exhaust setup for m30?

[clementine]

just recently swapped an m30 into the e30 and am wondering what is the best exhaust setup to use, i read a lot about guys using 2 1/2 straight pipes.

just wondering what my options are and which ones are better to use more or less

[sayed ali]

2.5'' straight pipe with a pretty good muffler is what i've noticed the most...

[quickervicar]

This is not really the answer to your question in particular but--based on my experience with my single 3" and my M20--I will be going with a dual system setup when the M30 gets slotted. A single system that flows well will often have dreadful drone (like mine does). I believe that this is the reason BMW goes with two smaller pipes. More expensive, but better noise control.

[nando]

It probably drones because of the muffler choice (or not enough of them), not because it was single 3".

as 2.5" is pretty good for a mild M20, I'd think you'd want 3" for an M30, but 2.5" may be just barely enough.

the big advantage with a 3" is you don't have to run a crappy sounding "straight pipe" with one loud, obnoxious muffler. you can add a cat, a muffler, and a second muffler/resonator and have a quieter exhaust that also flows better or just as well, while still being far lighter than the stock twin exhaust.

[tfritz]

im running a single 3" into a dynomax super turbo, it is pretty loud..

[nando]

more mufflers = more quiet

[tfritz]

or boost :D

[CorvallisBMW]

I run a 2.5" through a Magnaflow cat, 12" glasspack and Vibrant muffler. It's still fucking loud (probably a result of the Vibrant muffler more than anything). Going to switch in an 18" glasspack and see what that does.

[Bearmw]

I am running a 2 1/2" single mandrel bent pipe with a resonator and a smallish turbo muffler and it is too loud for my taste. I am going to try to fit some Schmiedmann M30 headers (will report results) and see how things sound and then maybe go to larger muffler.

[clementine]

cool thanks guys,
i went to an exhaust shop to get some suggestions and the guy told me to run 2 1/4 y pipe leading to a 2 1/4 straight pipe with resonater and muffler. he said the 2 1/2 all be to big
what do you guys think.

[CorvallisBMW]

I'm no expert, but 2.25" seems too small for a 3.5L motor

[nando]

cool thanks guys,
i went to an exhaust shop to get some suggestions and the guy told me to run 2 1/4 y pipe leading to a 2 1/4 straight pipe with resonater and muffler. he said the 2 1/2 all be to big
what do you guys think.

He's wrong.

[LowR3V'in]

I liked my 3'' with two big ass mufflers.

24'' magnaflow in the back and 18'' summit round in the middle.
Sounded sweet.

[quickervicar]

I liked my 3'' with two big ass mufflers.

24'' magnaflow in the back and 18'' summit round in the middle.
Sounded sweet.

This is what I had, since I was planning on boosting it. Waaay too loud. Had to keep it above 3k to keep the drone tolerable. I have since switched to a Dynomax VT in the rear position. Better, but still too loud below 2.5k

[nando]

here's mine with a magnaflow ceramic cat, borla pro-xs in the center and and dynomax turbo in the rear:

http://www.youtube.com/watch?v=Bx1TkKRiM9w

magnaflow mufflers are lame unless you're 19 and want a loud car.

my air filter is about 4x louder than my exhaust :)