From PCA Club Racing Rules Committee
July 15, 2016

Racers: Here are the rules change proposals 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 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 or terminology involved, helped us word rules better, modify proposals, and given us more confidence that changes adopted are likely to be improvements overall.

The wording (or the concept) of the proposed changes is in italics. What follows for most proposals is an extremely 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.

Comments may be submitted to crrules@pca.org until August 15th. 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.

GTA: Create a GTA3 class for modified 991 Cups and other 991 based Porsche factory race cars. The 991 Cups appear to be distinctly faster than their predecessors, and the modifications which move a car from GTC5 into GTA2 are not enough to overcome this.

GTB: 1) Bodywork: Except as specified, an unmodified production chassis is required. Bodywork changes are limited to those found on an equivalent GT3 Cup as follows: The 996 911 may use 996 GT3 Cup parts, the 997.1 and 987.1 Cayman may use 997.1 GT3 Cup parts, the 987.2 Cayman and 997.2 911 may use 997.2 GT3 Cup parts. The 981 Cayman may only use stock or GT4 parts as indicated below [the existing rules specify what parts the 981 can use, and allow for aftermarket alternate material replicas, and no changes are proposed for those].

The goal here is to remove ambiguity from the current rule. Some Cayman racers expressed a desire to limit Caymans to stock Cayman fender width, which is 1781mm, and which allows the 245-645/18 Pirelli to be used. This tire has been used successfully in racing, although it appears conflicting advice may have been given by different Pirelli representatives, and the rim width must be just right. A wider fender will allow the 265-645/18. But it is not clear how this could be implemented without requiring those who had installed allowed 997.1 Cup fenders (1815mm) to change. Banning factory Cup extensions on the 997.2 Cup fenders (1787mm without extensions) similarly presents a problem for those with those fenders on their Caymans.

3) Bodywork: Permitted front bumper covers not configured with an upward vent may have an opening cut into their upper surface to allow air from fluid coolers to vent upward, but any protrusions upward may be no more than the late model covers which come with this feature. Ducting for such venting is free as long as there is no modification to the tub. Heat is the enemy of mid-engined cars, and it should help longevity to give earlier models the opportunity of the venting Porsche eventually adopted.

4) Wings:
GTB1, GTB2, and all GTB3 except the 981: Wings are free with the following limitations:. A) The maximum chord is limited to 12 inches measured at the widest point of the wing, not including endplates. B) The maximum total wingspan is limited to 63 inches including endplates. C) The endplates must fit within a13.5 inch sided square on either side. D) The wing, excluding end plates, may not extend to the rear of the rear bumper cover. E) No part of the wing, excluding endplates, may be higher than 4’8” above the ground with the car sitting on the ground in its racing configuration. This proposal is intended to treat these wings more like GT, since two of the series with approved wings no longer exist, and dimensional limitations are easier to understand and to measure for compliance.

Note: The existing rules require that the GTB3 981s in GT3 (GT4 and clones) run the stock GT4 wing at the stock height, because these cars come with a wing, unlike the other models in GTB. For 2016 an exception was made because no aftermarket replica GT4 wing and upright was available. An aftermarket replica has become available, so this exception will no longer be in effect in 2017, and GT4s will have to run the GT4 wing and upright in the GT4 location.

5) Allow 911s and 987.1 Caymans in GTB1 to use the 82mm GT3 throttle body and plenum, or aftermarket versions of the same. The rationale is that these upgrades will help the first generation GTB1 cars and the 911s close the perceived performance gap with the 987.2s.

GTC: Allow aftermarket paddle shifters in GTC4 and 5. It is believed this will reduce the frequency of transmission repairs, because if the clutch pedal does not hit the floor before the new gear is selected every single shift, wear increases sharply.

SPB:
1) Remove minimum weight for battery. The proponents see this as a relatively inexpensive way for cars, especially with heavy drivers, to get down to minimum weight. Costs for light weight batteries have fallen significantly from when these rules were first adopted.

2) Allow spacers on rear wheels. This is believed to improve handling at minimal cost, and tires will still have to stay within unmodified fenders.

3) Allow 500/500 springs. This is believed to improve handling at a relatively minimal cost.

SPC:
1) Drop class minimum weight to 2,900 lbs. If the air conditioning is removed, as is allowed, the cars may need ballast to meet the current weight of 2950 pounds.

3) Allow "de-snorkeling" by removing the baffle/restrictor plate in front of the air intake before the air filter. Its protective function may be achieved, if desired, by a screen or grill. The cost of removing this stock obstruction is near zero, and it gives a modest power gain.

4) Allow two piece rotors if dimensionally the same as stock. The notion is that while the initial cost is higher than the stock one piece design, over time the lower replacement cost will lead to a savings.

SP3: The 968 six speed transmission may only be used in a 968 with a 968 motor. This prevents installing a 944 engine in a 968 chassis, with the 968 six speed, but running at the 944 weight, since the additional 968 weight over the 944 3.0 is premised on the advantage of a six speed, and only the 968 has been allowed to use the six speed.

SP996: Allow an additional shock package: the Motion Control 2WNR (2-way non remote). Stock:

1) Allow headlights to be removed. This was proposed in light of the substantial replacement expense of the newer headlights.

2) Reduce the weight of the E Boxster by 100 lbs. The proponent asserts that this car is uncompetitive at the current weight of 2929 pounds.

3) Reduce the E 968 weight to 3086 lbs. The proponent asserts that this car is still uncompetitive at the current weight (adjusted in January 2016) of 3136 pounds, which was a 100 pound reduction from the 2015 weight.

4 ) Allow aftermarket 2-piece lower control arms on 996/997/Boxster/Cayman as long as camber is not adjusted to exceed what can be achieved with the allowed GT3 part. Porsche GT3 LCAs are allowed, but aftermarket equivalents are less expensive