FB vs SRF vs F6 vs HP pace at Buttonwillow Raceway Park
Quickest here:HP 2:03.082 Lee Fleming, Super Tour Feb 2025 race
FBSRFF6HPsolid race · dashed qualifying · slower is lower
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Super Tour Feb 2026 CALCL262026-02-21
2:04.965Brian Linn · fastest of 3 · top 3 within 4.8s-1.805s (-1.42%)
2:03.324Lee Fleming · fastest of 3 · top 3 within 0.9s+0.242s (+0.20%)
126.2Lee Fleming+25.8 mph (+25.7%)
32 rule changes (SRF: 3, HP: 29)9 weight · 6 engine · 4 cars added · 4 induction · 1 tyres & wheels · 6 wording · 2 other · HP Triumph Spitfire 1296cc compression ratio increases from 11.0 to 12.0:1. · HP Toyota MR-2 1.6L 85-89 compression ratio set to 11.0:1. · BMW 2002 newly classified into H Production at 2350 lbs, 1990 cc SOHC iron block, 40 DCNF carburetor, 15x7 wheels. · Nissan/Datsun SPL 311 added to HP as 2050 lbs minimum weight, 1595 cc OHV four-cylinder with carburetors. · EP Triumph TR2–TR4A may use 5-speed gearbox without overdrive; Weber carburetors and weight reference deleted. · EP BMW Z3 2.5L and other models get smaller restrictors, 50mm to 55mm, and Z3 2.5L weight rises 50 to 78 lbs. · HP Honda Civic and CRX 84-91 wheels widen from 13×6 to 13×7 inches. · EP Nissan 280Z minimum weight lowered to 2400 lbs, 2460 lbs with *, 2520 lbs with **. · EP Mazda MX-5 1.8L 90-97 minimum weight reduced to 2125 lbs. · HP Spec Lines Austin-Healey Sprite/Midget 1098cc minimum weight drops to 1550 lbs. · HP Volvo 142 P-1800 engine gains compression ratio limit 12.0:1 and valve lift limit .425 inch. · HP Mini DOHC 1.6 valve lift limit drops to .390" from .450". · FP and HP Volkswagen Rabbit descriptions updated to clarify Cabriolet body style inclusion. · EP, FP, HP: rear drum-to-disc brake conversion clarified; rotors solid, diameter limited to largest front rotor permitted. · EP Ford Mustang 94-98 fuel injected throttle body inside diameter set to 60. · HP Plymouth Arrow gains 4 or 5 speed transmission option specification. · Appendix G.2.3 clarifies rim width and diameter are absolute maximums; wording corrected from 'is' to 'are'. · EP, FP, HP throttle body inside dimensions and butterfly now allow +/-.25mm tolerance from stock. · SRF3 adds HD Oil Cooler P/N G1148500 option alongside standard P/N G480503, no fan permitted. · EP BMW Z4 03-05 gains 52mm flat plate intake restrictor. · EP Fiat 124 Spider Competition 1600 and 2000 minimum weight drops 50 lbs to 2000; carburetors now allow 36mm chokes instead of 34mm. · HP Fiat X-1/9 and Bertone 1500 minimum weights reduced to 1740 lbs, 1784 lbs, 1827 lbs; 1300 models to 1600, 1640, 1680 lbs; additional 1300 and 1500 specs to 2010, 1900 lbs. · Chevrolet Spark 16-22 classified in HP Pre at 1850 lbs base, 1896 lbs modified, 1943 lbs. · HP Ford Festiva 88-93 minimum weight lowered to 1600 lbs, competition weight to 1640, prepared weight to 1680; compression ratio raised to 11.0:1. · SRF drivers with disabilities may modify seat and controls for safety and comfort with SCCA approval, noted in logbook, for that driver only. · SRF SADEV-SRF3 6-speed sequential transmission: effective date clarified to 1 April 2025 onward. · EP BMW Z3 2.5L, Z3 2.8L, 328i E36/E46, 325i E36/E46 intake restrictors reduced 4mm each, to 52–58mm. · HP Mazda 2 (11-14) gains 50 lbs to 2045; VW Golf/Jetta/Rabbit/Scirocco (85-92, 1780cc, 8-valve) gain 50 lbs to 2150 base. · EP, FP, HP may use any interior or exterior mirror meeting rule 9.3.36. · EP Honda S2000 1997cc minimum weight drops 75 lbs to 2375; 2157cc drops 60 lbs to 2450. · EP Mazda MX-5 Miata 99-05 minimum weight reduced to 2100 lbs, 2153 lbs with power, 2205 lbs modified. · HP Mini Cooper 07-13 engine corrected to DOHC; valve lift limit reduced to .390 inch.showhide
HP Triumph Spitfire 1296cc Compression Ratio Increase to 12:1 #39589enginefaster · engineHP Triumph Spitfire 1296cc compression ratio increases from 11.0 to 12.0:1.
HP E/O: Improve Consistency of the Spec Lines #39500engineengineHP Toyota MR-2 1.6L 85-89 compression ratio set to 11.0:1.
HP Request to Reclassify BMW 2002 Into H Production #39567cars addedaddedBMW 2002 newly classified into H Production at 2350 lbs, 1990 cc SOHC iron block, 40 DCNF carburetor, 15x7 wheels.
HP Request to Re-Classsify Datsun SPL-311 to HP from FP #39116cars addedaddedNissan/Datsun SPL 311 added to HP as 2050 lbs minimum weight, 1595 cc OHV four-cylinder with carburetors.
HP TR2 Notes E&O #39180wordingwordingEP Triumph TR2–TR4A may use 5-speed gearbox without overdrive; Weber carburetors and weight reference deleted.
HP Balance of Power #39187induction +50 lbsslower · inductionEP BMW Z3 2.5L and other models get smaller restrictors, 50mm to 55mm, and Z3 2.5L weight rises 50 to 78 lbs.
HP Alternative BOP Request for 84-87 Honda CRX/Civic #39223tyres & wheelsfaster · tyres & wheelsHP Honda Civic and CRX 84-91 wheels widen from 13×6 to 13×7 inches.
HP Please Lower Weight of 280Z #38871weight -160 lbsfaster · weightEP Nissan 280Z minimum weight lowered to 2400 lbs, 2460 lbs with *, 2520 lbs with **.
HP Miata Weight Adjustment Follow Up #38949weight -25 lbsfaster · weightEP Mazda MX-5 1.8L 90-97 minimum weight reduced to 2125 lbs.
HP Weight Break for 1098 Midget / Sprite #38970weight -80 lbsfaster · weightHP Spec Lines Austin-Healey Sprite/Midget 1098cc minimum weight drops to 1550 lbs.
HP HP Volvo 142 spec omission #38994engineslower · engineHP Volvo 142 P-1800 engine gains compression ratio limit 12.0:1 and valve lift limit .425 inch.
HP HP Mini DOHC 1.6 #38996engineslower · engineHP Mini DOHC 1.6 valve lift limit drops to .390" from .450".
