BoP Lab / Buttonwillow Raceway Park

EP + P + FV 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.

Pos	Car	Driver	Class	#	Lap	Theoretical	Qual	Race	5-lap stint	Consistency	Trap	S1	S2	S3
1	Elan DP02/Mazda	Jim Devenport	P	23, 28	1:32.576 A-P	1:32.284	1:32.872 B-Q2	1:33.972 B-R2	1:35.195 B-R1	+1.742 B-R1	171.9 A-P	25.461 B-Q2	26.606 A-P	40.217 A-P
2	Dauntless Stohr	Johnnie Crean	P	3, 135	1:36.516 B-Q1	1:36.516	1:36.516 B-Q1	1:39.209 B-R1	1:40.027 B-R1	+1.943 B-R1	157.4 B-P	25.956 B-Q1	28.143 B-Q1	42.417 B-Q1
3	Dauntless-Stohr P07d	John Manfroy	P	08	1:37.287 A-R2	1:36.339	1:41.818 A-Q1	1:37.287 A-R2	1:39.027 A-R2	+2.902 A-R2	160.4 A-R2	26.696 A-R2	27.257 A-R2	42.386 A-R2
4	Stohr WF1	Kevin Mitz	P	13	1:38.716 A-Q2	1:38.667	1:38.716 A-Q2	1:39.638 A-R2	1:40.087 A-R2	+0.641 A-R2	155.4 A-Q1	26.934 A-Q2	28.397 A-Q2	43.336 A-Q2
5	Penton Norma M20FC	Joseph Moran	P	7	1:39.296 A-Q2	1:38.868	1:39.296 A-Q2	1:40.832 A-R1	1:42.328 A-R1	+3.544 A-R1	149.0 A-Q2	27.106 B-Q1	28.111 A-Q1	43.651 A-Q1
6	Glamdring	Mark Edwards	FV	74	1:44.706 B-P	1:44.592	2:05.638 A-Q1	2:04.892 A-R2	2:06.364 A-R2	+2.303 A-R2	128.9 B-P	28.863 B-P	30.228 B-P	45.501 B-P
7	Caracal C1	Marjorie Lundberg	FV	24, 70	1:51.773 B-P	1:51.773	2:04.579 A-Q2	2:02.255 B-R1	2:02.701 B-R1	+0.787 B-R1	122.3 A-Q2	30.462 B-P	32.246 B-P	49.106 B-P
8	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
9	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
10	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
11	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
12	DART II	Mace Gjerman	FV	89	1:58.898 A-R2	1:56.799	2:04.535 A-Q1	1:58.898 A-R2	2:07.262 A-R2	+8.538 A-R2	121.9 A-Q1	26.541 A-R2	35.132 A-Q1	55.126 A-Q2
13	BMW E30	Sean Lovett	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
14	Protoform P4	Gavin Sweeney >115%	FV	107	2:01.197 B-R1	2:00.901	2:02.354 B-Q2	2:01.197 B-R1	2:02.073 B-R2	+0.598 B-R2	124.6 A-Q1	32.871 B-P	34.423 B-R1	53.607 B-R1
15	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
16	LYNXX	Donald Manthe >115%	FV	40	2:02.715 B-P	2:02.311	2:06.541 A-Q1	2:05.686 A-R2	2:08.709 A-R2	+3.944 A-R2	117.9 A-Q1	32.587 B-P	35.402 A-R2	54.322 B-P
17	Mazda MX-5	Whitfield Gregg	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
18	Crusader	Blake Tatum >115%	FV	3	2:04.723 A-R1	2:04.723	2:05.855 A-Q2	2:04.723 A-R1	2:06.212 A-R2	+1.581 A-R2	122.5 A-Q1	34.149 A-R1	35.231 A-R1	55.343 A-R1
19	Mysterian M2	Ronnie Chuck >115%	FV	50, 51	2:06.510 B-R2	2:05.089	2:08.877 B-Q2	2:06.510 B-R2	2:07.002 B-R2	+1.249 B-R2	115.9 A-R2	33.255 B-R2	35.637 B-R2	56.197 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
