P + T4 + HP at Buttonwillow Raceway Park

2024-03-01 T4 Reorganize Spec Lines

#35375 from Touring Committee · Rule change · TB 24-03 (2024-03 Fastrack)

In T2-T4 Spec Lines, change Spec Line as follows:
"Wheel- base (mm) Required Restrictor"

2024-03-01 T4 Allow any 400lb rear spring in the RX8

#35433 from Raymond Blethen · Rule change · TB 24-03 (2024-03 Fastrack)

In T4 Spec Lines, Mazda RX-8 Base/R3/Sport/ GT (04-12), change Notes as follows:
"Mazda Motorsports- 0000- 04-9700-08 or Eibach- 0800.250.0700 (R) Mazda Motorsports- 0000-04-9400-07 or Eibach
0700.250.0400, and helper 0000-04-9926 allowed. Springs allowed 700lb (f), 400(r)."

2024-03-01 T4 370Z Brake Rotor Size Correction

#35487 from Derek Chan · Rule change · TB 24-03 (2024-03 Fastrack)

In T2 Spec Lines, Nissan 370Z (09-17) / 370Z NISMO Edition (09-17), change Brakes (mm) as follows:
"(F)320 x 28 Vented R)320 x 16 Vented : (F) 355x32mm Vented(R) 350x20mm Vented”
In T3 Spec Lines, Nissan 370Z, incl. Nismo (2009-2022), change Brakes (mm) as follows:
"(F)320 x 28 Vented (R)320 x 16 Vented : (F) 355x32mm Vented(R) 350x20mm Vented”

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

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

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

2024-04-01 T4 Corrections to T4 RX8 Spec line

#35767 from Touring Committee · Rule change · TB 24-04 (2024-04 Fastrack)

In T4 Spec Lines, Mazda RX-8 Base/R3/Sport/ GT (04-12), change Notes as follows:
"Mazdaspeed radiator #0000-01-8501 allowed. Mazdaspeed coil spring kit #QSEA-34-01Z allowed. OE Rear spoiler allowed
#F151-V4-920F. OE front air dam allowed #F151-V4-900f-BB. Springs allowed 700lb (f) max, 400(r) max. Oil metering pump may
be bypassed. Alternate sway bars allowed max 32mm (f) 19mm (r)."

2024-05-01 T4 Allow T4 and T3 RX8 to Disable/Remove Factory Oil Inj.

#35761 from David Mead · Rule change · TB 24-05 (2024-05 Fastrack)

In T3 Spec Lines, Mazda RX-8 Base/R3/Sport/ GT (04-12), add to Notes as follows:
"OEM oil injection system may be removed or disabled."
In T4 Spec Lines, Mazda RX-8 Base/R3/Sport/ GT (04-12), add to Notes as follows:
"OEM oil injection system may be removed or disabled."

2024-05-01 T4 2023 ND2 Miata Classification and Allowances

#35837 from Coyote Black · Rule change · TB 24-05 (2024-05 Fastrack)

In T4 Spec Lines, Mazda MX5 Miata/Club/ RF (19-21), change Year as follows:
"(19-21 24)"
In T4 Spec Lines, Mazda MX5 Miata/Club/ RF (19-21), add to Notes as follows:
"Suspension package permitted with a 100 lbs. weight increase that includes the following parts: front springs #0000-04-9700-
08, springs up to 500lb front and 300lb rear allowed. Mazda tower brace 0000-04-5626 allowed."

2024-05-01 T4 Errors and Omissions for 06-09 VW Rabbit Rotor

#35851 from Andrew Burke · Rule change · TB 24-05 (2024-05 Fastrack)

In T4 Spec Lines, Volkswagen Rabbit 2.5 (06-09), change Brakes as follows:
"(F) 228 288 Vented Disc (R) 260 Solid Disc"

2024-05-01 HP Replace plastic panels

#35875 from Darryl Saylor · Rule change · TB 24-05 (2024-05 Fastrack)

In HP spec line "Honda CRX/Si (84-87)", make the following change to the Notes section:
"The plastic OE front header/nose body panel, lower rocker side-skirt, and lower door cap panel can be replaced by a
replica, which may be constructed of an alternate material, provided its appearance remains stock."

2024-05-01 T4 Driveshafts

#35916 from Scotty B White · Rule change · TB 24-05 (2024-05 Fastrack)

In GCR Section 9.1.9.2.D.4.b., add the following:
"6. T2-T3- Driveshafts may be replaced with alternative materials ie. carbon fiber, aluminum, steel. Two-piece driveshafts may
be replaced with one-piece units. If non-OEM driveshaft is used, add 25 lbs."