HP Add to Rabbit description #39019wordingwordingFP and HP Volkswagen Rabbit descriptions updated to clarify Cabriolet body style inclusion.
HP Clean-up 9.1.5.E.7e #39025otherotherEP, FP, HP: rear drum-to-disc brake conversion clarified; rotors solid, diameter limited to largest front rotor permitted.
HP Add TB size to Ford Mustang (94-98) Spec Line #39130inductionadded · inductionEP Ford Mustang 94-98 fuel injected throttle body inside diameter set to 60.
HP HP Plymouth Arrow spec omission #38995cars addedaddedHP Plymouth Arrow gains 4 or 5 speed transmission option specification.
HP Add Wheel Diameter to Appendix G #39008wordingwordingAppendix G.2.3 clarifies rim width and diameter are absolute maximums; wording corrected from 'is' to 'are'.
HP Add TB ID tolerance to general Prod rules #39009wordingaddedEP, FP, HP throttle body inside dimensions and butterfly now allow +/-.25mm tolerance from stock.
SRF Add HD Oil Cooler #38979engineadded · engineSRF3 adds HD Oil Cooler P/N G1148500 option alongside standard P/N G480503, no fan permitted.
HP BMW Z4 update #38490inductionslower · inductionEP BMW Z4 03-05 gains 52mm flat plate intake restrictor.
HP EP Fiat 124 Spider Competition Adjustment Request #38498weight -50 lbsfaster · weightEP Fiat 124 Spider Competition 1600 and 2000 minimum weight drops 50 lbs to 2000; carburetors now allow 36mm chokes instead of 34mm.
HP Base Weight Adjustment for H-Production X1/9 Spec Lines #38255weight -50 lbsfaster · weightHP Fiat X-1/9 and Bertone 1500 minimum weights reduced to 1740 lbs, 1784 lbs, 1827 lbs; 1300 models to 1600, 1640, 1680 lbs; additional 1300 and 1500 specs to 2010, 1900 lbs.
HP Request for Classification of Chevrolet Spark #37755cars addedaddedChevrolet Spark 16-22 classified in HP Pre at 1850 lbs base, 1896 lbs modified, 1943 lbs.
HP Request to Lower Ford Festiva Minimum Weight to 1600 LBS #37939weight -100 lbsfaster · weightHP Ford Festiva 88-93 minimum weight lowered to 1600 lbs, competition weight to 1640, prepared weight to 1680; compression ratio raised to 11.0:1.
SRF Driver Safety & Comfort #37966otheraddedSRF drivers with disabilities may modify seat and controls for safety and comfort with SCCA approval, noted in logbook, for that driver only.
SRF Update SADEV transmission specs #37992wordingwordingSRF SADEV-SRF3 6-speed sequential transmission: effective date clarified to 1 April 2025 onward.
HP Request Competition Adjustment to BMW Z3 2.5L #37120inductionslower · inductionEP BMW Z3 2.5L, Z3 2.8L, 328i E36/E46, 325i E36/E46 intake restrictors reduced 4mm each, to 52–58mm.
HP HP Class Adjustments #37459weight +50 lbsslower · weightHP Mazda 2 (11-14) gains 50 lbs to 2045; VW Golf/Jetta/Rabbit/Scirocco (85-92, 1780cc, 8-valve) gain 50 lbs to 2150 base.
HP Interpretation of Production Rules on Mirrors #37235wordingaddedEP, FP, HP may use any interior or exterior mirror meeting rule 9.3.36.
HP Weight Reduction for Honda S2000 #37466weightfaster · weightEP Honda S2000 1997cc minimum weight drops 75 lbs to 2375; 2157cc drops 60 lbs to 2450.
HP Mazda 1999 Miata 1.8L #37488weight -50 lbsfaster · weightEP Mazda MX-5 Miata 99-05 minimum weight reduced to 2100 lbs, 2153 lbs with power, 2205 lbs modified.
HP MINI Cooper (07-13) Spec Line Correction: Errors and Omissions #37560engineslower · engineHP Mini Cooper 07-13 engine corrected to DOHC; valve lift limit reduced to .390 inch.
Super Tour Feb 2025 CALCL252025-02-22
2:06.770Lee Fleming · fastest of 4 · top 4 within 4.3s
2:03.082Lee Fleming · fastest of 5 · top 5 within 6.2s
100.4Lee Fleming
140 earlier rule changes on record, in force before Super Tour Feb 2025 (from 2019)28 cars added · 27 weight · 12 engine · 8 induction · 6 tyres & wheels · 5 suspension & brakes · 4 aero · 1 removed · 33 wording · 16 other · EP BMW models now require flat plate intake restrictors: Z3 2.5L 52mm, Z3 2.8L 55mm, 328i E36 58mm, 328i/ci E46 58mm, 325i E46 56mm, 325i E36 56mm, 325is M-Technic 56mm. · EP BMW 325i/is E30 84-91 weight reduced to 2150 lbs base, 2204 lbs with turbo, 2258 lbs supercharged. · HP Honda Civic 1.5 88-91 minimum weight drops to 2175 lbs, 2229 lbs with power, 2284 lbs with both. · HP Mini Cooper 02-06 rear brake rotor diameter increased from 239 mm to 259 mm. · HP 1275 Spridget compression ratio raised to 12.0:1; 1098cc also raised to 12.0:1. · Suzuki Swift GT 1989-94 classified in HP Pre at 1900 lbs, 1298cc DOHC fuel injection, compression 11.0:1 max, valve lift 0.390 in. max. · SRF3 air filter rule removes K&N RC-9160 option, specifies Weems P/N WM301020 only. · SRF Wilwood vented rotor minimum thickness increases to 13.25mm, 0.522 inches. · SRF3 Hoosier decal placement changed from four logos on nose and tail to three logos on sides and center front. · FE and SRF protest fee rules redirected to GCR section 8.3.1.D for fees and procedure. · SRF Hoosier contingency decal requirement reduced from four decals in specific locations to three decals with simplified placement. · HP Volkswagen Golf and Jetta 85-92 track correction: front 1537 mm (60.5 in.), rear 1529 mm (60.2 in.). · SRF wet tyres: front P185/60R13 H20 or W2 and rear P205/60R13 H20 or W2 removed; front P185/65R13 W2 and rear P205/60R13 W2 now required. Hoosier decal placement specified. · Nissan 300ZX 84–89 added to EP, 2550–2678 lbs, 2960 cc SOHC, fuel injection, 12.0:1 compression, 0.500" valve lift limit. · Mazda RX-7 92-97 added to EP Prep as Level 2 rotary 13B 6-port, 2200–2310 lbs, carb or fuel injection, 42 mm choke. · EP Mazda RX-8 (04-11) alternate spec line removed; single spec line retained. · HP Honda CRX/Si 84-87 plastic front header, rocker, and door cap panels may be replica alternate material if stock appearance kept. · HP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve 83-88, Scirocco 1588. · HP Honda Civic 1.5 1988-91 minimum weight drops 70 lbs to 2175; also 2-speed and 3-speed minimums cut 72 and 73 lbs. · EP BMW Z3 2.5L minimum weight increased to 2500 lbs, 2563 lbs with power adder, 2625 lbs with two power adders. · HP Austin-Healey Sprite and MG Midget Mk I–IV compression ratio raised to 12.0:1. · HP Triumph Spitfire 1500 valve spec changes to 36.6 intake, 1.44 exhaust from 5.5 and 0.0 respectively. · EP Mazda MX-5 1.8L (90-97) minimum weight cut to 2150 lbs; (94-97) variants to 2000, 2050, 2100 lbs. · EP Triumph GT6 dual 1.75-inch carburetors weight rises to 1940 lbs; triple Weber 40 DCOE option added at 1990 lbs. · EP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm. · HP