BoP Lab / Buttonwillow Raceway Park

GT1 + STU + P2 at Buttonwillow Raceway Park

No mapCal Club 2024, Cal Club 2023

This track has been raced on 4 configurations (The Circuit, 2.57 mi; 2.92 mi; 1.83 mi; 3.02 mi). Laps on different configurations are not comparable, so only events on the 2.57 mile layout are shown; switch above to see the others.

6 laps are left out as timing errors (far too short to be a lap of this track). The rest of those sessions, sectors included, is used.

Pos	Car	Driver	Class	#	Lap	Theoretical	Qual	Race	5-lap stint	Consistency	Trap	S1	S2	S3
1	Stohr WF1 (2004)	Kevin Mitz	P2	13	1:12.573 D-Q2		1:12.573 D-Q2
2	Stohr WF1	Tim Day Jr >115%	P2	8	1:37.278 A-Q1	1:37.278	1:37.278 A-Q1	1:39.758 A-R2	1:40.037 A-R2	+1.010 A-R2	155.4 A-R2	26.848 A-Q1	28.010 A-Q1	42.420 A-Q1
3	Lamborghini Huracan GT3 Evo	Michael McAleenan	GT1	3	1:39.857 A-Q1	1:39.429	1:39.857 A-Q1	1:41.045 A-R2	1:42.375 A-R2	+4.109 A-R2	167.6 A-Q1	27.368 A-Q1	29.135 A-Q1	42.926 A-Q1
4	Jaguar XKR	Michael Lewis 2+ cars	GT1	12	1:39.901 A-Q1	1:39.901	1:39.901 A-Q1	1:41.635 A-R1	1:42.703 A-R1	+2.651 A-R1	151.5 A-R1	27.895 A-Q1	28.765 A-Q1	43.241 A-Q1
5	Mazda RX-3	Tony Rivera	STU	09	1:50.913 A-Q2	1:50.870	1:50.913 A-Q2	1:52.737 A-R2	1:54.126 A-R2	+2.638 A-R2	135.2 A-Q2	30.415 A-Q2	32.456 A-Q2	47.999 A-Q2
6	Mazda Miata	Whitfield Gregg	STU	17	1:51.602 B-P	1:51.602	2:02.264 B-Q2	2:01.538 B-R1	2:02.222 B-R1	+1.271 B-R1	116.3 A-Q1	30.652 B-P	32.263 B-P	48.687 B-P
7	BMW M3	Wilson Powell	STU	77	1:52.380 B-P	1:52.164	1:55.401 B-Q1	1:53.843 B-R1	1:54.699 B-R1	+1.965 B-R1	102.6 B-R1	30.577 B-P	32.372 B-P	49.215 B-P
8	Mazda RX-7	Michael Lewis 2+ cars	GT1	32	1:53.007 B-R2	1:52.514		1:53.007 B-R2	1:56.277 B-R2	+3.466 B-R2	110.9 B-R2	30.700 B-R2	32.429 B-R2	49.385 B-R2
9	Honda S2000	Rylan Hazelton	STU	49	1:53.640 B-R1	1:53.140	1:55.834 B-Q1	1:53.640 B-R1	1:54.534 A-R2	+0.714 A-R2	134.8 A-R2	30.582 B-R1	32.779 B-R1	49.779 A-R2
10	BMW 330	Sean Lovett	STU	37	1:56.492 A-Q2	1:56.426	1:56.492 A-Q2	1:57.049 A-R2	1:57.605 A-R2	+1.649 A-R2	133.7 A-R2	31.816 A-Q2	33.669 A-Q1	50.941 A-Q2
11	Nissan 300ZX	James Slechta	STU	75	1:59.183 A-Q2	1:59.183	1:59.183 A-Q2	2:00.458 A-R2	2:01.009 A-R2	+0.921 A-R2	132.0 A-Q1	32.882 A-Q2	34.528 A-Q2	51.773 A-Q2
12	Mazda MX-5	Oscar Jackson	STU	161	1:59.707 B-R2	1:58.888		1:59.707 B-R2	1:59.952 B-R2	+1.112 B-R2	103.9 B-R2	32.339 B-R2	34.219 B-R2	52.330 B-R2
13	Mazda RX-7	Michael Lewis 2+ cars	STU	32	2:00.248 A-R1	2:00.179		2:00.248 A-R1	2:02.190 A-R2	+1.431 A-R2	130.4 A-R1	32.729 A-R1	34.570 A-R1	52.880 A-R1
14	Mazda MX-5	Dale Shoemaker	STU	52	2:01.642 B-R2	2:01.176	2:04.115 B-Q1	2:01.642 B-R2	2:02.793 B-R2	+2.442 B-R2	125.9 A-Q2	32.956 B-R2	34.983 B-R2	53.237 B-R2

One row per driver and car (a driver who changed cars has a row for each). Each cell is that driver's best in that car across the selected events, with the session it was set in. Best 5-lap stint is the mean of the driver's quickest five consecutive race laps, and consistency is how far their median race lap sat behind their best in that race (small is a driver who does it every lap); both come from the race with the best stint. The fastest in each column is purple, and a car whose best lap is more than 115% of the fastest in its class is greyed (marked ">115%" beside the driver) and left out of the colour scale. Click a column to sort, a row to highlight it. Theoretical lap is the sum of the best sectors, whichever laps they came from, and never slower than the best lap (where a car's fastest laps were recorded without sector times, its best lap is used). The 115% mark is about the car's best lap only: a car whose best lap is within 115% of the fastest in its class is never marked. Greyed sectors with no theoretical lap mean the sector times on file do not add up to a believable lap. Letters refer to the events above; Q is qualifying, R a race.

Sectors

S1 SF → IM1 0.65 mi
S2 IM1 → IM2 0.75 mi
S3 IM2 → SF 1.17 mi
Spd In → Out 0.03 mi

Sectors are numbered in lap order from start/finish, whatever each event's timing called them; the loop names are SCCA timing's.

