BoP Lab / Buttonwillow Raceway Park

STL + STU + FF at Buttonwillow Raceway Park

No mapCal Club 2024

This track has been raced on 2 configurations (The Circuit, 2.57 mi; 2.92 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.

Pos	Car	Driver	Class	#	Lap	Theoretical	Qual	Race	5-lap stint	Consistency	Trap	S1	S2	S3
1	SWIFT DB-6 Honda	Edward Erlandson 2+ cars	FF	8	1:49.259 A-P									47.766 A-P
2	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
3	Piper DL7-Honda	Eric Poulsen	FF	48	1:51.118 B-R1	1:50.744	1:52.044 B-Q1	1:51.118 B-R1	1:51.583 B-R1	+3.025 B-R1	114.7 B-R1	30.276 B-R1	31.650 B-R1	48.818 B-R1
4	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
5	Mazda MX-5	Jared Korth	STL	27	1:51.665 B-P	1:51.645		1:58.002 A-R2	1:58.825 A-R2	+1.245 A-R2	134.8 A-R1, A-R2	30.616 B-P	32.218 B-P	48.811 B-P
6	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
7	Mazda Miata	Wesley Mollno	STL	11, 111	1:52.983 B-P	1:52.983	1:59.582 A-Q1	1:59.163 A-R1	1:59.870 B-R2	+0.510 B-R2	133.4 A-Q1	30.838 B-P	33.020 B-P	49.197 B-P
8	Mazda Miata	Jon Davies	STL	67	1:53.071 B-P	1:53.071	1:59.281 B-Q1	1:59.121 B-R1	1:59.683 B-R1	+1.145 B-R1	127.3 B-P	30.815 B-P	32.820 B-P	49.536 B-P
9	SWIFT DB-	Edward Erlandson 2+ cars	FF	54	1:53.098 A-Q1	1:53.041	1:53.098 A-Q1	1:54.741 A-R2	1:56.774 A-R2	+1.819 A-R2	133.7 A-Q1	30.951 A-Q1	32.299 A-Q1	49.791 A-Q1
10	Mazda RX-8	David LeCren	STL	2	1:53.515 B-P	1:53.253	2:09.464 A-Q2	2:11.372 A-R2	2:11.978 A-R2	+5.025 A-R2	121.0 A-Q2	31.217 B-P	32.486 B-P	49.550 B-P
11	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
12	Mazda Miata	Sayo Haraishi	STL	34	1:54.120 B-P	1:54.019	2:08.265 B-Q1	2:09.190 B-R1	2:09.557 B-R1	+0.759 B-R1	105.6 B-P	31.129 B-P	33.359 B-P	49.531 B-P
13	Mazda MX-5	Ricardo Arruda	STL	16	1:54.343 B-P	1:54.343	2:00.717 B-Q2	2:01.410 B-R1	2:02.207 B-R1	+0.929 B-R1	104.3 B-P	31.248 B-P	32.888 B-P	50.207 B-P
14	Mazda MX-5	Gavin Wardle	STL	169	1:54.845 A-R1	sector data unreliable	1:58.292 A-Q2	1:54.845 A-R1	1:59.598 A-R2	+0.868 A-R2	132.7 A-R2	8.264	33.984	51.822
15	Mazda Miata	Nick Leverone	STL	137, 37	1:54.963 B-Q2	1:54.891	1:54.963 B-Q2	1:55.682 B-R1	1:56.512 B-R1	+1.038 B-R1	106.0 B-Q1	31.458 B-Q2	32.979 B-Q2	50.454 B-Q2
16	Swift Db6	Johnnie Crean	FF	35	1:54.993 A-R2	1:54.490	1:55.247 A-Q2	1:54.993 A-R2	1:56.752 A-R2	+1.519 A-R2	124.5 A-R2	31.358 A-Q1	32.841 A-R2	50.291 A-R2
17	Honda Civic Si	Jonathan Lugod	STL	61	1:56.438 B-R1	1:56.128	1:57.331 B-Q2	1:56.438 B-R1	1:57.403 B-R1	+1.528 B-R1	106.8 B-P	31.787 B-P	33.468 B-P	50.873 B-P
18	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
19	Honda Prelude	Carl Young	STL	23	1:56.961 B-R1	1:56.631	1:57.917 B-Q2	1:56.961 B-R1	1:57.759 B-R1	+1.599 B-R1	104.5 B-Q2	31.994 B-R1	33.745 B-R1	50.892 B-R1
20	Mazda MX-5	Ryan Gutile	STL	116	1:57.404 B-Q1	1:57.004	1:57.404 B-Q1	1:57.483 B-R1	1:58.542 B-R1	+1.371 B-R1	128.4 A-Q2	31.829 B-R1	33.695 B-Q1	51.480 B-R1
21	Mazda Miata	Amy Mills	STL	114	1:57.757 A-Q2	1:57.494	1:57.757 A-Q2	1:58.239 B-R2	1:58.840 B-R2	+1.462 B-R2	122.6 A-R2	32.321 B-Q2	33.780 A-Q2	51.393 A-Q2
22	Mazda MX-5	Bryce Johnson	STL	15, 13	1:58.716 A-Q2	1:58.419	1:58.716 A-Q2	1:59.496 A-R2	1:59.874 A-R2	+0.878 A-R2	136.6 A-Q1	32.248 A-Q1	34.104 A-Q2	52.067 A-Q2
23	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
24	Mazda Miata	Patrick Drinkwine	STL	151	1:59.239 B-Q1	1:58.754	1:59.239 B-Q1	2:00.132 B-R1	2:00.548 B-R1	+0.505 B-R1	106.6 B-P	32.503 B-P	34.167 B-P	52.084 B-P
25	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
26	Mazda MX-5 (2015)	Adrian Comstock	STL	25	2:00.239 A-Q2	2:00.015	2:00.239 A-Q2	2:00.722 A-R1	2:01.250 A-R2	+0.672 A-R2	133.0 A-R2	32.847 A-R2	34.493 A-Q2	52.675 A-Q2
