BMW e46 engine question?

G

gpeluso

New member
Built a 323i e46 last year for NASA PT...... the build has run into many issues and I and currently solving one of them by adding a standalone ecu. I am curious about making the car crossover to SCCA and maybe STU. I am wondering with the addition of the E36 3.2 M3 (which i don't understand due to under 3 liter idea) what weight would i run if I added a:
323i e46 motor (2.5l)?
325i e46 motor (2.5l)?
328i e46 motor (2.8l)?
330 e46 motor (3.0l)?

or do i give up on these bmw motors and just put an e36 motor m50 or m52? Maybe the standalone will change things but it seems that BMW made these motors at a lower standard and do not seem to race well. I have heard of people putting different rod bears because of the weak e46 stuff. I really screwed this up and should have went down the e36 road. I have way to much $$$ in this project and my ITS rx7 is more fun to drive right now. Hopefully this will change.

I currently have in my possession a e46 323 and e46 328 motor...just seeing what makes the most sense or seeing if i need to buy or build another.

Thanks
Greg
 
STU engine displacement limit is being raised to 3.2L for 2012, weights will be a linear increase on existing table. - GA
 
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.
 
Greg Amy said:
STU engine displacement limit is being raised to 3.2L for 2012, weights will be a linear increase on existing table. - GA
Click to expand...

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

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.
 
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
 
gpeluso said:
Built a 323i e46 last year for NASA PT...... the build has run into many issues and I and currently solving one of them by adding a standalone ecu. I am curious about making the car crossover to SCCA and maybe STU. I am wondering with the addition of the E36 3.2 M3 (which i don't understand due to under 3 liter idea) what weight would i run if I added a:
323i e46 motor (2.5l)?
325i e46 motor (2.5l)?
328i e46 motor (2.8l)?
330 e46 motor (3.0l)?

or do i give up on these bmw motors and just put an e36 motor m50 or m52? Maybe the standalone will change things but it seems that BMW made these motors at a lower standard and do not seem to race well. I have heard of people putting different rod bears because of the weak e46 stuff. I really screwed this up and should have went down the e36 road. I have way to much $$$ in this project and my ITS rx7 is more fun to drive right now. Hopefully this will change.

I currently have in my possession a e46 323 and e46 328 motor...just seeing what makes the most sense or seeing if i need to buy or build another.

Thanks
Greg
Click to expand...

The linear weight addition is going to be killer for the 3.2L engines. That's 3520#...even with ans S54 engine that's a lot of weight. I think the hot 6cyl bmw is the 2.5L ex-WC-TC build like Phil Parlato's. He's running electromotive IIRC.
 
Greg Amy said:
Ron, Table A, STU allowances, p 476 in Dec GCR. - GA
Click to expand...

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.
 
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
 
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.
 
...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.
 
I too was against anything other than the M3 getting in to STU. My thought was that the e36 M3 was built with a 3.0 for only one year, so let the 3.2l run, but handicap it.
 
Greg Amy said:
...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".

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.
Click to expand...

Yes, I keep forgetting the ST ruleset is segregated based on displacement. I tend to agree that those larger displacement cars should not be in the U class as it creates inconsistencies that don't jive well with me.

I do believe that had ST used a classing process based on valve curtain area and displacement then it would have been possible to equalize the various engine types (small OHC four valve vs. large OHV two valves) without having "under" and "over" classes. An IT on steroids that would have had a broader mix of cars competing against one another in the same class. But that ship sailed long ago and ST is fine.
 
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