2020 Rules Proposals for Comment

Racers are invited to send comment on these rules proposals through August 18th, 2019 to rules@pcaclubracing.org.  Click on the address link to use your own e-mail client to compose and send the message.  All members of the Rules Committee have access to e-mails sent using that address.

It helps if comments in any single e-mail are limited to one class.  Racers may comment on rules for more than one class, of course, but please do so in separate e-mails.  This helps the rules chair a great deal when collating them for committee review.

Rule Book

If you need a copy of the 2019 rule book for comparison, download a copy.  Note that it won’t contain any updates found on the Rules webpage that were approved after publication.


Use the links below to jump directly to specific changes:

Below are the proposed rule changes as submitted by drivers and other interested parties for which the Rules Committee would like to receive comment.  Listing does not indicate that the Committee favors any of these proposed changes.  From time to time comments received on proposals have helped us avoid mistakes, especially those based on an incorrect understanding of the performance factors involved, helped with better wording, modified proposals, and given us more confidence that adopted changes are likely to be improvements overall.

The wording (or the concept) of the proposed changes, seen below, are listed in italics.  What follows for most proposals is a brief statement of why the proponent felt the change would be beneficial.  These may not be entirely accurate, but should help the reader understand the reasoning put forth.


  1. All cars are required to have at least one working tail or rain light which the driver can switch on in the rain.

Most cars already have this.  Those which have removed them or the wiring can add a rain light easily enough, but working stock tail lights qualify.


  1. Require tire treadwear rating of >= 100.

The proponent intended this to address the increasing cost of “track only” DOT tires and ought not to disadvantage anyone in the class.

  1. Reduce the E class 944S2 weight by 50 pounds.

This car, once competitive in E, seems to need a boost.

  1. Allow replacement of dual mass flywhees in all stock classes.

The dual mass flywheels cannot be reconditioned when worn.  It is suggested that inspection for the modern six cylinder water cooled cars for compliance is difficult if even possible at our events, and compliance may be a problem here.  If replacement is allowed:

  • Should this be restricted to steel flywheels (currently allowed single mass flywheels for 964, 993, and 968 have this restriction), or
  • Should aluminum flywheels with a ferrous friction surface be allowed, and
  • Should any of these be specified by aftermarket  maker and part number, as some spec classes do?


  1. Make switching to carburetors, but making not other Prepared changes, a one class bump.

Carbs on cars which didn’t come with them are currently a two class bump.  It appears that adding carbs to Stock D SCs would yield a motor equivalent in performance to the E class Euro SCs., and permit those cars to move up to E if the driver so chose.  However, there doesn’t appear to be a reason to restrict this to one model or class.  Allowing the full range of Prepared modifications here would upset performance balance, so those wanting other Prepared modifications would take the traditional two class bump.

10a. Allow EFI conversion for cars which did not come with it as a two class bump.

MFI or replacing the MAF is a two class bump, and this would allow EFI to join the group.  Crank fire or similar ignition is already a regular Prepared modification


  1. Allow turbo and approved aftermarket substitute rods.

The turbo rods don’t weigh any less than the stock 944 NA rods, and we have (because turbo rods are NLA new) an approved Poetl/Racers Edge substitute.  It appears that some models of the 2.5 NA 944 came with factory forged (turbo) rods anyway.

  1. Allow the 924S models to make fog light cut-outs to front valance.

This is intended to allow specifically a modification allowed to other models in the class.

  1. Allow SP1 cars to use any urethane front valance provided it is an exact replica.

There is no apparent reason to limit an exact urethane replica to a specific part or manufacturer.

  1. Allow Focus 9 DME for SP2.

This is an equivalent substitute for the stock pieces, which are NLA.

  1. Allow adjustable ball joints on the front lower control arms in SP2.

This proposal would align the rules with SP3 and allow the suspension to better adjusted for lowering the car.  It applies only to the outer ball joint which connects to the bottom of the strut.  The inner mounts must remain fixed on the A arm, as they are in SP3.


  1. Reduce SP3 weights as follows:
Current Weight New Weight
944S 2500 2415
944S2 2700 2610
951 2800 2705
951S 3000 2900
968 2900 2800

The proposal is intended to reduce the amount of ballast which highly lightened cars need, reducing the risk of ballast getting loose in a crash.


  1. Add 987.1 Boxster S to SPC.

This car should be competitive, and would add to the class numbers.

  1. Allow the Tarett TABKA02 billet caster adjustment inserts for the front lower control arms.

These cars need to push the front lower control arm back so that the tire doesn’t rub on the fender well.


  1. Allow PRC GTL cars to run in PCA GT4 at a set weight of 2380 lbs, plus whatever the additional weight for slicks is.

The Porsche Racing Club (San Francisco bay area generally)  has, in addition to the SP911 class, whose rules we have copied so they can race with us seamlessly, a 3.6 liter air cooled class called GTL.  The theory is that by restricting the intake and the exhaust – which can easily be checked – an otherwise GT motor can be made to last rather a long time.  At 2380 lbs, they are at a disadvantage in PCA GT3 when running in our events, and lightening  to the minimum would cut into structure and require a lot of ballast when competing in other venues.   The intake restrictions cause throttle lag, and 330 flywheel horsepower is what they make, which would be 92HP/Liter where the regular GT factor is 110 HP/Liter.  With slicks, the weight would increase to 2430 or 2480 lbs, which might be an equalizer?

  1. Increase the weight bonus for radial slicks in GT from 50 to 100 lbs.

The proponent claims slicks hold up longer, and their advantage over DOTs is more than 50 pounds.  And the cost of slicks is getting even more out of hand than for Hoosiers.

27a. Delete the bonus weight for slicks for bias ply slicks.

Experience has shown that this type of tire does not have the advantage over the nominal DOTs which radial slicks, which are the subject of continual development (and cost), have.              


  1. Decrease the 997 GT3 weights by 100 pounds.

The proponent believes the 997 is not competitive with the Caymans at the current weights of 2850, 2950, and 3050 depending on intake, plus 125 lbs if PDK.


  1. Allow paddle shifters in GTC4 and 5.

The proponent believes paddle shifters, allowed in some series for these cars,  are becoming more common, which is reducing the GTC fields.  He posits that a paddle shifter will double the transmission life.

  1. Allow aftermarket ABS in GTC4, 5, and 6.

This is becoming increasingly common in other venues, and not allowing ABS may be cutting into class participation.  It is not inexpensive, but neither is the cost of a flat spotted set of the spec tires.