By car

Car	Class	Drivers	Lap	Qual	Race	Trap	S1	S2	S3
Stohr WF1	P2	2	1:12.573Kevin Mitz	1:12.573Kevin Mitz	1:39.758Tim Day Jr	155.4Tim Day Jr	26.848Tim Day Jr	28.010Tim Day Jr	42.420Tim Day Jr
Stohr WF1 (2004)	P2	1	1:12.573Kevin Mitz	1:12.573Kevin Mitz
Stohr WF1	P2	1	1:37.278Tim Day Jr	1:37.278Tim Day Jr	1:39.758Tim Day Jr	155.4Tim Day Jr	26.848Tim Day Jr	28.010Tim Day Jr	42.420Tim Day Jr
Lamborghini Huracan GT3 Evo	GT1	1	1:39.857Michael McAleenan	1:39.857Michael McAleenan	1:41.045Michael McAleenan	167.6Michael McAleenan	27.368Michael McAleenan	29.135Michael McAleenan	42.926Michael McAleenan
Jaguar XKR	GT1	1	1:39.901Michael Lewis	1:39.901Michael Lewis	1:41.635Michael Lewis	151.5Michael Lewis	27.895Michael Lewis	28.765Michael Lewis	43.241Michael Lewis
Mazda RX-3	STU	1	1:50.913Tony Rivera	1:50.913Tony Rivera	1:52.737Tony Rivera	135.2Tony Rivera	30.415Tony Rivera	32.456Tony Rivera	47.999Tony Rivera
Mazda Miata	STU	1	1:51.602Whitfield Gregg	2:02.264Whitfield Gregg	2:01.538Whitfield Gregg	116.3Whitfield Gregg	30.652Whitfield Gregg	32.263Whitfield Gregg	48.687Whitfield Gregg
BMW M3	STU	1	1:52.380Wilson Powell	1:55.401Wilson Powell	1:53.843Wilson Powell	102.6Wilson Powell	30.577Wilson Powell	32.372Wilson Powell	49.215Wilson Powell
Mazda RX-7	GT1/STU	1	1:53.007Michael Lewis		1:53.007Michael Lewis	130.4Michael Lewis	30.700Michael Lewis	32.429Michael Lewis	49.385Michael Lewis
Honda S2000	STU	1	1:53.640Rylan Hazelton	1:55.834Rylan Hazelton	1:53.640Rylan Hazelton	134.8Rylan Hazelton	30.582Rylan Hazelton	32.779Rylan Hazelton	49.779Rylan Hazelton
BMW 330	STU	1	1:56.492Sean Lovett	1:56.492Sean Lovett	1:57.049Sean Lovett	133.7Sean Lovett	31.816Sean Lovett	33.669Sean Lovett	50.941Sean Lovett
Nissan 300ZX	STU	1	1:59.183James Slechta	1:59.183James Slechta	2:00.458James Slechta	132.0James Slechta	32.882James Slechta	34.528James Slechta	51.773James Slechta
Mazda MX-5	STU	2	1:59.707Oscar Jackson	2:04.115Dale Shoemaker	1:59.707Oscar Jackson	125.9Dale Shoemaker	32.339Oscar Jackson	34.219Oscar Jackson	52.330Oscar Jackson

The best any driver of each car managed across the selected events, with who set it. Spellings and model years of the same car are grouped; click a row marked ▸ to see each version. Grouping is worked out from the names, so tell us if two cars are wrongly merged or split.

Rule changes between these events

Cal Club 2023 → Cal Club 2024 2023-02-24 to 2024-02-23

2023-03-01 STU E&O STU NA Weight Chart.

#33737 from Eric Heinrich · Rule change · TB 23-03 (2023-03 Fastrack)

fasterSTU minimum weight chart updated: 2450cc to 2595lbs, 2600cc to 2710lbs.

In STU, GCR Section 9.1.4.1.H.1. chart, Factory Engine Displacement (cc) Minimum Weight (lbs), change as follows:
"2450 ~~2596~~ 2595"
"2600 ~~2860~~ 2710"

2023-04-01 GT1 Mercedes AMG GT3 Notes

#33804 from Gary D'Abate · Rule change · TB 23-04 (2023-04 Fastrack)

neutralGT1 Mercedes AMG GT3 16-19 preparation wording changed to per FIA GT3 homologation.

In GT1-ST Spec Lines, Mercedes Benz AMG GT3 (16-19), change Notes as follows:
"Car must be prepared to per its FIA GT3 homologation. ~~except as specified differently within the GT1 class rules.~~"

2023-04-01 STU Alternate OEM Miata Intake Manifold

#33827 from Brandon Steinhauer · Rule change · TB 23-04 (2023-04 Fastrack)

neutralSTU Mazda BP5A classified at 1839 cc maximum displacement, 2023-04-01.

In STU Spec lines, classify Mazda BP5A as follows:
STU Maximum Displacement (cc's) Minimum Weight Notes
Mazda BP5A 1839 Chart May use engine in its entirety or specific
components from the engine.

2023-04-01 P2 Remove redundant effective date language and update engine table

#34012 from Club Racing Board · Rule change · TB 23-04 (2023-04 Fastrack)

neutralP2 engine table wording updated; redundant effective date language removed.

In P2 Engine Table, Spec Line B.1, change as follows:

2023-04-01 P2 E&O - Correct dimensional equivalents

#34038 from Club Racing Board · Rule change · TB 23-04 (2023-04 Fastrack)

slowerP2 motorcycle engines: 2011+ Kawasaki restrictor reduced to 34mm, minimum weight raised to 1100 lbs; 2009+ other brands weight raised to 1100 lbs.

In P2, GCR section 9.1.8.C.D.2, change as follows:
"Height: No part of the vehicle having special or significant aerodynamic function shall exceed a height of 115cm (45.275 inches)
above the ground with the car in normal racing trim, driver aboard."
In P2, GCR section 9.1.8.C.D.3, change as follows:
"However, no portion shall extend more than 10cm (3.937 inches) beyond a plane tangent to the outer face of the front and rear
wheels with tires."
P2 Engine Table
Spec

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Line Engine Series

A specification table follows in the original; it is not shown here.