2024-05-01 T4 GCR ERROR - letter not properly applied to GCR

#35999 from Touring Committee · Rule change · TB 24-05 (2024-05 Fastrack)

In T4 Spec Lines, Mazda MX-5 Miata/Club (16-18), change Notes as follows:
"Factory bolt-in roll bar/ cross member may be removed to facilitate roll cage installation. The following item(s) must remain
stock: transmission differential unless specified below. Retractable hardtop option permitted but must be disabled from moving
action and positively fastened. Any OEM or aftermarket hardtop is permitted that retains the OEM roof silhouette, including
Mazda hardtop part #0000-07-5902-ND and part #0000-07-5901 (discontinued DG Motorsports). 29mm (f) 16mm (r) sway bars
allowed. Suspension package permitted with a 100 lbs. weight increase that includes the following parts: front springs #0000-
04-9700-08, rear springs #0000-04-9400-07, helper springs #0000-04-HLPR-EB (optional). Up to 500lb front and 300lb rear
springs allowed. Mazda Motorsports Header part #0000-06-5410 allowed. Mazda tower brace 0000-04-5626 allowed."

Applies to Mazda MX-5 on this page: Oscar Jackson

Applies to Mazda Miata on this page: Kristina Etherington, Kayla Etherington

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

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

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 T4 Allow OEM Front Spoiler 06-08 Miata in T4

#35941 from David Mead · Rule change · TB 24-06 (2024-06 Fastrack)

In T4 Spec Lines, Mazda MX-5 / Club Model (06-15), add to Notes the following: "Front
spoiler permitted (NF51-V4-900F)."

Applies to Mazda MX-5 on this page: Oscar Jackson

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

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

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

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

2024-06-01 T4 T4 Mustang Weight Reduction In T4 Spec

#36051 from Scotty B White · Rule change · TB 24-06 (2024-06 Fastrack)

Lines, Ford Mustang V6 (05-10), change as follows:
Weight: "3275 3225"
Notes: "14” Brembo Brake Kit#M-2300-S permitted."

2024-06-01 T4 R53 Mini Cooper S spec line request In

#36056 from Manvinder Singh · Rule change · TB 24-06 (2024-06 Fastrack)

T4 Spec Lines, Mini Cooper S (02-04), add to Notes the following:
"Milltek exhaust manifold #SSXM459 allowed. 25mm rear sway bar allowed."
T4 Spec Lines, Mini Cooper S (05-06), add to Notes the following:
"Milltek exhaust manifold #SSXM459 allowed. 25mm rear sway bar allowed."

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

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

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.

2024-07-01 T4 Mustang T2/T3

#35877 from Scotty B White · Rule change · TB 24-07 (2024-07 Fastrack)

In T2 Spec Lines, Ford Mustang GT 5.0L (15-17), add to Notes as follows:
"Track/Performance Package parts permitted."
In T2 Spec Lines, Ford Mustang GT 5.0L (2018-), add to Notes as follows:
"Track/Performance Package parts permitted."
In T3 Spec Lines, Ford Mustang V6 (15-17), change Notes as follows:
"Track/Performance package allowed."

2024-07-01 T4 Homologation of car to T4

#36030 from Patrick E Morgan · Rule change · TB 24-07 (2024-07 Fastrack)

In T4 Spec Lines, Mercedes C300 4Matic (2008-2011), classify as follows:

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

2024-07-01 T4 T2-T4 Driveshaft Mistake...?

#36050 from Scotty B White · Rule change · TB 24-07 (2024-07 Fastrack)

In GCR Section 9.1.9.2.D.4.b.6., remove as follows:
"If non-OEM driveshaft is used, add 25 lbs."
In T2 Spec Lines, Ford Mustang V6 (11-14), change Notes as follows:
"Driveshaft from Alternate metallic driveshaft is allowed."
In T2 Spec Lines, Ford Mustang Boss 302 (12-13), change Notes as follows:
"Alternate metallic driveshaft is allowed."
In T2 Spec Lines, Ford Mustang GT 5.0L (11-14)ki, change Notes as follows:
"Alternate metallic driveshaft is allowed."

2024-07-01 T4 MINI Cooper S Spec Lines Corrections.

#36086 from David Oliveira · Rule change · TB 24-07 (2024-07 Fastrack)

In T4 Spec Lines, Mini Cooper S (02-04), delete spec line in its entirety.
In T4 Spec Lines, Mini Cooper S (05-06), change Model as follows:
"Mini Cooper S R53 (0205-06)"
In T4 Spec Lines, Mini Cooper S (07-13), change Model and Notes as follows:
"Mini Cooper S R56 (07-13)"
Notes: "The following items must remain stock: shock/struts (including mounts), original wheels, and transmission
differential - unless specified below. Convertible model not allowed. Factory optional limited slip differential allowed.
JCW struts (F) 31 31 6 768 410 (R)33 52 6 768 412, springs (F)31 33 6 768 415 (R)33 53 6 768 418. May de-camber

2024-07-01 T4 Allow Removal of Sound Tubes

#36130 from Coyote Black · Rule change · TB 24-07 (2024-07 Fastrack)

In GCR Section 9.1.9.2.D.1.b., add the following:
"2. OEM intake- Chambers, resonators and acoustic devices may be removed, provided; that their ports are located
prior to any required restrictor, their ports are completely sealed, and that the part serves no other purpose."