Honda CRX/Si 84-87 front header/nose panel may now be alternate material replica, stock appearance required. · EP Triumph TR8 dry sump allowance moved from Carburetor line to Notes. · EP Porsche 944/924S 2.5L and 2.7L minimum weights corrected: 2479cc to 2306–2363 lbs, 2681cc to 2358–2415 lbs. · HP Mazda 2 (11-14) minimum weight rises to 1995 lbs base, 2045 lbs with one option, 2095 lbs with two. · SRF rain/brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24; secondary filament must connect to rain light switch. · SRF brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24, with SCCA Enterprises P/N 180427A pigtail and strobing rain light kit. · SRF adds mandatory front brake ducts 12–36 inches, throttle pedal heel-toe extension, braided stainless flex lines, camber limit 5.0 degrees, radiator opening height 3½ ± ½ inches, rear shift cable clamp P/N WM302007A. · HP Honda CRX 1.5 (88–91) minimum weight drops 70 lbs to 2175; supercharged and turbocharged versions also reduced. · EP Porsche 944/924S combines 2.5L and 2.7L variants (83-89), raises weight to 2250–2415 lbs, allows 2681cc displacement. · FP Toyota Corolla 2TC loses 43 lbs to 1810; HP Corolla loses 50–52 lbs to 1910–2006. · HP Mazda 626 84-87 base weight drops to 2200 lbs, *2255, **2310. · EP Triumph GT6 minimum weight drops to 1800 lbs. · SRF radiator options expanded: Enterprises P/N 480465 with baffle 480464, 480466, or Automotive 1R698 and CU698 allowed if cross-reference equivalent. · HP Nissan/Datsun PL510 carburetor chokes enlarge from 32mm to 34mm in DCN/DCNF and side draft options. · FP and HP Sprite and Spitfire 1500 intake valve size corrected to 36.6 mm, removing prior decimal specifications. · HP Volkswagen Rabbit Cabriolet 1780 removed; Rabbit 1588 and 1715 reclassified with year and body-type clarifications. · Ford Fiesta HP model years change to 11-19; Chevrolet Sonic FP model years change to 12-19. · SRF wet front tyre changes to Hoosier P/N 46100 P185/60R13 H20 or W2 with 2.5" ground clearance. · SRF front W2 rain tyre Hoosier part number changes from 46100 to 46101 P185/65R13. · SRF removes 1985 Renault Alliance solid front rotor option; restrictor sizes decrease 1mm for newer Kawasaki and multi-brand engines; minimum weights increase to 1100 lbs. · MGB & MGB-GT HP weight reduced to 2000, 2050, 2100 lbs; new MGB 1/2 Prep at 2175 lbs permitted. · HP Nissan/Datsun PL510 minimum weights reduced: base to 1910 lbs, * to 1958 lbs, ** to 2006 lbs. · EP, FP, HP port matching limited to 1 inch depth from mating surface. · Volkswagen New Beetle 2.5L 5-cyl DOHC classified in EP at 2400–2520 lbs with fuel injection. · EP Mazda RX-7 12A/13B and 13B now permit 2 bbl fuel injected throttle body with 42mm chokes on dual-y manifold. · EP VW Corrado 92-95 stroke corrected to 90.3 mm and displacement to 2792 cc. · EP Subaru BRZ title updated to include model years 13–20; Toyota 86/Scion FR-S title likewise updated to 13–20. · SRF tire rule wording clarified: tires must be run as delivered. · SRF brake rotor minimum thickness reduced from 13.25 mm to 12.20 mm; seals and air filter specs clarified. · 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 2996 cc engine, stock throttle body, 11.0:1 compression and 0.400" valve lift limits. · EP, FP, HP open cars now allow carbon fiber hardtops if they retain OEM exterior profiles. · EP Mazda RX-8 13B carburetor option replaced with fuel-injected throttle body or stock fuel injection. · EP, FP, HP Production clarify idle control valve options: stock original allowed, removable with blocked ports, or mechanical replaced with electronic stock type. · HP Spec Lines classify Volkswagen New Beetle 98-05 at 2350–2468 lbs, 1984 cc SOHC four-cylinder, fuel injection, 11.0:1 compression limit, valve lift to 0.425 inch. · HP Triumph Spitfire 1500 minimum weight increases to 1605 lbs base, 1645 lbs with *, 1685 lbs with **. · EP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate. · Ford Mustang 94-98 weight reduced to 2550/2614/2678 lbs; 99-03 3.8L classified EP at 2700/2768/2835 lbs. · EP, FP, HP Improved Touring cars may use any DOT-approved tyre as defined by 9.3.45. · EP, FP, HP: stock/original idle control devices permitted unmodified or completely removed with openings blocked. · HP Fiat X1/9 valve sizes corrected: intake to 36.3/(1.43) mm, exhaust to 33.3/(1.31) or 31.2/(1.23) by variant. · EP Porsche 968 intake valve size changes to 39.0 mm, 1.54 mm seat width. · EP, FP, HP front-wheel-drive cars may alter body and subframes to install alternate axle shaft, matching RWD freedom. · HP Fiat X1/9 models lose 50–55 lbs across all variants and levels, minimum weights adjusted downward. · Austin-Healey Sprite Mk I-IV and MG Midget classified in HP Prep at 1510–1586 lbs with 1493 cc OHV engine. · EP BMW Z3 2.5L adds alternate throttle body option with Turner adapter and permits head casting 1738400. · Austin-Healey Sprite Mk I–IV and MG Midget (all) added to HP at 1655 lbs minimum, 1493 cc OHV four-cylinder, 11.0:1 compression limit, .450" valve lift limit. · EP Porsche 944S2 89-91 requires 56mm flat plate intake restrictor; compression ratio 12.0:1 max, valve lift 0.500" max, dry sump allowed. · Toyota Corolla GTS RWD (84-87) and FX16 FWD (87-88) added to HP; old Corolla (84-87) removed. · SRF wet tyres front P185/65R13 W2 option added; air box clarified as-delivered; SRF3 restrictor plate G301048 mandatory Jan 1 2022; P2 motorcycle engines up to 1005cc with 35mm restrictor, 2009+ stock 1075 lbs, 2008 stock 1025 lbs, modifie… · Toyota MR-2 1.6L 85-89 HP track width corrected to 15×47 / 15×47 inches; stock track baseline now 103% plus 2.5 inches. · EP Honda S2000 now allows F22c engine in 1997cc and 2157cc displacements with revised weight brackets and specifications. · EP Nissan 240-SX S13/S14 weight drops to 2400 lbs base, 2460 turbo, 2520 supercharged; comp ratio raised to 12.0:1, valve lift to 0.500 inch. · SRF wet tyres add Hoosier W2 option alongside existing H20 from October 4, 2021. · SRF adds SADEV-SRF3 6-speed sequential transmission option with ratios 3.0–0.92:1 and 3.20 final drive. · SRF seal requirements clarified: seals now must be on driveline components in designated locations; unsealed components removed and inspected by CSR or Enterprises rather than engine shipped for testing. · EP Lotus/Caterham 7 America fuel injection permitted; IT preparation engine limitation removed. · Plymouth