2021 - RX Rules Change Proposals

[slowautoxr]

Looks like I didn't answer a post by JWA regarding stock class tires related to retreads. During the course of our investigation we found that although retreaded tires can be DOT compliant, the manufacturing process and the ability to get DOT approval was not consistent with the Stock class rules. In a nutshell pretty much anyone could set up an operation and start making retread tires of whatever tread design they want. We added the italicized text for the 2021 rules:

Change Stock rule 3.3.C.2: .....Tires marked “For competition only”, “Not for street use” or similar are not allowed. No part of the tire may be modified or altered from its original form, either through addition or subtraction, other than normal wear. Retreaded, recapped, and remolded tires are not permitted. No studded tires are permitted at National events unless ice or snow is present; Regional and Divisional events may allow studded tires any time.....

[slowautoxr]

The rules and rule changes have been sent to the SCCA board for approval. Assuming that they are approved, the new rules will be published early in January.

[Peterd123]

Hi There, any word on when the 2021 rules will be posted? Tick tock. Healthy regards Peter

[slowautoxr]

Thank you folks for taking the time to make these proposals. Here are the status of each:
Ojannon / Allow additional seat belts in Stock. / Already allowed in 3.2.G.
Ojannon / Allow removal of fog lights in Prepared. / Look for a rule change for 2021.
Ojannon / Allow fender rolling in Prepared. / Look for a rule change for 2021.
JWA / Allow any wheels in Stock. / The RXR-C does not recommend this change. The RXB did not approve this change.
JWA / Allow intercooler changes in Prepared. / The RXR-C does not recommend this change. The RXB did not approve this change.
So Close / Require pneumatic hoses at National events. / This is not a rule item. This item has been forwarded to the RX National Championship Committee.
JCarl / Limiting Aero in Modified. / The RXR-C likes the "Street Prepared" aero rules. Maybe big aero is for the Constructor class. The RXB did not approve this change.

[JCarl]

Just to get in before the end of August deadline, this is to start a conversation about several factors that are causing all three Stock classes (SF, SR, SA) to be moving toward there being only a handful of overwhelmingly dominant cars.

I believe what we want is for the widest possible number of different car models to be potentially competitive. As a corollary, we want very much to avoid any classes being dominated by rare, obscure, or particularily expensive car models.

In rallycross, the following factors are clear from a theoretical vehicle dynamics perspective, and are borne out by analysis of RX results -- especially the RXN results archive:
>> All other things being equal, a car with smaller diameter wheels (and higher aspect ratio tires) will always beat a car with larger diameter wheels.
>> All other things being equal, a 2WD car with a limited slip differential will always beat a 2WD car with (only) an open differential.
>> All other things being equal, an AWD car with more limited slip differentials will always beat an AWD car with fewer (or no) limited slip differentials.
>> All other things being equal, a RWD car with the engine and transmission in the rear will always beat a RWD car with the engine and transmission in the front.
>> All other things being equal, a car with the suspension with the right blend of compliance and control will always beat an otherwise similar car with suspension that is either too hard or lacking adequate control.

Of course, in real competition "all other things" are NEVER equal. On any particular day, conditions, driving, preparation, tires, luck, etc. can overwhelm any particular factor above. However, when we account for the uncontrollable variables, the factors above hold true.

There are various ways to equalize for these factors. I will add suggestions and detail over the next few days.

Thanks!
Donald Carl
150506

[JCarl]

Dear RXB;

On the last day for submissions and with apologies in advance to Brianne & Peter…

While it was fun to watch MR at Nationals this year, I believe the advent of Big Aero is not in the best interests of SCCA Rallycross. To put it simply:
• Anyone with any sort of motorsports background knows that Big Aero works. Even on dirt. If there is any questions about the potential performance benefits of Big Aero on dirt, look at sprint cars or the last few years of Pikes Peak Unlimited cars before the paving was completed.
• Once someone gets past the steep learning curve of car setup and driving with Big Aero, it will become a necessity to remain competitive in Modified Category.
• Cost to compete, technical complexity to compete, and safety will all be harmed by Big Aero becoming a competitive necessity.

