Miata and STS2: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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May 20, 2008 9:49 a.m. confuZion3 New Reader

I have a 1994 Miata M Edition. The car has a Racing Beat intake (but everything after the mass-air sensor is stock as far as the intake tract goes), KYB AGX shocks, Azenis RT-615s, and a gutted trunk. Also, the car has no radio or speakers. These are the only material modifications that I can think of right this second.

My question is about classing the car. Somebody told me at the first event I was at this year (and the first event for the car period) that the car is not allowed in STS2 because it has a torsen differential. The rules state that Miatas are allowed in STS2 and also that "no limited slip differentials will be allowed except for the OE 'viscous type'" or something to that effect. But the rules were very specific about this "Viscous" differential. Is the torsen differential a "viscous" differential? Or does the Miata not have a torsen? How could you allow a car and then also not-allow the same car because you create a rule that excludes it?

I really just want to be classed correctly so that I'm not viewed as a cheater. I got annihilated, by the way. The closest person to me in STS2 was 3 seconds faster with the leader beating me by almost 10 seconds. I'm just in it for fun.
May 20, 2008 9:54 a.m. amaff None

The torsen automatically bumps you to CSP. If you don't want to go quite that high, put the trunk carpet (what the heck else is back there to 'gut'??) back in and stock intake and run E-Stock. Or... run what you brung in whatever class it fits in and have some fun!
May 20, 2008 10:11 a.m. mistanfo New Reader

I believe that it would also be eligible for SM2.
May 20, 2008 10:13 a.m. Stargazer New Reader

I say you keep your car the way it is (how you like it), and run in CSP. If you're there to have fun, it shouldn't matter, plus you have room to do more other mods in the future.
May 20, 2008 10:13 a.m. confuZion3 New Reader

amaff wrote: The torsen automatically bumps you to CSP. If you don't want to go quite that high, put the trunk carpet (what the heck else is back there to 'gut'??) back in and stock intake and run E-Stock. Or... run what you brung in whatever class it fits in and have some fun!
Right. So even thought the car came equipped with it, it is not allowed in that class? Don't all Miatas have torsen diffs (unless they're open, I guess)?

I'm just trying to figure out what class to go in just to have fun. I'll run what I brung for now. I've been decently competitive with the Z3, but that car's days of autocrossing are over now that the Miata is on the scene. If I come in last place in every event this year, I don't care. Just as long as I have fun doing it, and I'm losing in the correct class. :cool:

Thanks!

edit: OK now. It looks like I'll go with CSP. Thank you everybody for your feedback. (Also, hooray for the new domain!)
May 20, 2008 10:34 a.m. Keith SuperDork

1990-93 Miatas had an optional viscous limited slip diff. 1994-05 Miatas may have come with either an open diff or a Torsen differential. It wasn't a standalone option but was attached to various packages. Your M-Edition has one, so it's not legal in STS2.
May 20, 2008 10:38 a.m. Salanis HalfDork

I have a spare open differential, in housing, sitting around. If you want to be competitive, I could bring myself to doing a direct swap with you. :grin:
May 20, 2008 10:57 a.m. mistanfo New Reader

I seem to have the only open diff in a '97. Every one that I have seen for sale since has come with a Torsen, either from the factory, or retrofit by PO. An instructor at an EVO school that I took last year said that he'd like to see an ABS equipped 1.8 in STS2, to see if the advantage in braking and torque could overcome the disadvantage of the open diff. However, I think that would result in a fully contented Miata, and having to swap the rear diff out for an open one (all the ABS cars that I see seem to be higher level cars).
May 20, 2008 11:03 a.m. confuZion3 New Reader

Salanis wrote: I have a spare open differential, in housing, sitting around. If you want to be competitive, I could bring myself to doing a direct swap with you. :grin:
Haha. Thanks! But I think I'll keep this one. :grin: