BoP Lab / Buttonwillow Raceway Park

EP + STU + FA 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.

One session is left out because the timing does not look like full laps: Cal Club 2023 Qualifying #2.

Pos	Car	Driver	Class	#	Lap	Theoretical	Qual	Race	5-lap stint	Consistency	Trap	S1	S2	S3
1	Swift 016	Greg Labadie	FA	35	1:35.792 A-Q1	1:35.351	1:35.792 A-Q1	1:37.275 A-R1	1:37.692 A-R1	+3.958 A-R1	163.8 A-R1	26.713 A-Q2	26.816 A-Q1	41.822 A-Q1
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	Mazda Miata	Whitfield Gregg 2+ cars	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
4	Mazda Miata	Joe Carr	EP	12	1:52.034 B-P	1:52.034	1:59.603 A-Q1	1:59.157 A-R1	1:59.373 A-R1	+0.724 A-R1	131.6 A-R1	31.719 B-P	32.405 B-P	49.966 B-P
5	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
6	Mazda MX-5	Glen McCready	EP	4	1:53.088 B-Q2	1:52.984	1:53.088 B-Q2	1:53.487 B-R2	1:54.617 B-R2	+2.232 B-R2	125.6 B-P	30.761 B-R2	32.765 B-Q1	49.458 B-Q2
7	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
8	Mazda RX-7	Kurt Frietzsche	EP	40	1:56.468 B-Q1	1:55.599	1:56.468 B-Q1	1:56.573 B-R1	1:57.721 B-R1	+1.914 B-R1	120.7 A-R2	31.324 B-Q1	34.071 B-R1	50.204 B-R1
9	BMW 330	Sean Lovett 2+ cars	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
10	Mazda RX-7	Brandon Droese	EP	02	1:56.943 B-Q1	1:56.657	1:56.943 B-Q1	1:58.611 B-R1	1:58.767 B-R1	+0.718 B-R1	94.1 B-Q1, B-R1	31.953 B-R1	33.891 B-Q1	50.813 B-Q1
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	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	BMW E30	Sean Lovett 2+ cars	EP	37	2:00.712 A-Q2	2:00.625	2:00.712 A-Q2	2:01.864 A-R2	2:02.200 A-R1	+0.528 A-R1	127.6 A-Q2	32.761 A-Q1	34.806 A-Q1	53.058 A-Q2
15	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
16	Porsche Boxster	William Robinson	EP	198	2:01.940 A-Q1	2:01.634	2:01.940 A-Q1	2:02.887 A-R1	2:03.347 A-R1	+1.312 A-R1	130.6 A-Q2	32.969 A-Q1	35.257 A-Q1	53.408 A-Q1
17	Mazda MX-5	Whitfield Gregg 2+ cars	EP	17	2:03.660 B-Q2	2:03.314	2:03.660 B-Q2	2:04.085 B-R1	2:05.470 B-R2	+2.529 B-R2	97.7 B-R2	33.862 B-R2	35.422 B-R1	54.030 B-Q2

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 016	FA	1	1:35.792Greg Labadie	1:35.792Greg Labadie	1:37.275Greg Labadie	163.8Greg Labadie	26.713Greg Labadie	26.816Greg Labadie	41.822Greg Labadie
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	EP/STU	2	1:51.602Whitfield Gregg	1:59.603Joe Carr	1:59.157Joe Carr	131.6Joe Carr	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 MX-5	EP/STU	4	1:53.088Glen McCready	1:53.088Glen McCready	1:53.487Glen McCready	125.9Dale Shoemaker	30.761Glen McCready	32.765Glen McCready	49.458Glen McCready
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
Mazda RX-7	EP/STU	3	1:56.468Kurt Frietzsche	1:56.468Kurt Frietzsche	1:56.573Kurt Frietzsche	130.4Michael Lewis	31.324Kurt Frietzsche	33.891Brandon Droese	50.204Kurt Frietzsche
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
BMW E30	EP	1	2:00.712Sean Lovett	2:00.712Sean Lovett	2:01.864Sean Lovett	127.6Sean Lovett	32.761Sean Lovett	34.806Sean Lovett	53.058Sean Lovett
Porsche Boxster	EP	1	2:01.940William Robinson	2:01.940William Robinson	2:02.887William Robinson	130.6William Robinson	32.969William Robinson	35.257William Robinson	53.408William Robinson

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 EP Investigate Parity of Z3

#33343 from Tim Schreyer · Rule change · TB 23-01 (2023-01 Fastrack)

slowerEP BMW Z3 2.5L intake restrictor reduced from 58mm to 56mm flat plate.

Effective 4/1/2023 In EP Spec Line BMW Z3 2.5L, change Notes as follows:
"58 56mm Flat Plate Intake Restrictor is required with both stock or alternate throttle body."

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.

2023-05-01 FA E&O - Correct Pro Formula Mazda spec line dimensional equivalent

#34085 from Club Racing Board · Rule change · TB 23-05 (2023-05 Fastrack)

fasterFA Pro Formula Mazda maximum bodywork width behind front wheels increases to 51.97 inches.

In FA Table 2, Pro Formula Mazda spec line, change as follows:
"The overall maximum width of the bodywork behind the front wheels shall not exceed 132cm (~~51.17~~ 51.97 inches)."

