Lap times across years say as much about the weather as the class. % of STL is each class's best lap as a share of STL'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:STL 1:35.439 John Schmitt, Runoffs 2016 qualifying · FE2 1:35.040 Flinn Lazier, Runoffs 2018 qualifying · FP 1:35.938 John Walker, Runoffs 2016 qualifying · FV 1:37.942 Alex Scaler, Runoffs 2016 qualifying
STLFE2FPFVsolid race · dashed qualifying · slower is lower
STLFE2FPFVsolid race · dashed qualifying · each class's best lap as a share of STL's at the same event (the reference class, changeable above); 100% is level, less is quicker, so up the chart is quicker
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%)
2:12.326Franklin Futrelle · fastest of 8 · top 5 within 1.9s-0.149s (-0.11%)
2:11.881Franklin Futrelle · fastest of 8 · top 5 within 1.6s-1.458s (-1.09%)
143.5Steve Whitston-5.5 mph (-3.7%)
-18.776squal -18.211s
87.5%qual 87.9%
2:33.275Stephen Simonds · fastest of 26 · top 5 within 1.0s+0.880s (+0.58%)
2:33.240David Strittmatter · fastest of 25 · top 5 within 1.7s-1.031s (-0.67%)
132.4David Strittmatter±0.0 mph (±0.0%)
+2.583squal +2.738s
101.7%qual 101.8%
2:46.536Zachary Whitston · fastest of 37 · top 5 within 1.7s+2.435s (+1.48%)
2:45.272Brian Farnham · fastest of 34 · top 5 within 1.3s-1.464s (-0.88%)
117.4Rick Shields+0.2 mph (+0.1%)
+14.615squal +15.999s
109.7%qual 110.6%
39 rule changes (STL: 4, FE2: 1, FP: 34)9 cars added · 8 weight · 5 induction · 4 engine · 1 aero · 9 wording · 3 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. · 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). · 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. · FP Volkswagen Jetta 82-84 carburation option 2 comma removed; all five models' carb specs clarified or confirmed. · FP Spec Line Volkswagen Rabbit and Scirocco 1789cc base weight corrected to 1803 lbs. · 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. · STL adds Mazda BP 1.6, 1600cc, minimum weight 2160 lbs. · FP Fiat X-1/9 1300 and 1500 intake and exhaust valve sizes corrected to 36.3/(1.43) and 31.2-33.3/(1.23-1.31). · FP Fiat X-1/9 & Bertone dual carburetors choke size increases from 28mm to 30mm on intake runner manifold. · FP adds Toyota 5E 1497cc DOHC engine, 1900 lbs, 23mm restrictor, SIR fuel induction. · FP class adds Toyota 4E DOHC 1331 cc engine, 1900 lbs minimum weight, unrestricted fuel induction. · FP Fiat X1/9 fuel injection carburetors simplified to one 36 or 40 DCNF option; exhaust valve enlarged to 33.0/1.30. · STL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs. · 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. · FP Lancia Scorpion minimum weight cut to 1950 lbs from 2030 lbs. · FP VW Rabbit Convertible no longer required to remove factory roll bar. · FP Acura Integra and Honda Civic models gain 50–79 lbs minimum weight; Mazda Miata and Mercury Capri compression ratio to 11.0:1 and valve lift to .425". · FP Honda D15, D16, B16A, B18 engines gain 105–120 lbs minimum weight across seven configurations. · 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 Scirocco 83–88 classified Prep Level 1: 1733–1803 lbs, 1715–1780 cc, iron block, aluminium head, carburetted or fuel injected. · 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. · FP Volkswagen Scirocco: remove two weight tiers at 1733 and 1803 lbs, two engine options, and 13-inch wheel option; allow 15-inch wheels. · FE and FE2 Enterprise bubble tail part WM138014 now allowed; FE2 must use this configuration only. · 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
FP Mini Cooper Compression Ratio #40517enginefaster · engineHP Mini Cooper 02-06 compression ratio increases from 10.6 to 11.0:1.
FP 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.
FP 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.
FP HP Honda Civic (92-95) #40464weight -70 lbsfaster · weightHP Honda Civic DX/LX 92–95 wheels 13x7 to 15x7, weight 2420 to 2350 lbs.
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).
STL Calculating Weight #40224wordingwordingSTL, STU weight calculation procedure clarified: positive percentages added first, negative subtracted second, then fixed weights applied.
FP Miata track width - errors and omissions #39976aerofaster · aeroEP Mazda MX-5 94-97 front track widens to 1516 mm, rear to 1534 mm.
FP GCR Spec Line Correction #39977wordingwordingFP Volkswagen Jetta 82-84 carburation option 2 comma removed; all five models' carb specs clarified or confirmed.
FP CGR Spec Line Weight Correction #39978wordingwordingFP Spec Line Volkswagen Rabbit and Scirocco 1789cc base weight corrected to 1803 lbs.
FP Triumph GT6 Spec Change. #40098inductionfaster · inductionEP Triumph GT6 auto-type drivetrain choke size increases from 44mm to 45mm.
FP Request to Classify BMW E21 320i #40110cars addedaddedBMW E21 320i/is (80–83) newly classified in HP Spec Lines effective 2026-05-01.