As of right now, my own observations suggest that very few current Modified competitors have made significant investments of money or labor in aerodynamic development. Only one car owner I know of has attempted what I would call Big Aero -- and we all know who that is… Therefore, this is the best time we are going to have to reign-in further advances in the direction of Big Aero.


Current “aerodynamic devices” allowance for Modified reads as follows:
3.3.E.3.i. Aerodynamic devices, including wings, splitters, spoilers and spats, may be added, removed or modified, and any such devices used must be securely mounted to the vehicle.

My personal preference is very simple from a rules standpoint -- simply DELETE existing 3.3.E.3.i. and re-identify 3.3.E.3.j as 3.3.E.3.i.

By implication, Modified Category will then have the same “aerodynamic devices” allowances/restrictions as Prepared Category. I personally believe this is the best all-around solution. Furthermore, I suspect that most current Modified competitors who do have minor “aerodynamic devices” would choose to give them up to avoid having to go “all-in” on Big Aero to stay competitive.

If it turns out that there is widespread resistance to pulling the Modified allowance for “aerodynamic devices” all the way back to Prepared, then a middle-ground position along the lines of SCCA Autocross Street Prepared “Full-Prep” would still be much better than the current 3.3.E.3.i. -- which is closer to SCCA Autocross A Modified.

Thank you for your consideration!

Best Regards,
Donald Carl
150506

[So Close]

I propose that we get a rule written that stipulates the use of a pneumatic system for the timing of runs at the National level events. We have suffered to many delays for too many years. The optical system has flaws that make it unsuitable for top caliber events. It has been a point of constant grief. Every one I have ever discussed the timing issues with agrees. It is proven that the pneumatic system is better for RallyCross. The time has come for the National crew to make a permanent, long lasting investment in improving the future of our marquee event.

[JWA]

Proposed rule to change:
3.3.D.5: Prepared Class intercooler changes


Current wording:

5. The intake system upstream from the throttle body may be replaced with any material. Forced induction components cannot be changed or added (turbochargers, superchargers, intercoolers). Turbocharger boost regulation systems, either electronic or mechanical, may be modified or replaced. The pulley on the supercharger may be replaced with an alternate size along with the supercharger drive belt.


Proposed wording:

5. The intake system upstream from the throttle body may be replaced with any material. Forced induction devices cannot be changed or added (turbochargers, superchargers). The pulley on a supercharger may be replaced with an alternate size along with the supercharger drive belt. Turbocharger boost regulation systems, either electronic or mechanical, may be modified or replaced. Turbocharger intercoolers and piping may be with replaced with alternate parts providing they and their installation serve no other purpose, and subject to the following restrictions:

a. Fluid capacity and dry weight of any intercooler being replaced must be no less than that of the OEM standard part.

b. Intercooler(s) and their lines must be securely mounted, reside in the engine bay area, or the general location of the OEM part being replaced or modified. No lines may be routed through the passenger compartment.

c. No body parts or structure may be altered in any way, except for the minimum holes to facilitate mounting brackets and fluid lines, for installation.


Rationale:
It has become common for many of the currently allowed modifications to modern turbocharged cars to be bundled with a higher capacity intercooler to protect the engine. The current exclusion limits many tuned street cars from entering in Prepared class if they otherwise qualify. The larger intercooler does not increase the power of the motor, it only allows it to be made for longer, something that is of little benefit in the context of most RallyCross run durations.

[JWA]

Proposed rule to change:
3.3.C.2: Stock Class tire requirements


Current wording:

2. Tires must be U.S. Department of Transportation (DOT) approved and display the applicable DOT symbol and Tire Identification Number (TIN) label. Tires with the equivalent Canadian DOT and TIN labels are allowed on Canada‐ registered vehicles at Regional events. Tires marked “For competition only”, “Not for street use” or similar are not allowed. No part of the tire may be modified or altered from its original form, either through addition or subtraction, other than normal wear. No studded tires are permitted at National events unless ice or snow is present; Regional and Divisional events may allow studded tires any time. Studded tires may not be homemade using bolts or screws. Only street‐legal studs are allowed. Alternate tire sizes are allowed but tires may not interfere with any parts of the car (fenders, fender liners, suspension, etc.). Inner tubes are considered an integral part of the tire.