Arrow 76–80 classified in HP Prep at 1800–1890 lbs with 1598 cc iron-block OHV four-cylinder. · BMW 318i/is E30 (84-85) reclassified from FP to HP at 2200–2310 lbs, SOHC 1797cc, fuel injection, 11.0:1 compression, .425" valve lift limit. · Daimler SP 250 classified in EP with 2165 lbs minimum weight, 2548 cc eight-cylinder OHV engine, SU or Stromberg carburetors. · HP Porsche 924 76-84 brakes change from solid to vented disc. · EP, FP, HP clarify percentage weight penalties sum before applying to base weight, round to nearest pound. · HP Mazda 626 84-87 carburettor spec corrected to allow carburation or fuel injection. · SRF3 alternator pulley specified as P/N G902130 or G902130A, minimum 12oz. · Volvo 142/142E moves from HP Spec to HP Prep with 1989cc OHV engine, 2450–2573 lbs, fuel injection, 11.0:1 compression limit. · HP adds Volkswagen Golf III / Jetta III 93-98, 1984cc SOHC, 2325–2441 lbs, fuel injected. · Porsche 924 76-84 added to HP class with 2400–2520 lbs, fuel injection, 1984cc, 11.0:1 compression limit. · 84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lb weight, 1998cc SOHC engine, two 32mm carburetors. · FP Fiat X1/9 and Bertone 1300 brake rotors now 257 x 12 mm, 10.1 inch diameter, 0.407 inch thickness. · HP Mini Cooper classification expands to include 2012-2015 Coupe alongside existing 2007-2013 and convertible models. · HP Volkswagen Rabbit GTI 1780 (83-84) now permits Mk2 VW front spindles, hubs and bearings. · SRF and SRF3 mandatory identification revised: removed Ford Performance and Blue Oval decals, added Hoosier logo placement. · EP Austin-Healey 3000 gains option to use TR-6 front calipers and discs as alternate. · FP Mk2 Golf and Jetta 1.8 lose 50 lbs to 1900; HP Jetta GLI engine code removed. · EP, FP, HP Level 1 and Level 2 induction systems: carburettor jets, needles, metering rods allowed; throttle body porting permitted; wording clarified. · EP Nissan Datsun SRL 311U Roadster minimum weight reduced 75 lbs to 1925. · EP Triumph TR8 78-81 minimum weight drops to 2500 lbs. · SRF rear springs limited to P/N 280390 only, previous part numbers no longer allowed; ground clearance wording clarified. · HP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches. · EP BMW Z3 2.5L cylinder head casting 1738400 permitted with iron block castings 1748933 or 1738566. · Porsche 911 S 67-68 classified in EP at 1800–1890 lbs, 1991cc opposed 6-cylinder SOHC with 36mm carburetors. · Request to allow dual carburetors on 1.8 VW GTI Mk1 denied; vehicle remains fuel-injected only. · EP BMW 2.8L, 328i E36/E46, and 325i E36 now require iron blocks only; 325i E46 aluminum block removed. · FP Pre: 1990–1994 Mazda Protégé classified at 2150–2258 lbs, 1839cc DOHC, fuel injection, 11.0:1 compression, .450" valve lift limit. · HP Mini Cooper 02-06 and 07-13 convertible model years corrected to 05-08 and 09-15 respectively. · SRF Penske shock P/N 280396 bump stop P/N 280407 becomes mandatory, maximum one per shock, effective 05/01/2020. · EP Caterham 7 America engine limited to IT prep with specific sections, comp ratio 10.0:1, valve lift .380 inch. · HP Volkswagen Rabbit and Scirocco 1588 carburetors clarified: 40 DCN/DCNF with 32mm chokes or fuel injection allowed; auto side drafts with 32mm chokes at 90lbs penalty. · HP Mini Cooper 02-06 and 07-13 now include convertible; 05-08 convertible spec deleted. · HP Datsun 510 Level 2 gains option to use Nissan/Datsun 240Z/260Z/280Z front rotors, calipers, and rear aluminum drums. · HP Datsun 510 allows 40 DCOE carburetor option alongside existing 40 DCNF and 36mm DCNVH; auto side drafts moved to penalty structure. · HP Ford Fiesta 78-80 loses 50-53 lbs across all configurations, base to 1725. · HP Datsun 1200 carburetor option changes from 26mm to 30mm choke(s) in 40 DCN, DCNF, IDF. · HP Mazda2 now 11-14, Honda Fit now 15-19, Mini Cooper now 07-13. · HP Porsche 914-4 1.8L now allows 2-stage cam-driven dry sump in OEM oil pump location. · HP Toyota Corolla 71-74 permitted to use rear axle housing from 84-87 Corolla. · Mazda Miata models EP and FP throttle body specified 55mm, brake rotor thickness figures removed. · HP VW Rabbit Convertible 1.6L and Scirocco 1588 minimum weights cut to 1735, 1778, 1822 lbs. · SRF rain and brake rule supersedes GCR 9.3.32.B.2 effective 1/1/2024 through 12/31/2024. · FP and HP: 1988–91 Honda Civic and CRX track widths corrected to 61.3 / 61.7 inches across multiple levels. · EP, FP, HP cylinder head rules reorganized for clarity; no performance change. · SRF adds tire warmer prohibition and specifies Hoosier dry and wet tire part numbers. · SRF front nose weight minimum reduced from 35 to 32 lbs. · SRF2 becomes Regional Only; SRF3 nomenclature changed from GEN3 to Ford 1.6L conversion; SRF and SRF3 no longer compete together for points. · FP and HP Austin-Healey Sprite Mk I / MG Midget may replace rear bodywork aft of cockpit with alternate material stock-appearing components. · EP Mazda MX-5 Global Cup classification updated to include 2019 model year. · Production classes: suspension rule clarified to specify spindles, hubs, bushings, bearings, and ball joints unrestricted. · Production carburetor and fuel injection rules clarified: permitted optional carburetors listed, Weber and auto-type substitutions specified, fuel injection throttle body and butterfly dimensions detailed, intake manifold port extension pr… · EP, FP, HP carburetors: jets, needles, metering rods, needle valves unrestricted; choke parts removable; stock or optional Weber 40 DCN permitted; Weber types, auto types listed. · EP Mazda MX-5/Miata model years expand from 1999-2002 to 1999-2005. · SRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102. · EP, FP, HP: clarified that tapered holes in ball joints can be reamed for bolt conversion, and wheel bearings and hubs unrestricted on all axles. · EP open cars may now use aftermarket hardtops if OEM-appearance and non-carbon-fiber; specific model allowances removed as redundant. · H Production Toyota Yaris 06-11, 07-12 sedan, and 12-18 minimum weights increased to 2100, 2153, and 2205 lbs respectively. · HP Ford Fiesta 2011–16 allowed Mazda front hub D651-33-06 and rear hub D651-26-15XE.showhide
HP Effective date for Jan 2025 GCR updates #37654inductionslower · inductionEP BMW models now require flat plate intake restrictors: Z3 2.5L 52mm, Z3 2.8L 55mm, 328i E36 58mm, 328i/ci E46 58mm, 325i E46 56mm, 325i E36 56mm, 325is M-Technic 56mm.