2024-07-01 T4 B8/8.5 Audi S4 T3 and T2

#36195 from Brian Leib · Rule change · TB 24-07 (2024-07 Fastrack)

In T3 Spec Lines, Classify Audi S4 (2000-2002) as follows and allow the T2 spec line to expire.

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

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

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

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 T4 T4 Camaro V6 weight reduction

#36232 from Ted Warning · Rule change · TB 24-08 (2024-08 Fastrack)

In T4 Spec Lines, Chevrolet Camaro V-6 (96-02), change weight as follows:
"3250 3150"

2024-08-01 T4 BOP adjustment for ND MX5s

#36345 from Touring Committee · Rule change · TB 24-08 (2024-08 Fastrack)

In T4 Spec Lines, change Weight (lbs) as follows:
Mazda MX-5 Miata/Club (16-18): "2700 2650"
Mazda MX5 Miata/Club/ RF (19-24): "2800 2750"

2024-11-01 HP 1275 HP Spridget Level 2 Only

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

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 HP Request for Classification of 1989-1994 Suzuki Swift GT 16V Twin

#36858 from Jorge Fabian · Rule change · TB 24-11 (2024-11 Fastrack)

In HP Spec Lines, Classify Suzuki Swift GT (89-94) as follows:

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

2024-11-01 T4 Bop Request 06-11 Honda Civic Si

#37013 from Mathew Milford · Rule change · TB 24-11 (2024-11 Fastrack)

In T4 Spec Lines, Honda Civic Si (06-11), add to Notes the following:
"LSD is permitted according to category rules."

2024-12-01 T4 Redundant Verbiage Regarding Mustang Spec Lines for Driveshaft

#36484 from David Mead · Rule change · TB 24-12 (2024-12 Fastrack)

In T2 Spec Lines, change Notes as follows:
Ford Mustang V6 (11-14): "Alternate driveshaft is allowed."
Ford Mustang Boss 302 (12-13): "Alternate driveshaft is allowed."
Ford Mustang GT 5.0L (11-14): "Alternate driveshaft is allowed."
Ford Mustang GT 5.0L (15-17): "Alternate driveshaft is allowed."
Ford Mustang GT 5.0L (2018-): "Alternate driveshaft is allowed. Springs up to 800#/in front and rear permitted. Alternate
metallic driveshaft permitted."
Ford Mustang Coupe GT & Shelby GT 4.6L (05-10): "Alternate driveshaft is allowed."

2024-12-01 T4 R53 Mini Cooper S Weight Reduction Request

#36612 from Manvinder Singh · Rule change · TB 24-12 (2024-12 Fastrack)

In T4 Spec Lines, Mini Cooper S R53 (02-06), add to Notes as follows:
"Alta 15% Pulley #AMPENG20X allowed."

2024-12-01 T4 Allowable Wheel Offset

#36855 from Robert Maples · Rule change · TB 24-12 (2024-12 Fastrack)

In GCR Section 9.1.9.2.D.7. Wheels and Tires, change as follows:
"a. Wheels
1. Any type wheel suitable for competition may be used, provided:
a. Any wheel not exceeding the specified diameter and rim width on the vehicle’s specification line may be used. Each wheel,
measured without weights, must weigh at least 15 lbs.
b. Wheels are permitted any offset provided the tire tread (that portion of the tire that contacts the ground) does not protrude
beyond the fender opening when viewed from 9.1.9.2.Touring (T2-T4) Category Specifications GCR - 660 the top perpendicular
to the ground, unless specified differently on the individual spec line for that car. To determine compliance the vehicle should be

2024-12-01 T4 Fuel Emissions Components

#37076 from Derrick Ambrose · Rule change · TB 24-12 (2024-12 Fastrack)

In GCR, Section 9.1.9.2.D.1.c. add the following:
"5. Removal of ancillary fuel tank equipment charcoal canisters, emissions valves, and sensors allowed for OEM or aftermarket
fuel cell installations."

