the way i understand it the engine in a 330i is similar to a M3 engine, so does that mean that with the rite parts a 330i sedan, after some work, can be transformed into a M3 engine? reason i ask, my friend lost (in a 2001 stang cobra) to a 330i, and the owner was feeding us this crap about him transforming the engine into a M3 engine. so what happened here is the engine now an M3 engine or by some freak accident the 330i is faster than the 320hp (questionable if u know the whole thing about cobras) stang?

 

Well power wise the new 330 engine is very close to the outgoing U.S. Spec M3 Engine. As for beating a Mustang Cobra, I don't know about that. Mustang Cobras, if driven correctly, should be able to walk away from a BMW 330... shouldn't it? Horsepower problems with the Cobra have been fixed, so that shouldn't be an issue. M3 engine is a good deal more sophisticated than the 330 engine. So I think it would be way too much money to try and "transform" the 330 engine into the M3 engine... I don't know. Just my opinions.

 

Short of an complete engine transplant (dropping the M3 engine into the 330), the regular 330 engine can't be simply "transformed" into a M3 engine.

 

thats what i though, but he did whip my friends CObra who had a good launch (not perfect little more tire spin than perfect). well when i go racing again (well not in the ML320 but in dads 82 turbo 3.3) im gonna seek him out, maybe i misunderstood and its a complete transplant. either way it blew my mind to see a cobra loose to a 330i. heres a new question would it be easy to put the m3 engine into a 2001 330i?

 

Maybe Loki, our resident M3 specialist can answer this better than myself, but given time and money, anything is possible. How much time and money to do this? Lots. Probably more than what's its really worth. Maybe he should of gotten the M3 in the first place?

 

Is he saying that he converted his E46 330i engine to an E46 M3 engine? The E46M3 motor has more displacement and higher compression...so we are already talking some major modifications. But even if we are talking transforming to the 3.0l E36M3 engine, the E46 330i has slightly different displacement...both bore and stroke are different. So, "transforming" to either is not an easy job.

I say all that big talk is worth doodly-squat.

 

M3 - Bore/Stoke 3.43 x 3.58
330 - Bore/Stoke 3.31 x 3.53

M3 - Compression ratio 11.5:1
330 - Compression ratio 10.2:1

 

I have a 330i, 3.0 liter engine (330 -> 3 series 3 liters, 325 -> 3 series 2.5 liters). Anyway, what I'm getting at is that the dealer told me the M3 has a 3.2 liter straight 6. Also, I test drove both and the 330i stock is nowhere near as quick as the M... like u didn't know that

Would the extra .2 liters come from the difference in bore/stroke as explained by xHawkeye?

 

Yes. The displacement of the engine is calculated by finding the volume of each cylinder and multiplying that by the number of cylinders. The volume of a cylinder is: [(bore/2)^2]*pi*stroke

For the 330:

Bore: 3.31 inches or 84 mm = 8.4 cm
Stroke: 3.53" or 89.6 mm = 8.96 cm

[(.8.4/2)^2]*pi*.8.96 = 496.5 cc

496.5 * 6 cylinders = 2979 cc

Which is roughly 3.0 liters.

 

Did you look under the hood? There are many mods for non M3 3 series cars including the 330. There are a couple of different FI options including Superchargers and turbochargers all of which put that car in the low to mid 300 hp range.