2023-05-01 GT1 Please classify Fields Cardinal V8

#33784 from James Rogersn · Rule change · TB 23-05 (2023-05 Fastrack)

neutralFields Cardinal V8 classified in GT1 with Ford V8 engine, 4.9L displacement, 2100 lbs minimum weight.

In GT Spec Lines, GT1 Cars - Fields Cardinal, classify Fields Cardinal V8 as follows:
GT1 Cars – Fields Cardinal
Model Years Body Style Drive-
line
Wheel-
base (in)
Notes
Fields Cardinal V8 2023 2 Dr. RWD 92.0 Roll Cage MUST be modified to comply with

Show 6 more lines

GCR Section 9.4.
In GT Spec Lines, GT1Engines - classify Ford V8 as follows:
GT1 Engines - Ford
Engine
Family
Engine Type Bore x

A specification table follows in the original; it is not shown here.

2023-05-01 P2 Clarify minimum side body height requirement

#34143 from Club Racing Board · Rule change · TB 23-05 (2023-05 Fastrack)

neutralP2 side body height requirement clarified: outermost surface between wheel openings must equal front axle centerline height.

In P2, GCR section 9.1.8.C.D.6, change as follows:
"As viewed from the side, T the outermost surface of ~~side pods~~ body between the front and rear wheel openings and above the
floor must have a minimum height equal to the height of the front axle centerline."

2023-05-01 P2 Clarify closed cockpit single seat car allowance

#34144 from Club Racing Board · Rule change · TB 23-05 (2023-05 Fastrack)

neutralP2 closed cockpit single seat cars now prohibited unless specifically allowed in Table 1.

In P2, GCR section 9.1.8.C.C, add a section as follows:
"4. Closed cockpit single seat cars are not permitted unless specifically allowed by a spec line in Table 1."

2023-07-01 STU 2022 Toyota GR Cup for STU

#34449 from Club Racing Board · Rule change · TB 23-06 (2023-05 Fastrack)

neutralToyota GR Cup and GR86 Cup (2022-) newly classified in STU at 2700 lbs with 2387 cc engine.

In STU Spec Lines, Toyota GR Cup (2022-), classify as follows:

A specification table follows in the original; it is not shown here.

2023-12-01 GT1 Errors in GTCS Headings and Use of the Terms Category and ClassChange existing GTL and GTA Rules

#34453 from David Gomberg · Rule change · TB 23-12 (2023-12 Fastrack)

neutralGTL spec lines moved to contiguous position with GT2 and GT3; GTA category and spec lines renumbered and moved behind GTL.

from the current (or before) Table of Contents (TOC), to what is shown in the after TOC.
GTL spec lines will now be contiguous with GT2 and 3 spec lines.
GTA category and spec lines will be moved and renumbered behind GTL. GTA Section will not change but page numbers will, (as
shown in Red italics).
9.1.2.F. GT-2, 3, LITE Category Specifications 314
GT2 Cars 327
GT2/ST 341
GT3 Cars 348

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GTL Cars 364
GTA Cars 377
P2 Engine Table B.1
2010 and older
Stock Kawasaki
38.5mm
minimum width 52 inches. AMAC-AM5:
minimum width 54 inches.
P2 Engine Table B.1
2008 and older
Stock ~~Engine~~ Suzuki,
Yamaha,
Honda, BMW
38.5mm
P2 Engine Table B.2 Not required
P2 Engine Table B.3 38.5mm
Modified Engine
950 lbs.
1005cc max
P2 Engine Table B.1 37mm
P2 Engine Table B.2 Not required
P2 Engine Table B.3 39mm
Stock Engine
1050 lbs.

2023-12-01 P2 Correct Table 1 for Engine Date Range Specifications

#35182 from Formula/Sports Racing Committee · Rule change · TB 23-12 (2023-09 Fastrack)

neutralP2 Table 1 corrects engine date ranges and brand specifications for Stock and Modified engines across multiple car models.

In P2 Table 1, change as follows:
P2 Table 1 (Spec Line Cars)

A specification table follows in the original; it is not shown here.

2024-01-01 GT1 Request for Acceptance of Lamborghini Huracan GT3 in GT1-ST

#34929 from Michael McAleenan · Rule change · TB 24-01 (2024-01 Fastrack)

neutralLamborghini Huracan GT3 EVO(1) and GT3 added to GT1-ST at 3000 and 3100 lbs minimum weight respectively.

In GT1-ST Spec Lines, classify Lamborghini Huracan GT3 EVO(1) (2018-) as follows:
GT1-ST Maximum Displacement Minimum Weight Restrictor Notes
Lamborghini Huracan
GT3 EVO(1)
(2018-)
5204 3000 2 X39mm Per FIA Homologation
GT3-040
In GT1-ST Spec Lines, classify Lamborghini Huracan GT3 (2019-) as follows:

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GT1-ST Maximum Displacement Minimum Weight Restrictor Notes
Lamborghini
Huracan GT3
2019-
5204 3100 52mm Per FIA Homologation
GT3-040

2024-01-01 GT1 Cylinder heads

#35040 from Pater Mumford · Rule change · TB 24-01 (2024-01 Fastrack)

neutralGT1 Trick Flow Specialties Ultra 18 Degree GM Cylinder Head Part #TFS-3181T001-CO1 allowed.

In GCR, Section 9.1.2.D.1.e.3., add at the end of section add the follows:
"Trick Flow Specialties Ultra 18 Degree GM Cylinder Head assembly Part #TFS-3181T001-CO1 is allowed."

2024-01-01 P2 E&O - Clarify B.1 modified engine range in AMAC spec lines

#35225 from Club Racing Board · Rule change · TB 24-01 (2024-01 Fastrack)

neutralP2 AMAC modified engine range clarified to 2008 and older stock engines only, restrictor 38mm, weight 1025 lbs.

In P2 Table 1, change as follows:
P2 Table 1 (Spec Line Cars)

A specification table follows in the original; it is not shown here.

2024-01-01 P2 Replacement Engine Crankcase for 07/08 Suzuki GSX-R1000 Engines

#35340 from Michael A Reupert · Rule change · TB 24-01 (2024-01 Fastrack)

unclearP2 Suzuki GSX-R1000 07/08 engine crankcase may swap to GSX-S1000 16/19 part #11301-04840.