2024-12-01 T4 2019-2024 Mazda 3 for T4

#37077 from Derrick Ambrose · Rule change · TB 24-12 (2024-12 Fastrack)

In T4 Spec Lines, classify Mazda 3 (19-24), as follows:

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

2024-12-01 T4 fix brake wording

#37129 from Touring Committee · Rule change · TB 24-12 (2024-12 Fastrack)

In GCR, Section, 9.1.9.2.D.6. Brakes, change as follows:
"a. Components
1. The make and material of brake pads and linings may be changed.
2. Brake fluid may be substituted with any brake fluid.
3. Brake rotor dust shields may be removed or replaced to accommodate brake ducts.
4. Flexible rubber brake lines may be replaced with Teflon lined, metal braided hoses.
5. Any brake ducts are permitted, but they must serve no other purpose. Fender liners may be modified solely for routing and
attachment of brake ducts. Duct intake openings may be created by the opening of 2 sections up to 14.5 square inches each in

2024-12-01 T4 Evaporative emissions systems

#37130 from Touring Committee · Rule change · TB 24-12 (2024-12 Fastrack)

In GCR, Section, 9.1.9.2.D.1.c., add the following:
"5. Removal of ancillary fuel tank equipment; charcoal canisters, emissions valves, and sensors allowed for OEM or aftermarket
fuel cell installations."

2024-12-01 T4 Allow Spec MX5 upgrade kit for 2009-11 RX8 S2 Transmision

#37140 from Chris Braunlich · Rule change · TB 24-12 (2024-12 Fastrack)

In T4 Spec Lines, add the following to Notes:
Mazda RX-8 Base/R3/Sport/ GT (04-12): "Transmission kit # 0000-02-5700 permitted.
Mazda MX-5 / Club Model (06-15): "Transmission kit # 0000-02-5700 permitted."
In T3 Spec Lines, add the following to Notes:
Mazda MX-5 / Club Model (06-15): "Transmission kit # 0000-02-5700 permitted."
Mazda RX-8 Base/R3/Sport/ GT (04-12): "Transmission kit # 0000-02-5700 permitted."

2024-12-01 T4 Move Spec Boxster to T4

#37158 from Rob Piekarczyk · Rule change · TB 24-12 (2024-12 Fastrack)

In T4 Spec Lines, classify Porsche Spec Boxster, as follows:

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

Applies to Porsche Boxster on this page: Lynne Griffiths

2024-12-01 HP MINI Cooper Spec Line Correction - Rear Brake Rotor Diameter

#37176 from Robert Bax · Rule change · TB 24-12 (2024-12 Fastrack)

In HP Spec Lines, Mini Cooper (02-06), change Brakes Std.mm/(in.) as follows:
"(F) 276/(10.9) Vented Disc (R) 239/(9.4) 259/(10.2) Solid Disc"

Applies to Mini Cooper on this page: Tom Tuttle

2024-12-01 T4 3.7 Mustangs to T4

#37188 from Scotty B White · Rule change · TB 24-12 (2024-12 Fastrack)

In T4 Spec Lines, classify Ford Mustang V6 (05-14), as follows:

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

2024-12-01 T4 BMW 320i Spec Line

#37204 from chi ho · Rule change · TB 24-12 (2024-12 Fastrack)

In T4 Spec Lines, BMW 320i (14-15), change Notes as follows:
"**This Spec line will expire 12/31/24, Please submit to appeal** Turner Motorsports intercooler #024703TMS02 allowed."

2024-12-01 T4 MX5 2006-2015 NC Help

#37221 from Richard Mooney · Rule change · TB 24-12 (2024-12 Fastrack)

Thank you for your letter. Please see changes in letter #37281 in current Fastrack.

2024-12-01 T4 Classification for a 2005 Cadillac CTS 3.6 liter 6 speed manual

#37224 from Timothy Nash · Rule change · TB 24-12 (2024-12 Fastrack)

In T3 Spec Lines, classify Cadillac CTS (02-07) as follows:

2024-12-01 T4 Civic SI in T4

#37248 from Touring Committee · Rule change · TB 24-12 (2024-12 Fastrack)

In T4 Spec Lines, Honda Civic Si (06-11), change as follows:
Required Restrictor: "55mm flat plate restrictor required."
Min Weight: "2950 2900"
Notes: "The following items must remain stock: transmission differential - unless specified below. 55mm flat plate restrictor
required. LSD IS PERMITTED ACCORDING TO CATEGORY RULES"

2024-12-01 T4 2006-2015 T4 NC Mx5 spec line

#37278 from Touring Committee · Rule change · TB 24-12 (2024-12 Fastrack)

