Lap times across years say as much about the weather as the class. % of HP is each class's best lap as a share of HP's on the same day, so the conditions drop out: 100% is level, less is quicker, and a move in it is the class getting faster or slower against the field.
Quickest here:HP 1:39.954 Jason Isley, Runoffs 2016 qualifying · SM 1:40.514 Justin Hille, Runoffs 2016 qualifying · FB 1:19.886 Alex Mayer, Runoffs 2016 qualifying · STL 1:35.439 John Schmitt, Runoffs 2016 qualifying
HPSMFBSTLsolid race · dashed qualifying · slower is lower
HPSMFBSTLsolid race · dashed qualifying · each class's best lap as a share of HP's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker
2:39.406Chris Schaafsma · fastest of 15 · top 5 within 7.7s+0.621s (+0.39%)
2:38.036Steve Sargis · fastest of 11 · top 5 within 4.6s-0.234s (-0.15%)
122.7Jesse Prather-2.2 mph (-1.8%)
2:42.173Brett Kowalski · fastest of 34 · top 5 within 0.3s-0.938s (-0.58%)
2:42.725Francisco Barroso · fastest of 35 · top 5 within 0.2s-1.705s (-1.04%)
119.6Wyatt Couch+0.3 mph (+0.3%)
+4.689squal +2.767s
103.0%qual 101.7%
2:30.537Derek Ketchie · fastest of 16 · top 5 within 2.9s-1.528s (-1.00%)
2:30.657Danny Steyn · fastest of 16 · top 5 within 0.6s-1.470s (-0.97%)
134.8Mike Taylor+2.6 mph (+2.0%)
-7.379squal -8.869s
95.3%qual 94.4%
35 rule changes (HP: 29, SM: 2, STL: 4)7 cars added · 5 engine · 5 induction · 5 weight · 2 aero · 1 tyres & wheels · 8 wording · 2 other · HP Mini Cooper 02-06 compression ratio increases from 10.6 to 11.0:1. · 1996-2000 Honda Civic CX/DX/LX with D16Y7 engine newly classified in HP. · HP 1275 Midget/Sprite alternate intake manifold from MG-B now permitted; balance tube shortening and flange modification allowed. · HP Honda Civic DX/LX 92–95 wheels 13x7 to 15x7, weight 2420 to 2350 lbs. · SM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361. · STL removes Mazda MX-5 Cup entirely; renames Spec MX5 Challenge to Spec MX5; renames Global Cup to MX-5 Cup (16-18); removes Global Cup (2019). · HP Austin-Healey Sprite and MG Midget 1275 gains alternate 1.5" SU carbs with narrowed intake manifold option. · STL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied. · EP Mazda MX-5 94-97 front track widens to 1516 mm, rear to 1534 mm. · EP Triumph GT6 auto-type drivetrain choke size increases from 44mm to 45mm. · BMW E21 320i/is (80–83) newly classified in HP Spec Lines effective 2026-05-01. · HP BMW 318is 84-85 displacement corrected to 1767 cc, 89.0 x 71.0 mm bore and stroke. · SM/SMX part number 0000-10-6900 replaced with 0000-06-5016-KT in GCR 9.1.7.C.1.j.1.c. · STL adds Mazda BP 1.6, 1600cc, minimum weight 2160 lbs. · HP mid and rear engine cars may cut single inlet and outlet holes for engine oil cooler ducting, sized to cooler area maximum. · HP Honda Fit 2015-19 engine reclassified from SOHC to DOHC. · 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. · STL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs. · 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.showhide
HP Mini Cooper Compression Ratio #40517enginefaster · engineHP Mini Cooper 02-06 compression ratio increases from 10.6 to 11.0:1.
HP 1996-2000 Honda Civic (CX, DX, VP, LX) with Engine Code D16Y7 #40322cars addedadded1996-2000 Honda Civic CX/DX/LX with D16Y7 engine newly classified in HP.
HP 1275 Midget/Sprit Alternate intake manifold E/O #40370inductionadded · inductionHP 1275 Midget/Sprite alternate intake manifold from MG-B now permitted; balance tube shortening and flange modification allowed.
