Tire/Wheel set ups

[Gotsol]

Hello

I'm sure this topic has discussed but I'm very confused about the ideal wheel/tire size for the E30. It seems like buys are fitting a wide variety of wheel sizes, widths and ET's on this chassis.

I'm specifically wondering about applications for auto cross. It looks like I might be picking up an 89 327IS. Since the block was swapped that should bump me into SM class with the SCCA (correct?)

Is anyone else running in SM? What are the typical tire/wheels sizes and specs you guys are running?

Thanks in advance. I look forward to being a more active member of this forum.

[Wh33lhop]

Yes you'll technically be in SM if you keep your interior. You will be up against the fastest street cars out there... Giant slicks on 400whp corn-burning Evos, STis, etc. As for tires, it depends on how far down the rabbit hole you want to go. If you want to be semi-competitive in the class (note: this will be an uphill battle and quite expensive. You will need lots more power and tire to be truly competitive, even if you can out drive the competition... I've been there and done that) you will likely want Hoosier A7s... you can put as big A7s on it as you can fit. To start out and fit with minimal fender modification this will probably be a 225/50R15 on a 15x8 +20ish or perhaps a (don't quote me that this size Hoosier will fit because I haven't seen it done) 235/40R17 on a 17x8 +20.

Alternately you can try SM-T2 which is the street tire version of SM if they offer it in your region. It tends to be a lot less popular than SM but you will spend a lot less on tires.

[z31maniac]

I'd think to be halfway competitive in SM, you're talking 285/30/18 A7s and more HP than you can put down, and then still get killed by the boost buggies.

[Wh33lhop]

Like I said it all depends on how far you want to go. It's going to be a losing battle in SM for a 2.7i.

[IronFreak]

and fitting 285/30/18 on an e30 is no easy task, and will likely push you out of SM.

[Wschnitz]

225-45-16 also works If you can find the tires.

[agent]

It's going to be a losing battle in SM for an E30.

[matthugie]

Swapping the block doesn't put you in SM as long as it's still an M20 and doesn't have any internal or head work done. If those conditions are met you can run STX or DSP. If you're 24v swapped (or any other swap) then you're definitely in SM.

[TobyB]

...this is why you start with a bone- stock car when you go racing...

...where you go from there, well, at least you don't have to go backwards to get there.

t

[Wh33lhop]

Swapping the block doesn't put you in SM as long as it's still an M20 and doesn't have any internal or head work done. If those conditions are met you can run STX or DSP. If you're 24v swapped (or any other swap) then you're definitely in SM.

No way. You can't just frankenstein anything you want together and still be in those classes.

[IronFreak]

No way. You can't just frankenstein anything you want together and still be in those classes.

Well......you can....doesn't make it right.

[matthugie]

No way. You can't just frankenstein anything you want together and still be in those classes.

You are correct, I should have been more specific. Just because a car isn't numbers matching doesn't mean you have to run in Modified. All he said is that he has replaced the block. The internals and head must still be stock, but just because the block doesn't have the correct VIN stamped on it doesn't make it illegal for Street, ST, or SP.

[blasphemy101]

If you aren't competing for trophies at nationals and someone calls you out for having a 2.7i instead of a stock M20B25, they're a dick.

[E92E30Nut]

225/45/16s wrapped in Hoosier R6s...in my experience as much wheel/tire that a stock E30 body/fenders can handle. I would like to know if anyone here has flared the stock fenders rather than cutting and going over-fenders?

[matthugie]

I doubt that this day in age anyone would bother trying to flare stock fenders rather than cut and rivet with the options available. Yes, it is a bit more work, but you get so much more space that it isn't really worth the trouble to flare.

In more relevant information, I ran square 235/40/17 NT01's on Apex ARC-8's with just a roll in the rear and had no issues. That said, I'm pretty sure anything that is or runs wider would require more fender work to fit.