27	Mazda RX-7	Michael Lewis	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
28	Mazda MX-5	Andy Chittum	STL	99	2:00.296 A-Q2	1:59.684	2:00.296 A-Q2	2:00.787 A-R1	2:01.366 A-R1	+1.093 A-R1	132.9 A-R2	32.848 A-Q1	34.467 A-Q2	52.369 A-Q2
29	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
30	Mazda Miata	Richard James	STL	91	2:02.318 B-R1	2:01.786	2:02.441 A-Q1	2:02.318 B-R1	2:03.149 B-R2	+0.867 B-R2	126.7 A-R1	32.990 B-R1	35.132 A-Q1	53.664 B-R1
31	Mazda Miata	Todd Launchbaugh	STL	73	2:02.759 B-R1	2:02.624		2:02.759 B-R1	2:03.974 B-R1	+1.599 B-R1	98.5 B-R1	33.210 B-R1	35.059 B-R1	54.355 B-R1
32	Mazda Miata	Ayden Vaillancour	STL	88	2:03.022 B-R1	2:02.301	2:03.653 B-Q2	2:03.022 B-R1	2:03.841 B-R1	+0.936 B-R1	100.4 B-P	33.072 B-P	35.168 B-P	54.061 B-R1
33	Mazda Miata	Lauren Lewis >115%	STL	45	2:17.307 A-R1	2:16.162		2:17.307 A-R1	2:18.705 A-R1	+1.938 A-R1	108.6 A-R1	36.821 A-R1	39.026 A-R1	1:00.315 A-R2
34	Acura integra	Jack McEachern >115%	STL	21	2:24.310 B-Q2	2:22.511	2:24.310 B-Q2	2:24.550 B-R2	2:32.162 B-R1	+2.229 B-R1	77.6 B-Q1	38.960 B-Q1	41.141 B-Q2	1:02.410 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
Swift Db6	FF	2	1:49.259Edward Erlandson	1:55.247Johnnie Crean	1:54.993Johnnie Crean	124.5Johnnie Crean	31.358Johnnie Crean	32.841Johnnie Crean	47.766Edward Erlandson
SWIFT DB-6 Honda	FF	1	1:49.259Edward Erlandson						47.766Edward Erlandson
Swift Db6	FF	1	1:54.993Johnnie Crean	1:55.247Johnnie Crean	1:54.993Johnnie Crean	124.5Johnnie Crean	31.358Johnnie Crean	32.841Johnnie Crean	50.291Johnnie Crean
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
Piper DL7-Honda	FF	1	1:51.118Eric Poulsen	1:52.044Eric Poulsen	1:51.118Eric Poulsen	114.7Eric Poulsen	30.276Eric Poulsen	31.650Eric Poulsen	48.818Eric Poulsen
Mazda Miata	STL/STU	20	1:51.602Whitfield Gregg	1:54.963Nick Leverone	1:54.845Gavin Wardle	136.6Bryce Johnson	8.264Gavin Wardle	32.218Jared Korth	48.687Whitfield Gregg
Mazda Miata	STL/STU	11	1:51.602Whitfield Gregg	1:54.963Nick Leverone	1:55.682Nick Leverone	133.4Wesley Mollno	30.652Whitfield Gregg	32.263Whitfield Gregg	48.687Whitfield Gregg
Mazda MX-5	STL/STU	8	1:51.665Jared Korth	1:57.404Ryan Gutile	1:54.845Gavin Wardle	136.6Bryce Johnson	8.264Gavin Wardle	32.218Jared Korth	48.811Jared Korth
Mazda MX-5 (2015)	STL	1	2:00.239Adrian Comstock	2:00.239Adrian Comstock	2:00.722Adrian Comstock	133.0Adrian Comstock	32.847Adrian Comstock	34.493Adrian Comstock	52.675Adrian Comstock
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
SWIFT DB-	FF	1	1:53.098Edward Erlandson	1:53.098Edward Erlandson	1:54.741Edward Erlandson	133.7Edward Erlandson	30.951Edward Erlandson	32.299Edward Erlandson	49.791Edward Erlandson
Mazda RX-8	STL	1	1:53.515David LeCren	2:09.464David LeCren	2:11.372David LeCren	121.0David LeCren	31.217David LeCren	32.486David LeCren	49.550David LeCren
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
Honda Civic Si	STL	1	1:56.438Jonathan Lugod	1:57.331Jonathan Lugod	1:56.438Jonathan Lugod	106.8Jonathan Lugod	31.787Jonathan Lugod	33.468Jonathan Lugod	50.873Jonathan Lugod
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
Honda Prelude	STL	1	1:56.961Carl Young	1:57.917Carl Young	1:56.961Carl Young	104.5Carl Young	31.994Carl Young	33.745Carl Young	50.892Carl Young
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 RX-7	STU	1	2:00.248Michael Lewis		2:00.248Michael Lewis	130.4Michael Lewis	32.729Michael Lewis	34.570Michael Lewis	52.880Michael Lewis
Acura integra	STL	1	2:24.310Jack McEachern	2:24.310Jack McEachern	2:24.550Jack McEachern	77.6Jack McEachern	38.960Jack McEachern	41.141Jack McEachern	1:02.410Jack McEachern

