[Wrngway]

Originally Posted by chaFT328i

Someone correct me if I'm wrong, but isn't it that 328s in California uses the SULEV engine(AKA N51) which has a 3 stage due to different emissions?? IIRC, only difference is that the 328s are detuned so the 3 stage isn't at its full potential, and that a tune would solve this.

Yes, the N51 does have the 3 stage intake manifold. However it also has a lower compression ratio than an N52 due to a redesigned combustion chamber (10.0 vs 10.5 I think). I think the 3-stage intake was meant to help make up for that or maybe it has some benefit for emissions.

I have an N51 with an AA tune and modified exhaust. I can tell you that it's plenty fun to drive and not at all short on power.

[accel]

Originally Posted by chaFT328i

Someone correct me if I'm wrong, but isn't it that 328s in California uses the SULEV engine(AKA N51) which has a 3 stage due to different emissions??

My 328i is ulev and I'm in CA.

[Wrngway]

Originally Posted by accel

My 328i is ulev and I'm in CA.

There were several states that received SULEV 328's, but not every 328 in those states is SULEV.

It's possible that the 328i you purchase in other states is SULEV as well. My car is a pre-owned car used as a loaner at a dealership in Maryland. I didn't know it had an N51 for several months.

If in doubt, check the emissions sticker under the hood to see what you have.