HP HP Honda Civic (92-95) #40464weight -70 lbsfaster · weightHP Honda Civic DX/LX 92–95 wheels 13x7 to 15x7, weight 2420 to 2350 lbs.
SM Rear Toe Link #40271wordingwordingSM/SMX Mazda rear toe link part number revised from 0000-04-5361426 to 0000-04-5361.
STL Spec Line Clean Up #40344cars addedremoved · cars addedSTL removes Mazda MX-5 Cup entirely; renames Spec MX5 Challenge to Spec MX5; renames Global Cup to MX-5 Cup (16-18); removes Global Cup (2019).
HP Austin Healy Sprite/ MG Midget 1275 Induction Change Request #40213inductionfaster · inductionHP Austin-Healey Sprite and MG Midget 1275 gains alternate 1.5" SU carbs with narrowed intake manifold option.
STL Calculating Weight #40224wordingwordingSTL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied.
HP Miata track width - errors and omissions #39976aerofaster · aeroEP Mazda MX-5 94-97 front track widens to 1516 mm, rear to 1534 mm.
HP Triumph GT6 Spec Change. #40098inductionfaster · inductionEP Triumph GT6 auto-type drivetrain choke size increases from 44mm to 45mm.
HP Request to Classify BMW E21 320i #40110cars addedaddedBMW E21 320i/is (80–83) newly classified in HP Spec Lines effective 2026-05-01.
HP BMW 318is 84-85 engine displacement correction #40116wordingwordingHP BMW 318is 84-85 displacement corrected to 1767 cc, 89.0 x 71.0 mm bore and stroke.
SM Part Number Change Request #39914otherunclearSM/SMX part number 0000-10-6900 replaced with 0000-06-5016-KT in GCR 9.1.7.C.1.j.1.c.
HP Clarification On Oil Cooler Ducting #39604aeroadded · aeroHP mid and rear engine cars may cut single inlet and outlet holes for engine oil cooler ducting, sized to cooler area maximum.
HP Honda Fit 2015-19 Error in Engine Classification #39853wordingwordingHP Honda Fit 2015-19 engine reclassified from SOHC to DOHC.
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.
STL Weight adjustment for STL #39579weightslower · weightSTL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs.
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.
2:38.785Steve Sargis · fastest of 17 · top 5 within 1.9s+0.340s (+0.21%)
2:38.270Steve Sargis · fastest of 14 · top 5 within 2.4s+0.539s (+0.34%)
124.9Chris Schaafsma+2.1 mph (+1.7%)
2:43.111Bobby Gossett · fastest of 32 · top 5 within 0.3s+2.005s (+1.24%)
2:44.430Kyle Greenhill · fastest of 28 · top 5 within 0.3s+2.944s (+1.82%)
119.3Francisco Barroso-0.6 mph (-0.5%)
+6.160squal +4.326s
103.9%qual 102.7%
2:32.065Jose Osiris Pena · fastest of 14 · top 5 within 3.4s+2.002s (+1.33%)
2:32.127Jose Osiris Pena · fastest of 13 · top 5 within 2.4s+1.882s (+1.25%)
132.2Jon Sewell-2.1 mph (-1.5%)
-6.143squal -6.720s
96.1%qual 95.8%
24 rule changes (HP: 17, SM: 4, STL: 3)9 weight · 3 cars added · 3 induction · 2 engine · 1 suspension & brakes · 5 wording · 1 other · Lotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs. · 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. · 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 fines, level 2 and 4 may carry $500 fines. · SM tire marking rules clarified: one Hoosier SM 7.5 P205/50/ZR17 set per Super Tour weekend, impound after first dry session, damaged tires may be replaced with used tires only. · STL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1; mandatory component spec list removed, alternative tires only allowed. · 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. · 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. · 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. · SMX OE instrument cluster must stay unmodified and connected; aftermarket dash allowed if wiring only re-routed; alternate gauges now permitted; foot pedal comfort mods allowed without relocation. · STL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved. · 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.showhide
STL Lotus Weight Reduction #38772weight -50 lbsfaster · weightLotus Evora GT4 minimum weight drops to 2700 lbs; Elise Cup R to 2250 lbs; Elise SC and Exige SC to 2450–2550 lbs.