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 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."

2024-08-01 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~~"

2024-10-01 FF Update to FF EGR Blanking Plate Rule

#36633 from Matt Boian · Rule change · TB 24-10 (2024-10 Fastrack)

neutralFF VTEC activation valve must function; EGR blanking plate rule clarified with Fast Forward part numbers.

In FF, GCR section 9.1.1.B.14.r.1, change as follows:
"All emission control devices must be removed and blocked off by the blanking plate provided by HPD or Fast Forward as noted
below, except for the VTEC activation valve. The VTEC activation valve must be retained; and it must be functioning. No
modifications are permitted.
a. EGR Plate: Fast Forward PN: FF200-301.
b. EGR Port Cover: Fast Forward PN: FF200-302."

2024-11-01 FF Change FF/FC Weight with Sequential Gearbox

#36651 from Robert Wright · Rule change · TB 24-11 (2024-11 Fastrack)

fasterFF and FC cars with sequential gearbox must add 10 lbs. to minimum weight, down from 25 lbs.

In FF, GCR section 9.1.1.B.20.A.3, change as follows:
"Cars running with a sequentially shifted gear box ~~shall~~ must add 25 10 lbs. to minimum weight."
In FC, GCR section 9.1.1.B.20.B.4, change as follows:
"Cars running with a sequentially shifted gear box ~~shall~~ must add 25 10 lbs. to minimum weight."

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."

2024-11-01 FF Alternative Oversize Honda Fit Pistons

#37064 from Formula/Sports Racing Committee · Rule change · TB 24-11 (2024-11 Fastrack)

neutralFF Honda Fit allows Fast Forward 0.25mm oversize pistons PN FF800-110 as alternative; piston diameter spec clarified to 2.8835 inches.

In FF, GCR section 9.1.1.B.14.e.1, change as follows:
"Honda Fit OEM standard size pistons, PN: 13010-RB1-000, or Honda Fit OEM 0.25mm oversize pistons, PN: 13020-RB7-Z00, or
Fast Forward 0.25mm oversize pistons, PN: FF800-110, may be used."
In GCR section 9.1.1.B.14.e.2, change as follows:
"a. Maximum standard piston diameter, measured at a point 16mm from the bottom of the skirt: 73.240mm
(~~2.8834~~ 2.8835 inches).
b. Centerline of wrist pin to crown maximum: 26.21mm (1.032 inches).
c. Maximum overall height from skirt to crown edge: 47.80mm (1.882 inches).

Show 13 more lines

d. Minimum weight: 198.0 grams (6.984 ounces).
e. Minimum weight of piston pin: 66 grams (2.25 ounces).
f. Combined minimum weight of piston, piston pin and connecting rod: 543.5 grams (18.85 ounces).
g. Combined minimum weight of piston, wrist pin, and circlips: 267 grams (9.418 ounces).
h. Centerline of wrist pin to crown edge: 26.289mm (1.035 inches).
i. Ring groove widths:
Top ring groove: 1.003mm (0.0395 inches).
Middle ring groove: 1.016mm (0.0400 inches).
Oil ring groove: 1.981mm (0.0780 inches).
j. Ring groove distance from wrist pin center to bottom of groove:
Top ring groove: 19.63mm (0.7730 inches).
Middle ring groove: 15.29mm (0.6020 inches).
Oil ring groove: 10.91mm (0.4295 inches)."

2024-12-01 STL 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 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.

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.

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 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 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 FF Formula F Proposal to Invite Older Cars Via a Tire Rule Change

#37802 from Anthony Stefanelli · Rule change · TB 25-03 (2025-03 Fastrack)

fasterFF allows older cars with rocker arm or outboard suspension to use bias ply slicks or VFF tires instead of radials.

In FF, GCR section 9.1.1.B.10.e, change as follows:
"Formula F shall be limited to the following tires (front tires may not be used as rears):
Dries:
Front - Hoosier R60A Radial 43322 or F1600 Radial 43321 185/60R13
Rear - Hoosier R60A Radial 43327 or F1600 Radial 43326 205/60R13
Wets:
Front - Hoosier Wet or W3 Radial 44421 185/60R13
Rear - Hoosier Wet or W3 Radial 44426 205/60R13

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Alternatively, Formula F cars with rocker arm suspension (e.g., Swift DB1, 1987-90 Reynard) and/or outboard suspension on at
least one chassis end may use the following tires:
Dries:
Front - Hoosier H43130 R60A 20.0 x 6.0-13 or H43164 R60A 20.5 x 7.0-13 bias ply slick
Rear – Hoosier H43307 R60A 22.5 x 7.2-13 bias ply slick
Wets:
Radial wets listed above
or
Front - Hoosier 44165 135/545-13 VFF
Rear - Hoosier 44170 165/580-13 VFF
Front tires may not be used as rears, and tires may not be mixed, i.e., radial tires may not be mixed with bias ply slick tires, bias
ply slick tires may not be mixed with VFF tires, and radial tires may not be mixed with VFF tires."

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 STL E&O: SMX Allowance in STL

#37945 from Greg Amy · Rule change · TB 25-05 (2025-05 Fastrack)

unclearSTL Mazda MX5 Challenge minimum weight now references GCR 9.1.7.1 instead of 2500 lbs; spec components removed, only alternative tires allowed.

In STL Spec Lines, Table B, Mazda Spec MX5 Challenge, change as follows:
Minimum Weight: "~~2500~~ See 9.1.7.1."
Notes: "~~Mazda MX5 Challenge car must utilize the following components: Roush CNC cylinder head 0000-01-5300,Mahle~~
~~standard or +0.005 0000-01-5310, OEM camshaft, 11:1 compression ratio, header 0000-06-5407-NC, exhaust 0000-06-5427-NC,~~
~~cold air intake 0000- 06-5150-KT, ECU flash 0000-01-5379, Pagid front brake pads 0000-03-5104-SP or endurance pads 0000-03-~~
~~5104-EN, Pagid rear brake pads 0000-03-5114-SP or endurance pads 0000-03-5114-EN, Penske front shock 0000-04-5291-SA,~~
~~Penske rear shock 0000-04-5292-SA, Penske rear mount kit 0000-04-5358, Front mount kit 0000-04-5359, Front offset bushing~~
~~0000-04-5407-NC, Eibach front springs 0000-04-9700-08, Eibach rear springs 0000-04-9400-07, Eibach helper springs 0000-04-~~

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~~9926, Eibach front sway bar 0000-04-5306-FT, Eibach rear sway bar 0000-04-5306-RR, Interior finish panels 0000-07-5822, C&R~~
~~radiator/oil cooler assembly 0000-01-5504-CR, Oil cooler adapter and lines 0000-01-5511-KT, ACT clutch 0000-02-5004-G6,~~
~~wheels 17x8 #0000-04-5706-GM, # 0000- 04-5706-SL, and Toyo RR 235-40-17 dry, Toyo RA1 235-40-17 wet. Alternative tires on~~
~~17x7 wheels per STL rules. No other Super Touring modifications or allowances permitted except as noted in this spec line.~~ Must
conform completely to GCR 9.1.7.1, except alternative tires (only) per STL regs allowed."

Applies to Mazda Miata on this page: Jared Korth, Ricardo Arruda, Gavin Wardle, Ryan Gutile, Bryce Johnson, Andy Chittum, Adrian Comstock

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 FF Page 228, FF tire rule 9.1.1.10.e

#38251 from Anthony Stefanelli · Rule change · TB 25-05 (2025-05 Fastrack)

neutralFF adds rocker arm and outboard suspension cars optional bias ply and VFF tires; removes front-as-rear rule, adds mixing restrictions.

In FF, GCR section 9.1.1.B.10.e, change as follows:
"Formula F shall be limited to the following tires ~~(front tires may not be used as rears)~~:
Dries:
Front - Hoosier R60A Radial 43322 or F1600 Radial 43321 185/60R13
Rear - Hoosier R60A Radial 43327 or F1600 Radial 43326 205/60R13
Wets:
Front - Hoosier Wet or W3 Radial 44421 185/60R13
Rear - Hoosier Wet or W3 Radial 44426 205/60R13

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Alternatively, Formula F cars with rocker arm suspension (e.g., Swift DB1, 1987-90 Reynard) and/or outboard suspension on at
least one chassis end may use the following tires:
Dries:
Front - Hoosier H43130 R60A 20.0 x 6.0-13 or H43164 R60A 20.5 x 7.0-13 bias ply slick
or
Hoosier 44165 135/545-13 VFF
Rear – Hoosier H43307 R60A 22.5 x 7.2-13 bias ply slick
or
Hoosier 44170 165/580-13 VFF
Wets:
Radial wets or VFF tires listed above
or
~~Front - Hoosier 44165 135/545-13 VFF~~
~~Rear - Hoosier 44170 165/580-13 VFF~~
Front tires may not be used as rears, and tires may not be mixed, i.e., radial tires may not be mixed with bias ply slick tires, bias
ply slick tires may not be mixed with VFF tires, and radial tires may not be mixed with VFF tires."

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 STL 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"

2025-08-01 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.

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"

2025-11-01 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 FF Formula F Alternative Tire Rule Proposed Clarifications

#39281 from Jay Messenger · Rule change · TB 26-01 (2026-01 Fastrack)

neutralFF clarifies alternative tire eligibility for cars homologated 1989 or earlier with rocker arm or outboard suspension on all four corners.

In FF, GCR section 9.1.1.B.10.e, change as follows:
"Alternatively, Formula F cars ~~with rocker arm suspension (e.g., 1987-90 Reynard, Swift DB1,) and/or outboard suspension on at~~
~~least one chassis end~~ homologated in 1989 or earlier with any combination of rocker arm or outboard suspension on all four
corners (e.g., 1987 – 1990 Reynard, Swift DB1) may use the following alternative tires. Note: This rule is intended to allow older
cars with the described suspension design to use the alternative tires. It is not to be exploited by modifying cars with push-rods or
pull-rods to meet the above requirements or by modifying either end of older cars to push- or pull-rod suspension to be eligible to
run the alternative tires. Cars that were homologated in 1989 or earlier with push- or pull-rod suspension on no more than two
corners may seek approval to run the alternative tire by utilizing the compliance process outlined in GCR section 8.1.4."

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.

2026-01-01 STL Weight adjustment for STL

#39579 from Super Touring Committee · Rule change · TB 26-01 (2026-01 Fastrack)

slowerSTL minimum weights increase across all classes, 1300 cc gains 195 lbs to 1950, up to 1850 cc at 2500.

In GCR, Section 9.1.4.2.H.1. change Minimum Weight on chart as follows:

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

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