Magner

This roll centre kit would push you from STH to SMS (Street Modified on Street tires)

All the mods would be legal for the Street Touring group. The Genesis fits into STU specifically. This assumes you still have 1 catalytic converter in the car, the rules allow the removal of one if 2 were originally present.

@Scott The +1 -1 rule is based on the car's original wheel package size. In your example you could go 18 19 or 20in in diameter (width must always be the same in street). In order to use a 17" wheel legally based on the SCCA Street rules you would be need to replace any and all R3 trim spefic pieces with a trim that has the 17" wheel. This rule is in place to prevent people making Frankenstein cars that never existed from the factory. That being said locally, I really don't think there's much of an issue or a huge performance difference between rx8 models to warrant you not using 17's especially considering the cost difference in tires between those sizes! As long as the 17 wheels are the correct stock width and +/- 8mm in offset I would say ask fellow street competitors if they are ok with and try pursuing it.

Original post updated with current 2022 links and info.

The interior gutting would automatically put you in the prepared category. The RX-8 fits into the F class of prepared. Your class would be FPS under the modified group if using the 200 or 300tw tires, hower the 120tw tires would class you in the mixed group under FP.

Chris Magne Member #5976 Renewing #47 Kaela Rose Member #7273 Requesting: #33 Thank you Helix!

It appears the posted results incorrectly display cone penalties as +1 second instead of +2 seconds.

Hello, The correct class for the M37x would be SS or Super street. F Street has a catch-all clause but it's for v8 sedans, not v6 so I don't think it applies. The correct class for the Rabbit would FSP due to the tires. Since the tires are 180 TW they are not considered street tires. Only tires with a rating of 200 TW or more can be considered street tires. If the tires were changed the car would be legal for STS. Hope that helps!

Those modification are not allowed in ST. St is meant for street cars with simple bolt ons (cat converter required, full interior, oem type flywheel). This is sounds like a gutted track car. Prepared class allows for fully gutted interiors and sounds like a great fit for this RX8. The correct classification would be FP on street tires or (FP-S) based on the RX8 chassis configuration.

Hi @BradlyW You are correct, this appears to fall into STS based on your modifications. Just a heads up, all ST classes are subject to maximum wheel width and tire width. STS allows wheels up to 7" wide and tires up to 225.

Another data point here on the RT660 vs Re71R size. I received my 215/45/17 RT660 and compared them to a new never used 225/45/17 RE71R. Mounted on the same 7" wheels side by side they are almost identical height less than 1/8" difference. If you have clearance issues or already run a pinched Re71R setup absolutely consider going down a size in width if available. And another not so apples to apples comparison. 245/40/15 RT660 are about 10.5" worth of tread from sidewall to sidewall where as a 245/40/17 RE71R mounted on a 8.5" wheel is under just under 10". In theory they should be the same width but based on brand, diameter, mounting they are not. Again not a good comparison but just shows the RT660's appear to run wide.

The supercharger would make the the car go to SSM on street tires SSM-S.

@rjames The correct class would be CAM-T under the WSCC mixed devision. I checked and the classes are available in MSR for registrationat the very bottom of the list. Use CAMT "traditional" since it looks like the other CAMT is a typo for CAMC contemporary. Since this is a C1500 1/2 truck just a reminder it must be wider than it is tall. (The width must be measured with the track width) Also, Internal engine modifications like a cam are not allowed under Street Prepared rules.

Asking for a tire to last a full season of autocross, (all or most?) open lapping and 300km a week is not likely for most cars. RE-71R was the easy answer for most Winnipeg autocrossers for years however Bridgestone has discontinued the tire and the replacement RE-71RS is not available in North America. further complicating things there's been a few new tire options available in the last 2 years each with their strengths and drawbacks. No clear tire choice at the moment, it will depend heavily on your cars characteristics, tire size option and your needs. If you want long lasting that can hold up to lapping and are willing to give up some lap time maybe a Hankook RS-4 would be worth considering if they come in your size.

All the mods except the cat converter appear to be legal for ST. As stated above if your catalytic converter is located mote then 6" further along the exhaust than stock it will not be legal for ST. If the cat is within 6" it's legal for STH. Those tires are also not legal for use in ST. The minimum tire in street and ST is 200 UTQG. If you use these tires the car would be classed is ASP-R under the mixed group. The ASP-S class is grouped under the modified group and is meant to allow ASP cars to run on 200 UTQG tires. I see a Legacy 2.5 GT is listed under ESP. I assume this is the NA version, since your car is the turbo version it would fall under ASP.