FP 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.
FP Correct Valve Sizes on FP Fiat x19 1300 and 1500 #39850otherotherFP Fiat X-1/9 1300 and 1500 intake and exhaust valve sizes corrected to 36.3/(1.43) and 31.2-33.3/(1.23-1.31).
FP Dual Carburetor Adjustments #39851inductionfaster · inductionFP Fiat X-1/9 & Bertone dual carburetors choke size increases from 28mm to 30mm on intake runner manifold.
FP Request Toyota 5E Series Engines #38208otheraddedFP adds Toyota 5E 1497cc DOHC engine, 1900 lbs, 23mm restrictor, SIR fuel induction.
FP Request for Toyota 4E Series Engines #38209cars addedaddedFP class adds Toyota 4E DOHC 1331 cc engine, 1900 lbs minimum weight, unrestricted fuel induction.
FP Dual Carbs for the Fiat X1/9 #39593enginefaster · engineFP Fiat X1/9 fuel injection carburetors simplified to one 36 or 40 DCNF option; exhaust valve enlarged to 33.0/1.30.
STL Weight adjustment for STL #39579weightslower · weightSTL minimum weights increase across all engine sizes, 1300cc to 1850cc up to 195–250 lbs.
FP TR2 Notes E&O #39180wordingwordingEP Triumph TR2–TR4A may use 5-speed gearbox without overdrive; Weber carburetors and weight reference deleted.
FP 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.
FP Competition Adjustment Request #39259weight -80 lbsfaster · weightFP Lancia Scorpion minimum weight cut to 1950 lbs from 2030 lbs.
FP Factory Roll Bar Removal on VW Convertible #39268wordingwordingFP VW Rabbit Convertible no longer required to remove factory roll bar.
FP FP Parity Request #39325weight +50 lbsslower · weightFP Acura Integra and Honda Civic models gain 50–79 lbs minimum weight; Mazda Miata and Mercury Capri compression ratio to 11.0:1 and valve lift to .425".
FP Adjust former-GTL Honda's with B/D-Series Engines #39374weightslower · weightFP Honda D15, D16, B16A, B18 engines gain 105–120 lbs minimum weight across seven configurations.
FP Please Lower Weight of 280Z #38871weight -160 lbsfaster · weightEP Nissan 280Z minimum weight lowered to 2400 lbs, 2460 lbs with *, 2520 lbs with **.
FP 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.
FP HP Mini DOHC 1.6 #38996engineslower · engineHP Mini DOHC 1.6 valve lift limit drops to .390" from .450".
FP 83-88 FP Scirocco Spec Line Creation #38997cars addedaddedFP Scirocco 83–88 classified Prep Level 1: 1733–1803 lbs, 1715–1780 cc, iron block, aluminium head, carburetted or fuel injected.
FP Add to Rabbit description #39019wordingwordingFP and HP Volkswagen Rabbit descriptions updated to clarify Cabriolet body style inclusion.
FP 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.
FP 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.
FP Correct Existing VW Scirocco Spec Line #39140cars addedremoved · cars addedFP Volkswagen Scirocco: remove two weight tiers at 1733 and 1803 lbs, two engine options, and 13-inch wheel option; allow 15-inch wheels.
FE2 FE & FE2 Bubble Tail #38978cars addedaddedFE and FE2 Enterprise bubble tail part WM138014 now allowed; FE2 must use this configuration only.
FP HP Plymouth Arrow spec omission #38995cars addedaddedHP Plymouth Arrow gains 4 or 5 speed transmission option specification.
FP Add Wheel Diameter to Appendix G #39008wordingwordingAppendix G.2.3 clarifies rim width and diameter are absolute maximums; wording corrected from 'is' to 'are'.
FP Add TB ID tolerance to general Prod rules #39009wordingaddedEP, FP, HP throttle body inside dimensions and butterfly now allow +/-.25mm tolerance from stock.
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%)
2:12.475Franklin Futrelle · fastest of 11 · top 5 within 1.4s+0.969s (+0.74%)
2:13.339Franklin Futrelle · fastest of 10 · top 5 within 0.6s+0.591s (+0.45%)
149.0Steve Whitston+3.7 mph (+2.6%)
-18.788squal -19.590s
87.6%qual 87.1%
2:32.395David Strittmatter · fastest of 20 · top 5 within 2.9s+0.068s (+0.04%)
2:34.271Chris Bovis · fastest of 19 · top 5 within 1.8s+1.025s (+0.67%)
132.4David Strittmatter-1.1 mph (-0.8%)
+2.144squal +0.330s
101.4%qual 100.2%
2:44.101Andrew Abbott · fastest of 34 · top 5 within 1.3s+1.458s (+0.90%)
2:46.736Zachary Whitston · fastest of 29 · top 5 within 0.6s+1.902s (+1.15%)
117.2Zachary Whitston+0.7 mph (+0.6%)
+14.609squal +12.036s
109.6%qual 107.9%
21 rule changes (STL: 3, FE2: 1, FP: 17)7 weight · 5 induction · 4 cars added · 1 engine · 3 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. · STL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1; mandatory component spec list removed, alternative tires only allowed. · FE2 allows pre-approved driver safety and comfort seat and control modifications for drivers with disabilities, per logbook. · 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. · FP Acura Integra and Honda Civic models restricted from 55mm to 51mm intake; Del Sol VTEC weight raised to 2290, 2347, 2405 lbs. · 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. · FP Volkswagen Jetta Mark IV 4dr FWD added to GTL-FP Cars classification with 98.2 in wheelbase. · FP adds optional induction chokes as alternative to SIR, same size as listed restrictor. · 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. · FP Sprite and Midget 1275cc and 1500cc bore, stroke, displacement, and valve specifications corrected to factory dimensions. · F Production now permits GT-Lite cars meeting Appendix N specs to compete, governed by Appendix N not PCS 9.1.5. · 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.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.