HP Request to Reduce Weight of BMW 325i/is E30 (84-91) Spec Line #37119weight -50 lbsfaster · weightEP BMW 325i/is E30 84-91 weight reduced to 2150 lbs base, 2204 lbs with turbo, 2258 lbs supercharged.
HP Request to Update 1988-1991 Civic to Match 1988-1991 CRX #37444weight -70 lbsfaster · weightHP Honda Civic 1.5 88-91 minimum weight drops to 2175 lbs, 2229 lbs with power, 2284 lbs with both.
HP MINI Cooper Spec Line Correction - Rear Brake Rotor Diameter #37176suspension & brakessuspension & brakesHP Mini Cooper 02-06 rear brake rotor diameter increased from 239 mm to 259 mm.
HP 1275 HP Spridget Level 2 Only #36518enginefaster · engineHP 1275 Spridget compression ratio raised to 12.0:1; 1098cc also raised to 12.0:1.
HP Request for Classification of 1989-1994 Suzuki Swift GT 16V Twin #36858cars addedaddedSuzuki Swift GT 1989-94 classified in HP Pre at 1900 lbs, 1298cc DOHC fuel injection, compression 11.0:1 max, valve lift 0.390 in. max.
SRF Update SRF3 Air Filter Rule #36681wordingremovedSRF3 air filter rule removes K&N RC-9160 option, specifies Weems P/N WM301020 only.
SRF Hoosier Tire Decal Placement #36739wordingwordingSRF3 Hoosier decal placement changed from four logos on nose and tail to three logos on sides and center front.
SRF Protest Fee Clarification #36540wordingwordingFE and SRF protest fee rules redirected to GCR section 8.3.1.D for fees and procedure.
SRF Update to Letter 36619 with new Hoosier Contingency Decal Info #36624wordingwordingSRF Hoosier contingency decal requirement reduced from four decals in specific locations to three decals with simplified placement.
HP Errant entry in HP production line item #36231wordingwordingHP Volkswagen Golf and Jetta 85-92 track correction: front 1537 mm (60.5 in.), rear 1529 mm (60.2 in.).
SRF Update Rain Tire Rule and Hoosier Decal Placement #36436tyres & wheelstyres & wheelsSRF wet tyres: front P185/60R13 H20 or W2 and rear P205/60R13 H20 or W2 removed; front P185/65R13 W2 and rear P205/60R13 W2 now required. Hoosier decal placement specified.
HP NIssan 300ZX Z31 to EP #35830cars addedaddedNissan 300ZX 84–89 added to EP, 2550–2678 lbs, 2960 cc SOHC, fuel injection, 12.0:1 compression, 0.500" valve lift limit.
HP RX7 1993 and Up Request In EP Spec Lines, classify #36031cars addedaddedMazda RX-7 92-97 added to EP Prep as Level 2 rotary 13B 6-port, 2200–2310 lbs, carb or fuel injection, 42 mm choke.
HP Clean-up Multiple EP RX-8 Spec Lines In EP #36156cars addedremoved · cars addedEP Mazda RX-8 (04-11) alternate spec line removed; single spec line retained.
HP Replace plastic panels #35875otheraddedHP Honda CRX/Si 84-87 plastic front header, rocker, and door cap panels may be replica alternate material if stock appearance kept.
HP GCR Correction - Redundant HP Spec Lines #35623removedremovedHP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve 83-88, Scirocco 1588.
HP Update 1988-1991 Civic to Match 1988-1991 CRX #35399weightfaster · weightHP Honda Civic 1.5 1988-91 minimum weight drops 70 lbs to 2175; also 2-speed and 3-speed minimums cut 72 and 73 lbs.
HP Request to Review Z3 2.5 Spec Line #35073weight +50 lbsslower · weightEP BMW Z3 2.5L minimum weight increased to 2500 lbs, 2563 lbs with power adder, 2625 lbs with two power adders.
HP Parity in HP #35138enginefaster · engineHP Austin-Healey Sprite and MG Midget Mk I–IV compression ratio raised to 12.0:1.
HP Spitfire classification #35224otherunclearHP Triumph Spitfire 1500 valve spec changes to 36.6 intake, 1.44 exhaust from 5.5 and 0.0 respectively.
HP Miata Alternate Head #35253weight -50 lbsfaster · weightEP Mazda MX-5 1.8L (90-97) minimum weight cut to 2150 lbs; (94-97) variants to 2000, 2050, 2100 lbs.
HP Triumph GT6 Adjustments #35255weightslower · weightEP Triumph GT6 dual 1.75-inch carburetors weight rises to 1940 lbs; triple Weber 40 DCOE option added at 1990 lbs.
HP Honda S2000 throttle body #35272inductionfaster · inductionEP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm.
HP Front Header/Nose Panel Alternate Material For 84-87 CRX #35301cars addedaddedHP Honda CRX/Si 84-87 front header/nose panel may now be alternate material replica, stock appearance required.
HP Correction within Triumph TR8 Spec Line #35315wordingwordingEP Triumph TR8 dry sump allowance moved from Carburetor line to Notes.
HP Correction to EP 924S/944 Spec Line #35317weightweightEP Porsche 944/924S 2.5L and 2.7L minimum weights corrected: 2479cc to 2306–2363 lbs, 2681cc to 2358–2415 lbs.
HP Review Classification of HP Mazda 2 #35318weight +75 lbsslower · weightHP Mazda 2 (11-14) minimum weight rises to 1995 lbs base, 2045 lbs with one option, 2095 lbs with two.
SRF Update SRF Rain / Brake Rule #34706otherotherSRF rain/brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24; secondary filament must connect to rain light switch.
SRF Update SRF Brake Light Rule v1 #34853otherotherSRF brake light must be Super Bright LEDs Inc. P/N PT-STRB-R24, with SCCA Enterprises P/N 180427A pigtail and strobing rain light kit.
HP Request to Adjust Weight of 1988-1991 CRX/Civic #35115weight -70 lbsfaster · weightHP Honda CRX 1.5 (88–91) minimum weight drops 70 lbs to 2175; supercharged and turbocharged versions also reduced.