2023-05-01 FA Add new spec line for MSR Formula Mazda FMzR to Table 2

#34139 from Club Racing Board · Rule change · TB 23-05 (2023-05 Fastrack)

neutralFA MSR Formula Mazda FMzR added to Table 2 classification.

RM 23-06 – MSR - FMzR Formula Atlantic Classification dated 4/21/2023
In FA Table 2, add a spec line as follows:

2023-06-01 EP 914-6 Valve Size Correction

#34185 from Kip VanSteenburg · Rule change · TB 23-06 (2023-05 Fastrack)

fasterEP Porsche 914-6 2.0L intake valves increase to 2.0 mm, exhaust valves corrected to 38.0 mm.

In EP Spec Lines, Porsche 914 - 6 2.0L, change Valves IN & EX mm/(in.) as follows:
"(I) 4~~1.9~~ 2.0/(1.65)
(E) 38.1 0/(1.50)"

2023-06-01 FA Simplify Pro Formula Mazda wheel allowance

#34190 from Club Racing Board · Rule change · TB 23-06 (2023-06 Fastrack)

unclearFA Pro Formula Mazda front wheels widen to 10 in. max; rear wheels narrow to 14 in. min.

In FA, Pro Formula Mazda spec line, change wheel width as follows:
"~~Pro Mazda series wheels~~

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

2023-07-01 EP Correct Intake Valve Size on 1500cc Midget/Spitfire

#34419 from Production Committee · Rule change · TB 23-06 (2023-05 Fastrack)

neutralFP and HP Sprite, Midget, and Spitfire 1500 intake valve size corrected to 36.6/(1.44).

In FP Spec Lines, Austin-Healey Sprite Mk. I, II,III, IV MG Midget Mk I,II, III, IV & 1500, change Intake Valve Size as follows:
"(I) 36.6~~5.3~~/(1.44)"
In FP Spec Lines, Triumph Spitfire Mk. IV & 1500, change Intake Valve Size as follows:
"(I) 36.6~~5.5~~/(1.440)"
In HP Spec Lines, Triumph Spitfire 1500, change Intake Valve Size as follows:
"(I) 36.6~~5.5~~/(1.440)"
In HP Spec Lines, Triumph Spitfire Mk. III & IV 1500, change Intake Valve Size as follows:
"(I) 36.6~~5.5~~/(1.440)"

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.

2023-09-01 EP Hub Note Clean Up In EP TR8 Spec Line

#34649 from Jeff young · Rule change · TB 23-09 (2023-09 Fastrack)

neutralEP Triumph TR8 78-81 removes alternate front hub allowance note; stock hubs now required.

In the EP Spec Lines, Triumph TR8 (78-81), remove the following wording from Notes:
"~~Alternate front hubs are allowed provided they are of the same external dimensions as stock and weigh no less than the stock~~
~~hubs.~~"

2023-09-01 EP Triumph GT6 Adjustments

#34662 from ANTHONY PARKER · Rule change · TB 23-09 (2023-09 Fastrack)

unclearEP Triumph GT6 carburetors change from SU or Stromberg to 1.5" Auto-type.

In EP Spec Lines, Triumph GT6, change Carburetor. No. & Type as follows:
"(2) 1.5” ~~SU or Stromberg~~ Auto-type carburetor(s)"

2023-09-01 EP Triumph GT6 Adjustments: Brakes

#34663 from ANTHONY PARKER · Rule change · TB 23-09 (2023-09 Fastrack)

neutralEP Triumph GT6 brakes may now use TR-6 standard or alternate calipers and discs.

In EP Spec Lines, Triumph GT6, add the following to Brakes Alt.: mm/(in.):
"(F) Calipers & discs from TR-6 (std. or alt)"

2023-12-01 EP Porsche 944/924S Rule Change Request

#35002 from Adam Achepohl · Rule change · TB 23-12 (2023-12 Fastrack)

neutralEP Porsche 944/924S combines 2.5L and 2.7L variants with new weights: 2250–2415 lbs depending on engine and year.

In EP Spec Lines, delete the Porsche 944/924S 2.5L (2V) (83-88) spec line entirely, and create a new spec line for Porsche
944/924S 2.5L(2V) 2.7L(2V) (83-89) as follows:

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

2023-12-01 EP Triumph GT6 Adjustments

#35054 from ANTHONY PARKER · Rule change · TB 23-12 (2023-12 Fastrack)

fasterEP Triumph GT6 minimum weight reduced to 1800 lbs.

In EP Spec Lines, Triumph GT6, change weight as follows:
"~~1830~~ 1800"

2024-01-01 EP Request to Review Z3 2.5 Spec Line

#35073 from Tim Schreyer · Rule change · TB 24-01 (2024-01 Fastrack)

slowerEP BMW Z3 2.5L weight increases to 2500 lbs, 2563 lbs with turbo, 2625 lbs with supercharger.

In EP spec line, BMW Z3 2.5L, change weight as follows:
"~~2450~~ 2500
*~~2511~~ 2563
**~~2573~~ 2625"

2024-01-01 EP Miata Alternate Head

#35253 from Don Tucker · Rule change · TB 24-01 (2024-01 Fastrack)

fasterEP Mazda MX-5 1.8L 1990-97 minimum weight drops to 2150 lbs; 1994-97 variants to 2000, 2050, 2100 lbs respectively.

In EP Spec Lines, Mazda MX-5 /Miata 1.8L (90-97), change weight as follows:
"~~2200~~ 2150"
Mazda MX-5 /Miata (94-97)
"~~2035~~ 2000
*~~2086~~ 2050
**~~2137~~ 2100"

Applies to Mazda Miata on this page: Joe Carr

Applies to Mazda MX-5 on this page: Glen McCready, Whitfield Gregg

2024-01-01 EP Triumph GT6 Adjustments

#35255 from Anthony Parker · Rule change · TB 24-01 (2024-01 Fastrack)

fasterEP Triumph GT6 dual 1.75" carbs weight drops to 1940 lbs; triple Weber 40 DCOE options consolidated.

In EP spec line, Triumph GT6, make the following change in the Notes section:
"Two (2) 1.75” auto-type carburetors @ 1970 40 lbs. Three (3) Weber 40 DCOE on IR manifold with 28mm chokes @ 1990
lbs. Laycock overdrive, May use 5 speed gearbox w/o overdrive. ~~Three (3) Weber 40mm DCOE w/28mm venturi on individual~~
~~runner manifold @ 2020 lb.~~"

2024-01-01 EP Honda S2000 throttle body

#35272 from Aaron Johnson · Rule change · TB 24-01 (2024-01 Fastrack)

fasterEP Honda S2000 fuel injected throttle body inside diameter increases from 62mm to 64mm.

In EP spec line, Honda S2000, make the following changes to its spec line:
Fuel Injected Equipped Throttle Body Inside Diameter: "62 64"
Notes: "Comp. Ratio limited to 12.0:1. Valve lift limited to .500”. An adaptor plate can be used to mount the 62mm throttle body
from '00-05 to the '06-09 intake manifold. The adaptor plate can be no more than 1.25" thick, and its bore must not exceed the
"Fuel Injected Equipped Throttle Body Inside Diameter" maximum spec of 64mm."

2024-01-01 EP Correction within Triumph TR8 Spec Line

#35315 from Production Committee · Rule change · TB 24-01 (2024-01 Fastrack)

neutralEP Triumph TR8 dry sump allowance moved from carburetor line to notes section.

In EP spec line, Triumph TR8 (78-81), move the "Dry sump allowed" wording to the appropriate location as follows:
Carburetor. No. & Type: “Zenith Stromberg carbs or fuel injection. ~~Dry sump is allowed.~~”
Notes: “Comp. Ratio limited to 12.0:1, Valve lift limited to .500”. Dry sump is allowed.”

2024-01-01 EP Correction to EP 924S/944 Spec Line

#35317 from Production Committee · Rule change · TB 24-01 (2024-01 Fastrack)

neutralEP Porsche 944/924S 2.5L and 2.7L weight minimums corrected: 2479cc to 2306/2363 lbs, 2681cc to 2358/2415 lbs.

In EP spec line, Porsche 944/924S 2.5L (2V) / 2.7L (2V) (83-89), change Weight as follows:

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

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 EP Update 1988-1991 Civic to Match 1988-1991 CRX

#35399 from Enrik Benazic · Rule change · TB 24-02 (2024-01 Fastrack)

fasterHP Honda Civic 1.5 (88-91) weight reduced to 2175 lbs base, 2229 lbs with power adder, 2284 lbs with two.

In HP, make the following weight change:
Honda Civic 1.5 (88-91)
~~“2245~~ 2175
*~~2301~~ 2229
**~~2357~~ 2284”

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."

2024-03-01 EP GCR Correction - Redundant HP Spec Lines

#35623 from Production Committee · Rule change · TB 24-03 (2024-03 Fastrack)

neutralHP removes four redundant VW spec lines: Rabbit Cabriolet 1780, Scirocco 1588, Scirocco 1780 8-valve, Scirocco 1588.

In HP Spec Lines, delete the following redundant spec lines in their entirety:
Spec line #10 - VW Rabbit Cabriolet 1780
Spec line #3 - VW Scirocco 1588
Spec line #4 - VW Scirocco 1780 (8-valve) (83-88)
Spec line #5 - VW Scirocco 1588

2024-06-01 EP NIssan 300ZX Z31 to EP

#35830 from Murphy Nichols · Rule change · TB 24-06 (2024-06 Fastrack)

neutralNissan 300ZX 84-89 classified to EP at 2550 lbs minimum, 2960cc 6-cyl SOHC, fuel injection, 12.0:1 compression limit, 0.500" valve lift limit.

In EP Spec Lines, classify Nissan 300ZX (84-89), as follows:

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

2024-06-01 EP RX7 1993 and Up Request In EP Spec Lines, classify

#36031 from Edward Zabinski · Rule change · TB 24-06 (2024-06 Fastrack)

neutralMazda RX-7 92-97 newly classified EP Prep Level 2 at 2200–2310 lbs with 13B 6-port rotary engine.

Mazda RX-7 (92-97) as follows:

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

2024-06-01 EP Clean-up Multiple EP RX-8 Spec Lines In EP

#36156 from Production Committee · Rule change · TB 24-06 (2024-06 Fastrack)

neutralEP Mazda RX-8 (04-11) alternate spec line removed; one primary line remains.