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.
SM SMX Data Submission - Penalties #38248otheraddedSMX drivers must submit data acquisition files on time or face suspension and $250 fine.
SM Committee) SMX Penaly Clarification updated language #38337wordingwordingSMX penalty language clarified: level 1 and 3 infractions may carry $1,000 fines, level 2 and 4 may carry $500 fines.
SM Clarify Tire Marking Regs #38005wordingwordingSM tire marking rules clarified: one Hoosier SM 7.5 P205/50/ZR17 set per Super Tour weekend, impound after first dry session, damaged tires may be replaced with used tires only.
STL E&O: SMX Allowance in STL #37945wordingunclearSTL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1; mandatory component spec list removed, alternative tires only allowed.
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.
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.
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.
SM E&O SMX Regs 9.1.7.1.D.5.u-.w #37070wordingwordingSMX OE instrument cluster must stay unmodified and connected; aftermarket dash allowed if wiring only re-routed; alternate gauges now permitted; foot pedal comfort mods allowed without relocation.
STL Request to Remove Miata Hubs from General category #37138cars addedaddedSTL STU Mazda Miata alternate front hubs Mazda Motorsports Development Part #0000-04-5HUB-S1 approved.
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.
2:38.445Chuck Mathis · fastest of 20 · top 5 within 3.4s-1.250s (-0.78%)
2:37.731Chuck Mathis · fastest of 19 · top 5 within 2.3s-9.713s (-5.80%)
122.8William Trainer-0.3 mph (-0.2%)
2:41.106Ethan Goulart · fastest of 49 · top 5 within 0.5s-1.103s (-0.68%)
2:41.486Brett Kowalski · fastest of 43 · top 5 within 0.3s-2.262s (-1.38%)
119.9Alex Bertagnoli-1.4 mph (-1.2%)
+3.755squal +2.661s
102.4%qual 101.7%
2:30.063Joe Moser · fastest of 18 · top 5 within 3.7s-1.357s (-0.90%)
2:30.245Joe Moser · fastest of 16 · top 5 within 4.2s-1.870s (-1.23%)
134.3Joe Moser+1.3 mph (+1.0%)
-7.486squal -8.382s
95.3%qual 94.7%
30 rule changes (HP: 22, SM: 4, STL: 4)12 weight · 4 cars added · 4 engine · 1 aero · 1 induction · 1 removed · 4 wording · 3 other · SMX Spec MX-5 camera requirement: non-functioning recorder now will instead of may warrant penalty or disqualification. · SM and SMX must run latest AIM Data Logger Spec MX-5 ECU Protocol, effective 2024-09-01. · SMX Mazda MX-5 OE versus OEM definitions clarified in GCR section 9.1.7.1; wording change only. · SM and SMX now allow an alternate shifter bushing at the bottom of the shift lever. · HP Volkswagen Golf and Jetta 85-92 track correction: front 1537 mm (60.5 in.), rear 1529 mm (60.2 in.). · 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. · STL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems. · STL normally aspirated minimum weights reduced: 1900cc to 2540 lbs, 1950cc to 2583 lbs, 2000cc to 2625 lbs; short-wheelbase FWD adds 1.25%; Honda B16/B17/B18C1 throttle to 51mm, B18C Type R and Mazda MZR to 50mm. · STL Mazda 12A: 5th and 6th intake port actuators and valves may no longer be removed or disabled. · 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. · STL 79-85 RX7 12A now allows auto-type 2 bbl carburetor with 42mm choke on dual-y manifold, not just stock Nikki. · 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.showhide
SM SMX Camera Rule Correction #36496wordingwordingSMX Spec MX-5 camera requirement: non-functioning recorder now will instead of may warrant penalty or disqualification.
SM Committee) AIM ECU Protocol #36556engineadded · engineSM and SMX must run latest AIM Data Logger Spec MX-5 ECU Protocol, effective 2024-09-01.
SM Committee) OE versus OEM Definitons #36608wordingwordingSMX Mazda MX-5 OE versus OEM definitions clarified in GCR section 9.1.7.1; wording change only.
SM Committee) Shifter Bushing #36611otheraddedSM and SMX now allow an alternate shifter bushing at the bottom of the shift lever.
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.).
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.
STL ST Electric-Assisted Steering Systems #35066aeroadded · aeroSTL and STU now permit electric power steering pumps, OEM electric-assisted steering, or column-mounted electric steering assist systems.
STL BOP Adjustments #35112weightfaster · weightSTL normally aspirated minimum weights reduced: 1900cc to 2540 lbs, 1950cc to 2583 lbs, 2000cc to 2625 lbs; short-wheelbase FWD adds 1.25%; Honda B16/B17/B18C1 throttle to 51mm, B18C Type R and Mazda MZR to 50mm.
STL Mazda 12A #35320engineremoved · engineSTL Mazda 12A: 5th and 6th intake port actuators and valves may no longer be removed or disabled.
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.
STL Alternate Carburetor Request for 79-85 RX7 12a #35181engineadded · engineSTL 79-85 RX7 12A now allows auto-type 2 bbl carburetor with 42mm choke on dual-y manifold, not just stock Nikki.
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.
2:14.029Chris Schaafsma · fastest of 25 · top 5 within 2.7s+0.077s (+0.06%)
2:14.681Chris Schaafsma · fastest of 24 · top 5 within 2.5s+2.878s (+2.18%)
119.4William Trainer-0.8 mph (-0.7%)
2:14.986Danny Steyn · fastest of 52 · top 5 within 0.1s+0.322s (+0.24%)
2:16.229Julian DaCosta · fastest of 46 · top 5 within 0.3s-2.878s (-2.07%)
120.3Jim Drago+1.1 mph (+0.9%)
+1.548squal +0.957s
101.1%qual 100.7%
2:05.779Danny Steyn · fastest of 22 · top 5 within 3.4s+0.305s (+0.24%)
2:06.682Joe Moser · fastest of 20 · top 5 within 1.5s-1.150s (-0.90%)
131.8Danny Steyn+0.1 mph (+0.1%)
-7.999squal -8.250s
94.1%qual 93.8%
10 rule changes (HP: 7, SM: 1, STL: 2)3 cars added · 3 weight · 1 engine · 3 wording · 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. · STL ITA and ITS RX7, and ITS/ITA/ITB/ITC 1985+ models clarified to require tires per 9.1.4.2. · 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. · SM Mazda MX-5 Miata 01-05 minimum weight rises to 2450 lbs, or 2465 with alternate bore. · Spec MX5 in STL allows ACT clutch 0000-02-5004-G6, wheels 17x8, Toyo RR and RA1 235-40-17 tyres, or alternatives on 17x7 per rules.showhide
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.
STL Clarify STL table B - IT spec notes on Tires #34187wordingwordingSTL ITA and ITS RX7, and ITS/ITA/ITB/ITC 1985+ models clarified to require tires per 9.1.4.2.
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.
SM BOP for NB1 and NB2 #32309weightslower · weightSM Mazda MX-5 Miata 01-05 minimum weight rises to 2450 lbs, or 2465 with alternate bore.
STL Spec MX5 in STL #33473cars addedaddedSpec MX5 in STL allows ACT clutch 0000-02-5004-G6, wheels 17x8, Toyo RR and RA1 235-40-17 tyres, or alternatives on 17x7 per rules.