FP BMW Z4 update #38490inductionslower · inductionEP BMW Z4 03-05 gains 52mm flat plate intake restrictor.
FP 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.
FP 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.
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.
FE2 Driver Safety & Comfort #37965otheraddedFE2 allows pre-approved driver safety and comfort seat and control modifications for drivers with disabilities, per logbook.
FP Request for Classification of Chevrolet Spark #37755cars addedaddedChevrolet Spark 16-22 classified in HP Pre at 1850 lbs base, 1896 lbs modified, 1943 lbs.
FP 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.
FP 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.
FP FP Class Adjustments #37458inductionslower · inductionFP Acura Integra and Honda Civic models restricted from 55mm to 51mm intake; Del Sol VTEC weight raised to 2290, 2347, 2405 lbs.
FP Interpretation of Production Rules on Mirrors #37235wordingaddedEP, FP, HP may use any interior or exterior mirror meeting rule 9.3.36.
FP Weight Reduction for Honda S2000 #37466weightfaster · weightEP Honda S2000 1997cc minimum weight drops 75 lbs to 2375; 2157cc drops 60 lbs to 2450.
FP Errors & Omissions #37648cars addedaddedFP Volkswagen Jetta Mark IV 4dr FWD added to GTL-FP Cars classification with 98.2 in wheelbase.
FP GTL/FP consolidation 2025 Rules #37659inductionadded · inductionFP adds optional induction chokes as alternative to SIR, same size as listed restrictor.
FP 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.
FP 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.
FP Fix Error in Spridget Spec Line #37437wordingwordingFP Sprite and Midget 1275cc and 1500cc bore, stroke, displacement, and valve specifications corrected to factory dimensions.
FP Create ruleset that allows GTL cars to run in FP #37485cars addedaddedF Production now permits GT-Lite cars meeting Appendix N specs to compete, governed by Appendix N not PCS 9.1.5.
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.
FP 1275 HP Spridget Level 2 Only #36518enginefaster · engineHP 1275 Spridget compression ratio raised to 12.0:1; 1098cc also raised to 12.0:1.
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%)
2:11.506Porter Aiken · fastest of 18 · top 5 within 0.5s-1.300s (-0.98%)
2:12.748Porter Aiken · fastest of 17 · top 5 within 2.0s-0.523s (-0.39%)
145.3Porter Aiken+1.9 mph (+1.3%)
-17.497squal -18.557s
88.4%qual 87.6%
2:32.327Cliff Ira · fastest of 26 · top 5 within 2.1s+0.913s (+0.60%)
2:33.246Kevin Ruck · fastest of 24 · top 5 within 1.4s-0.787s (-0.51%)
133.5David Strittmatter+0.3 mph (+0.2%)
+3.001squal +2.264s
102.0%qual 101.5%
2:42.643Andrew Whitston · fastest of 27 · top 5 within 2.3s-1.351s (-0.82%)
2:44.834Andrew Abbott · fastest of 27 · top 5 within 0.9s-0.982s (-0.59%)
116.5Brian Farnham-0.7 mph (-0.6%)
+14.589squal +12.580s
109.7%qual 108.4%
27 rule changes (STL: 4, FP: 21, FV: 2)10 weight · 4 cars added · 3 engine · 2 induction · 1 aero · 1 removed · 6 wording · FP Honda CRX/CRX Si 84-87 block material changes from iron to aluminium. · FV ferrous rotor must not be cross-drilled; pad cleaning grooves limit unchanged at three per side. · 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. · FP Honda CRX 84-87 plastic front header nose panel, rocker skirts, door caps can now be replica alternate material stock appearance. · FP Acura Integra 90-01 and Honda Civic Del Sol VTEC, Civic Si 99-00 require 55mm flat plate intake restrictor. · HP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve 83-88, Scirocco 1588. · FP Mazda Protégé ES (01-03) renamed to Mazda Protégé ES/5 (01-03). · 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. · FP Honda throttle body inside diameters corrected across seven models: Civic 1.5 to 42", Civic Si to 55", CRX 1.5 to 42", CRX 84-87 to 33/42", CRX Si 88-91 to 55". · 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. · 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. · STL 79-85 RX7 12A now allows auto-type 2 bbl carburetor with 42mm choke on dual-y manifold, not just stock Nikki. · 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. · EP Triumph GT6 minimum weight drops to 1800 lbs. · FV front wheel bearings wording clarified; specification unchanged.showhide
FP Errors/emissions Honda Civic/CRX #36700enginefaster · engineFP Honda CRX/CRX Si 84-87 block material changes from iron to aluminium.
