Club Racing Rule Changes Adopted for 2023

From: PCA Club Racing Rules Committee

The changes summarized below will be made to the Rules, effective for the 2023 season.

Comments noting ambiguities in this announcement, typographical or other errors in the specifications, and problems with changes which may have been overlooked may be addressed to the Rules Committee via  Click on the address link to use your own e-mail client to compose and send the message.  Your message will be sent to all members of the Rules Committee.

Rule Book

Download your copy of the existing 2023 rule book.  You can use this link to download a PDF copy of these changes.


Use the links below to jump directly to specific changes:


  1. All minimum weights in Stock Classes G and above are reduced by 100 pounds.
  2. The plastic quarter window allowance is expanded to cover all models.


  1. The minimum weight of the 944S 2.5 is reduced from 2500 to 2400.


    1. Aftermarket gears of the stock ratios and design (e.g., no straight-cut gears) are allowed


    1. The weight of the 06-08 987.1 Caymans is reduced by 50 pounds.
    1. Aftermarket replica carbon fiber doors, with or without a window frame, in GTB Caymans, are allowed.


    1. GTC6 and GTC7 may run aftermarket adjustable shocks.
    2.  (updated 12/13/22) GTC6 and GTC7 wheels may be of any type of manufacturer but must have the same width, diameter, and offsets, and be of the same metal as the original factory wheels.  GTC4, and GTC5 wheels must be 3-piece wheels of the same width, diameter, and offsets, and be of the same metal as the original factory wheels. GTC2 and GTC3 cars are allowed to replace the pressure-cast aluminum control arms with steel control arms of identical dimensions
    3. Aftermarket/alternate drive axles and CVs are allowed for all GTC models.
    4. GTC4s may raise the wing like the GTC3.

The following additional “updates” are allowed for GTC5, based on what the GTC3/4s are allowed, in line with the policy of providing more parts substitution as original parts become unrealistically priced for the function, or hard to obtain if even still available from the manufacturer. It was intended to include these allowances in the September proposals for comment, but that didn’t happen. Racers who believe any of these are inconsistent with the needs of GTC5 should send objections with reasons to by December 2, 2022:

AA. “Any type of non-floating brake rotor of equivalent thickness and diameter and iron-based friction surfaces is allowed in GTC1, GTC2, and GTC3. GTC4 and 5 may use any aftermarket rotors of equivalent thickness and diameter.”

BB. “GTC4 and 5 may use any adjustable shock. Remote reservoirs, if used, must be mounted without modification of any stock component.”

CC. “GTC4 and 5 cars may change the brake master cylinders.”


    1. Aftermarket GTD1 headers, with or without catalytic converters, which bolt onto the factory stock tailpipes are allowed.


The following modifications beyond Stock (note – these do not apply to SP911 rule-based cars, though they are largely similar) are allowed on cars based on Stock class rules running in 911CUP:

17a. Chassis reinforcement is free without limitation on bars through firewalls as long as firewall integrity is not compromised. Note that this does not allow removal of chassis parts (tube framing).

17b. Stock bodywork parts which are bolted on may be replaced with aftermarket replica parts, which may be of alternate materials. Rear fenders may be replaced with such parts so long as a steel perimeter remains.

17c. Any caliper and metal rotor may be used. Single master cylinders are free and need not be boosted. Brake balance adjusters are free as long as they are not cockpit adjustable. Balance bars and ABS systems are not allowed.

17d. Tub sheet metal interior to the body skin in the trunk forward of the firewall may be cut out, altered, and ducted for oil and brake cooling airflow, but may not exit out the bumper cover, hood, cowl, or fender or through the firewall (i.e, may only exit downward or into the front wheel wells).

17e. Removal of front headlights and metal headlight buckets is allowed, but the opening must be covered with a solid material.

17f. SP911 glazing and rear spoiler and wing rules (SP911 1.C. and 1.D apply, but only the windshield needs to be polycarbonate (Lexan).

Carburetors on Stock-based 3.0s in 911CUP

17g. Carburetors may be substituted for CIS with the following limitations:

  • Maximum size carburetor 46mm.
  • Maximum venturi size (to be designated). Those interested should contact Jeff Wiggins (Jeff.Wiggins at so he can contact you when the size has been determined.
  • Horsepower limited to 225 RWHP, and average horsepower of 220 RWHP, measured (as in SP911) at 500 RPM above HPMax and 500 RPM and 1,000 RPM below HPMax, on a standard DynoJet machine.
  • A dyno sheet conforming to the SP911 requirements at the end of the SP911 engine rules in the rule book is required for carbureted cars. The dyno sheet must include the numerical data table from which the curves are generated in order to calculate the average horsepower.

Note: Until further notice, the horsepower limits in 17g apply to the stock-based 3.2-liter model, but dyno sheets are not required for Stock-based 3.2s and CIS 3.0s running in 911CUP .

17i. The stock-based version of the 911Cup car weights are reduced to 2500 pounds for the 3.0 and 3.2s. The MFI 2.7s weight is reduced to 2400 pounds, and the 996 C2/RSA weight is reduced to 3025 pounds.

17x. If these weight reductions in practice place the SP911-based cars at a BOP disadvantage, they may be adjusted upward on one month’s notice. Similar adjustments to the weights of other Stock-based 911s may be made if these prove too generous.

PCA Club Racing Enduro Protocol Rule Clarification

Paragraph 2 of Appendix E is changed to read:

    1. “All required pit stops shall be started under Green flag conditions. In the event of a restart, a driver may enter pit road to make the required pit stop on the ‘restart’ lap, provided that driver has crossed the Start/Finish line on the track under Green Flag conditions on the restart.”