HP Porsche 944/924S Rule Change Request #35002weightslower · weightEP Porsche 944/924S combines 2.5L and 2.7L variants (83-89), raises weight to 2250–2415 lbs, allows 2681cc displacement.
HP FP and HP Toyota Corolla #35030weight -43 lbsfaster · weightFP Toyota Corolla 2TC loses 43 lbs to 1810; HP Corolla loses 50–52 lbs to 1910–2006.
HP Weight Reduction for Mazda 626 #35031weight -100 lbsfaster · weightHP Mazda 626 84-87 base weight drops to 2200 lbs, *2255, **2310.
HP Triumph GT6 Adjustments #35054weight -30 lbsfaster · weightEP Triumph GT6 minimum weight drops to 1800 lbs.
SRF SRF Radiator Rule Update #34805otheraddedSRF radiator options expanded: Enterprises P/N 480465 with baffle 480464, 480466, or Automotive 1R698 and CU698 allowed if cross-reference equivalent.
HP Larger chokes #34681enginefaster · engineHP Nissan/Datsun PL510 carburetor chokes enlarge from 32mm to 34mm in DCN/DCNF and side draft options.
HP Correct Intake Valve Size on 1500cc Midget/Spitfire #34419wordingwordingFP and HP Sprite and Spitfire 1500 intake valve size corrected to 36.6 mm, removing prior decimal specifications.
HP ITC to FP? #34286cars addedremoved · cars addedHP Volkswagen Rabbit Cabriolet 1780 removed; Rabbit 1588 and 1715 reclassified with year and body-type clarifications.
HP Request to Classify Sonic and Fiesta in HP #34264cars addedaddedFord Fiesta HP model years change to 11-19; Chevrolet Sonic FP model years change to 12-19.
SRF Hoosier SRF Wet Front Tire Rule Update #34189tyres & wheelstyres & wheelsSRF wet front tyre changes to Hoosier P/N 46100 P185/60R13 H20 or W2 with 2.5" ground clearance.
SRF Update SRF Front W2 Rain Tire Part Number #34118tyres & wheelstyres & wheelsSRF front W2 rain tyre Hoosier part number changes from 46100 to 46101 P185/65R13.
SRF Update SRF Brake Rule #33469enginefaster · engineSRF removes 1985 Renault Alliance solid front rotor option; restrictor sizes decrease 1mm for newer Kawasaki and multi-brand engines; minimum weights increase to 1100 lbs.
HP MGB HP Weight Break and/or Hybrid 1/2 Prep in HP #33127weightfaster · weightMGB & MGB-GT HP weight reduced to 2000, 2050, 2100 lbs; new MGB 1/2 Prep at 2175 lbs permitted.
HP Datsun 510 Help #33568weight -50 lbsfaster · weightHP Nissan/Datsun PL510 minimum weights reduced: base to 1910 lbs, * to 1958 lbs, ** to 2006 lbs.
HP Review Limited Prep Port Matching Rules #33600wordingwordingEP, FP, HP port matching limited to 1 inch depth from mating surface.
HP Request to classify VW New Beetle 2.5L in EP #32725cars addedaddedVolkswagen New Beetle 2.5L 5-cyl DOHC classified in EP at 2400–2520 lbs with fuel injection.
HP Request Rotary Injection on Dual Y manifold #32775inductionadded · inductionEP Mazda RX-7 12A/13B and 13B now permit 2 bbl fuel injected throttle body with 42mm chokes on dual-y manifold.
HP Request for Corrado Stroke & Displacement Correction #32985wordingwordingEP VW Corrado 92-95 stroke corrected to 90.3 mm and displacement to 2792 cc.
HP Subaru BRZ Model Years #32500wordingwordingEP Subaru BRZ title updated to include model years 13–20; Toyota 86/Scion FR-S title likewise updated to 13–20.
SRF SRF Tire Rule Update #32614wordingwordingSRF tire rule wording clarified: tires must be run as delivered.
SRF Brake, seal, and air filter clarifications #32670otherfasterSRF brake rotor minimum thickness reduced from 13.25 mm to 12.20 mm; seals and air filter specs clarified.
HP EP MX-5 Global Cup Car #32218weightweightEP Mazda MX-5 Global Cup 16-22 minimum weight set to 2400 lbs; sequential gearbox allowed with 150 lbs penalty.
HP Please Class BMW 128i in EP #32370cars addedaddedBMW 128i (08-13) classified in EP at 2700 lbs minimum with 2996 cc engine, stock throttle body, 11.0:1 compression and 0.400" valve lift limits.
HP Inconsistency in Body Work Descriptions #32396aeroadded · aeroEP, FP, HP open cars now allow carbon fiber hardtops if they retain OEM exterior profiles.
HP Mazda RX8 with 13b Rotary #32170engineengineEP Mazda RX-8 13B carburetor option replaced with fuel-injected throttle body or stock fuel injection.
HP Request Idle control valve clarification #32178wordingwordingEP, FP, HP Production clarify idle control valve options: stock original allowed, removable with blocked ports, or mechanical replaced with electronic stock type.
HP Classify VW New Beetle in HP. #32241cars addedaddedHP Spec Lines classify Volkswagen New Beetle 98-05 at 2350–2468 lbs, 1984 cc SOHC four-cylinder, fuel injection, 11.0:1 compression limit, valve lift to 0.425 inch.
HP Weight Change for Competition Adjustment #31182weight +45 lbsslower · weightHP Triumph Spitfire 1500 minimum weight increases to 1605 lbs base, 1645 lbs with *, 1685 lbs with **.
HP EP Adjustments #31858inductionslower · inductionEP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate.
HP 1999 3.8L Ford Mustang to EP? #31635weightfaster · weightFord Mustang 94-98 weight reduced to 2550/2614/2678 lbs; 99-03 3.8L classified EP at 2700/2768/2835 lbs.
HP Improved Touring Tires #32064tyres & wheelsadded · tyres & wheelsEP, FP, HP Improved Touring cars may use any DOT-approved tyre as defined by 9.3.45.
HP Throttle Body and Idle Air #31800wordingwordingEP, FP, HP: stock/original idle control devices permitted unmodified or completely removed with openings blocked.
HP Incorrect Valve Size Changes in Jan 2022 GCR for FIAT X1/9 #31990engineengineHP Fiat X1/9 valve sizes corrected: intake to 36.3/(1.43) mm, exhaust to 33.3/(1.31) or 31.2/(1.23) by variant.
HP Porsche 968 Engine Questions #31478engineengineEP Porsche 968 intake valve size changes to 39.0 mm, 1.54 mm seat width.
HP PCS E. 2. n. 4. Add Axle Shaft to Allow FWD the Same Freedom #31592otheraddedEP, FP, HP front-wheel-drive cars may alter body and subframes to install alternate axle shaft, matching RWD freedom.
HP Weight Adjustment To Fiat X1/9 Spec Lines, H-Production #31653weight -50 lbsfaster · weightHP Fiat X1/9 models lose 50–55 lbs across all variants and levels, minimum weights adjusted downward.