In T4 Spec Lines, Mazda MX-5 / Club Model (06-15), change Notes as follows:
"Factory bolt-in roll bar/cross member may be removed to facilitate roll cage installation. MSR option permitted. Suspension
package permitted with a 100 lbs. weight increase that includes the following parts: front spring mount PT#-0000-04-5259, front
springs #0000-04-9700-08, rear spring mount PT#-0000-04-5258, rear springs #0000-04-9400-07, helper springs #0000-04-HLPR-
EB (optional), Swaybar kit – PT#-0000-04-5306-EB that includes (front sway bar kit PT#0000-04- 5306-FT, rear sway bar kit PT#-
0000-04-5306-RR), offset front camber bushing PT#-0000-04- 5407-NC. Mazda Motorsports cold air intake part #0000-06-5150-
KT allowed. Mazda Motorsport RX8 rear Hub Conversion kit part number 0000-04-5811-KT allowed, RX8 front hubs PT# F189-33-
04X allowed. The SM5 suspension (only) is allowed with a 100 lbs. weight increase. Allow Mazda header part numbers 0000-06-

Applies to Mazda MX-5 on this page: Oscar Jackson

2024-12-01 T4 ND MX-5 wheel allowance

#37279 from Josh Smith · Rule change · TB 24-12 (2024-12 Fastrack)

In T4 Spec Lines, Mazda MX-5 Miata/Club (16-18), change Wheel Size as follows:
"17 x 7.5"

Applies to Mazda MX-5 on this page: Oscar Jackson

Applies to Mazda Miata on this page: Kristina Etherington, Kayla Etherington

2024-12-01 T4 T4 BOP

#37281 from Touring Committee · Rule change · TB 24-12 (2024-12 Fastrack)

In T4 Spec Lines, Mazda RX-8 Base/R3/Sport/ GT (04-12), change as follows:
Required Restrictor: "60mm 59mm"
Weight: "3125 3200"
In T4 Spec Lines, Mazda MX-5 / Club Model (06-15), change weight as follows:
"2600 2550"

Applies to Mazda MX-5 on this page: Oscar Jackson

2024-12-01 T4 Allow 7.5

#37286 from Touring Committee · Rule change · TB 24-12 (2024-12 Fastrack)

In T4 Spec Lines, Mazda MX5 Miata/Club/ RF (19-24), change Wheel Size as follows:
"17 x 7.5"

2025-01-01 T4 2016-2018 Mazda Miata MX5

#37085 from Nic Piekarski · Rule change · TB 25-01 (2025-01 Fastrack)

In T4 Spec Lines, Mazda MX-5 Miata/Club (16-18), change Min Weight as follows:
"2650 2575"
In T4 Spec Lines, Mazda MX5 Miata/Club/ RF (19-24), add to Notes the following:
"Mazda header 0000-06-5410 allowed."

Applies to Mazda MX-5 on this page: Oscar Jackson

Applies to Mazda Miata on this page: Kristina Etherington, Kayla Etherington

2025-01-01 HP 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)

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

2025-01-01 T4 Remove spec lines that have expired

#37269 from Touring Committee · Rule change · TB 24-12 (2024-12 Fastrack)

In T2, Effective 1/1/2025, delete for following Spec Lines in their entirety:
"Acura TL SHAWD (10-13)
Audi S4 (12-14)
Audi S5 (13-14)
Audi TT RS (2018-)
Cadillac ATS-V (16-17)
Cadillac CTS-V (06-07)
Chevrolet Camaro SS (98-02)

2025-01-01 HP Request to Update 1988-1991 Civic to Match 1988-1991 CRX

#37444 from ENRIK BENAZIC · Rule change · TB 25-01 (2025-01 Fastrack)

In HP SPEC LINES, Honda Civic 1.5 (88-91), change Weight as follows:
"2245 2175
*2301 2229
**2357 2284"

2025-02-01 T4 Ford Mustang V6 (05-14)

#37516 from Touring Committee · Rule change · TB 25-02 (2025-02 Fastrack)

In T4 Spec Lines, Ford Mustang V6 (05-14), change as follows:
Final drive: "3.45"
Notes: "GT/CS front bumper cover #AR3Z-17D957-BA, allowed if used with front fascia."

2025-02-01 T4 Request to Classify Club Spec in Appropriate Touring Classes

#37523 from Andrew Benagh · Rule change · TB 25-02 (2025-02 Fastrack)

In T3 Spec Lines, classify Ford SCCA Club Spec Mustang (CSM) as follows:

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

Applies to Mazda MX-5 on this page: Oscar Jackson

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

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

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)

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:

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

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

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."

