We ran 255 RE-71Rs on the ND but can only fit 245's in the yokes (and you still can never go full lock). 255 yokes should fit fine on the S2k.

 

I know some like the idea of the X classes, but you better have deep pockets

 

Yes, Bob Endicott runs 18x10.5 +55 with 295 Square on rolled fenders. He does have shorter upper control arms (modded) to achieve his camber more inboard. I think the 285 would fit better on that rim IMO.

 

You're telling me that a stock body S2000 with rolled, but not pulled fenders can fit 295 square? I am not a pioneer here and am just copying other people's setups but I don't see how that's possible. I want to see that...

I can't go full lock without rubbing my wheel on the a-arm as is. I guess I'd rather the tire rub than the wheel unless it really grabs. I'm completely stock fender, nothing pushed in or rolled so I went pretty conservative moving things inboard. Hopefully the 255s don't cause any additional contact but we shall see in a few weeks here.

I like the idea and it really depends who runs it. I figured the first few years are unlikely to have fully developed cars unless some of the race tire class cars start migrating. Before modding my car in the off-season, I considered jumping ship. I saw someone putting feelers out for a LFX (Chevy V6) swapped RX-8 and loosely considered offering my AP2 for trade. I think the LFX RX-8 would fit pretty well into the class. Great chassis with a decent amount of development and can stuff huge tires under the stock body. Big wing, some basic front aero work and see what happens. As time goes on, sure you'll need more HP but a lot can be done with roughly 2800 lbs, 315s all around, and 300hp/300tq. Totally rough spitball idea but I thought it would be a fun combo with a much more replaceable chassis/engine and better at serving double duty on the track than a prepped S2k. Most obvious issue to the LFX swap that I saw is that the front swaybar needs to be modded due to the engine protruding into its way. Therefore the off-the-shelf aftermarket options would not fit. I'm spoiled in using front-swaybar adjustments to change the behavior of the chassis in the middle of a heat and it's one of my go-to changes.

 

Probably a combination of your ride height and camber settings. At -2.6 degrees of camber, lowered about one inch with 17X9's with 255's I can go full lock with zero issues on my AP1. I believe if your ride height is a bit higher and with a lot of camber the inside of the wheel can rub the control arm in some cases but have not had that occur on mine before.

 

18" wheels give you more clearance on your control arms lock to lock - it's the other reason for moving to 18"s over 17"s.

 

I'm -3.4 degrees in the front with a 13" static ride height (center hub to bottom fender). It's pretty much only at a hard full lock that it rubs but it can rub pretty hard. I'd rather that than hit a fender. My wheels are cheapo TR C3's which I'd way rather polish the inner lip of than catch an outer fender. Even at that camber, my Rival S 1.5's were rolling over the outer edges a bit at 32 PSI hot. I do not have a pyrometer to check actual temps.

Makes sense. 18' tires cost significantly more but it's pretty cool to hear we can fit 285/295's. I did find a post from the past selling some custom CCW's that ran that setup. Specs were:

Fronts: 18" diameter, 10" wide, 8.5" backspacing which uses a 1" spacer to net an installed 7.5" backspacing ~ 57mm offset with spacer (82mm offset w/o spacer).

Rears: 18" diameter, 10.5" wide, 8.5" backspacing and no spacer (net 8.5" backspace installed) with ~76mm offset.

User also indicated that extended front studs were necessary. Also needed 2.25" ID springs for clearance.

https://www.s2ki.com/forums/wheels-t.../#post23344053

 

I really do love that idea and have driven a few good examples but there are two ways to do it.

The LFX, Camaro trans, and Camaro diff using the drop in kit which keeps the EPS and RX8 ECU. Those seem to have electrical issues and the Camaro diff just doesn't lock the best so you would want a different LSD.

The LFX, V8R Subframe using the NC Steering rack and Ford diff seems to be much better. You can have a hydraulic power steering rack and have more differential options while also not having to deal with two ECUs. Problem is V8R doesn't have a ton of development in this. You would need to make or buy a wiring harness for this.

The LFX is a cheap engine too. The SRX engine with a Camaro ECU, some brackets, and the Camaro Intake manifold can be had affordably. I had a 36k mile engine for $750 last May.

 

Would CAMC be a better comparison or ESP for this new ST class? Looking at times it seems like ST classes are generally faster than CAMC. I have been out of the autocross loop for a moment but I’d imagine the biggest difference between ESP and CAMC would be the slicks? It seems like CAMC would be more analogous given the tire limitation. Were there differences in run conditions at the 2019 nationals event to explain the differences?

 

All hard items to answer. Yeah, varying conditions also can play into it and while I was there I would have to go back and find the schedule to see who ran when. Always hard to measure/compare since at nats you have heats spread across the days and classes that run days apart (T/W vs Th/R). For example, STR always has seemed to run in the first heat or two when I have been in that class, and the most frequent chances of rain (and of course coolest weather of the day) always seemed to be in the early AM, so even if running the same day, conditions change a lot. Especially in Nebraska!