Elan DP02/Mazda	P	1	1:32.576Jim Devenport	1:32.872Jim Devenport	1:33.972Jim Devenport	171.9Jim Devenport	25.461Jim Devenport	26.606Jim Devenport	40.217Jim Devenport
Dauntless Stohr	P	2	1:36.516Johnnie Crean	1:36.516Johnnie Crean	1:37.287John Manfroy	160.4John Manfroy	25.956Johnnie Crean	27.257John Manfroy	42.386John Manfroy
Dauntless Stohr	P	1	1:36.516Johnnie Crean	1:36.516Johnnie Crean	1:39.209Johnnie Crean	157.4Johnnie Crean	25.956Johnnie Crean	28.143Johnnie Crean	42.417Johnnie Crean
Dauntless-Stohr P07d	P	1	1:37.287John Manfroy	1:41.818John Manfroy	1:37.287John Manfroy	160.4John Manfroy	26.696John Manfroy	27.257John Manfroy	42.386John Manfroy
Stohr WF1	P	1	1:38.716Kevin Mitz	1:38.716Kevin Mitz	1:39.638Kevin Mitz	155.4Kevin Mitz	26.934Kevin Mitz	28.397Kevin Mitz	43.336Kevin Mitz
Penton Norma M20FC	P	1	1:39.296Joseph Moran	1:39.296Joseph Moran	1:40.832Joseph Moran	149.0Joseph Moran	27.106Joseph Moran	28.111Joseph Moran	43.651Joseph Moran
Glamdring	FV	1	1:44.706Mark Edwards	2:05.638Mark Edwards	2:04.892Mark Edwards	128.9Mark Edwards	28.863Mark Edwards	30.228Mark Edwards	45.501Mark Edwards
Caracal C1	FV	1	1:51.773Marjorie Lundberg	2:04.579Marjorie Lundberg	2:02.255Marjorie Lundberg	122.3Marjorie Lundberg	30.462Marjorie Lundberg	32.246Marjorie Lundberg	49.106Marjorie Lundberg
Mazda Miata	EP	1	1:52.034Joe Carr	1:59.603Joe Carr	1:59.157Joe Carr	131.6Joe Carr	31.719Joe Carr	32.405Joe Carr	49.966Joe Carr
Mazda MX-5	EP	2	1:53.088Glen McCready	1:53.088Glen McCready	1:53.487Glen McCready	125.6Glen McCready	30.761Glen McCready	32.765Glen McCready	49.458Glen McCready
Mazda RX-7	EP	2	1:56.468Kurt Frietzsche	1:56.468Kurt Frietzsche	1:56.573Kurt Frietzsche	120.7Kurt Frietzsche	31.324Kurt Frietzsche	33.891Brandon Droese	50.204Kurt Frietzsche
DART II	FV	1	1:58.898Mace Gjerman	2:04.535Mace Gjerman	1:58.898Mace Gjerman	121.9Mace Gjerman	26.541Mace Gjerman	35.132Mace Gjerman	55.126Mace Gjerman
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
Protoform P4	FV	1	2:01.197Gavin Sweeney	2:02.354Gavin Sweeney	2:01.197Gavin Sweeney	124.6Gavin Sweeney	32.871Gavin Sweeney	34.423Gavin Sweeney	53.607Gavin Sweeney
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
LYNXX	FV	1	2:02.715Donald Manthe	2:06.541Donald Manthe	2:05.686Donald Manthe	117.9Donald Manthe	32.587Donald Manthe	35.402Donald Manthe	54.322Donald Manthe
Crusader	FV	1	2:04.723Blake Tatum	2:05.855Blake Tatum	2:04.723Blake Tatum	122.5Blake Tatum	34.149Blake Tatum	35.231Blake Tatum	55.343Blake Tatum
Mysterian M2	FV	1	2:06.510Ronnie Chuck	2:08.877Ronnie Chuck	2:06.510Ronnie Chuck	115.9Ronnie Chuck	33.255Ronnie Chuck	35.637Ronnie Chuck	56.197Ronnie Chuck

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

2023-04-01 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."