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

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

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 HP Interpretation of Production Rules on Mirrors

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

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 HP HP Class Adjustments

#37459 from Production Committee · Rule change · TB 25-01 (2025-01 Fastrack)

In HP SPEC LINES, change Weight as follows:
Mazda 2 (11-14)
"(Effective 3/1/2025) 1995 2045
*2045 2096
**2095 2147"
Volkswagen Golf (GTI, GT, GL) (85-92)
"(Effective 3/1/2025) 2100 2150
*2153 2204

2025-03-01 HP Weight Reduction for Honda S2000

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

In EP, Spec Lines make the following weight changes:

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

2025-03-01 HP Mazda 1999 Miata 1.8L

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

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

2025-03-01 HP MINI Cooper (07-13) Spec Line Correction: Errors and Omissions

#37560 from Robert Bax · Rule change · TB 25-03 (2025-03 Fastrack)

In HP Spec Lines, Mini Cooper (07-13) (includes 09-15 convertible and 12-15 Coupe), change as follows:
Engine Type:
"4 Cyl
SOHC DOHC"
Notes:
"Compression ratio limited to 11.0:1, Valve lift limited to .450”.390"."

Applies to Mini Cooper on this page: Tom Tuttle

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

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

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 HP Request to Lower Ford Festiva Minimum Weight to 1600 LBS

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

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 T4 Correct Ring and Pinion Ratio to T3, Sorry I Mean T4 3.7 V6 Stang

#38041 from David Mead · Rule change · TB 25-05 (2025-05 Fastrack)

In T4 Spec Lines, Ford Mustang V6 (05-14), add to Notes the following:
"GT 8.8 rear axle assembly allowed. 3.45 or 3.55 final drive ratio allowed. 7.5 rear axle assembly with 3.45:1 final drive allowed."

2025-05-01 T4 T4 Mustang

#38058 from Scotty B White · Rule change · TB 25-05 (2025-05 Fastrack)

In T4 Spec Lines, Ford Mustang V6 (05-14), add to Notes as follows:
"OEM style rear deck spoiler similar to Laguna/CS packages permitted.”

2025-05-01 P Add missing punctuation marks

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

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:

2025-06-01 T4 T4 Mustang

#38059 from Scotty B White · Rule change · TB 25-06 (2025-06 Fastrack)

In T4 Spec Lines, Ford Mustang V6 (05-14), change as follows:
Final Drive: "3.45 or 3.31"
"Weight: "3400 3300"

2025-06-01 T4 SSC tire allowance

#38216 from Benjamin Bunk · Rule change · TB 25-06 (2025-06 Fastrack)

In T4 Spec Lines, Scion FR-S Solo Spec Coupe (13-16), change Notes as follows:
"Any 200TW 225/45/17 or 215/45/17 DOT tire permitted."
In T4 Spec Lines, Subaru BRZ Solo® Spec Coupe (13-16), change Notes as follows:
"Any 200TW 225/45/17 or 215/45/17 DOT tire permitted."

Applies to Scion FR-S on this page: Tony Kiratsous

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

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

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 T4 Allow B-Spec cars to run in T4

#38439 from Derrick Ambrose · Rule change · TB 25-07 (2025-07 Fastrack)

In GCR, Section 9.1.9.2, Touring car eligibility, change as follows:
"Touring car eligibility: Cars are eligible for the class they are listed with a specification line and with the specific allowances
permitted. In addition T2-T4 cars may race one class up in touring classes above their specification line class as long as they are a
legal T2-T4 car and conform to their specification line allowances as classified. Cars conforming to B-Spec or C-Spec rules are
permitted to compete in Touring 4."

2025-07-01 HP BMW Z4 update

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

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

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

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

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 T4 Incorrect Touring Heading

#38451 from Terry Hanushek · Rule change · TB 25-08 (2025-08 Fastrack)

In T2-T4 Spec Lines, change Table Header as follows:
"T2 ET"

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)

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)

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)

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)

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 HP HP Plymouth Arrow spec omission

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

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

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

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

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

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

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

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 HP Please Lower Weight of 280Z

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

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

2025-11-01 HP Miata Weight Adjustment Follow Up

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

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 T4 02-06 Mini Cooper Gear Ratios

#38966 from Trenton Kramer · Rule change · TB 25-11 (2025-11 Fastrack)

In T4 Spec Lines, Mini Cooper S R53 (02-06), change Gear Ratios as follows:
"12.79, 7.79, 5.65, 4.62, 3.83, 3.13 or overall- 11.42, 7.18, 5.39, 4.40, 3.65, 2.96"

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

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

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

2025-11-01 T4 Reinstatement of the 2005-2010 Cobalt into T4

#38987 from Tim Little · Rule change · TB 25-11 (2025-11 Fastrack)

In T4 Spec Lines, classify Chevrolet Cobalt SS, Sport Coupe (06-10) as follows:

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

2025-11-01 HP HP Volvo 142 spec omission

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

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 HP HP Mini DOHC 1.6

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

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 HP Add to Rabbit description

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

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 HP Clean-up 9.1.5.E.7e

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

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. Note 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