FV Disc Brakes #36822wordingwordingFV ferrous rotor must not be cross-drilled; pad cleaning grooves limit unchanged at three per side.
FP 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.).
FP 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.
FP 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.
FP 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.
FP Request to Replace CRX Plastic Panels #35876cars addedaddedFP Honda CRX 84-87 plastic front header nose panel, rocker skirts, door caps can now be replica alternate material stock appearance.
FP FP data and parity #35896inductionadded · inductionFP Acura Integra 90-01 and Honda Civic Del Sol VTEC, Civic Si 99-00 require 55mm flat plate intake restrictor.
FP Update FP Protege (01-03) Model Info #35715wordingwordingFP Mazda Protégé ES (01-03) renamed to Mazda Protégé ES/5 (01-03).
FP 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.
FP 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.
FP Corrections to Honda Spec Lines in FP #35250wordingunclearFP Honda throttle body inside diameters corrected across seven models: Civic 1.5 to 42", Civic Si to 55", CRX 1.5 to 42", CRX 84-87 to 33/42", CRX Si 88-91 to 55".
FP 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.
FP Honda S2000 throttle body #35272inductionfaster · inductionEP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm.
FP Correction within Triumph TR8 Spec Line #35315wordingwordingEP Triumph TR8 dry sump allowance moved from Carburetor line to Notes.
FP 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.
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.
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%)
1:50.665Charles Russell Turner · fastest of 26 · top 5 within 2.3s-0.188s (-0.17%)
1:51.098Franklin Futrelle · fastest of 19 · top 5 within 1.4s-20.947s (-15.86%)
141.3Franklin Futrelle-0.6 mph (-0.4%)
-15.584squal -15.114s
87.7%qual 88.0%
2:08.248Cliff Ira · fastest of 21 · top 5 within 1.0s+2.031s (+1.61%)
2:07.787Cliff Ira · fastest of 20 · top 5 within 0.8s-9.854s (-7.16%)
133.7Cliff Ira+1.1 mph (+0.9%)
+1.105squal +2.469s
100.9%qual 102.0%
2:15.639Andrew Whitston · fastest of 27 · top 5 within 1.4s+0.523s (+0.39%)
2:16.611Andrew Abbott · fastest of 23 · top 5 within 1.6s-1.482s (-1.07%)
115.6Brian Farnham-0.2 mph (-0.2%)
+9.929squal +9.860s
107.8%qual 107.8%
8 rule changes (STL: 2, FP: 6)5 cars added · 3 wording · 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. · Toyota Celica 78-80 classified FP Prep level 2, 2100–2205 lbs, 2190 cc SOHC four-cylinder, stock carburetion, 11.0:1 compression limit, .450" valve lift limit. · FP Mazda Protégé ES (01-03) renamed to Protégé ES/5 (01-03) to include P5 model variant. · EP, FP, HP port matching limited to 1 inch depth from mating surface. · 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
FP 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.
FP ITC to FP? #34286cars addedremoved · cars addedHP Volkswagen Rabbit Cabriolet 1780 removed; Rabbit 1588 and 1715 reclassified with year and body-type clarifications.
FP 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.
FP Request to Add Mazda Protege P5 to FP #33664cars addedaddedFP Mazda Protégé ES (01-03) renamed to Protégé ES/5 (01-03) to include P5 model variant.
FP Review Limited Prep Port Matching Rules #33600wordingwordingEP, FP, HP port matching limited to 1 inch depth from mating surface.
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.
2:05.474Danny 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%)
1:50.853Charles Russell Turner · fastest of 25 · top 5 within 1.1s-0.209s (-0.19%)
2:12.045Jason Conzo · fastest of 22 · top 5 within 1.8s+19.891s (+17.74%)
141.9Eric Cruz-0.6 mph (-0.5%)
+4.213squal -14.621s
103.3%qual 88.3%
2:06.217Eric Prill · fastest of 18 · top 5 within 1.5s-1.219s (-0.96%)
2:17.641Mason Workman · fastest of 15 · top 5 within 3.2s+9.565s (+7.47%)
132.5Cliff Ira+1.2 mph (+0.9%)
+9.809squal +0.743s
107.7%qual 100.6%
2:15.116Brian Farnham · fastest of 29 · top 5 within 1.1s-0.596s (-0.44%)
2:18.093Andrew Whitston · fastest of 28 · top 5 within 1.2s-0.196s (-0.14%)
115.8Jonathan Weisheit+1.1 mph (+0.9%)
+10.261squal +9.642s
108.0%qual 107.7%
34 rule changes (STL: 5, FP: 25, FV: 4)8 engine · 4 cars added · 4 weight · 3 induction · 2 tyres & wheels · 1 aero · 1 suspension & brakes · 10 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. · FP Lotus Super Seven 91.7 ci minimum weight increases 50 lbs, to 1580. · 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. · Mazda Protégé ES 99-00 classified FP, 2150–2258 lbs, 1839 cc DOHC, fuel injection, 11.0:1 compression, 0.450" valve lift. · 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. · FP BMW 325e/es displacement corrected to 2693 cc. · 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. · FP VW Golf III/Jetta III 93-98 intake valve shrinks to 39.5 mm (1.56 in), exhaust to 32.9 mm (1.30 in). · FV connecting rod options expanded to include BrianCrower part BC6417 and Newland Group part 4M113077. · FV connecting rods minimum weight 425.0 grams, center-to-center length 130 +0.10/-0.25 mm; Crower, BrianCrower, Newland Group parts allowed if meeting specs. · 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. · 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. · EP BMW Z3 2.5L adds alternate throttle body option with Turner adapter and permits head casting 1738400. · FP Honda Civic Del Sol VTEC compression ratio limited to 11.0:1, valve lift to .425", removes dry sump and internal engine prep allowances. · FP Honda Prelude 84-87 and Mazda GLC/323 86-88 valve lift measurement method clarified, Level 1 parts list removed. · FV Crower connecting rods SP93280B and BC6417 allowed as direct replacement, must meet OEM minimum weight. · 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. · FV allows Crower SP93280B and Brian Crower Racing Rods connecting rods as direct replacements, matching OEM minimum weight. · 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
FP 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.
