What exhaust system is most efficient for S50 engine?

[sharky]

I use OBD 2 S52 headers, OBD2 midpipe and cats (downpipes slightly modded) to a E36 M3 OBD2 rear box slightly shortened. Is perfect for me as I dont like loud exhausts especialy on my E30. Seems to work just great.

[5ickride]

When I did my swap I felt it was important to go with BMW specs as a minimum.

For my S50 I used the cast exhaust manifolds (I know these aren't the best). I used E36 M3 cats and a Remus M3 cat back exhaust. I had a local muffler shop handle the transition from the exhaust manifolds into the cats.

I like the sound. It's aggressive but not noisey. It's got a raspy growl that sounds cool.

These videos give you an idea of the sound. One video is on the street the other is autocrossing.

http://vimeo.com/9594657

http://vimeo.com/9639079

Thanks for the videos. I like how this sounds.

[e30pq]

Thanks for the videos. I like how this sounds.

More details on my build and my car if your interested. You can see from the engine bay photo that I had the exhaust manifolds Jet Hot Coated. It makes they look better and they say it provides some benefits.

http://www.r3vlimited.com/board/showthread.php?t=107147

[nando]

on an S50/S52 I'd do single 3" pipe from the headers (no cast manifolds!) back. No magnaflow mufflers either unless you like rasp. The tone of my dynomax/borla combo is pretty good. you could eliminate one or the other if you want it louder, mine's not very loud at all.

I've said it before and I'll say it a million times more probably - a single 2.5" is approximately equal in flow to the stock M20/M50 exhaust system. all you're doing is making it loud, especially with no cat and a single magnaflow.

if you do get a cat don't waste money on a ceramic core.

[M-technik-3]

Single pipe is nice for ease of fabrication but can be a down fall in ground clearance issues at the subframe, if someone had some nice ovalized pipes that were not squished and round at both ends then that would be great.

[nando]

Single pipe is nice for ease of fabrication but can be a down fall in ground clearance issues at the subframe, if someone had some nice ovalized pipes that were not squished and round at both ends then that would be great.

it's actually fine, I need to take a pic of mine as it crosses under there. I didn't say anything specific to the guy who built it, but I was impressed by the job he did. basically a well placed bend right at the subframe. Ground clearance is excellent with 3" all the way back. I scraped more with the stock cat section and supersprint..

the only reason to do dual pipes is for looks. But it weighs more, costs more, and there's no flow or sound advantage on an inline 6.

[5ickride]

Could you post pics of your setup?

it's actually fine, I need to take a pic of mine as it crosses under there. I didn't say anything specific to the guy who built it, but I was impressed by the job he did. basically a well placed bend right at the subframe. Ground clearance is excellent with 3" all the way back. I scraped more with the stock cat section and supersprint..

the only reason to do dual pipes is for looks. But it weighs more, costs more, and there's no flow or sound advantage on an inline 6.

[nando]

I would except I don't really have any :p

[e30s50dan]

SS eBay headers y pipe 2.5 pipe universal cat borla X1 muffler. Simple quiet at idle nice growl on gas. No tinny noise. Had this on M50 didn't like. But I can't believe how nice it sounds on S50 very happy

[Lakis]

I kept the stock header on my 99' M3 6 cyl.
I still have my 91' E30 m3 cats but I don't know if I can use them.
My concern is getting around emissions if I run with no cats.

E30PQ: I like your sound. It's mild in my opinion and you can hear your engine; reminds me of my Stromung that I used to have. Then again, I'm sure you hear more than the video suggests; but still I like your "range" of sound.

I too don't want to be that guy!!!

I cut some flanges of another system to give to the exhaust guy saving me some money hopefully when the system is built.

ANY suggestions are welcome. My engine is the stock 99' e36 m3 6 cyl.

[Adrian_Visser]

On the s52 I have raceland euro supersprint knockoff headers into a twin 2" to single 3" magnaflow y pipe into a 3" twister resonator with a 3" redline muffler in the back. This setup was recommended to me by the local exhaust shop I have never heard of either of these brands before, apparently both are made in North America though, the muffler is Canadian so I assume that is why it sounds so good.

I'm going to try and get a sound clip up of it soon.

Long story short it is pretty loud as would be expected from a 3" exhaust but the sound is hollow and clean almost like a straight piped 5.0L mustang. It is quieter than my old m20's 2.25" with a magnaflow and an exhaust leak at the headers though.

[e30polak]

I had both single 3" and single 2.5", and the 2.5" gets my vote. Dual with a proper x-pipe will probably get the best performance, but it's also 2x as heavy.

Here is how my car sounded with the 3" set-up:

s52 manifolds > flowmaster 3" y-pipe > Vibrant Race Cat > single 3" tubing > 26" Accelerator truck Muffler > 3" tubing > 3" Vibrant Street Power muffler

http://www.youtube.com/watch?v=j4YUuLrjBrw

Here is the 2.5": God I miss that car!

Ebay SS headers > flowmaster 3" y-pipe > single 2.5" tubing > Borla Muffler > 2.5" tubing > 3" Vibrant Street Power muffler

http://www.youtube.com/watch?v=nS2RJCk_itY

http://www.youtube.com/watch?v=r2H5YreLZqk

[e30s50dan]

still have a set of S52 headers for sale if anyone is interested $35 + shipppp

[nando]

3" exhaust doesn't have to be loud! if it's loud it's your choice of mufflers that's causing it, not the size of the pipe.

also, there's definitely not a performance advantage of dual pipes with an X v.s. a single pipe with a Y. Assuming both peices are built correctly, which they usually aren't..

[e30polak]

Dual with a proper X pipe, that is designed around the header set-up, WILL perform better throughout the powerband. The exhaust pulses and velocity usually aren't tuned with many single systems. 3" is too big for any m/s 50/2 without high duration cams and headwork.

I ran 3" and 2.5" on my s52 car, and the 2.5" dyno'd better numbers throughout the powerband except for maybe 3-4whp up top. The 2.5" had better drive-ability, and made better midrange torque.