HP 1500 Midget #31665cars addedaddedAustin-Healey Sprite Mk I-IV and MG Midget classified in HP Prep at 1510–1586 lbs with 1493 cc OHV engine.
HP BMW Z3 2.5L Spec Line #31724engineadded · engineEP BMW Z3 2.5L adds alternate throttle body option with Turner adapter and permits head casting 1738400.
HP Request weight requirement for 1500 MG Midget #31802cars addedaddedAustin-Healey Sprite Mk I–IV and MG Midget (all) added to HP at 1655 lbs minimum, 1493 cc OHV four-cylinder, 11.0:1 compression limit, .450" valve lift limit.
HP Classing Clarification for 1986 Toyota Corolla FX16 #31527cars addedaddedToyota Corolla GTS RWD (84-87) and FX16 FWD (87-88) added to HP; old Corolla (84-87) removed.
SRF Three Updates to SRF Rules #31523otherotherSRF wet tyres front P185/65R13 W2 option added; air box clarified as-delivered; SRF3 restrictor plate G301048 mandatory Jan 1 2022; P2 motorcycle engines up to 1005cc with 35mm restrictor, 2009+ stock 1075 lbs, 2008 stock 1025 lbs, modifie…
HP E&O; MR2 Track #31120suspension & brakessuspension & brakesToyota MR-2 1.6L 85-89 HP track width corrected to 15×47 / 15×47 inches; stock track baseline now 103% plus 2.5 inches.
HP Request to Allow F22c Engine for 2000-2003 Honda S2000 #30548cars addedaddedEP Honda S2000 now allows F22c engine in 1997cc and 2157cc displacements with revised weight brackets and specifications.
HP Request a review of the S14 240SX in EP. #30873weight -200 lbsfaster · weightEP Nissan 240-SX S13/S14 weight drops to 2400 lbs base, 2460 turbo, 2520 supercharged; comp ratio raised to 12.0:1, valve lift to 0.500 inch.
SRF SADEV-SRF3 Transmission #30926cars addedaddedSRF adds SADEV-SRF3 6-speed sequential transmission option with ratios 3.0–0.92:1 and 3.20 final drive.
SRF SRF Update Maintenance, Repairs and Seals #30961wordingwordingSRF seal requirements clarified: seals now must be on driveline components in designated locations; unsealed components removed and inspected by CSR or Enterprises rather than engine shipped for testing.
HP Lotus/Caterham 7 America Request #30392wordingwordingEP Lotus/Caterham 7 America fuel injection permitted; IT preparation engine limitation removed.
HP Request to classify ITC Plymouth Arrow #30588cars addedaddedPlymouth Arrow 76–80 classified in HP Prep at 1800–1890 lbs with 1598 cc iron-block OHV four-cylinder.
HP Reclassification of the 1984/85 BMW 318i from FP to HP #30661cars addedaddedBMW 318i/is E30 (84-85) reclassified from FP to HP at 2200–2310 lbs, SOHC 1797cc, fuel injection, 11.0:1 compression, .425" valve lift limit.
HP Reclassify Daimler SP 250 #30721cars addedaddedDaimler SP 250 classified in EP with 2165 lbs minimum weight, 2548 cc eight-cylinder OHV engine, SU or Stromberg carburetors.
HP 924 Brakes- and Thank You. #30614suspension & brakessuspension & brakesHP Porsche 924 76-84 brakes change from solid to vented disc.
HP Clarify Application of Percentage Based Weight Penalties #30669wordingwordingEP, FP, HP clarify percentage weight penalties sum before applying to base weight, round to nearest pound.
HP Correct Induction Error on new HP Mazda 626 Spec Line #30702wordingwordingHP Mazda 626 84-87 carburettor spec corrected to allow carburation or fuel injection.
SRF SRF3 Alternator Pulley #30684engineadded · engineSRF3 alternator pulley specified as P/N G902130 or G902130A, minimum 12oz.
HP Volvo 142 spec line complete. #29479cars addedaddedVolvo 142/142E moves from HP Spec to HP Prep with 1989cc OHV engine, 2450–2573 lbs, fuel injection, 11.0:1 compression limit.
HP Request to Classify 93-98 Volkswagen Golf to HP #29790cars addedaddedHP adds Volkswagen Golf III / Jetta III 93-98, 1984cc SOHC, 2325–2441 lbs, fuel injected.
HP Appeal of Request to Move Porsche 924 to HP #30132cars addedaddedPorsche 924 76-84 added to HP class with 2400–2520 lbs, fuel injection, 1984cc, 11.0:1 compression limit.
HP Change Classification of 84-87 Mazda 626 from FP to HP #30350cars addedadded84-87 Mazda 626 reclassified from FP to HP with 2300–2415 lb weight, 1998cc SOHC engine, two 32mm carburetors.
HP Fiat X1/9 brake rotors #30423otherotherFP Fiat X1/9 and Bertone 1300 brake rotors now 257 x 12 mm, 10.1 inch diameter, 0.407 inch thickness.
HP Request to Classify 2012-2015 MINI Cooper Coupe in HP #30167cars addedaddedHP Mini Cooper classification expands to include 2012-2015 Coupe alongside existing 2007-2013 and convertible models.
HP Request clarification on VW 1.8 Rabbit GTI Spec Line #30368otheraddedHP Volkswagen Rabbit GTI 1780 (83-84) now permits Mk2 VW front spindles, hubs and bearings.
SRF Mandatory identification: #30223wordingwordingSRF and SRF3 mandatory identification revised: removed Ford Performance and Blue Oval decals, added Hoosier logo placement.
HP Alternate Front Brake Rotors and Calipers for EP AH 3000 #29893otherotherEP Austin-Healey 3000 gains option to use TR-6 front calipers and discs as alternate.
HP Mk2 VW Consistency and Cleanup of FP and HP Spec Lines #29195weight -50 lbsfaster · weightFP Mk2 Golf and Jetta 1.8 lose 50 lbs to 1900; HP Jetta GLI engine code removed.
HP Correct Wording for Level 1 and Level 2 Induction Systems #29406inductionfaster · inductionEP, FP, HP Level 1 and Level 2 induction systems: carburettor jets, needles, metering rods allowed; throttle body porting permitted; wording clarified.
HP Weight Reduction for Datsun Roadster #29409weight -75 lbsfaster · weightEP Nissan Datsun SRL 311U Roadster minimum weight reduced 75 lbs to 1925.
HP EP TR8 Adjustment #29512weight -100 lbsfaster · weightEP Triumph TR8 78-81 minimum weight drops to 2500 lbs.
SRF SRF Shocks, Springs and Ride Height. #29688otherotherSRF rear springs limited to P/N 280390 only, previous part numbers no longer allowed; ground clearance wording clarified.
HP 84-87 Toyota Corolla HP Wheel Diameter Allowance Proposal E&O #29458otherfasterHP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches.
HP EP BMW Z3 Rule Clarification #28998wordingwordingEP BMW Z3 2.5L cylinder head casting 1738400 permitted with iron block castings 1748933 or 1738566.
