Which exhaust for S50 E30???

[CleanE30]

I can't find anthing out there... any ideas??? I would like to keep it dual tip with single sheet cut of tips on the end, but what about the rest of the system??? Any suggestions and pics would be appreciated.

[equate975]

Custom

Easiest and cheapest way to go.

[rede30]

I plan to do ebay headers to dual 2.5 pipes to a cat to a m coupe exhaust.

[PiercedE30]

I got the TMS Shorty Tubular headers for my m50 swap and i'm going custom to the cat and then an e36 cat back.

[MR 325]

I plan to do ebay headers to dual 2.5 pipes to a cat to a m coupe exhaust.

Dual 2.5 is overkill IMHO

[rede30]

Oh, I thought i rememberd thats what people were telling me to do but maby it was dual 2.25. Shit I should figure this out.

[rede30]

Yea it was dual 2.25 that I am planning, i have all my info writen down i just forgot.

[MR 325]

Yea it was dual 2.25 that I am planning, i have all my info writen down i just forgot.

Surrrrre. :)

[CleanE30]

What mufflers are you guys using for the Custom??? It seems that all magnaflow dual in/out mufflers are 2.5" or larger.

[bmws50b30]

What mufflers are you guys using for the Custom??? It seems that all magnaflow dual in/out mufflers are 2.5" or larger.

i like the sound of my dynomax. it has a little rumble, burblr but quiet. I'd rather hear the engine than the exhaust.

[LINUS]

I have the eBay headers, and I plan to use (at least temporarily) a e36 cat section and a Stromung for e30 m3 - if I cant fit the stromung to the center section I'll just make my own with SS tube from work and butcher the cats out of it. My working idea - haven't even seen a stromung pic for the e30, but I like the way those things sound.

[matt]

Yea it was dual 2.25 that I am planning, i have all my info writen down i just forgot.

That's still too big, you'll lose torque with that setup over a stock-ish size.(under dual 2") 2.5" is about right for any M3 motor.

[rede30]

That's still too big, you'll lose torque with that setup over a stock-ish size.(under dual 2") 2.5" is about right for any M3 motor.

What is the stock size? I wasnt wanting anything extreme. If a single 2.5 works then i will just do that. Does anyone else have anything to add to this?

[cheades]

I believe the stock S50 has dual 50mm and a 60mm combined section before the cat. The S52 stayed dual 50mm the whole time I believe.

[matt]

I believe the stock S50 has dual 50mm and a 60mm combined section before the cat. The S52 stayed dual 50mm the whole time I believe.

Nope. It's 40 something on the inside, but it's a dual wall pipe with an airgap for insulation. The AA trackpipe uses 2 1.9" secondaries into one 3" collector. This is a little big, but OK for supercharged motors and such making huge power. I would go with the stock OBD2 cats and a nice e36 catback like the AA, B&B triflow, or UUC.

Single 2.5, strictly from a flow perspective, is big enough for as much as 350hp+, according to Corky Bell. With a turbo a bigger pipe will generally help your spool a little, but won't cost you too much torque. 3" is still plenty for a lot of turbo power, too.

Using a 3" pipe on an NA motor that isn't making massive power will cost you exhaust velocity and scavenging at lower RPM (loss of torque), which you may not make up for with more top end power.