BMW e46 engine question?

[Greg Amy]

STU engine displacement limit is being raised to 3.2L for 2012, weights will be a linear increase on existing table. - GA

[Z3_GoCar]

As I understand it, the double vanos motors require a pretty sophisticated ecu to correctly control. Best bet may be the Bosch motorsports DME as used in GrandAM. As for weight, all 2.5's weigh the same doesn't matter generation or even who's (it could be a Nissan 2.5 liter four would weight the same.) That said, the intake manifold it the key choke point, I'd consider swapping for one of the higher performance one that came in the same chassis. More info can be found searching the Bimmer boards.

[Ron Earp]

STU engine displacement limit is being raised to 3.2L for 2012, weights will be a linear increase on existing table. - GA

Get it up to 3.8L and some other cars might come and play....I could have an STU engine and an ITS engine.....

[Greg Amy]

Get it up to 3.8L and some other cars might come and play....I could have an STU engine and an ITS engine.....

Ron, Table A, STU allowances, p 476 in Dec GCR. - GA

[gpeluso]

I must be an idiot because it looks to me the 330(3.0) bmw motor weights are HIGHER than 3.2l BMW M3??????

Greg

[Z3_GoCar]

I must be an idiot because it looks to me the 330(3.0) bmw motor weights are HIGHER than 3.2l BMW M3??????

Greg

That's under this years rules and only applies to the S-52 e-36 M3 motor with limited modifications. I haven't seen if that exception will still be in next years STCS.

[Greg Amy]

That line's staying. As I recall, that was in response to a request to classify a BMW Club category, maybe Spec M3? As noted, to get that lower weight you have fewer mods; you're free to config it either way.

GregP, keep in mind that STU rules are an open set, meaning there's no specific classification requests needed. That Table A "alternate vehicle allowances" are ONLY to allow specific deviations from the open ruleset.

GA

[Ron Earp]

Ron, Table A, STU allowances, p 476 in Dec GCR. - GA

Fast Track?

I found this around p476 in the 2011 GCR:

G. Weight Requirements
1. Minimum weights for cars with piston engines will be determined
by 1.3 lbs/cc displacement for the installed engine (see following

That' would be a 4940 lb Mustang 3.8L!

Let me go check the Fast Track.

[Greg Amy]

Nope, not Fastrack, the actual STU regs' Table A. We allow the 3.8L Mustang and Camaro in, albeit with porky weight (compared to ITS) and lesser mods (pretty damn close to ITS).

Then again, per the STU regs, "Any GCR listed IT cars, 1985 and newer, under their current IT specifications may compete in STU. GCR listed IT cars of 2 liters and less engine displacement, 1985 and newer, may compete in STL under their current IT specifications."

Unless there's some other ST mods you want to do (cams, porting, wings, etc), it kinda doesn't make a lot of sense to toss in that extra ~700+ poundages.

- GA

[Ron Earp]

So valve lift is 0.600" and 12:1 compression for most cars in STU, except for the cars on the table, the Mustang and Camaro being two of them limited to 0.5 compression and a stock cam?

At 3200 lbs a two valve push rod engine might have a chance against the Wonderimports if allowed the same cam and compression rules, but no way if limited to stock lift and compression. I'd have to ballast up a lot to hit 3200 lbs with no extra power to speak of.

[Greg Amy]

...and that is the point. Someone convinced the STAC/CRB to let those cars run in a "3L and under" (now 3.2) class*, but no way were they going to be allowed to be cars to have. "Come play, but don't expect to win a National Championship with it".

You're better off running the ITS car in STU as-is. But if you want to build a full-tilt-boogie 3.8L Mustang, STO beckons. Good luck with that, though we'd give you AWESOME weight breaks and probably anything else you wanted, including a supercharger...

GA

P.S., It was before my time on the STAC, I think, as I'd have been opposed to the allowances greater-than-3L cars, even at hobbled prep. BTW, it's stock cam lift, not stock cams.