Spec Lines, make the following changes to the two Mazda RX-8 spec lines.
Remove spec line entirely:
~~Mazda RX-8 (04-11)~~
Remove the wording "alternate":
Mazda RX-8 (04-11)~~(alternate)~~
Spec Mazda (SM/SMX) None.

2024-08-01 EP Errant entry in HP production line item

#36231 from Angus Crome · Rule change · TB 24-08 (2024-08 Fastrack)

neutralHP Volkswagen Golf and Jetta 85-92 track correction: front 1537mm (60.5in), rear 1529mm (60.2in).

In HP Spec Lines, change Track (F/R)mm/(in.) as follows:
Volkswagen Golf (GTI, GT, GL) (85-92): "2 1537/1529 (60.5/60.2)"
Volkswagen Jetta (GLI, GL) (85-92): "2 1537/1529 (60.5/60.2)"

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 EP 1275 HP Spridget Level 2 Only

#36518 from Darryl Saylor · Rule change · TB 24-09 (2024-09 Fastrack)

fasterHP Sprite and Midget 1275cc and 1098cc Level 2 compression ratio raised to 12.0:1.

In HP Spec Lines, Austin-Healey Sprite MkI, II, III, IV MG Midget (ALL) - Level 2 - 1275cc, change Notes as follows:
"(Effective 11/1/2024) Compression ratio limited to 11 12.0:1"
In HP Spec Lines, Austin-Healey Sprite MkI, II, III, IV MG Midget (ALL) - Level 2 - 1098cc, change Notes as follows:
"(Effective 11/1/2024) Compression ratio limited to 11 12.0:1"

2024-11-01 EP NA Miata Track Width Correction

#36902 from Production Committee · Rule change · TB 24-11 (2024-11 Fastrack)

neutralEP Mazda Miata front and rear track widths increased to 1516/1534 mm (59.7/60.4 in.) across all generations.

In EP Spec Lines, Track (F/R) mm/(in.), change as follows:
Mazda MX-5 /Miata 1.6L (-1993) - ~~"1478/1491 (58.2/58.7)~~ 1516/1534 (59.7/60.4)"
Mazda MX-5 /Miata 1.8L (90-97) - ~~"1483/1509 (58.4/59.4)~~ 1516/1534 (59.7/60.4)"
Mazda MX-5 /Miata (94-97) - "~~1483/1509 (58.4/59.4)~~ 1516/1534 (59.7/60.4)"

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 EP Triumph GT6 Adjustments

#37112 from Anthony Parker · Rule change · TB 24-12 (2024-12 Fastrack)

slowerEP Triumph GT6 switches to three Weber 40 DCOE carbs with 28mm chokes, weight rises 50 lbs to 1990.

In EP Spec Lines, make the following changes in the "Triumph GT6" spec line:
Carburetor No. & Type: (2): "~~1.5”~~ 1.75" Auto-type carburetor(s)"
Notes: "~~Two (2) 1.75” auto-type carburetors @ 1940 lbs.~~ Three (3) Weber 40 DCOE on IR manifold with 28mm chokes @ 1990
lbs. Laycock overdrive, May use 5 speed gearbox w/o overdrive."

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.

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 EP Request to Reduce Weight of BMW 325i/is E30 (84-91) Spec Line

#37119 from Tim Schreyer · Rule change · TB 25-01 (2025-01 Fastrack)

fasterEP BMW 325i/is E30 (84-91) weight reduced 50–52 lbs across three spec lines to 2150, 2204, 2258.

In EP SPEC LINES, BMW 325i/is (E30) (84-91), change Weight as follows:
"~~2200~~ 2150
*~~2255~~ 2204
**~~2310~~ 2258"

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."

2025-02-01 FA Classify FR European Championship car as spec line car in Table 2

#37658 from Club Racing Board · Rule change · TB 25-02 (2025-02 Fastrack)

neutralFA adds Tatuus F.3 T-318 or FR-19 as spec line car in Table 2 for Formula Regional European Championship.

In FA Table 2, add the following:
Table 2 (Spec Line Cars)
Car Engine
Wheel
Width (in)
± .060
Aero Transmission Weight Notes

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

2025-02-21 EP Effective date for Jan 2025 GCR updates

#37654 from Doug Piner · Rule change · TB 25-02 (2025-02 Fastrack)

slowerEP BMW Z3 2.5L requires 52mm flat plate intake restrictor; Z3 2.8L 55mm; 328i/is E36 58mm; 328i/ci E46 58mm; 325i/is E46 56mm; 325i/is E36 56mm; 325is M-Technic 56mm.

In EP Spec Lines, add to Notes as follows:
BMW Z3 2.5LL "(Effective 2/21/2025) 52mm Flat Plate Intake Restrictor is required."
BMW Z3 2.8L (97-00): "(Effective 2/21/2025) 55mm Flat Plate Intake Restrictor is required."
BMW 328i/is E36 (96-99): "(Effective 2/21/2025) 58mm Flat Plate Intake Restrictor is required."
BMW 328i/ci E46 (01-06): "(Effective 2/21/2025) 58mm Flat Plate Intake Restrictor is required."
BMW 325i/is E46 (01-06): "(Effective 2/21/2025) 56mm Flat Plate Intake Restrictor is required."
BMW 325i/is E-36 (92-95): "(Effective 2/21/2025) 56mm Flat Plate Intake Restrictor is required."
BMW 325is M-Technic (1994): "(Effective 2/21/2025) 56mm Flat Plate Intake Restrictor is required."

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

2025-03-01 EP Request Competition Adjustment to BMW Z3 2.5L

#37120 from Tim Schreyer · Rule change · TB 25-01 (2025-01 Fastrack)

slowerEP BMW Z3 and 3-series models get smaller intake restrictors: Z3 2.5L to 52mm, Z3 2.8L to 55mm, 328i to 58mm, 325i to 56mm.

In EP Spec Lines, change Notes as follows:
BMW Z3 2.5LL "(Effective 3/1/2025) ~~56mm~~ 52mm Flat Plate Intake Restrictor is required."
BMW Z3 2.8L (97-00): "(Effective 3/1/2025) ~~59mm~~ 55mm Flat Plate Intake Restrictor is required."
BMW 328i/is E36 (96-99): "(Effective 3/1/2025) ~~62mm~~ 58mm Flat Plate Intake Restrictor is required."
BMW 328i/ci E46 (01-06): "(Effective 3/1/2025) ~~62mm~~ 58mm Flat Plate Intake Restrictor is required."
BMW 325i/is E46 (01-06): "(Effective 3/1/2025) ~~60mm~~ 56mm Flat Plate Intake Restrictor is required."
BMW 325i/is E-36 (92-95): "(Effective 3/1/2025) ~~60mm~~ 56mm Flat Plate Intake Restrictor is required."
BMW 325is M-Technic (1994): "(Effective 3/1/2025) ~~60mm~~ 56mm Flat Plate Intake Restrictor is required."

2025-03-01 EP Interpretation of Production Rules on Mirrors

#37235 from Lawrence Slivinski · Rule change · TB 25-03 (2025-03 Fastrack)

neutralEP, FP, HP: interior or exterior mirrors meeting rule 9.3.36 now permitted.

In GCR, add new rule as Section 9.1.5.E.10.f:
"Any interior or exterior mirror(s) that meets rule 9.3.36 may be used."

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 EP Weight Reduction for Honda S2000

#37466 from Michael Unger · Rule change · TB 25-03 (2025-03 Fastrack)

fasterEP Honda S2000 1997cc base loses 75 lbs to 2375; 2157cc base loses 60 lbs to 2450.

In EP, Spec Lines make the following weight changes:

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

2025-03-01 EP Mazda 1999 Miata 1.8L

#37488 from Joe Carr · Rule change · TB 25-03 (2025-03 Fastrack)

fasterEP Mazda MX-5/Miata 99-05 minimum weight drops to 2100 lbs, 2153 lbs with power adder, 2205 lbs with two adders.

In EP Spec Lines, make the following weight change:
Mazda MX-5 /Miata (99-05):
"~~2150~~ 2100
*~~2204~~ 2153
**~~2258~~ 2205"

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 FA Update Formula Renault 2.0 spec line notes

#37853 from Club Racing Board · Rule change · TB 25-03 (2025-03 Fastrack)

neutralFA Formula Renault 2.0 (10-17) spec notes clarified: engine sealed, manual compliance required, tire choice unrestricted, no alterations except repairs.

In FA Table 2, Formula Renault 2.0 (10-17) spec line, change the notes as follows:
"Engine must remain sealed. Car must comply with year-specific Formula Renault 2.0 manual, technical regulations, and all
applicable bulletins ~~found here:~~. Competitors must have copies of these materials in their possession and present them upon
request.
~~https://sites.google.com/a/renault-sport.com/formule-renault-2-0-en/bulletins-techniques/2017,~~
~~https://sites.google.com/a/renault-sport.com/formule-renault-2-0-en/manuel-d-utilisateur/2017.~~
The following exceptions apply: Tire choice is unrestricted. No part of the car may be altered from original Formula Renault 2.0
components, except for necessary repairs that do not affect performance."

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"

2025-04-01 EP Request for Classification of Chevrolet Spark

#37755 from Kristian Smith · Rule change · TB 25-04 (2025-04 Fastrack)

neutralChevrolet Spark 16-22 classified HP Pre at 1850 lbs minimum weight, fuel injected, 1399 cc.

In HP Spec Lines, classify the Chevrolet Spark (16-22):

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

2025-04-01 EP Request to Lower Ford Festiva Minimum Weight to 1600 LBS

#37939 from Doug DeRonne · Rule change · TB 25-04 (2025-04 Fastrack)

fasterHP Ford Festiva 88-93 minimum weight drops to 1600 lbs, variants to 1640 and 1680 lbs; compression ratio raised to 11.0:1.

In HP Spec Lines "Ford Festiva (88-93)" change as follows:
Weight:
"~~1700~~ 1600
*~~1743~~ 1640
**~~1785~~ 1680"
Notes:
"Compression ratio limited to ~~10.5~~ 11.0:1. Valve lift limited to .450”."

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."

2025-06-01 EP Base Weight Adjustment for H-Production X1/9 Spec Lines

#38255 from Matthew Brannon · Rule change · TB 25-06 (2025-06 Fastrack)

fasterHP Fiat X-1/9 base weights reduced 50–53 lbs across 1300 and 1500 spec lines.

In HP Spec Lines, change Weight as follows:
Fiat X-1/9 & Bertone1500: “~~1790~~ 1740 *~~1835~~ 1784 **~~1880~~ 1827”
Fiat X-1/9 1300: “~~1650~~ 1600 *~~1691~~ 1640 **~~1733~~ 1680”
Fiat X-1/9 1300: “~~2060~~ 2010”
Fiat X-1/9 1500: “~~1950~~ 1900”

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 FA Ligier JS F3 Tire Choice

#38434 from Rocco Magni · Rule change · TB 25-07 (2025-07 Fastrack)

neutralFA Ligier JS F3 front tires may be Hoosier 43363 240/580R13 MS, rear 43368 300/590R13 MS.

In FA Table 2, FR Americas Ligier JS F3 spec line, change the notes as follows:
"Engine must be sealed in compliance with FR Americas or prior F3 Americas requirements. Car must comply with FR Americas
rules, with the following exception: front tires may be Hoosier P/N 43363, size 240/580R13 in MS compound, and rear tires may
be Hoosier P/N 43368, size 300/590R13 in MS compound. Competitors must have current copies of Formula Regional Americas
Championship Sporting Regulations, Onroak Automotive Ligier JS F3 Information Manual, and HPD engine-related specifications
and instructions in their possession and present them upon request."

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.

2025-07-01 EP BMW Z4 update

#38490 from Bryce McGuire · Rule change · TB 25-07 (2025-07 Fastrack)

slowerEP BMW Z4 03-05 restricted to 52mm flat plate intake restrictor.

In EP Spec Lines, BMW Z4 (03-05), add to Notes the following:
“52mm Flat Plate Intake Restrictor.”

2025-07-01 EP EP Fiat 124 Spider Competition Adjustment Request

#38498 from John Baucom · Rule change · TB 25-07 (2025-07 Fastrack)

fasterEP Fiat 124 Spider 1600 & 2000 weight drops 50 lbs to 2000; carburetors gain 2mm chokes to 36mm.

In EP Spec Lines, Fiat 124 Sport Spider 1600 & 124 Spider 2000, change as follows:
Weight: "~~2050~~ 2000"
Carburetor No. & Type: "(2) Weber 40 IDF-40IFI, (2) Solex C40P116, 34 36mm choke(s) req’d, (2) Weber 45DCOE w/ 34 36 mm
choke(s) on I.R. manifold or fuel injection."

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 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 EP HP Plymouth Arrow spec omission

#38995 from Production Committee · Rule change · TB 25-10 (2025-10 Fastrack)

neutralHP Plymouth Arrow transmission max speeds clarified to 4 or 5.

In HP Spec Lines, Plymouth Arrow (76-80), add the following wording to Trans. Speeds(max):
"4 or 5"

2025-10-01 EP Add Wheel Diameter to Appendix G

#39008 from Production Committee · Rule change · TB 25-10 (2025-10 Fastrack)

neutralEP, FP, HP wheel diameter added to Appendix G as absolute maximum specification.

In Appendix G.2.3, change as follows:
"Rim width and diameter are is absolute maximums."

2025-10-01 EP Add TB ID tolerance to general Prod rules

#39009 from Production Committee · Rule change · TB 25-10 (2025-10 Fastrack)

neutralEP, FP, HP throttle body inside dimensions must remain stock with +/-.25mm tolerance; butterfly dimensions stock in FP, HP only.

In GCR, Section 9.1.5.E., change as follows:
9.1.5.E.1.b.4: "The inside dimensions of the throttle body casting/housing (as measured at the throttle butterfly) must remain
stock (tolerance of +/-.25mm), but the throttle body can otherwise be ported and polished."
9.1.5.E.2.b.4: "The inside dimensions of the throttle body casting/housing and all dimensions of the throttle butterfly must
remain stock (tolerance of +/-.25mm)."

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%~~"

2025-11-01 FA Re-Consider USF Pro 2000 Car for Formula Atlantic Class

#38783 from Augie Pabst · Rule change · TB 25-09 (2025-09 Fastrack)

neutralFA class adds USF Pro 2000 car eligibility for Formula Atlantic racing.

Effective 11/1/25 in FA Table 2, add the following:

2025-11-01 EP Please Lower Weight of 280Z

#38871 from Matthew Miller · Rule change · TB 25-09 (2025-09 Fastrack)

fasterEP Nissan 280Z minimum weight reduced from 2560 to 2400 lbs.

In EP Spec Lines, Nissan 280Z, change Weight (lbs) as follows:
"(Effective 11/1/2025) ~~2560~~ 2400
*~~2624~~ 2460
**~~2688~~ 2520"

2025-11-01 EP Miata Weight Adjustment Follow Up

#38949 from Don Tucker · Rule change · TB 25-10 (2025-10 Fastrack)

fasterEP Mazda MX-5 1.8L 90-97 weight reduced to 2125 lbs from 2150 lbs.

In EP Spec Lines, Mazda MX-5 / Miata 1.8L (90-97), Effective 11/1/2025 make the following weight change:
"~~2150~~ 2125"

2025-11-01 EP Weight Break for 1098 Midget / Sprite

#38970 from Kendall Jones · Rule change · TB 25-10 (2025-10 Fastrack)

fasterHP Austin-Healey Sprite/Midget 1098cc minimum weight drops 80 lbs to 1550.

In HP Spec Lines, Austin-Healey Sprite/Midget 1098cc, Effective 11/1/2025make the following weight change:
"~~1630~~ 1550"

2025-11-01 EP HP Volvo 142 spec omission

#38994 from Production Committee · Rule change · TB 25-10 (2025-10 Fastrack)

slowerHP Volvo 142/142E gains compression ratio limit 12.0:1 and valve lift limit .425".

In HP Spec Lines, Volvo 142/142E P-1800 Engine, Effective 11/1/2025 add the following wording to Notes:
"Comp. Ratio limited to 12.0:1. Valve lift limited to .425”."

2025-11-01 EP HP Mini DOHC 1.6

#38996 from Production Committee · Rule change · TB 25-10 (2025-10 Fastrack)

slowerHP Mini Cooper 07-15 valve lift reduced to .390", from .450".

In HP Spec Lines, Mini Cooper (07-13) (includes 09-15 convertible and 12-15 Coupe), Effective 11/1/2025 make the following
changes to the Notes:
"Compression ratio limited to 11.0:1, Valve lift limited to ~~.450”~~.390"."

2025-11-01 EP Add to Rabbit description

#39019 from Production Committee · Rule change · TB 25-11 (2025-11 Fastrack)

neutralFP and HP Volkswagen Rabbit descriptions updated: Convertible changed to Cabriolet in FP; Cabriolet added to three HP engine variants.

In FP Spec Lines, make the following spec line correction:
"Volkswagen Rabbit (Includes ~~Convertible~~ Cabriolet)"
In HP Spec Lines, make the following spec line correction:
"Volkswagen Rabbit 1588 (Includes Cabriolet)"
"Volkswagen Rabbit 1715 (Includes Cabriolet)"
"Volkswagen Rabbit 1780 (Includes Cabriolet)"

2025-11-01 EP Clean-up 9.1.5.E.7e

#39025 from Production Committee · Rule change · TB 25-11 (2025-11 Fastrack)

neutralEP, FP, HP: rear drum brake to disc conversion clarified; rotors solid, diameter limited to largest front rotor permitted.

In GCR, Section 9.1.5.E.7., change as follows:
"e. Cars fitted with rear drum brakes, can convert to rear disc brakes without penalty. N~~ote that the “Brakes Std.” and “Brakes~~
~~Alt.” listings on a vehicle’s spec line do not prohibit a car that was fitted with rear drum brakes stock, from converting to rear~~
~~disc brakes under this rule~~. When converting from rear drum brakes to rear disc brakes:
1. Rear brake rotors must be solid and can be no larger in diameter than the largest permitted front brake rotor, as defined on
the vehicle’s spec line.
2. Rear calipers and mounting brackets are unrestricted but must be made of a ferrous or aluminum material. ~~The standard and~~
~~alternate brake listings on a vehicle’s specification line, does not prohibit a car that was fitted with rear drum brakes as stock~~

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~~from converting to rear disc brakes under this rule.~~
3. The “Brakes Std.” and “Brakes Alt.” listings on a vehicle’s spec line do not prohibit a car that was fitted with rear drum brakes
as stock from converting to rear disc brakes under this rule."

2025-11-01 EP Add TB size to Ford Mustang (94-98) Spec Line

#39130 from Production Committee · Rule change · TB 25-11 (2025-11 Fastrack)

neutralEP Ford Mustang (94-98) fuel injected throttle body inside diameter specified at 60.

In EP Spec Lines, Ford Mustang (94-98) add the following to the Fuel Injected Equipped Throttle Body Inside Diameter column:
"60"

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 EP TR2 Notes E&O

#39180 from Anthony Parker · Rule change · TB 25-12 (2025-12 Fastrack)

unclearEP Triumph TR2-TR4A allows 5-speed gearbox without overdrive; removes Weber carb and weight specification.

In EP Spec Lines, Triumph TR2, 3, 3A, 4, 4A, TR4, TR4A, IRS, make the following change to the Notes:
"Front apron assembly may be made of alternate material. ~~Three (3) Weber 40 DCOE on IR manifold with 28mm chokes @ 1990~~
~~lbs.~~ Laycock overdrive, may use 5 speed gearbox without overdrive."

2025-12-01 EP Balance of Power

#39187 from Jim Simaras · Rule change · TB 25-12 (2025-12 Fastrack)

slowerEP BMW Z3 2.5L restrictor reduced 52mm to 50mm, weight increased to 2550 lbs base; five other BMW models get smaller restrictors.