FP 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.
FP Request for Corrado Stroke & Displacement Correction #32985wordingwordingEP VW Corrado 92-95 stroke corrected to 90.3 mm and displacement to 2792 cc.
FP 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.
FP Weight Adjustment of Lotus 7 #32213weight +50 lbsslower · weightFP Lotus Super Seven 91.7 ci minimum weight increases 50 lbs, to 1580.
FP 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.
FP 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.
FP Inconsistency in Body Work Descriptions #32396aeroadded · aeroEP, FP, HP open cars now allow carbon fiber hardtops if they retain OEM exterior profiles.
FP Request to classify the 1999-2000 Mazda Protege in FP #32398cars addedaddedMazda Protégé ES 99-00 classified FP, 2150–2258 lbs, 1839 cc DOHC, fuel injection, 11.0:1 compression, 0.450" valve lift.
FP Mazda RX8 with 13b Rotary #32170engineengineEP Mazda RX-8 13B carburetor option replaced with fuel-injected throttle body or stock fuel injection.
FP 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.
FP Correct FP BMW 325e/es Displacement #32394wordingunclearFP BMW 325e/es displacement corrected to 2693 cc.
FP EP Adjustments #31858inductionslower · inductionEP BMW Z3 2.5L intake restrictor reduced from 59mm to 58mm flat plate.
FP 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.
FP Improved Touring Tires #32064tyres & wheelsadded · tyres & wheelsEP, FP, HP Improved Touring cars may use any DOT-approved tyre as defined by 9.3.45.
FP VW Golf Jetta 2.0L intake and exhaust size correction. #32173engineslower · engineFP VW Golf III/Jetta III 93-98 intake valve shrinks to 39.5 mm (1.56 in), exhaust to 32.9 mm (1.30 in).
FV Connecting Rod Update Request for 9.1.1.C Formula Vee (FV) 5.C.6 #32160engineadded · engineFV connecting rod options expanded to include BrianCrower part BC6417 and Newland Group part 4M113077.
FV E&O clarification of connecting rod center-to-center length #32183wordingwordingFV connecting rods minimum weight 425.0 grams, center-to-center length 130 +0.10/-0.25 mm; Crower, BrianCrower, Newland Group parts allowed if meeting specs.
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.
FP Throttle Body and Idle Air #31800wordingwordingEP, FP, HP: stock/original idle control devices permitted unmodified or completely removed with openings blocked.
FP Porsche 968 Engine Questions #31478engineengineEP Porsche 968 intake valve size changes to 39.0 mm, 1.54 mm seat width.
FP 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.
FP 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.
FP FP Del Sol VTEC #31859engineslower · engineFP Honda Civic Del Sol VTEC compression ratio limited to 11.0:1, valve lift to .425", removes dry sump and internal engine prep allowances.
FP Standardize Level 2 Classifications in FP #31868wordingwordingFP Honda Prelude 84-87 and Mazda GLC/323 86-88 valve lift measurement method clarified, Level 1 parts list removed.
FV Update direct replacement connecting rod information #31843wordingwordingFV Crower connecting rods SP93280B and BC6417 allowed as direct replacement, must meet OEM minimum weight.
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.
FP 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.
FV Formula V Connecting Rod Replacement #31448engineadded · engineFV allows Crower SP93280B and Brian Crower Racing Rods connecting rods as direct replacements, matching OEM minimum weight.
FP 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.
1:51.665Danny 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
1:36.395Max Grau · fastest of 28 · top 5 within 0.7s
1:36.655Max Grau · fastest of 28 · top 5 within 0.7s
146.2Gray Fowler
-26.056squal -15.270s
78.8%qual 86.3%
1:51.082Craig Chima · fastest of 39 · top 5 within 1.2s-1.009s (-0.90%)
1:59.933Cliff Ira · fastest of 33 · top 5 within 5.4s+6.926s (+6.13%)
131.8Cliff Ira
-2.778squal -0.583s
97.7%qual 99.5%
1:57.479Andrew Whitston · fastest of 48 · top 5 within 0.8s+1.720s (+1.49%)
1:57.234Alex Scaler · fastest of 47 · top 5 within 1.0s+1.311s (+1.13%)
124.0Mark Edwards
-5.477squal +5.814s
95.5%qual 105.2%
36 rule changes (STL: 15, FP: 21)11 cars added · 8 weight · 4 engine · 2 aero · 2 induction · 1 suspension & brakes · 4 wording · 4 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. · FP Fiat X1/9 1300 loses 50 lbs to 1665; X1/9 Bertone loses 50 lbs to 1765. · Daimler SP 250 classified in EP with 2165 lbs minimum weight, 2548 cc eight-cylinder OHV engine, SU or Stromberg carburetors. · Porsche 924 Level 1 Prep moved from EP to FP classification. · EP, FP, HP clarify percentage weight penalties sum before applying to base weight, round to nearest pound. · STL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs. · 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. · Mazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC four-cylinder, fuel injected with 55mm throttle body, comp ratio 12.0:1 max, valve lift 0.500" max. · FP Volkswagen Golf and Jetta III and IV intake valves increase to 40.0 mm, exhaust to 33.0 mm. · 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. · FP Volkswagen Golf 1.8, Jetta, Rabbit and Scirocco gain 50 lb weight breaks, minimum weights to 1900–1733 lbs. · 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. · Honda Civic EX 96-00 classified FP2 at 1975 lbs, SOHC 1590cc, fuel injection, 56mm throttle body, comp ratio 12.0:1 max, valve lift 0.450" max. · FP adds FAJS to permitted Weber-type and auto-type carburetor substitutes in two sections. · 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.
FP 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.
FP 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.
FP Lotus/Caterham 7 America Request #30392wordingwordingEP Lotus/Caterham 7 America fuel injection permitted; IT preparation engine limitation removed.
FP 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.
FP 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.
FP Fiat x1/9 Competition Adjustments #30711weight -50 lbsfaster · weightFP Fiat X1/9 1300 loses 50 lbs to 1665; X1/9 Bertone loses 50 lbs to 1765.
FP 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.
FP Move Porsche 924 in Level 1 Prep From EP to FP #30135cars addedaddedPorsche 924 Level 1 Prep moved from EP to FP classification.
FP Clarify Application of Percentage Based Weight Penalties #30669wordingwordingEP, FP, HP clarify percentage weight penalties sum before applying to base weight, round to nearest pound.
STL VW Engine Request #30625engineadded · engineSTL Volkswagen 2.0L TFSI 1984 cc engine permitted without turbocharger, meeting all other STL specs.
FP 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.
FP 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.
FP Please Classify Mazda3 in FP #30165cars addedaddedMazda 3 S 04-08 classified in EP at 2350 lbs minimum, 2.26L DOHC four-cylinder, fuel injected with 55mm throttle body, comp ratio 12.0:1 max, valve lift 0.500" max.
FP Golf MkIII Valve Size Request #30268enginefaster · engineFP Volkswagen Golf and Jetta III and IV intake valves increase to 40.0 mm, exhaust to 33.0 mm.
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.
FP 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.
FP Request VW weight break #29963weight -50 lbsfaster · weightFP Volkswagen Golf 1.8, Jetta, Rabbit and Scirocco gain 50 lb weight breaks, minimum weights to 1900–1733 lbs.
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.
FP 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.
FP 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.
FP EP TR8 Adjustment #29512weight -100 lbsfaster · weightEP Triumph TR8 78-81 minimum weight drops to 2500 lbs.
FP Request to Classify 1996-2000 Honda Civic EX #29515cars addedaddedHonda Civic EX 96-00 classified FP2 at 1975 lbs, SOHC 1590cc, fuel injection, 56mm throttle body, comp ratio 12.0:1 max, valve lift 0.450" max.
FP FAJS Carburetor #29576cars addedaddedFP adds FAJS to permitted Weber-type and auto-type carburetor substitutes in two sections.
STL Request clarification on wing measurement #29640aeroaeroST aero devices and reference areas must include end plates, exclude fasteners under 1/2" protrusion.
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
2:12.806Scott Rettich · fastest of 25 · top 5 within 0.6s
2:13.271Owen McAllister · fastest of 23 · top 5 within 0.7s
143.4Owen McAllister
-18.844squal -18.614s
87.6%qual 87.7%
2:31.414Ethan Shippert · fastest of 23 · top 5 within 2.2s
2:34.033Kevin Ruck · fastest of 21 · top 5 within 2.3s
133.2Sam Henry
+1.918squal -0.006s
101.3%qual 100.0%
2:43.994Hunter Phelps-Barron · fastest of 28 · top 5 within 0.6s
2:45.816Alex Scaler · fastest of 24 · top 5 within 1.5s
117.1Hunter Phelps-Barron
+13.701squal +12.574s
109.0%qual 108.3%
38 rule changes (STL: 11, FE2: 2, FP: 19, FV: 6)11 cars added · 6 engine · 5 tyres & wheels · 2 weight · 1 induction · 11 wording · 2 other · HP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches. · FE2 oil cooler rule clarified: Setrab 50-625-7612 or any cooler with max core 13 inches wide by 6.5 inches high allowed. · EP BMW Z3 2.5L cylinder head casting 1738400 permitted with iron block castings 1748933 or 1738566. · 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. · FP Mazda 626 84-87 carburetor spec clarified to two auto-type sidedraft 32mm choke or fuel injection. · FV now permits 4 bolt wheels in addition to existing specifications. · FV now allows 4-bolt pattern wheels in addition to existing specifications. · 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. · FP Volkswagen Scirocco E&O adds four engine variants with weights 1520–1853 lbs and displacements 1471–1780 cc. · 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. · 1989-90 Nissan 240-SX SOHC added to FP Pre L2 at 2400–2520 lbs, 2389 cc, fuel injection, 11.0:1 compression, .450" valve lift limit. · 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. · FP Volkswagen Jetta, Rabbit, Scirocco reclassified with weights 1520–1853 lbs, intake valves 40.0 mm, exhaust 33.0 mm, throttle 35/52 mm. · HP Datsun 510 allows 40 DCOE carburetor option alongside existing 40 DCNF and 36mm DCNVH; auto side drafts moved to penalty structure. · Porsche 914-4 2.0L classified in FP Prep 2 at 2030–2132 lbs with 1968cc OHV engine, Solex/Weber/Dellorto carbs or fuel injection, 11.0:1 compression limit, .450" valve lift limit. · FP Ford Fiesta 78-80 minimum weight reduced 130 lbs, to 1660. · FV rain tyre changes to Hoosier #44266 22.5 x 5.0 x 15 WET or W3. · 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. · Mazda Miata models EP and FP throttle body specified 55mm, brake rotor thickness figures removed. · FP Mazda Protégé ES 2001–2003 newly classified at 2350–2468 lbs with 1991 cc DOHC four-cylinder, fuel injection, 11.0:1 compression, .450 in. valve lift limit. · FV allows non-spec Hoosier tyres at Regional races only; Majors, Super Tour, and Runoffs require spec tyres from 1/1/2020. · Formula Vee now allows 22.5 x 5.5 x 15 rear tires on front axle; rain tire mandated as Hoosier #44266 22.5 x 5.0 x 15 from 1/1/2020. · FE minimum weight rises to 1270 lbs; FE2 minimum weight rises to 1270 lbs; new spring options added; tire warmers prohibited. · 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. · FV wheels may now be 15-inch 4.5J steel VW with same 5-bolt pattern as standard 4J, within track limits.showhide
FP 84-87 Toyota Corolla HP Wheel Diameter Allowance Proposal E&O #29458otherfasterHP 84-87 Toyota Corolla wheel diameter increases from 13 to 15 inches.
FE2 FE/FE2 Oil Cooler #29293wordingwordingFE2 oil cooler rule clarified: Setrab 50-625-7612 or any cooler with max core 13 inches wide by 6.5 inches high allowed.
FP EP BMW Z3 Rule Clarification #28998wordingwordingEP BMW Z3 2.5L cylinder head casting 1738400 permitted with iron block castings 1748933 or 1738566.
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.
FP 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.
FP Request to change to Carburetor Spec Line 84-87 Mazda 626 #28926wordingwordingFP Mazda 626 84-87 carburetor spec clarified to two auto-type sidedraft 32mm choke or fuel injection.
FV Support for Recommended Item - 4 bolt wheels in FV #29084cars addedaddedFV now permits 4 bolt wheels in addition to existing specifications.
FV Support for 4-bolt pattern wheels #28955 #29118tyres & wheelsadded · tyres & wheelsFV now allows 4-bolt pattern wheels in addition to existing specifications.
STL Request for Addition to GT3 Approved Turbo List #27576cars addedaddedGT3 and STU add Borg-Warner EFR6258 turbocharger to approved turbo lists.
FP 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.
FP Correct Scirocco Spec line E&O #28892cars addedaddedFP Volkswagen Scirocco E&O adds four engine variants with weights 1520–1853 lbs and displacements 1471–1780 cc.
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.
FP 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.
FP 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.
FP Request to classify SOHC 1989-90 240SX in F prod L2 #28553cars addedadded1989-90 Nissan 240-SX SOHC added to FP Pre L2 at 2400–2520 lbs, 2389 cc, fuel injection, 11.0:1 compression, .450" valve lift limit.
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.
FP VW Weight and Valve Size Request #27886wordingwordingFP Volkswagen Jetta, Rabbit, Scirocco reclassified with weights 1520–1853 lbs, intake valves 40.0 mm, exhaust 33.0 mm, throttle 35/52 mm.
FP 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.
FP Request to classify Porsche 914 2L in LPrep FProd #28231cars addedaddedPorsche 914-4 2.0L classified in FP Prep 2 at 2030–2132 lbs with 1968cc OHV engine, Solex/Weber/Dellorto carbs or fuel injection, 11.0:1 compression limit, .450" valve lift limit.
FP Request Ford Fiesta Weight Adjustment #28336weightfaster · weightFP Ford Fiesta 78-80 minimum weight reduced 130 lbs, to 1660.
FV Update rain tire designation #28444tyres & wheelstyres & wheelsFV rain tyre changes to Hoosier #44266 22.5 x 5.0 x 15 WET or W3.
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.
FP Request for Help for Datsun 1200 #27934inductionfaster · inductionHP Datsun 1200 carburetor option changes from 26mm to 30mm choke(s) in 40 DCN, DCNF, IDF.