In P2 Engine Table, Spec Line B.1, add to notes as follows:
"No modifications allowed on engines manufactured after 2008 model year. 2007-2008 Suzuki GSX-R1000 crankcase part
#11300-21860 may be replaced with 2016-2019 Suzuki GSX-S1000 crankcase part #11301-04840."

2024-02-01 STU ST Electric-Assisted Steering Systems

#35066 from Jose Osiris Pena · Rule change · TB 24-02 (2024-01 Fastrack)

neutralSTL and STU power steering rules clarified to permit electric-assisted and hydraulic-assisted steering systems.

In GCR, Section 9.1.4.M.16., change as follows:
"Power steering may be modified in any of the following ways:
a. disconnected , pump, belt, pulley, and hoses may be removed. Hoses may also be looped. Steering rack or box may be
modified internally to work without pump.
b. an OEM manual steering rack for that model may be fitted
c. an electric power steering pump may be fitted
d. an OEM electric-assisted steering system may be used or any column mounted electric steering assist may be used
e. an OEM hydraulic-assisted steering system may be used"

2024-02-01 GT1 Rear Blade Spoiler Clarification

#35261 from Butch Kummer · Rule change · TB 24-02 (2024-01 Fastrack)

fasterGT1, GT2, GT3, GTL, GTX rear spoiler maximum surface area limit of 295.0 square inches removed.

In GCR Section 9.1.2.G (GTA Category Specifications), change as follows:
“9.1.2.G.III.I
The single-plane rear spoiler must be mounted at an ~~angel~~ angle from 50 to 75 degrees (perpendicular to the ground
being 90 degrees) and may not extend beyond the rear bumper when viewed from directly above the rear
bumper. Spoilers must be a minimum of .063 aluminum or Lexan and may vary in overall height to match the contours
of the bodywork. The rear spoiler dimensions shall not exceed 59.0 inches wide by 5.0 inches in height, (measured on
the material surface) ~~, or 295.0 square inches total surface area.~~ Braces to prevent spoiler deflection are allowed, but
may serve no other purpose.”

2024-02-01 GT1 GT Direct Injection allowance and rules

#35437 from Grand Touring Committee · Rule change · TB 24-02 (2024-01 Fastrack)

fasterGT1/GT2/GT3/GTL/GTX Direct Injection now permitted if OE, using only OE pump, hoses, injectors.

In GCR, Section 9.1.2.F.7.5.E. change as follows:
“Direct Injection is ~~not~~ permitted only if it came OE and must be installed using only OE high pressure pump(s), hard and
soft hoses and injectors.”

2024-02-01 GT1 GT2/3 remove Direction Injection not allowed in Spec line notes

#35439 from Grand Touring Committee · Rule change · TB 24-02 (2024-02 Fastrack)

fasterGT2/3 Nissan, Mazda, Mitsubishi 4G93, QR25DE/DD, QE25DE/DD Direct Injection now permitted per 9.1.2.F.7.5.E.

In GT2/3 modify Spec Line notes as follows:
GT2:
Nissan: “Direct Injection ~~not~~ permitted, may be used per 9.1.2.F.7.5.E.”
GT3:
Mazda: “Direct Injection ~~not~~ permitted, may be used per 9.1.2.F.7.5.E.”
Mitsubishi 4G93: “Direct Injection ~~not~~ permitted, may be used per 9.1.2.F.7.5.E. ”
Nissan QR25DE/DD 1988cc: “Direct Injection ~~not~~ permitted, may be used per 9.1.2.F.7.5.E.”
Nissan QE25DE/DD 2489cc: “Direct Injection ~~not~~ permitted, may be used per 9.1.2.F.7.5.E.”

Cal Club 2024 → Cal Club 2025 2024-02-23 to 2025-02-22

2024-03-01 STU Letter #35397 addendum

#35453 from Aaron Fitzsimmons · Rule change · TB 24-03 (2024-03 Fastrack)

neutralSTU Mini Cooper S SC: alternate LEAP OMICRON hood scoop LEP-OMICRON3 permitted.

In STU Spec Lines, Mini Cooper S SC with Minimum Weight 1900 and 2100, add to Notes:
"Alternate LEAP OMICRON hood scoop part # LEP-OMICRON3 is permitted."

2024-03-01 STU S54 Drysump

#35464 from Macey Urso · Rule change · TB 24-03 (2024-03 Fastrack)

neutralSTU BMW S54 B32 OEM now permits dry sump oiling system.

In STU Spec Lines, BMW S54 B32 OEM, add to Notes as follows:
"Dry Sump oiling system permitted."

2024-05-01 GT1 Request for Spec Line 1010 Reconsideration

#35009 from Kristofer Olson · Rule change · TB 24-05 (2024-05 Fastrack)

slowerGT2-ST Acura NSX minimum weight raised to 3000 lbs, restrictor increased to 45mm TIR.

In GT2-ST Spec Lines, Acura NSX, change as follows:
Minimum Weight: "~~2700~~ 3000"
Restrictor: "43 45mm TIR"

2024-05-01 GT1 Camaro 1993- and 2010-

#35652 from John Bodnar · Rule change · TB 24-05 (2024-05 Fastrack)

neutralGT1 Camaro 1993-2002 classification updated; 2010- model separately classified.

In GCR, Section 9.1.2.E.1.b.3., change as follows:
"Camaro (1993-2002)"

2024-05-01 P2 CN Spec ECU

#35835 from Bart Wolf · Rule change · TB 24-05 (2024-05 Fastrack)

neutralP2 Spec ECU engine modifications clarified: oil system, ECU, and exhaust unrestricted only.

In P2 Engine Table, Spec Line E, change the notes as follows:
"No engine modifications except f~~or dry sump oil system, ECU mapping, and exhaust system~~ the following: oil system, ECU, and
exhaust are unrestricted."