Proposed wording:

2. Tires must be U.S. Department of Transportation (DOT) approved and display the applicable DOT symbol and Tire Identification Number (TIN) label. Tires with the equivalent Canadian DOT and TIN labels are allowed on Canada‐ registered vehicles at Regional events. Tires marked “For competition only”, “Not for street use” or similar are not allowed. No part of the tire may be modified or altered from its original form, either through addition or subtraction, other than normal wear. Retread, recapped, or similar tires are considered to be modified from their original form. No studded tires are permitted at National events unless ice or snow is present; Regional and Divisional events may allow studded tires any time. Studded tires may not be homemade using bolts or screws. Only street‐legal studs are allowed. Alternate tire sizes are allowed but tires may not interfere with any parts of the car (fenders, fender liners, suspension, etc.). Inner tubes are considered an integral part of the tire.

Rationale:
Provide clarification of previous rulings.

[JWA]

Proposed rule to change:
3.3.C.12: Stock Class wheel allowances

Current wording:

12. Any type wheel may be used provided it complies with the following:
a. Wheel diameter may be increased or decreased one inch (1”) from the OEM wheel;
b. Wheel width may be increased or decreased one-half inch (0.5”) from the OEM wheel;
c. Wheel offset (backspace) must be within 0.394" (10mm) of the OEM wheel offset. Wheel spacers are considered part of the wheel;
d. Extended length wheel studs/bolts are allowed but the type of fastener (bolt or stud) may not be changed.


Proposed wording:

12. Any wheel may be used.
a. Wheel spacers are considered part of the wheel;
b. Extended length wheel studs/bolts are allowed but the type of fastener (bolt or stud) may not be changed.


Rationale:
The thoughts are two-fold:

• Modern cars are being delivered from the factory with larger and larger wheels and the current wheel rule effectively eliminates many potentially desirable cars from RallyCross use. One example would be the 2017+ Honda Civic Type R, which is fairly popular in other SCCA programs but whose 20” diameter wheels effectively preclude from Stock class RallyCross use.
• The current ruleset now allows for changes to the diameter, width, and offset of wheels in Stock class so at this point it would be easier and cheaper for competitors for any wheel to be allowed. Calipers and rotors must still remain stock and rule 3.3.C.2’s limitations on tires interfering with any part of the car would remain, so this rule change should only serve to simplify wheel choice and open up more cars into eligibility.

[ojannen]

Here are a couple of rules ideas I have been kicking around. I am not sure if they are all necessary. Depending on the interpretation of the rules, these things may already be allowed.

Add a rule to stock class that allows adding to seat belts to cars that didn't come with seat belts from the factory. Right now, they are banned due to a safety rule requiring them and no stock allowance for changing seat belts. I don't know how to word this rule to avoid encouraging stock class drivers to replace oem seatbelts.

Loosen up the rules for fog lights in prepared. So far, I have lost two fog lights on course and 1 while driving to an event. I carry lights with me when I travel in case I get protested but nobody has cared in four years of events. I am interested in a new rule with the text, "Auxiliary lights below the bumper structure may be removed".

POST NATIONALS EDIT: Trophies at nationals in SF and SR could have been affected if someone had filed a protest against all cars missing auxiliary lights in those classes based on impound/grid shots I have seen. PF would have been affected but none of the Minis trophied. The lights could have been damaged during a run but an average a Mini or BMW has more than 1 auxiliary light missing.

Rolling a fender bumps you up to modified and I think it should be allowed in prepared. There is a fender flare rule in Stock but it does not allow you to cut the fender, only to add an external flare. Autocross/drag/cars-and-coffee cars often have their fenders rolled and changing them back often means $1000 in new parts. I don't know if there is a fender rolling performance benefit but I believe this change meets the spirit of the Prepared ruleset. I like the Street Touring autocross rule here, "Fenders may not be cut or flared but the inside lip may be rolled to gain additional tire clearance. (The outer fender contour may not be changed.)".

[gsxnut]

Have a rule change or clarification you would like to propose for the 2021 RallyCross rules? Submit your proposal on this thread. Be sure to include the proposed language for the change and a brief explanation of why you are proposing the change. The rule change submission period runs through August. Member comment on proposed changes will take place in September, followed by Rules Committee review in October, and final review and approval by the RallyCross Board (RXB) and the SCCA Board by year-end.