HP Request to Classify Porsche 911 2.0L #28456cars addedaddedPorsche 911 S 67-68 classified in EP at 1800–1890 lbs, 1991cc opposed 6-cylinder SOHC with 36mm carburetors.
HP Request Dual Carbs for 1.8 VW GTI Mk1 #28922wordingremovedRequest to allow dual carburetors on 1.8 VW GTI Mk1 denied; vehicle remains fuel-injected only.
HP BMW Cylinder Head Casting and Part Numbers #28708engineslower · engineEP BMW 2.8L, 328i E36/E46, and 325i E36 now require iron blocks only; 325i E46 aluminum block removed.
HP Request to Classify 1990-1994 Mazda Protege #28381cars addedaddedFP Pre: 1990–1994 Mazda Protégé classified at 2150–2258 lbs, 1839cc DOHC, fuel injection, 11.0:1 compression, .450" valve lift limit.
HP Error in Mini Cooper Spec Line #28713wordingwordingHP Mini Cooper 02-06 and 07-13 convertible model years corrected to 05-08 and 09-15 respectively.
SRF SRF Bump Stop Correction #27019wordingwordingSRF Penske shock P/N 280396 bump stop P/N 280407 becomes mandatory, maximum one per shock, effective 05/01/2020.
HP Caterham 7 Spec Line #28498wordingwordingEP Caterham 7 America engine limited to IT prep with specific sections, comp ratio 10.0:1, valve lift .380 inch.
HP Letter #27917 #28085wordingwordingHP Volkswagen Rabbit and Scirocco 1588 carburetors clarified: 40 DCN/DCNF with 32mm chokes or fuel injection allowed; auto side drafts with 32mm chokes at 90lbs penalty.
HP Request to Classify 2007 - 2013 Mini Cooper Convertible #28111cars addedaddedHP Mini Cooper 02-06 and 07-13 now include convertible; 05-08 convertible spec deleted.
HP Allow HP Datsun 510 Under Level 2 to Utilize Datsun Z Brakes #28121otheraddedHP Datsun 510 Level 2 gains option to use Nissan/Datsun 240Z/260Z/280Z front rotors, calipers, and rear aluminum drums.
HP Request to allow 40 DCOE carb for the Datsun 510 #28195engineadded · engineHP Datsun 510 allows 40 DCOE carburetor option alongside existing 40 DCNF and 36mm DCNVH; auto side drafts moved to penalty structure.
HP Request Ford Fiesta Weight Adjustment #28337weightfaster · weightHP Ford Fiesta 78-80 loses 50-53 lbs across all configurations, base to 1725.
HP Request for Help for Datsun 1200 #27934inductionfaster · inductionHP Datsun 1200 carburetor option changes from 26mm to 30mm choke(s) in 40 DCN, DCNF, IDF.
HP Update years for the Mazda2, Honda Fit, & Mini #27782wordingwordingHP Mazda2 now 11-14, Honda Fit now 15-19, Mini Cooper now 07-13.
HP Allow Dry Sump, Limited Prep Porsche 914 #27814engineadded · engineHP Porsche 914-4 1.8L now allows 2-stage cam-driven dry sump in OEM oil pump location.
HP Please Allow Alternate Rear Axle Housing for RWD Toyota Corolla #27854otheraddedHP Toyota Corolla 71-74 permitted to use rear axle housing from 84-87 Corolla.
HP Request to List Mazda Miata Throttle Body Size #27907wordingwordingMazda Miata models EP and FP throttle body specified 55mm, brake rotor thickness figures removed.
HP HP VW Rabbit Convertible 1.6L #1922 and 32mm chokes #27917weightfaster · weightHP VW Rabbit Convertible 1.6L and Scirocco 1588 minimum weights cut to 1735, 1778, 1822 lbs.
SRF SRF Rain / Brake Rule - BoD approved as follows #34958wordingwordingSRF rain and brake rule supersedes GCR 9.3.32.B.2 effective 1/1/2024 through 12/31/2024.
HP Request to Correct Track of 1988-91 Honda Civic #27487otherotherFP and HP: 1988–91 Honda Civic and CRX track widths corrected to 61.3 / 61.7 inches across multiple levels.
HP Re-organize Prep2 Cylinder Head Rules for Clarity & Consistency #27661wordingwordingEP, FP, HP cylinder head rules reorganized for clarity; no performance change.
SRF SRF Tire Warmer Rule #27622tyres & wheelstyres & wheelsSRF adds tire warmer prohibition and specifies Hoosier dry and wet tire part numbers.
SRF SRF / SRF3 Nose Weight Reduction #27706weightfaster · weightSRF front nose weight minimum reduced from 35 to 32 lbs.
SRF SRF / SRF3 Majors & Regional Class Updates #27723wordingwordingSRF2 becomes Regional Only; SRF3 nomenclature changed from GEN3 to Ford 1.6L conversion; SRF and SRF3 no longer compete together for points.
HP Request bodywork for Austin Healey Bugeye Sprite MK1 #27106aeroadded · aeroFP and HP Austin-Healey Sprite Mk I / MG Midget may replace rear bodywork aft of cockpit with alternate material stock-appearing components.
HP Request to classify the GMX5 2019 #27263cars addedaddedEP Mazda MX-5 Global Cup classification updated to include 2019 model year.
HP level one susp. component rule #27270wordingwordingProduction classes: suspension rule clarified to specify spindles, hubs, bushings, bearings, and ball joints unrestricted.
HP Clarification of Carb Rules - Prep 1 #27300wordingwordingProduction carburetor and fuel injection rules clarified: permitted optional carburetors listed, Weber and auto-type substitutions specified, fuel injection throttle body and butterfly dimensions detailed, intake manifold port extension pr…
HP Clarification of Carb Rules - Prep 2 #27301inductioninductionEP, FP, HP carburetors: jets, needles, metering rods, needle valves unrestricted; choke parts removable; stock or optional Weber 40 DCN permitted; Weber types, auto types listed.
HP Request Miata Eligibility - 2003 #27121cars addedaddedEP Mazda MX-5/Miata model years expand from 1999-2002 to 1999-2005.
SRF SRF Dash Windscreen Kit #27028aeroadded · aeroSRF drivers may now use Dash Windscreen Kit P/N 1180103 or P/N 180102.
HP Rollcenter Correction Clarification #25873wordingaddedEP, FP, HP: clarified that tapered holes in ball joints can be reamed for bolt conversion, and wheel bearings and hubs unrestricted on all axles.
HP Hardtops #26476aeroadded · aeroEP open cars may now use aftermarket hardtops if OEM-appearance and non-carbon-fiber; specific model allowances removed as redundant.
HP Do Something About the Toyota Yaris In H Production #25834weight +130 lbsslower · weightH Production Toyota Yaris 06-11, 07-12 sedan, and 12-18 minimum weights increased to 2100, 2153, and 2205 lbs respectively.
HP Request to Allow 2011+ Fiesta to Change Bolt Pattern on Wheels #25929wordingwordingHP Ford Fiesta 2011–16 allowed Mazda front hub D651-33-06 and rear hub D651-26-15XE.
About this data
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. 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.