2024-05-01 P2 E&O - Correct FIA Group CN spec line notes

#35900 from Club Racing Board · Rule change · TB 24-05 (2024-05 Fastrack)

neutralP2 FIA Group CN spec notes clarified: Series changed to Challenge, documentation requirement moved to online link.

In P2 Table 1, FIA Group CN spec line, change the notes as follows:
"FIA Group CN homologated chassis, brake calipers and discs, hub carriers, and suspension components are required. V de
V European Proto Endurance ~~Series~~ Challenge permitted bodywork, rear diffuser, wing, wheels, and assisted
shifting are allowed. Car M must comply with all other P2 requirements. ~~Competitors must have copies of~~ FIA Group CN
Technical Regulations and V de V European Proto Endurance ~~Series~~ Challenge Sporting and Technical Regulations ~~in their~~
~~possession and present them upon request~~ are available here: https://www.scca.com/pages/technical-forms-and-downloads."

2024-08-01 STU RWD Turbo Disadvantage

#36255 from David Fiorelli · Rule change · TB 24-08 (2024-08 Fastrack)

fasterSTU RWD turbo cars no longer required to reduce restrictor by 1 mm from table.

In GCR, Section 9.1.4.1.H.3 - Inlet Restrictor (mm) Minimum Weight (lbs) table, change as follows:
"~~RWD cars must reduce restrictor 1 mm from this table~~"

2024-11-01 GT1 Request to Classify Mazda 26B Engine

#36230 from Wayne Graham · Rule change · TB 24-09 (2024-09 Fastrack)

neutralGT1 Mazda 26B engine classified at 2850 lbs minimum weight.

In GT1 Spec Lines, GT1 Approved Automobile List, Mazda, add the following:
"(Effective 11/1/2024) 26B engine = 2850 lbs."

2024-11-01 STU R53 15% Pulley Request

#36980 from Aaron Fitzsimmons · Rule change · TB 24-11 (2024-11 Fastrack)

slowerSTU Mini Cooper S SC 1900 restricts to 2.565 diameter pulley; 2100 allows 2.285 diameter pulley.

In STU Spec Lines, Mini Cooper S SC, add to notes:
1900: "Stock supercharger pulley. 2.565 diameter."
2100: "~~JCW Pulley permitted.~~ May run a 2.285 diameter pulley."

2024-12-01 GT1 Lamborghini Huracan GT3 Evo Restrictor Help

#36254 from Michael McAleenan · Rule change · TB 24-12 (2024-12 Fastrack)

fasterGT1-ST Lamborghini Huracan GT3 Evo and 2019+ GT3 both shift to Unrestricted from 39mm and 52mm restrictors.

In GT1-ST Spec Lines, Lamborghini Huracan GT3 EVO(1) (2018-), change Restrictor as follows:
"2 X 39mmUnrestricted"
In GT1-ST Spec Lines, Lamborghini Huracan GT3 (2019-), change Restrictor as follows:
"~~52mm~~ Unrestricted"

2024-12-01 STU Request to Remove Miata Hubs from General category

#37138 from Christopher Childs · Rule change · TB 24-12 (2024-12 Fastrack)

neutralSTL/STU: 90-05 Mazda Miata alternate front wheel hubs moved from General to specific part approval.

In GCR, Section 9.1.4.M.18., change as follows:
"18. Allow alternate front wheel front hubs, Mazda Motorsports Development Part #0000-04-5HUB-S1, for the 90-05 Mazda
Miata~~: Mazda Motorsports Development Part #0000-04-5HUB-S1~~."

2024-12-01 STU BMW N54/N55 Engine Allowance

#37146 from Martin Sarukhanyan · Rule change · TB 24-12 (2024-12 Fastrack)

slowerSTU BMW N54/N55 turbo inlet restrictors now required per GCR definition; turbo swapping prohibited.

"Turbo inlet restrictors designed per GCR Appendix F Technical Glossary definition of “Turbo Inlet Restrictor” may be required;
see table 9.1.4.1.H.~~h.2~~ 3. Swapping of turbochargers between engine makes and models is prohibited. Supercharged cars may be
approved on a case-by-case basis; twin turbo engines are allowed on a case-by-case basis only. Contact the Road Racing
Technical Office for details. Twin turbo engines may be converted to single turbo using one of the allowed alternate turbos (see
9.1.4.1.H.3 2). Aftermarket turbocharger and supercharger kits will be allowed on a case-by-case basis.

2024-12-01 P2 2000 cc Pinto Engine Car Weight

#37187 from Marvin Hodges · Rule change · TB 24-12 (2024-12 Fastrack)

slowerP2 2000cc Pinto engine car minimum weight set to 1335 lbs.

In P2 Engine Table, Line E Note 2, add the following:
"8. Minimum weight 1335 lbs."

2025-01-01 STU Audi 1.8t Wagon STU Table B

#36685 from Mike McLaughlin · Rule change · TB 25-01 (2025-01 Fastrack)

fasterSTU Audi 1.8T wagon deleted; Porsche 944 1800 weight to Chart, turbo inlet restrictor removed.

In STU Spec Lines, Table B: Alternate Vehicle and Engine Requirements, delete Audi/VW 1.8 Turbo in its entirety.
In STU Spec Lines, Table B: Alternate Vehicle and Engine Requirements, Porsche 944 w/Max Displacement 1800, change as
follows:
Weight: "~~3050~~ Chart"
Notes: "VW/Audi 1.8L ~~35mm~~ turbo engine permitted~~inlet restrictor required~~."

2025-01-01 GT1 Addition of a limited prep LS Chevy engine for GT1

#37045 from Robert Logsdon · Rule change · TB 25-01 (2025-01 Fastrack)

neutralGT1 LS1 Limited Prep engine added, 2600 lbs with driver, 383 cubic inches max, hydraulic roller cam, 750 cfm carb.

