5L Audi TFSI I5, 2000 lbs minimum weight.
  • 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.
  • EP Request to Classify Porsche 911 2.0L #28456cars addedneutralPorsche 911 S 67-68 classified in EP at three weight levels: 1800, 1845, or 1890 lbs.
  • GTX 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.
  • GTX STO Gurney flap wicker clarification #28883wordingneutralSTO rear wing wording clarified: 'wicker' changed to 'Gurney flap' in maximum chord and mounting height rules.
  • GTX GT Gurney flap wicker clarification #28909wordingneutralGT classes clarify Gurney flap wording, replacing wickerbill/tab terminology with flap; specifications unchanged.
  • EP BMW Cylinder Head Casting and Part Numbers #28708engineslowerEP BMW 2.8L, 328i E36/E46, and 325i E36 blocks now iron only; 325i E46 aluminum only.
  • GTX Request to Re-classify SP Stock car to GTX #28333cars addedneutralGTX tube frame cars must weigh 2780 pounds; stock car bodies now permitted.
  • EP Request to Classify 1990-1994 Mazda Protege #28381cars addedneutral1990-1994 Mazda Protege classified in FP Pre at 2150–2258 lbs with 1839cc DOHC engine, fuel injection.
  • EP Error in Mini Cooper Spec Line #28713wordingneutralHP Mini Cooper model year ranges for convertibles revised: 02-06 now includes 05-08, 07-13 now includes 09-15.
  • GTX Request to Classify Lotus Evora GTS #27057cars addedneutralGTX adds Lotus Evora GTS with 3.5L 2GR-FE engine, no restrictor, 2950 lbs minimum weight.
  • EP Caterham 7 Spec Line #28498wordingneutralEP Caterham 7 Spec Line removes redundant suspension note, clarifies engine prep limits and comp ratio to 10.0:1.
  • EP Request to Review Horsepower Parity #27662engineslowerEP BMW Z3 2.5L compression ratio capped 12.0:1, valve lift .500, 59mm restrictor required; Z3 2.8L same limits added; 944S2 compression 12.0:1, valve lift .500, 56mm restrictor required.
  • EP E36 (92-95) Brakes Errors and Omissions #28058weightfasterEP BMW 325is M-Technic loses 100–105 lbs across three weight configurations, to 2550–2678.
  • EP Request to allow 40 DCOE carb for the Datsun 510 #28195inductionfasterHP Datsun 510 gains 40 DCOE carburetor option alongside existing 40 DCN and 36mm DCNVH choices.
  • EP Add Throttle Body Size these EP BMW Spec Lines #28422inductionslowerEP BMW fuel injected throttle body maximum inside diameter set to 64mm.
  • EP Request for Help for Datsun 1200 #27934inductionfasterHP Datsun 1200 carburetor choke size increases from 26mm to 30mm.
  • GTX Windshield Clips #27323wordingneutralGT1, GT2, GT3, GTL, GTX may omit windshield clips if factory glass is bonded per original specifications.
  • EP Request to List Mazda Miata Throttle Body Size #27907wordingneutralFP and EP Mazda Miata models standardized to 55mm throttle body diameter; brake spec clarified.
  • GTX 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.
  • EP Re-organize Prep2 Cylinder Head Rules for Clarity & Consistency #27661wordingneutralEP, FP, HP cylinder head rules reorganized for clarity; no performance change.
  • EP Request bodywork for Austin Healey Bugeye Sprite MK1 #27106wordingneutralFP and HP Austin-Healey Sprite Mk I and MG Midget variants may replace rear bodywork aft of cockpit with stock-appearing alternate material components.
  • EP Request to classify the GMX5 2019 #27263wordingneutralEP Mazda MX-5 Global Cup classification year changes from 16-18 to 16-19.
  • EP level one susp. component rule #27270wordingneutralProduction suspension rule clarifies spindles, hubs, bushings, bearings, ball joints unrestricted.
  • EP Clarification of Carb Rules - Prep 1 #27300wordingneutralProduction carb rules clarified: carburetor options, fuel injection throttle body dimensions, and intake manifold restrictions reorganised and refined.
  • EP Clarification of Carb Rules - Prep 2 #27301wordingneutralEP, FP, HP carburetors clarified: jets, needles, metering rods, needle valves unrestricted; choke parts removable; permitted optional carburetors listed.
  • EP Request Miata Eligibility - 2003 #27121cars addedneutralEP Mazda MX-5/Miata eligibility years expanded from 1999-2002 to 1999-2005.
  • EP Allow Firewall Modification for Fitment of 13B into RX8 #26726wordingneutralEP Mazda RX-8 firewall modification allowed for 13B engine fitment in stock location.
  • GTX Request GTX Fuel injection for previous GT-1 tube frame cars #26141inductionfasterGTX tube frame cars gain fuel injection with 90mm maximum throttle body size.
  • GTX Request to Classify Ligier JS2 R #26535cars addedneutralLigier JS2 R classified in GTX, no performance parameters specified in filing.
  • EP Rollcenter Correction Clarification #25873suspension & brakesfasterEP, FP, HP clarified: tapered holes in ball joints now allowed for bolt conversion; wheel bearings and hubs unrestricted at any wheel.
  • EP Hardtops #26476wordingneutralEP open cars may now use aftermarket hardtops if they retain OEM appearance; specific model hardtop allowances removed.
  • GTX 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.
  • EP Request for Competition Adjustment for 2nd Generation RX7 #25935weight -50 lbsfasterEP Mazda RX-7 12A and 13B (79-85) lose up to 80 lbs; 13B (86-91) loses up to 79 lbs.
  • GTX Replace FIA references with SRO #26427wordingneutralGTX replaces all FIA GT4 references with SRO GT4.
  • SM Request to allow aftermarket fuel filters. #26370wordingneutralSM fuel pump and filter must be Mazda or OEM Equivalent part.
  • 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.
  • GTX 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.

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 GTX" is the class's best as a share of GTX'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 GTX'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.