2025-11-01 T4 Request to Classify Mercedes C230K

#39080 from Patrick Morgan · Rule change · TB 25-11 (2025-11 Fastrack)

In T4 Spec Lines, classify Mercedes C230 Kompressor (2002-2005) as follows:

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

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

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

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

2025-11-01 T4 ND Gearset Request for T4

#39166 from Josh Smith · Rule change · TB 25-11 (2025-11 Fastrack)

In T4 Spec Lines, Mazda MX5 Miata/Club/ RF (19-24), add to Notes the following:
"Gear kit Kit PT#- 0000-02-6100."
In T4 Spec Lines, Mazda MX-5 Miata/Club (16-18), add to Notes the following:
"Gear kit Kit PT#- 0000-02-6100."
In T3 Spec Lines, Mazda MX-5 Miata (16-18), add to Notes the following:
"Gear kit Kit PT#- 0000-02-6100."
In T3 Spec Lines, Mazda MX-5 Global Cup Miata (2016-2021) ND1, ND, add to Notes the following:
"Gear kit Kit PT#- 0000-02-6100."

Applies to Mazda MX-5 on this page: Oscar Jackson

Applies to Mazda Miata on this page: Kristina Etherington, Kayla Etherington

2025-11-01 T4 E&O wheel size on ND

#39168 from Josh Smith · Rule change · TB 25-11 (2025-11 Fastrack)

In T4 Spec Lines, Mazda MX-5 Miata/Club (16-18), change Wheel Size (in.) as follows:
"17 x 7.5"

Applies to Mazda MX-5 on this page: Oscar Jackson

Applies to Mazda Miata on this page: Kristina Etherington, Kayla Etherington

2025-11-01 T4 ND Spec Lines Wrong PT#'s

#39170 from Josh Smith · Rule change · TB 25-11 (2025-11 Fastrack)

In T4 Spec Lines, Mazda MX5 Miata/Club/ RF (19-24), change Notes as follows:
"Factory bolt-in roll bar/ cross member may be removed to facilitate roll cage installation. The following item(s) must remain
stock: transmission differential unless specified below. Retractable hardtop option permitted but must be disabled from moving
action and positively fastened. Any OEM or aftermarket hardtop is permitted that retains the OEM roof silhouette, including
Mazda hardtop part #0000-07-5902-ND and part #0000-07-5901 (discontinued DG Motorsports). 29mm (f) 16mm (r) sway bars
allowed. 3rd and 4th gear may be replaced with the following parts- (0000-02-5803-02, 0000-02-5803-01, 0000-02-5804-02,
0000-02-5804-01). Suspension package permitted with a 100 lbs. weight increase that includes the following parts: front springs
#0000-04-9700-08, springs up to 500lb front and 300lb rear allowed. Mazda tower brace 0000-04-5626 allowed. Mazda header

Applies to Mazda MX-5 on this page: Oscar Jackson

Applies to Mazda Miata on this page: Kristina Etherington, Kayla Etherington

2025-11-01 T4 Touring 4 Post-Runoffs BOP Adjustments and Changes

#39251 from Touring Committee · Rule change · TB 25-11 (2025-11 Fastrack)

In T4 Spec Lines, Acura RSX/ RSX Type-S (02-06), change Restrictor as follows:
"55mm FPR"
In T4 Spec Lines, Acura TSX (2004-2008), change Restrictor as follows:
"47mm FPR 52mm FPR"
In T4 Spec Lines, BMW Z4 2.5L (03-05) , change Weight as follows:
"3050 2950"
In T4 Spec, BMW 320i (14-15), remove this spec line in its entirety.
In T4 Spec Lines, BMW 323 (98-00), change as follows:

Applies to Mazda MX-5 on this page: Oscar Jackson

2025-12-01 HP Request to Re-Classsify Datsun SPL-311 to HP from FP

#39116 from Robert Heatwole · Rule change · TB 25-12 (2025-12 Fastrack)

In HP Spec Lines, classify Nissan/Datsun SPL 311 as follows:

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

2025-12-01 HP TR2 Notes E&O

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

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 HP Balance of Power

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

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"

2025-12-01 HP Alternative BOP Request for 84-87 Honda CRX/Civic

#39223 from Bill Lamkin · Rule change · TB 25-12 (2025-12 Fastrack)

In HP Spec Lines, change Wheels as follows:
Honda Civic: "13 x 6 7"
Honda Civic DX (92-95): "13 x 6 7"
Honda Civic/Si (84-87): "13 x 6 7"
Honda Civic 1.5 (88-91): "13 x 6 7"
Honda CRX/Si (84-87): "13 x 6 7"
Honda CRX 1.5(88-91): "13 x 67"

2025-12-01 T4 Classing 1995-99 Dodge Neon SOHC

#39285 from Preston Obremski · Rule change · TB 25-12 (2025-12 Fastrack)

In T4 Spec Lines, classify Dodge/Plymouth Neon ACR SOHC/DOHC (2/4 door) (95-99) as follows:

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

2026-01-01 T4 Alternate Placement of Fuse Panel and Electronics Request

#39370 from Aaron Stehly · Rule change · TB 26-01 (2026-01 Fastrack)

In GCR, Section 9.1.9.2.D.9.d, add the following:
"8. Under-dash electronics including computers, modules and fuse boxes may be relocated so they can be easily accessed after
roll cage installation."

2026-01-01 P Request to Continue to Allow Carbon Brakes

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

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."

2026-01-01 HP E/O: Improve Consistency of the Spec Lines

#39500 from Robert Bax · Rule change · TB 26-01 (2026-01 Fastrack)

In HP Spec Line, Toyota MR-2 1.6L (85-89), change Comp. Ratio as follows:
"11.0:1"

2026-01-01 T4 Clarify T4 Brake Rotor Allowance

#39503 from David Mead · Rule change · TB 26-01 (2026-01 Fastrack)

In GCR, Section 9.1.9.2.D.6.a.6., change as follows:
"In T2-Performance alternative rotors, including 2 piece rotors are permitted. Rotors must be within 5% of OE diameter or a
maximum diameter of 360mm.
In T3- Performance alternative rotors, including 2 piece rotors are permitted with a maximum diameter of 360mm.
T4- Performance alternative 1-piece rotors are permitted but rotors must meet the sizes listed in the spec line. Spec lines
showing alternate brake kits are also permitted to use 1-piece performance alternative rotors of the same size."

2026-01-01 HP Request to Reclassify BMW 2002 Into H Production

#39567 from Jonathan Kinberg · Rule change · TB 26-01 (2026-01 Fastrack)

In HP Spec Lines, classify BMW 2002, as follows:

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

2026-02-01 T4 T4 and T3 Feedback

#39230 from Tim Myers · Rule change · TB 26-02 (2026-02 Fastrack)

In T4 Spec Lines, remove Ford Mustang V6 (05-14) in its entirety.

2026-02-01 T4 T4 Mustang 4.0

#39489 from Scotty B White · Rule change · TB 26-02 (2026-02 Fastrack)

In T4 Spec Lines, Ford Mustang V6 (05-10), change as follows:
Tire: "245 255"
Notes: "ABS (option code 552) allowed. FR3 Handling Pack #M-2007-FR3V6 allowed (kit does not need to be run in its entirety).
The kit includes: Dampers M-18000-A, Lowering Springs M-5300-N, Sway Bars M- 5490-C, Strut Tower Brace M-20201-F. Ford
Positraction LSD part #M-4204-C75 is allowed. Any springs max F: 500 and R: 400 permitted. Any sway bar up to F: 35mm and R:
28mm permitted. Aftermarket Shocks conforming to T4 rules allowed. Panhard bar, part # BAR-M-4264-A permitted, or any pan
hard bar permitted must be set at same length as a stock bar, center mounting hole to center mounting hole +/- 0.25 inch. An
alternative steel drive shaft is permitted; this drive shaft is otherwise unrestricted, but no modifications to other components

2026-02-01 HP Triumph Spitfire 1296cc Compression Ratio Increase to 12:1

#39589 from Neil Verity · Rule change · TB 26-02 (2026-02 Fastrack)

In HP Spec Lines, make the following spec line changes:
Triumph Spitfire:
Carburetion
"Valves: (I) 33.0/(1.30) (E) 29.7/(1.17)
Comp. ratio 11.0 12.0:1, Valve lift .450”
Trans. Speeds: 4"
Triumph Spitfire Mk. III & IV 1500:
Carburetion

2026-02-01 T4 Allow Alt Bushing Material in Toe Links

#39607 from David Mead · Rule change · TB 26-02 (2026-02 Fastrack)

In GCR, Section 9.1.9.D.5.a.1., change as follows:
"T2-T4: A maximum of 3.5 degrees of negative camber is allowed on front and rear suspensions. Spec line part(s) may not be
modified to increase caster and camber. Strut suspensions may adjust camber and caster by the use of eccentric bushings,
eccentric bolts (crash bolts) at the strut-to-spindle, and/or by use of slotted adjustment plates at the top of the strut mounting
plate. If upper strut slotted adjustment plates are used, they shall be located on existing chassis structure, utilizing the
unmodified manufacturer’s original bolt holes and may not serve as reinforcement for that structure. Slotted adjustment plates
(strut camber plates) may incorporate a single spherical bearing (spherical bushing) and a ball thrust bearing per strut tower. On
other forms of suspension, camber and caster adjustment may be achieved by the use of shims and/or eccentric