In GCR, Section 9.1.2. GT1 Spec Lines, GT1 Approved Automobile List, LS1 V8 engine allowed with stock intake, add the
following:
"LS1 Limited Prep GT1 motor
2600 # with driver
Blocks : GM castings or aftermarket, no lightening, Max volume 383 cubic inches
Cylinder Heads: GM LS castings or aftermarket, stock valve angle, intake and exhaust ports must be in stock location, porting
and polishing allowed
Valves: No titanium valves, must be stock size for head part number

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Rockers: Factory 1.7 rockers only, aftermarket trunion mod allowed
Pushrods: Free
Intake manifold: stock EFI for variant used or GM 525 carb intake or Edelbrock carb variants ie: Performer RPM, Victor, Victor Jr.
or similar.
Camshaft: Hydraulic roller only, standard journal size, lift and duration free
Timing chain: single or double roller type only
water pump: stock or aftermarket in stock location
Harmonic dampener: SFI approved,
Pistons: Factory or aftermarket flat top pistons only, valve reliefs allowed, coatings allowed
Crankshaft: Factory or forged steel aftermarket, 50 lb min. weight
Rods: GM stock or aftermarket forged steel
Carburetor: one 4150 type 750 cfm max"

2025-01-01 GT1 Correct language regarding OEM Areo Devices

#37137 from Christopher Childs · Rule change · TB 25-01 (2025-01 Fastrack)

neutralTA2 rear wing height rule clarified: OEM aerodynamic devices exempt from peak-of-roof requirement.

In GCR, Section APPENDIX L. 2013 TA2 TECHNICAL REGULATIONS, B.2.c., change as follows:
"B. Aerodynamic Devices
2. Rear wing
c. The entire rear wing assembly, including the end plates and any Gurney flap, shall be mounted level
with, or below, the peak of the roof. OEM aerodynamic devices do not need to adhere to the height rule."

A specification table follows in the original; it is not shown here.

2025-01-01 GT1 GT1-ST Adjustments

#37481 from Grand Touring Committee · Rule change · TB 25-01 (2025-01 Fastrack)

unclearGT1-ST restrictor sizes removed for 13 cars; new specs not printed in letter.

In GT1-ST SPEC LINES, change as follows:
Aston Martin Vantage GT3 (2012) :
Restrictor: "~~2 x 41.5mm~~"
Audi R8 LMS Ultra GT3 (10-14) :
Restrictor: "~~2 x 49mm~~"
BMW Z4 GT3 (10-13):
Restrictor: "~~70mm~~"
Chevrolet Corvette C8 (20-):

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Restrictor: "~~71mm- Flat Plate~~"
Dodge Viper GT3R (2012-):
Restrictor: "~~2 x 40mm~~"
Dodge Viper, incl Comp Coupe, ACR/ACR-X Max Displacement 8400, Weight 3200:
Restrictor: "~~68mm flat plate~~"
Ferrari 458 GT3 (2011-):
Restrictor: "~~2 x 43mm~~"
Lamborghini Gallardo GT3 (2013):
Restrictor: "~~2 x 47mm~~"
Lamborghini Huracan GT3 EVO(1) (2018-):
Restrictor: "~~2 X39mm~~"
McLaren MP12C GT3 (2013-):
Restrictor: "~~2 x 36mm~~ 1.50 bar"
Lamborghini Huracan GT3 (2019-):
Restrictor: "~~2 x 40 mm~~"
McLaren MP12C GT3 (2013-):
Restrictor: "~~2 x 40 mm~~"
Mercedes Benz SLS GT3 (2011-):
Restrictor: "~~2 x 36 mm~~"
Porsche 991 GT3-R (2016):
Restrictor: "~~(2) 35 mm~~"
Porsche 997 GT3 R (2013-):
Restrictor: "~~65mm~~"

2025-01-01 STU Merger GT3 to STU

#37486 from Club Racing Board · Rule change · TB 25-01 (2025-01 Fastrack)

neutralSTU-GT3 reclassified as STU-GT3U effective January 1, 2026.

In STU, Table C, change STU-GT3 charge as follows:
"(Effective January 1, 2026) TABLE C: STU-GT3U"

2025-01-01 STU GT3 TCR Tire allowance

#37494 from Club Racing Board · Rule change · TB 25-01 (2025-01 Fastrack)

slowerSTU GT3 TCR gains 275-width tire option with 100 lb weight penalty, but not in A compound.

In STU, Table C, GT3 TCR, add to Notes the following:
"May run DOT approved tire with maximum section width of 275 with 100 pound weight adder. May not run A compound with
275."

Cal Club 2025 → Cal Club 2026 2025-02-22 to 2026-02-21

2025-03-01 GT1 Request to Classify Acura NSX GT3 Evo 22

#37367 from Taz Harvey · Rule change · TB 25-03 (2025-03 Fastrack)

neutralAcura NSX GT3 EVO 22 classified in GT1 with 3500cc twin turbo V-6, 3100 lbs, max RPM 7500.

In GT1 Spec Lines, GT 1 Cars - ACURA, classify Acura NSX GT3 EVO 22 as follows:
GT 1 Cars - ACURA
Model Years Body Style Drive-
line
Wheel-
base (in)
Notes
Acura NSX GT3 EVO 22 N/A 2dr RWD 103.5 Ground Clearance 50mm

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In GT1 Spec Lines, GT 1 Engines - ACURA, classify Crossflow V-6 as follows:
GT 1 Engines - ACURA
Engine
Family
Engine Type Bore x

A specification table follows in the original; it is not shown here.

2025-03-01 STU BMW N54/N55 Engine Allowance Follow Up

#37447 from Martin Sarukhanyan · Rule change · TB 25-03 (2025-03 Fastrack)

neutralSTU BMW N54/N55 3.0L classified at Chart +3% minimum weight; N54 twin turbo not allowed.

In STU Spec Lines, Table A, classify BMW N54/N55 as follows:
STU Maximum Displacement
(cc's) Minimum Weight Notes
BMW N54/N55 3.0 Chart +3% (DI) Short blocks, heads, and intakes may be
freely swapped within these engine
designations. N54 twin turbo not allowed

2025-03-01 STU STU Mini Cooper pulley size clarification re: letter #36980

#37717 from Aaron Fitzsimmons · Rule change · TB 25-03 (2025-03 Fastrack)

fasterSTU Mini Cooper S SC supercharger pulley diameter reduced from 2.285 to 2.185.