2023-06-01 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)"

2023-07-01 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)"

2023-09-01 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"

2023-12-01 FV FV Wheel Bearing Clarification

#35150 from Formula/Sports Racing Committee · Rule change · TB 23-12 (2023-12 Fastrack)

neutralFV front wheel bearings wording clarified in GCR 9.1.1.C.10.G.

In FV, GCR section 9.1.1.C.10.G, change as follows:
"Front W wheel bearings"

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 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 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)"

2024-10-01 FV Disc Brakes

#36822 from Guy Bellingham · Rule change · TB 24-10 (2024-10 Fastrack)

neutralFV ferrous rotor no longer required to be smooth; may have up to three pad cleaning grooves per side.

In FV, GCR section 9.1.1.C.4.D, change as follows:
"Any ferrous alloy, unvented rotor may be used, but must have a maximum diameter of 11.75 in. and a minimum thickness of
0.20 in. The ~~otherwise smooth~~ rotor may not be cross-drilled and may have a maximum of three pad cleaning grooves per side."

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)"

2024-12-01 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."

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"

2025-02-01 P Correct text in engine table notes

#37606 from Club Racing Board · Rule change · TB 25-02 (2025-02 Fastrack)

neutralPrototype Staudacher and unrestricted engine notes corrected for minimum weight wording.

In Prototype Engine Table, Spec Line B, change the notes as follows:
"Staudacher cars may run 950 lb ~~min. wt.~~ minimum weight with 38.5mm flat plate intake restrictor."
In Prototype Engine Table, Spec Line D, change the notes as follows:
"No restrictor required at 1150 lb ~~min. wt.~~ minimum weight."

2025-02-01 P Update Prototype class designation

#37653 from Club Racing Board · Rule change · TB 25-02 (2025-02 Fastrack)

neutralPrototype class renamed from P1 to P, affecting designation throughout rules with no performance changes.

In Categories and Classes, GCR section 9.1, change as follows:
"9.1.8. SPORTS RACING CATEGORY CLASSES
A Sports Racing (ASR) Regional Class
Prototype 1 (P1)"
In Homologation Requirements, GCR section 9.2.2, change as follows:
"All Formula, Sports Racing, ~~and~~ P1, and P2 cars must be constructed in strict accordance with the rules and regulations
contained in the current GCR unless specifically excepted."
In Non-Metallic Wheel/Chassis Construction, GCR section 9.3.37, change as follows:

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"Non-metallic wheel construction is prohibited. Non-metallic chassis construction is prohibited, except in ASR, P1, FS and FA."
In Appendix B, GCR section 1.4.2.G, change as follows:
"It is preferable not to combine GT1, AS, T1, T2, T3, and STU with P1, P2, SRF, FP, HP, or GTL."
In Appendix C, GCR section 2.6.G, change as follows:
"A 14 or 15 year-old must complete his first SCCA driver school in a car not classed in GT1, GT2, FA, F~~B, F~~ S, ITR, ASR, P1, P2, or
T1."
In Appendix E, section 1, change as follows:
"Depending on the length and banking of the oval course being used, it is recommended that Regions consider restricting the
faster classes (GT1, FA, and P 1) from competition at oval track events."
In Sports Racing Category, GCR section 9.1.8.1, change as follows:
"The SCCA Sports Racing Category shall be for automobiles which are designed and constructed for road racing competition,
offering provisions for a driver and passenger, or a driver alone (single-seater). They shall conform to the following
requirements. Sports Racers Cars except SRF & SRF3 homologated prior to 1-1-2014 are eligible to compete as P1 or P2 as long
as they meet applicable class rules,; no re-homologation is required."
"Single seat Formula car chassis (Ex.: FA, FC, FF, FV) fitted with enclosed bodies (as specified in these rules) may run in a Sports
Racing/Prototype Class (ASR, P 1, P2) provided they comply with the requirements of the Classification Specification and GCR
Section 9."
In Sports Racing Category, GCR section 9.1.8.2, change as follows:
"In an effort to control shock/damper technology and cost to a level reasonable for Road Racing, in ASR, P1, and P2, any fluid
dampers are allowed with the following restrictions:"

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 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"

2025-04-01 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 P Add missing punctuation marks

#38150 from Club Racing Board · Rule change · TB 25-05 (2025-05 Fastrack)

neutralClass P adds clarification notes on restrictor requirements, throttle bodies, Mazda 12A engine spec, and P2 auto-based engine rules.

In P Engine Table, Spec Line D notes, add the following:
"No restrictor required at 1150 lbs. minimum weight."
In P Engine Table, Spec Line G notes, add the following:
"Group CN non-composite chassis with Honda K20A-FD2 may use unrestricted individual throttle bodies at 1500 lbs. minimum
weight."
In P Table 1, Beasley B2 spec line notes, add the following:
"Engine must be Mazda 12A rotary with 40.5mm venturi. Car must comply with all other Prototype requirements."
In P Table 1, P2 cars built to 2000cc auto-based specification spec line notes, add the following:

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"Car must comply with all other P2 rules applicable to cars using stock production-based four-cylinder automotive engines.
Note: Competitors are also free to modify their cars to comply with the general Prototype rules and Engine Table Spec Line H
instead."

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 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 P RM 25-05 - Prototype Engine Table A, 2 Cycle Restrictor Change

#38929 from Club Racing Board · Rule change · TB 25-09 (2025-09 Fastrack)

slowerPrototype Engine Table A 2-cycle restrictor reduces from 40mm to 38mm venturi size.

Effective 8/1/25 in Prototype Engine Table, Spec Line A, change the restrictor as follows:
"~~40mm~~ 38mm Restricted Venturi Size"

2025-09-01 P 13B Rotary Engine Rules Change Request

#38856 from Jason Vinkemulder · Rule change · TB 25-09 (2025-09 Fastrack)

unclearP class 13B rotary engine restrictor changes to 40mm SIR fuel injection or 41.5mm venturi carburetor.

Effective 9/1/25 in Prototype Engine Table, Spec Line K, change the restrictor as follows:
"40mm SIR with fuel injection or 41.5mm venturi with carburetor"

2025-09-01 P Add Radical Cup series Radical SR3 spec line to Table 1

#38916 from Club Racing Board · Rule change · TB 25-09 (2025-09 Fastrack)

neutralPrototype class adds Radical SR3 spec line to Table 1 effective 9/1/25.

Effective 9/1/25 in Prototype Table 1 (Spec Line Cars), add the following:

2025-09-01 P Clarify spec line cars language

#38943 from Club Racing Board · Rule change · TB 25-09 (2025-09 Fastrack)

neutralPrototype P2 cars may now run P2 spec or modified Prototype spec in Prototype class; clarified language and added Radical Cup series table.

Effective 9/1/25, in Prototype, GCR section 9.1.8.B.K, change as follows:
"~~P2 cars may compete in either the Prototype class or the P2 class but must participate in the Prototype class to the extent~~
~~necessary to qualify for an invitation to the Runoffs in Prototype.~~ P2 cars may be modified to comply with the general Prototype
rules and Prototype Engine Table or may continue to run in P2 specification in the Prototype class as permitted in Table 1 below."
Table 1 (Spec Line Cars)

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

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 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 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"

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 P Request to Continue to Allow Carbon Brakes

#39476 from Jeffrey Lederman · Rule change · TB 26-01 (2026-01 Fastrack)

neutralPrototype carbon-carbon and carbon-ceramic brake rotors now permitted instead of prohibited.

In Prototype, GCR section 9.1.8.B.F.2, change as follows:
"Brake calipers may be ferrous or aluminum alloy. ~~Effective 1/1/2026, carbon-carbon and carbon-ceramic brake rotors are~~
~~prohibited and rotors must be ferrous.~~ Brake rotor material is unrestricted."

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