FP Request to List Mazda Miata Throttle Body Size #27907wordingwordingMazda Miata models EP and FP throttle body specified 55mm, brake rotor thickness figures removed.
FP Request to Classify 2001-2003 Mazda Protege ES in FP #27922cars addedaddedFP Mazda Protégé ES 2001–2003 newly classified at 2350–2468 lbs with 1991 cc DOHC four-cylinder, fuel injection, 11.0:1 compression, .450 in. valve lift limit.
FV FV Allow non-spec tire in Regional competition #26284tyres & wheelsadded · tyres & wheelsFV allows non-spec Hoosier tyres at Regional races only; Majors, Super Tour, and Runoffs require spec tyres from 1/1/2020.
FV Request to Allow Rear Tires on the Front of Formula Vee #26537tyres & wheelsadded · tyres & wheelsFormula Vee now allows 22.5 x 5.5 x 15 rear tires on front axle; rain tire mandated as Hoosier #44266 22.5 x 5.0 x 15 from 1/1/2020.
FE2 FE / FE2 Update Rules #27624weightslower · weightFE minimum weight rises to 1270 lbs; FE2 minimum weight rises to 1270 lbs; new spring options added; tire warmers prohibited.
FP 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.
FP Re-organize Prep2 Cylinder Head Rules for Clarity & Consistency #27661wordingwordingEP, FP, HP cylinder head rules reorganized for clarity; no performance change.
FV Clarification on Wheel Bolt Pattern #27603tyres & wheelsadded · tyres & wheelsFV wheels may now be 15-inch 4.5J steel VW with same 5-bolt pattern as standard 4J, within track limits.
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
1:51.062Liam Snyder · fastest of 20 · top 5 within 1.3s
1:52.154Liam Snyder · fastest of 19 · top 5 within 0.7s
142.6Robert Vanman
-15.119squal -16.141s
88.1%qual 87.3%
2:07.436Eric Prill · fastest of 19 · top 5 within 0.6s
2:08.076Eric Prill · fastest of 18 · top 5 within 0.8s
131.4Ken Kannard
+0.803squal +0.233s
100.6%qual 100.2%
2:15.712Andrew Whitston · fastest of 26 · top 5 within 1.5s
2:18.289Zachary Whitston · fastest of 19 · top 5 within 0.4s
114.8Roger Siebenaler
+11.016squal +8.509s
108.7%qual 106.7%
26 rule changes (STL: 11, FP: 9, FV: 6)5 cars added · 3 engine · 3 weight · 2 aero · 1 induction · 1 suspension & brakes · 1 tyres & wheels · 8 wording · 2 other · FV exhaust exit opening repositioned: minimum one inch, maximum four inches behind rear body. · 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. · FV allows fifteen-inch steel wheels at 4J or 4.5J width, standard VW sedan or within track dimensions. · 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. · FV exhaust outlet opening max distance from body rear increased from 3 to 4 inches. · STL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate. · FV front track maximum 52.500 inches; rear track 49.125–50.750 inches; spacers now allowed. · 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. · FV disc brake assembly minimum weight clarified to 16.5 lbs total; caliper minimum weight requirement of 1.65 lbs removed. · FP Dodge Daytona/Chrysler Laser 84-85 added at 2100 lbs; Shelby Charger/Omni 024 83-84 weight cut to 2100 lbs. · 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. · FV intake manifold horizontal tube measurement location clarified; removed specific distance ranges from rule text. · 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
FV Allowed Modifications E&O #27398wordingwordingFV exhaust exit opening repositioned: minimum one inch, maximum four inches behind rear body.
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.
FP 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.
FP Request to classify the GMX5 2019 #27263cars addedaddedEP Mazda MX-5 Global Cup classification updated to include 2019 model year.
FP level one susp. component rule #27270wordingwordingProduction classes: suspension rule clarified to specify spindles, hubs, bushings, bearings, and ball joints unrestricted.
FP 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…
FP 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.
FV E&O Wheels #27230tyres & wheelsadded · tyres & wheelsFV allows fifteen-inch steel wheels at 4J or 4.5J width, standard VW sedan or within track dimensions.
FP 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.
FV Exhaust termination rule E&O #26702wordingwordingFV exhaust outlet opening max distance from body rear increased from 3 to 4 inches.
STL Request Restrictor Plate correction #26779enginefaster · engineSTL Acura/Honda B18 except C engine restrictor increased from 53mm to 54mm flat plate.
FV E&O Dimensions #26674suspension & brakessuspension & brakesFV front track maximum 52.500 inches; rear track 49.125–50.750 inches; spacers now allowed.
STL Request Ride Height Clarification #26597wordingwordingSTL and STU ride height measurement clarified: lowest rocker panel point without driver, excluding pinch weld.
FP 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.
FP Hardtops #26476aeroadded · aeroEP open cars may now use aftermarket hardtops if OEM-appearance and non-carbon-fiber; specific model allowances removed as redundant.
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.
FV FV Intake Manifold Clarification #26008wordingwordingFV intake manifold horizontal tube measurement location clarified; removed specific distance ranges from rule text.
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 STL'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.