Club Racing Rule Changes Adopted for 2021

From: PCA Club Racing Rules Committee

After consideration of submitted comments, the rule changes summarized below have been adopted for the 2021 racing 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 the address  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 rule book — sans the changes summarized here — for comparison purposes.  Use this link to download a PDF copy of the 2021 rule changes listed below.


Use the links below to jump directly to specific changes:

Safety and Miscellaneous

  1. Safety Rule 10 is modified to allow aftermarket air/oil separators in addition to the currently allowed factory racing part.

Brake caliper piston material is free in all classes (e.g., stainless pistons may be substituted for stock steel pistons).


2010 Snell helmets expire (no longer comply with the rules) 1 March 2021.

Snell helmets from the 2015 standard expire at the end of the 10th year after the date of manufacture.  This is the same as the rule for FIA helmets.

Seat Belts

To conform with the PCA DE rules, SFI seat belts expire two years after the date of manufacture, or on their listed expiration date if present, whichever is later.


  1. 911 SCs and 84-5 Carrera 3.2s (915 Transmissions) may run US or ROW 2ds, 4ths, and 5ths.
  2. 911s from 1970-1998 may use the aluminum housing/cast iron plate Sachs Sport pressure plate (approximately 8 lbs).  Note that this does not allow any flywheel change – allowed flywheel replacements are in another rule.
  3. 911 SCs may use any CIS setting, and any CIS parts found in a Porsche are allowed.  Aftermarket electronic WURs are allowed.  Control of the frequency valve on US models from 1980-1983 may be aftermarket.
  4. Any ignition system for 911 SCs is allowed as long as it uses a distributor to distribute the spark (i.e., no crank fire or COP).  This allows aftermarket distributors which can alter the advance curve electronically, and MSD ignition systems where the rev limit may be changed with a plug (this rule does not allow for rev limit changes).
  5. 1980-83 US 911s may adjust the rev limit to 7,000 RPM using a limiting rotor or otherwise.
  6. 911s through1998 may enlarge the camber/caster holes in the sheet metal on the top of the front strut tower to allow more adjustment (e.g, more negative camber).  Note that this does not allow cutting/welding the shock tower generally for side clearance of the shock body, just the top where the camber adjusters sit.
    1. 911s through 1998 may replace the rear quarter window glass with plastic as long as it includes an air duct for driver comfort.
      1. Chassis structural elements may be reinforced to repair existing cracks or fractures with plating no more than double stock gauges.  Failed spot welds may be repaired, but pinch weld flanges may not be seam welded.  This does not allow reinforcements that increase the structural rigidity of the chassis beyond what it was when the car was new.


  1. Approved aftermarket clone pistons are allowed in SP1.  CP-Carillo part number NASA-944-3937 (for engines using original 100mm bore size) and CP-Carillo NASA-944-3957 (100.5mm) for bored blocks are approved.


The 90mm minimum ride height requirement in Rule 4.G is replaced with the following:  “Any ride height is allowed, as long as no part of the vehicle other than the tire patch touches the ground.”


  1. The engine driven power steering may be switched to an electro/hydraulic power steering system as long as the hoses mate up to an otherwise unaltered stock rack.


  1. The minimum weight of the 981 is increased from 3050 lbs to 3100, subject to adjustment as experience may dictate during the year.

911 CUP

  1. 911 Cups may remove the cabin air system under the cowl in the front trunk.
    1. Stock class 964 C2s may run in 911 Cup at 3081 lbs., subject to adjustment as experience may dictate during the year.


Front rotor diameter may be increased to 350mm.

The Spec dry tire is the Hankook Z214/C51 compound:  245/35ZR18 or 275/35ZR18 front, and 315/30ZR18 rear.


Ride height is at whatever pressure is in the tire when you come off the track.

Three intake options are deleted – logbooked cars with them are grandfathered at a set weight and may continue to race in the class.

Chassis dyno horsepower and weight limits are:

Engine Displacement
IntakeMax Peak (hp)Max Avg (hp)Min Weight
3.0Porsche 3.6
3.2Stock Intake2402352,340

AT power stacks grandfathered per 2019 log book – 2,475 lbs

MFI grandfathered per 2019 log book – 2,340 lbs

CIS grandfathered per 2019 log book – 2,310 lbs

GTC3 (996)

There is no longer a spec tire for these cars.  Rims must stay the same, but tires are free (same as GTC1 and 2).

GTC8 (992)

These new Cup cars will run under the usual German Cup rules but may run the ABS allowed in the Porsche Carrera Cup North America series.  Pirelli will be the spec tire.  Tire specs and minimum weight will be announced when available.  Cars running on other tires can run in GTA3.