In STU Spec Lines, Mini Cooper S SC, add to notes:
2100: "May run a ~~2.285~~ 2.185 diameter pulley."

2025-03-01 STU Question About a Weight Modifier

#37782 from Peter St Pierre · Rule change · TB 25-03 (2025-03 Fastrack)

fasterSTU Honda K20C1 Turbo I4 exempted from 3% DI weight adder in Spec Lines Table A.

In STU Spec Lines, Table A, Honda K20C1 Turbo I4, add to Notes the following:
"The 3% DI weight adder does not need to be applied."

2025-03-01 STU Increase Minimum Weight

#37919 from Club Racing Board · Rule change · TB 25-03 (2025-03 Fastrack)

slowerSTU GT3U minimum weight increases 150 to 250 pounds.

In STU Spec Lines, Table C: STU-GT3U, change Minimum Weight as follows:
"~~150~~ 250 pounds"

2025-05-01 STU Wheel Size Inconsistency

#38018 from David Fiorelli · Rule change · TB 25-05 (2025-05 Fastrack)

neutralSTU wheel width rules clarified: cars ≤2,850 lbs max 8 inches, cars >2,850 lbs max 9 inches.

In GCR, Section 9.1.4.1.F.1., change as follows:
"Wheels may not exceed 18 inches in diameter. ~~or 8.0 inches in width for vehicles 2950 lbs. and under minimum allowed race~~
~~weight. Vehicles over 2850 minimum allowed race weight may use a 9 inch wide wheel.~~ Cars equal to or less than 2,850 lbs.
minimum allowed race weight may not use wheels wider than 8 inches. Cars greater than 2,850 lbs. minimum allowed race
weight may not use wheels wider than 9 inches."

2025-05-01 STU Table C: STU-GT3U Clarification

#38268 from Club Racing Board · Rule change · TB 25-05 (2025-05 Fastrack)

fasterSTU Spec Line GT3U minimum weight reduced from plus 250 to plus 225 pounds; wheel and tire options clarified with weight adjustments.

In STU Spec Line, Table C: STU-GT3U, change as follows:
Minimum Weight: “Current GT3 race weight plus ~~250~~ 225 pounds”
Notes: "~~DOT approved tire with maximum section width of 245. GT3 cars base wheel is a maximum of 15”x9”. 18”x9” wheels~~
~~allowd with a 3% weight addition. GT3 cars utilizing 15”x7” wheels are limited to a maximum section width of 225 with a 25~~
~~pound weight reduction~~"
"All GT3U (Majors and Runoffs) cars using up to 15"x7" wheels limited to 225 section width tires shall run at current GT3 race
weight plus 225lbs. All Gt3U cars shall run a DOT approved tire with a maximum section width of 245. GT3U cars are allowed
optional 15"x9" wheels with a 1.5% weight addition or up to 18"x9" wheels with a 3.0% weight addition to the total weight

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including the 225 lbs."

2025-07-01 STU 2.8-3.2L N/A Engine Allowances

#38007 from Ben Slechta · Rule change · TB 25-07 (2025-07 Fastrack)

unclearSTU 2.8-3.2L N/A engines now allow 245 max tire width; over 3150 lbs may run 275 with 2% weight penalty.

In GCR, Section 9.1.4.G.1, add the following:
"A maximum section width of 245 is permitted. Cars over 3150 lbs. may run a 275 tire with a 2% weight adder."

2025-07-01 STU 2006-2015 Mazda Miata Intake Manifold

#38422 from German Candelario Candelario · Rule change · TB 25-07 (2025-07 Fastrack)

neutralSTU Mazda MZR may use Goodwin 61-2510 or Gato Performance 31972 intake manifold.

In STU, Table A, Mazda MZR (LF, L3, L5), change Notes as follows:
"May use Goodwin Part # 61-2510 or Gato Performance Part #31972 Intake manifold . "

2025-07-01 STU Requesting Approval of the JDM Honda h23a

#38489 from Eric Fiest · Rule change · TB 25-07 (2025-07 Fastrack)

neutralSTU Honda JDM H23a added, 2259cc displacement, minimum weight per Chart, must meet ST engine regulations.

In STU, Table B, classify Honda JDM H23a as follows:
STU Maximum Displacement (cc's) Minimum Weight Notes
Honda JDM H23a 2259 Chart Must meet all ST engine regulations.

2025-08-01 STU STU-TCR Adjustments

#38723 from Club Racing Board · Rule change · TB 25-08 (2025-08 Fastrack)

slowerSTU-TCR tire width increases to 275 with weight adder raised from 100 to 150 pounds.

In STU Spec Lines, Table C: STU-GT3U, GT3-TCR, change as follows: Remove the current TCR spec line and add the TCR spec lines
from GT3 that are being removed, adding the below to the notes.
"DOT approved tire with maximum section width of 245. May run DOT approved tire with maximum section width of 275 with
~~100~~ 150 pound weight adder. May not run A-compound with 275. STU-TCR spitters and side valance must comply with
9.1.4.D.3.f. STU-TCR chassis ride height must comply with 9.1.4.1.A.1."

2025-08-01 STU Lotus Weight Reduction

#38772 from Club Racing Board · Rule change · TB 25-08 (2025-08 Fastrack)

fasterSTL/STU Lotus weight reduced: Evora GT4 to 2700 lbs, Elise Cup R to 2250 lbs, Elise/Exige SC to 2450-2550 lbs.

In 9.1.2. GT2/ST Spec Lines, Lotus Evora GT4, change Weight as follows:
"~~2750~~ 2700"
In STU Table B: Alternate Vehicle and Engine Allowances, change Weight as follows:
Lotus Elise Cup R: "~~2300~~ 2250"
Lotus Elise SC/ Lotus Exige SC: ~~"2300~~ 2550
~~2500~~ 2450"

2025-09-01 GT1 Correction to Limited prep LS Chevy engine for GT1

#38902 from Robert Logsdon · Rule change · TB 25-09 (2025-09 Fastrack)

neutralGT1 LS Limited Prep Engine expands to include LS1, LS2, LS3, LS6 with 11:1 max compression.