2:13.952Steve Sargis · fastest of 23 · top 5 within 3.9s-0.870s (-0.65%)
2:11.803Vesa Silegren · fastest of 21 · top 5 within 6.3s-3.259s (-2.41%)
120.2Chris Schaafsma-4.7 mph (-3.8%)
2:14.664Danny Steyn · fastest of 60 · top 5 within 0.2s+0.112s (+0.08%)
2:19.107Travis Wiley · fastest of 58 · top 5 within 0.9s+2.648s (+1.94%)
119.2Jonathan Neudorf-0.6 mph (-0.5%)
+7.304squal +0.712s
105.5%qual 100.5%
2:05.474Danny Steyn · fastest of 24 · top 5 within 2.3s-1.729s (-1.36%)
2:07.832Danny Steyn · fastest of 22 · top 5 within 1.9s+0.559s (+0.44%)
131.7Trever Degioanni-3.2 mph (-2.3%)
-3.971squal -8.478s
97.0%qual 93.7%
31 rule changes (HP: 25, SM: 1, STL: 5)6 cars added · 5 engine · 5 weight · 3 induction · 2 tyres & wheels · 1 aero · 1 suspension & brakes · 7 wording · 1 other · 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. · 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. · SM Majors must run authorized Penske shock and mount; Regional competitors not required until further evaluation. · 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. · STU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs. · STL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels. · 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. · STL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed. · STL Mazda Renesis flat plate restrictor increases from 55mm to 60mm. · STL 79-85 RX7 12A allows emissions removal and jet correction on stock Nikki carb. · 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. · 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.showhide
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.
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.
SM Update GCR Section 9.1.7.3.A.1. #32217wordingwordingSM Majors must run authorized Penske shock and mount; Regional competitors not required until further evaluation.
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.
STL Single TB Weight Modifiers #31449weightfaster · weightSTU single throttle body weight reduction removed; minimum weights revised down to 2990 lbs at 3000cc from 3300 lbs.
STL Improved Touring Tires #32063tyres & wheelstyres & wheelsSTL and STU Improved Touring vehicles must now conform to section 9.1.4 Tires & Wheels.
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.
STL Throttling Device Clarification #31323wordingwordingSTL/STU intake manifold and cylinder head porting clarified as free; intake and exhaust porting wording removed.
STL Mazda Renesis Restriction #31467enginefaster · engineSTL Mazda Renesis flat plate restrictor increases from 55mm to 60mm.
STL Clarification of 79-85 RX7 Spec line #31621wordingwordingSTL 79-85 RX7 12A allows emissions removal and jet correction on stock Nikki carb.
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.
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.
1:54.417Steve Sargis · fastest of 42 · top 5 within 3.7s-3.004s (-2.56%)
1:56.188Steve Sargis · fastest of 42 · top 5 within 2.9s-1.381s (-1.17%)
122.0William Trainer
1:57.695Brian Henderson · fastest of 90 · top 5 within 0.5s-0.611s (-0.52%)
1:58.837Brian Henderson · fastest of 88 · top 5 within 0.3s-0.263s (-0.22%)
119.8Kyle Greenhill
+2.649squal +3.278s
102.3%qual 102.9%
1:51.665Danny Steyn · fastest of 42 · top 5 within 1.7s-0.982s (-0.87%)
2:02.711Joe Moser · fastest of 37 · top 5 within 3.2s+10.122s (+8.99%)
131.8Max Gee
+6.523squal -2.752s
105.6%qual 97.6%
37 rule changes (HP: 21, SM: 1, STL: 15)11 cars added · 6 weight · 3 engine · 2 aero · 2 induction · 2 suspension & brakes · 6 wording · 5 other · STL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations. · 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. · 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. · STL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs. · 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. · STL Pontiac Solstice/Saturn Sky allowed 4 inch ride height. · STL Mazda B5 DOHC added to class; must meet all STL regulations. · STL Honda B16A (JDM) restrictor reduced from 54mm to 53mm. · 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. · SM adds procedure for CRB-approved obsolete parts and BOP testing in sanctioned events with point forfeiture. · ST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section. · STL GM Ecotec LNF now permits any Ecotec engine family with 55mm flat plate restrictor. · ST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1. · ST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment. · STL rear wing trailing edge may be mounted no further rearward than the center of the rearmost part approved bodywork. · STL alternate transmissions now allow OEM gear sets and input shaft modifications for fitment. · EP Austin-Healey 3000 gains option to use TR-6 front calipers and discs as alternate. · STL RWD strut-front cars lose 2.5% weight penalty, others lose 3% penalty for FWD parity. · STL Honda F20C drops 2% weight penalty, minimum weight reduced. · STL Honda B16/B17/B18C1 restrictor reduced to 53mm, B18C variants and Mazda MZR to 52mm. · 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. · ST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.showhide
STL Request to clean up Spec MX-5 Redundancy #31069wordingwordingSTL Mazda Spec MX-5 removes redundant specification line referencing 2014 regulations.
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.
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.
STL VW Engine Request #30625engineadded · engineSTL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs.
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.
STL Request Mazda B5 DOHC #30420cars addedaddedSTL Mazda B5 DOHC added to class; must meet all STL regulations.
STL Honda B16A (JDM) Restrictor change #30531engineslower · engineSTL Honda B16A (JDM) restrictor reduced from 54mm to 53mm.
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.
SM Updates - Obsolete Parts & BOP Parts #30438wordingaddedSM adds procedure for CRB-approved obsolete parts and BOP testing in sanctioned events with point forfeiture.
STL ST Oil Coolers E&O Correction to 9.1.4.2.H #30388wordingwordingST oil coolers and filters now explicitly listed as addable or substitutable parts in vents and breathers section.
STL GM Ecotec engines in STL #30247engineadded · engineSTL GM Ecotec LNF now permits any Ecotec engine family with 55mm flat plate restrictor.
STL Super Touring Alternate Miata Hubs #30345cars addedaddedST 90-05 Mazda Miata allowed alternate front wheel hub Mazda Motorsports Development Part #0000-04-5HUB-S1.
STL Brake Component Relocation #29990suspension & brakessuspension & brakesST cars may now relocate ABS actuation hardware and wiring anywhere in the engine compartment.
STL Super Touring Wing Clarification #30111aeroaeroSTL rear wing trailing edge may be mounted no further rearward than the center of the rearmost part approved bodywork.
STL Transmission Options #30118otheraddedSTL alternate transmissions now allow OEM gear sets and input shaft modifications for fitment.
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.
STL Request for FWD and RWD Parity #29728weightfaster · weightSTL RWD strut-front cars lose 2.5% weight penalty, others lose 3% penalty for FWD parity.
STL Request for FWD and RWD Parity #30023inductionslower · inductionSTL Honda B16/B17/B18C1 restrictor reduced to 53mm, B18C variants and Mazda MZR to 52mm.
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.
STL Request clarification on wing measurement #29640aeroaeroST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.
2:39.695Daniel Meller · fastest of 19 · top 5 within 3.3s
2:47.444Steve Sargis · fastest of 15 · top 5 within 6.1s
123.1William Trainer
2:42.209Kyle Greenhill · fastest of 77 · top 5 within 0.5s
2:43.748Preston Pardus · fastest of 75 · top 5 within 1.0s
121.3Kyle Greenhill
-3.696squal +2.514s
97.8%qual 101.6%
2:31.420Danny Steyn · fastest of 33 · top 5 within 3.1s
2:32.115Joe Moser · fastest of 30 · top 5 within 1.5s
132.9Darin Treakle
-15.329squal -8.275s
90.8%qual 94.8%
34 rule changes (HP: 21, SM: 2, STL: 11)7 cars added · 7 engine · 2 weight · 1 induction · 1 suspension & brakes · 12 wording · 4 other · HP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches. · SM allows aftermarket radiators in original location with stock OEM cooling fan, and permits 1990-1997 cars to install upper radiator seal NA75-50-OK7A. · EP BMW Z3 2.5L cylinder head casting 1738400 permitted with iron block castings 1748933 or 1738566. · SM rear brake caliper may use single bracket under upper retaining bolt head to prevent pin failure. · STL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds. · STL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules. · 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. · GT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists. · EP BMW 2.8L, 328i E36/E46, and 325i E36 now require iron blocks only; 325i E46 aluminum block removed. · STL adds Mazda MX-5 Global Cup 16-18 at 2450 lbs minimum and 2019 at 2550 lbs minimum. · STL Mazda MX-5 Club 06-15 allowed header part number 0000-06-5407-NC. · STL Acura/Honda B18 and B18C engines: restrictor sizes swapped, B18C1 removed from allowed variants. · 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. · STL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants. · EP Caterham 7 America engine limited to IT prep with specific sections, comp ratio 10.0:1, valve lift .380 inch. · STU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs. · STL Mazda MZR restrictor reduced from 54 mm to 53 mm. · STL Mazda MZR restrictor reduces from 55 mm to 53 mm. · 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. · STL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL to notes. · 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. · 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.showhide
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.
SM Radiator E&O Clarifications #29294wordingwordingSM allows aftermarket radiators in original location with stock OEM cooling fan, and permits 1990-1997 cars to install upper radiator seal NA75-50-OK7A.
HP EP BMW Z3 Rule Clarification #28998wordingwordingEP BMW Z3 2.5L cylinder head casting 1738400 permitted with iron block castings 1748933 or 1738566.
SM Modifications to prevent failures of Rear Brake Caliper Pin #28953suspension & brakessuspension & brakesSM rear brake caliper may use single bracket under upper retaining bolt head to prevent pin failure.
STL Minimum Weight Determination #27695wordingwordingSTL and STU clarify weight adjustment calculation order: engine adjustments first, then chassis percentage additions, subtractions, and fixed pounds.
STL ST Gurney flap Wicker clarification #29012wordingwordingSTL STU rear wing Gurney flap terminology clarified from wicker to Gurney flap in mounting and chord rules.
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.
STL Request for Addition to GT3 Approved Turbo List #27576cars addedaddedGT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists.
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.
STL Request to add 2016-2019 GMX-5 Spec line #28604cars addedaddedSTL adds Mazda MX-5 Global Cup 16-18 at 2450 lbs minimum and 2019 at 2550 lbs minimum.
STL Request to update PN for MX-5 #28622cars addedaddedSTL Mazda MX-5 Club 06-15 allowed header part number 0000-06-5407-NC.
STL Correction - Clarification Honda/Acura B18B engine Letter # 26209 #28873wordingwordingSTL Acura/Honda B18 and B18C engines: restrictor sizes swapped, B18C1 removed from allowed variants.
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.
STL STL Honda B18 restrictor changes #28794enginefaster · engineSTL Honda B18 loses 53mm restrictor requirement; B18C1 added with 54mm restrictor, B18C1 removed from other variants.
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.
STL Change GM LNF 2.0 Allowance to LSJ Engine for Viable STL 2.0 #27884engineadded · engineSTU GM Ecotech LNF now permitted without turbo, with LE5 head and intake manifold, meeting STL specs.
STL Acura/Honda B18C engine chart. Reduce the current 54 mm flat plat #28663engineslower · engineSTL Mazda MZR restrictor reduced from 54 mm to 53 mm.
STL Mazda MZR engine chart. Reduce the current 55 mm flat plate to 53 #28664engineslower · engineSTL Mazda MZR restrictor reduces from 55 mm to 53 mm.
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.
STL Request to add wheel part numbers #28342cars addedaddedSTL Mazda Spec MX5 Challenge adds approved wheel part numbers 0000-04-5706-GM, 0000-04-5706-SL to notes.
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.
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.
2:14.822Steve Sargis · fastest of 29 · top 5 within 1.1s
2:15.062Ron Bartell · fastest of 28 · top 5 within 1.2s
124.9William Trainer
2:14.552Todd Buras · fastest of 60 · top 5 within 0.2s
2:16.459Elivan Goulart · fastest of 56 · top 5 within 0.4s
119.8Jim Drago
+1.397squal -0.270s
101.0%qual 99.8%
1:54.469Pete Frost · only car
1:57.688Pete Frost · only car
145.9Pete Frost
-17.374squal -20.353s
87.1%qual 84.9%
2:07.203Danny Steyn · fastest of 36 · top 5 within 1.8s
2:07.273Cliff Ira · fastest of 35 · top 5 within 1.4s
134.8Cliff Ira
-7.789squal -7.619s
94.2%qual 94.3%
25 rule changes (HP: 10, SM: 4, STL: 11)5 cars added · 3 engine · 2 aero · 2 weight · 1 induction · 8 wording · 4 other · STL adds Mazda Spec MX-5 Challenge, 2000cc displacement, 2500 lb minimum weight, with mandatory Roush, Penske, Eibach, and other specified components. · 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. · STU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required. · STL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate. · STL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld. · 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. · SM fuel pump and filter now permitted as Mazda or OEM equivalent part. · STL adds VW 1.8L R4 20VT 1781 cc, 1781 minimum weight, naturally aspirated only. · STL Mazda Renesis minimum weight reduced to 2700 lbs. · STL Mazda MX-5 Cup brake pad compound now open. · STL adds Acura/Honda B18C1 GSR with 1797cc displacement, 54mm flat plate restrictor required, porting outside 1" allowance prohibited. · STL Mazda 12 and 13B now permit port matching; porting ban removed. · SM allows factory Mazda ECU and injector harnesses (P/N 0000-10-020E-99, 0000-10-080D-99) on 1999–2000 model year cars, unmodified. · SM electrical rules reorganized and clarified; alternator now externally regulated only by OEM ECU or master kill switch; harness repair by splicing permitted. · SM tire tread protrusion language removed from GCR 9.1.7.C.5. · STL B17 now requires 54mm flat plate restrictor; B18C Type R variants move to 54mm restrictor, weight chart baseline. · STL Mazda Miata removes maximum displacement limit; minimum weight corrected to unspecified figure.showhide
STL Request to Classify Spec MX-5 Challenge in STL #27399cars addedaddedSTL adds Mazda Spec MX-5 Challenge, 2000cc displacement, 2500 lb minimum weight, with mandatory Roush, Penske, Eibach, and other specified components.
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.
STL Request clarification for manifold and throttle in STU #27004wordingwordingSTU allows alternate intake manifolds on case-by-case basis; stock throttle device and manifold otherwise required.
STL Request Restrictor Plate correction #26779enginefaster · engineSTL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate.
STL Request Ride Height Clarification #26597wordingwordingSTL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld.
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.
SM Request to allow aftermarket fuel filters. #26370otheraddedSM fuel pump and filter now permitted as Mazda or OEM equivalent part.
STL Request to reduce weight of RX8 with Renesis rotary #25781weight -100 lbsfaster · weightSTL Mazda Renesis minimum weight reduced to 2700 lbs.
STL Request for Open Brake Pads On Mazda MX-5 Cup NC #25821otheraddedSTL Mazda MX-5 Cup brake pad compound now open.
STL Request to clarify B18C1 GSR Honda B motor table #26209cars addedaddedSTL adds Acura/Honda B18C1 GSR with 1797cc displacement, 54mm flat plate restrictor required, porting outside 1" allowance prohibited.
STL Port Matching #26415enginefaster · engineSTL Mazda 12 and 13B now permit port matching; porting ban removed.
SM Request 99-00 replacement Wire harnesses #25602otheraddedSM allows factory Mazda ECU and injector harnesses (P/N 0000-10-020E-99, 0000-10-080D-99) on 1999–2000 model year cars, unmodified.
SM Organize and Clarify 9.1.7.C.1.o. #25913wordingwordingSM electrical rules reorganized and clarified; alternator now externally regulated only by OEM ECU or master kill switch; harness repair by splicing permitted.
SM Strike Tire Tread Language #26123wordingremovedSM tire tread protrusion language removed from GCR 9.1.7.C.5.
STL Request to equalize FPR Reduction on all B-Series Vtec Engines #24746enginefaster · engineSTL B17 now requires 54mm flat plate restrictor; B18C Type R variants move to 54mm restrictor, weight chart baseline.
STL Request E&O for Mazda Miata Spec Line #25955otherunclearSTL Mazda Miata removes maximum displacement limit; minimum weight corrected to unspecified figure.
Every event the class ran, at any track, oldest to newest on the chart and newest first in the table. Each point is the class's best lap as a share of HP's best on the same day: the weather, the track and its configuration cancel out, so one figure compares across tracks and years where lap times cannot. It still moves when the yardstick's own balance changes or its field thins, and an event the yardstick did not run has no point. A best from fewer than three cars is greyed. The rule changes that took effect between two events are folded between their rows.