In EP Spec Lines, make the following changes to Restrictors:
BMW Z3 2.5L: "~~52mm~~ 50mm Flat Plate Intake Restrictor"
BMW Z3 2.8L (97-00): "~~55mm~~ 53mm Flat Plate Intake Restrictor"
BMW 328i/is E36 (96-99): "~~58mm~~ 55mm Flat Plate Intake Restrictor"
BMW 328i/ci E46 (01-06): "~~58mm~~ 55mm Flat Plate Intake Restrictor"
BMW 325i/is (E46) (01-06): "~~56mm~~ 53mm Flat Plate Intake Restrictor"
BMW 325is M-Technic (1994): "~~56mm~~ 53mm Flat Plate Intake Restrictor"
BMW 325i/is E-36 (92-95): "~~56mm~~ 53mm Flat Plate Intake Restrictor"

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In EP Spec Lines, BMW Z3 2.5L, change Weight as follows:
"~~2500~~ 2550
*~~2563~~ 2614
**~~2625~~ 2678"

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 FA Alternate Intake Manifold for MZR

#38223 from Ove Olsson · Rule change · TB 26-01 (2026-01 Fastrack)

unclearFA MZR gains alternate Noor P/N 0088-8-00 intake manifold with AT Power runners as option to Elan or Mazda Speed Elite.

In FA, GCR section 9.1.1.2.d, modify as follows:
"9. Intake manifold must be unmodified Elan DP02-60-003 or Mazda Speed equivalent Elite USF2015AT, 1.882” maximum bore
diameter at throttle plates. Elan or Mazda Speed equivalent Elite intake manifold may be replaced with unmodified intake Noor
P/N 0088-8-00 with intake runners AT Power P/N 13624."
"10. Elan DP02-60-003 or Mazda Speed equivalent Elite USF2015AT intake manifold must use an A aluminum spacer ~~must be~~
~~used~~ between the intake manifold and cylinder head castings; minimum spacer length is 2.200”."

2026-01-01 FA Engine Compression Rule Change Request

#39302 from Reilly Harris · Rule change · TB 26-01 (2026-01 Fastrack)

fasterFA Formula 1000 motorcycle-based engine loses maximum compression ratio 14.5:1 limit.

In FA Table 2, Formula 1000 spec line, change the Engine as follows:
"Motorcycle-based 4-cycle up to 1000cc~~, maximum compression ratio 14.5:1;~~. o Otherwise, current FA engine rules apply."

2026-01-01 EP Request to Update E30 BMW Throttle Body Diameter Verbiage

#39363 from Tim Schreyer · Rule change · TB 26-01 (2026-01 Fastrack)

neutralEP BMW 325i/is E30 throttle body specified as 60mm in fuel injection notes.

In EP Spec Line BMW 325i/is E30 (84-91), change Drivetrain Notes as follows:
"Fuel Injection, TB: 60mm"

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 FA Change Formula 1000 allowances

#39608 from Club Racing Board · Rule change · TB 26-01 (2026-01 Fastrack)

fasterFA Formula 1000 allows carbon fiber external panels, forward-facing gaps, raises floor to 125mm, adds eight 75×125mm rub blocks, expands diffuser to 110cm with 75mm radius transitions.

In FA Table 2, Formula 1000 spec line, change the Notes as follows:
"Car must comply with December 2019 GCR Formula 1000 (FB) Preparation Rules, https://www.scca.com/downloads/48184-
gcr-december-2019/download, except as modified by this spec line. The prohibition of using carbon fiber in any external panels
or any panels licked by the airstream in Part 3.C of the December 2019 GCR F1000 (FB) Preparation Rules is removed, with the
exception that the car's floor pan/undertray must comply with the requirements of Part 2.D of the December 2019 GCR F1000
(FB) Preparation Rules. The prohibition of forward-facing gaps or openings in the bodywork in Part 3.I of the December 2019 GCR
F1000 (FB) Preparation Rules is removed. Part 3.D of the December 2019 GCR F1000 (FB) Preparation Rules is modified as
follows: "Between the rear of the front tire and the front of the rear tire, no point on the lower surface of the car (the surface

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licked by the air stream) shall be more than 125mm above the plane determined by the reference area designated by the entrant
and on a line perpendicular to that reference plane." Part 3.D of the December 2019 GCR F1000 (FB) Preparation Rules is also
modified as follows: "A maximum of eight (8) rub blocks of maximum dimension 75mm by 125mm are allowed anywhere on the
lower surface of the chassis and may extend below the reference plane." Part 3.E of the December 2019 GCR F1000 (FB)
Preparation Rules is modified as follows: "The radius of transitions between the diffuser sides and adjacent horizontal structures
may be up to 75mm. The width of the diffuser, as measured between its sides and above any radiused transitions, may not
exceed 110cm in any lateral section." The CRB may require the use of Flat Plate Intake Restrictors at any time."

2026-02-01 FA Pro Mazda Classification and Performance Enhancement Proposal

#39411 from Stephen Lamana · Rule change · TB 26-02 (2026-02 Fastrack)

fasterFA Pro Mazda: lower intake manifold now unrestricted, throttle body raised to 80mm, wing height must not exceed 99cm, bodywork width must not exceed 132cm.

In FA Table 2, Pro Formula Mazda spec line, change the notes as follows:
"All current FA rules apply to areas not covered by this spec line. Apex seals unrestricted. Street port or bridge port
allowed. ~~Unmodified OEM l~~ Lower intake manifold ~~required~~ unrestricted, upper intake manifold unrestricted. Balance tube not
permitted. Fuel injection only. Maximum 70 80mm T throttle B body. The maximum height of the wing and/or
endplates ~~shall~~ must not exceed 99cm (38.98 inches). The overall maximum width of the bodywork behind the front
wheels ~~shall~~ must not exceed 132cm (51.97 inches)."

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