In GCR, Section 9.1.2. GT1 Spec Lines, GT1 Approved Automobile List, LS1 engine allowed with stock intake, make the following
change:
"~~LS1 Limited Prep GT1 Motor~~ Chevy LS Limited Prep Engine including LS1, LS2, LS3 and LS6."
"Pistons: Factory or aftermarket flat top pistons only, valve reliefs allowed, coatings allowed. Maximum compression ratio
11:1."

2025-09-01 STU Lotus Weight Reduction E&O

#38919 from Club Racing Board · Rule change · TB 25-09 (2025-09 Fastrack)

fasterSTU Lotus Elise SC and Exige SC weight reduced from 2450 to 2250 lbs.

In STU Table B: Alternate Vehicle and Engine Allowances, change Weight as follows:
Lotus Elise SC/ Lotus Exige SC: ~~"2450~~ 2250"

2025-10-01 GT1 RM 25-06 GT1 reclassify the Acura NSX GT3 EVO 22 to GT1-ST

#39101 from Club Racing Board · Rule change · TB 25-10 (2025-10 Fastrack)

neutralAcura NSX GT3 EVO 22 reclassified from GT1 to GT1-ST with 3100 lbs minimum weight.

IN GT1 reclassify the Acura NSX GT3 EVO 22 to GT1-ST as follows:
GT1 Approved Automobile List
Make/Model Wheelbase
~~ACURA~~
~~NSX GT3 EVO 22 103.5”~~
~~DOHC 4v per cylinder EFI Twin Turbo Crossflow V-6 Displacement 3500cc Bore and Stroke 91x90~~
~~MAX RPM 7500 MAX BOOST 2.1 bar Weight 3100 lbs~~
GT1-ST Maximum

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Displacement
Minimum
Weight Restrictor Notes
ACURA NSX GT3 EVO 22 3500cc 3100 Per FIA Homologation GT3-047

2025-11-01 STU Non-Homologated Engine Swaps - Specifically K24A2 w/ Honda CRZ

#38746 from William Rori · Rule change · TB 25-09 (2025-09 Fastrack)

slowerSTU Honda K24 engine swap weight increases by 2% effective November 1, 2025.

In STU Spec Lines, Table B: Alternate Vehicle and Engine Allowances, Honda K24, change Weight as follows:
"(Effective 11/1/2025) Chart ~~+ 2%~~"

2025-12-01 STU Turbo Inlet Restrictor Table

#38961 from John Weisberg · Rule change · TB 25-12 (2025-12 Fastrack)

slowerSTU 36mm restrictor allows 2830 lbs (up 10 lbs from 2820); 37mm allows 2980 lbs (down 5 lbs from 2985).

In GCR, Section 9.1.4.H.3, change chart as follows:

A specification table follows in the original; it is not shown here.

2025-12-01 STU 275 Tire Rule

#38983 from Peter Federlin · Rule change · TB 25-12 (2025-12 Fastrack)

slowerSTU cars over 3150 lbs lose 275-tire option with 2% weight adder.

In GCR, Section 9.1.4.G.1., change as follows:
"A maximum section width of 245 is permitted. ~~Cars over 3150 lbs. may run a 275 tire with a 2% weight adder.~~"

2025-12-01 STU STU Honda Engine weight penalty

#39375 from Super Touring Committee · Rule change · TB 25-12 (2025-12 Fastrack)

fasterSTU Honda K20 and K24 engines lose 2% minimum weight penalty.

In STU Spec Lines, Table B: Alternate Vehicle and Engine Allowances, change Minimum Weight as follows:
Honda K20: "Chart ~~+ 2%~~"
Honda K24: "Chart ~~+ 2%~~"

2026-01-01 GT1 NSX Parity With Other GT3s Let Alone a GT1 Car

#39311 from Taz Harvey · Rule change · TB 26-01 (2026-01 Fastrack)

fasterGT1-ST Acura NSX GT3 EVO 22 weight drops 100 lbs to 3000 lbs.

In GT1-ST, Acura NSX GT3 EVO 22, change Weight as follows:
"~~3100~~ 3000"

2026-01-01 STU Request for Permission on Aftermarket Turbo Kit and Intake

#39529 from John Grim · Rule change · TB 26-01 (2026-01 Fastrack)

fasterSTU Mazda MZR (LF, L3, L5) Turbo classified; Jack Spania Racing 70 mm intake manifold and Fab9 Tuning bottom-mount turbo kit approved.

In STU Spec Lines, Table A: Alternate Vehicle and Engine Allowances, Mazda MZR (LF, L3, L5), change Notes as follows:
"Short blocks, heads, and intakes may be freely swapped within these engine designations. May use Goodwin Part # 61-
2510 or, Gato Performance Part #31972 or Jack Spania Racing 70 mm sheet-metal aluminum Intake manifold. Must use stock
throttle body or Acura part number 16400-PND-A17."
In STU Spec Lines, Table A: Alternate Vehicle and Engine Allowances, classify Mazda MZR (LF, L3, L5) Turbo as follows:
STU Maximum Displacement (cc's) Minimum Weight Notes
Mazda MZR (LF, L3,
L5) Turbo

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Varies Chart Short blocks, heads, and intakes may be freely
swapped within these engine designations. May
use Jack Spania Racing 70 mm sheet-metal
aluminum Intake manifold. Must use stock
throttle body or Acura part number 16400-PND-
A17. Fab9 Tuning bottom-mount turbo kit
approved with one of the STU approved Turbos.

2026-02-01 GT1 Request for Addition of Porsche 992.1 GT3 Cup into GT1

#39322 from Erik Madsen · Rule change · TB 26-02 (2026-02 Fastrack)

neutralGT1 adds Porsche 992.1 GT3 Cup (2022-2025) with OEM ABS, traction control, RSR bumper, canards, and any exhaust allowed.

In 9.1.2. GT1 Spec Lines, add the following:
"992.1 GT3 Cup (2022-2025)
OEM ABS and Traction Control allowed. Porsche OEM RSR bumper and canards allowed. Any exhaust system may be utilized."

What the rules allowed changed as listed; this does not say what any particular car ran.