S50 swap exhaust...

[genocide98]

I'm posting up a thread to try and decide on the best performance/dollar setup for my up and coming E30/S50 swap. Yes, search. I know, I know. I figure this time its a little bit different-

Why?

It's an 84, and thus does not have to pass emissions here in WA. That means no cats.

It's going to be a relatively common bolt-on S50, minus cams, and later down the road I think I'm going to be going FI and aiming for 400whp. This is where I run into a problem. My gut says if I'm going NA that I should rock a 2.5" setup, but I know that the 2.5" might be restrictive for a 400hp turbo motor, and that 3" would be proper.

So far my favorite cat-backs have been Remus, Eisennman, and Borla. I don't mind noise, or rasp, but I hate droning anything. I speed, and thus I tend to cruise around 3,000~ rpms and I have to hit the highway every day to make it to school.

The problem is I'm not sure how to approach an exhaust. I've never built one before and this will definitely be my first.

The only component I'm sure on is the ebay supersprint knock offs, unless there is something that will give me better performance/$$

So... How does one construct a respectable and proper E30 S50 exhaust? Which components would YOU use?

[MattM]

get it done by someone who knows what they are doing, i got a local automotive shop to do mine, 84 with M50, no cat, supersprint reps, magnaflow, single 2.5. I love it. this vid was filmed before it was running perfectly, since i filmed it i fixed afew vacum leaks and installed the o2 sensor....

http://www.youtube.com/watch?v=uj5k7oatxPA

[FredK]

I ran a 2.5" Magnaflow 5x11x22 muffler with a cat and Aero Turbine AR25 resonator with mandrel bent tubing that I welded together. It is reasonably quiet at idle and fairly manageable on the highway. At 3000 rpm it isn't that obtrusive. At 4000 rpm (highway cruising) it gets a little louder / higher pitched.

If you want to quiet the exhaust down more, install a turbo. :razz:

[richardb]

I'm going the same route... Turbo in the spring so 3". I'm going 3" full stainless after eBay ss rep headers, through a custom spd merge dual 2" inlet to single 3" out, to magnaflow 3" stainless high flow cat, to stainless JBA chambered/baffled muffler. It will so have a vband after the merge. My eBay headers are junk a d need to be heated and bent... Go with obd2 manifolds and downpipes. Jon at 666 fabrication is doing the fab work next week

[zav3n]

3" all the way back ;-)

[nrubenstein]

The standard N/A exhaust for an S50 is a 3" single. So do that.

[e30polak]

I used to have 3", but now I have 2.5". The 3" is really loud unless you muffle the hell out of it. It did pull nice in higher rpm's, but suffered down low. However, I love the 2.5"! It sounds better with my newer muffler set-up, and pulls nicer throughout the entire powerband.

Since you're going turbo I'd say go with the 3", if you weren't then 2.5" is better for NA.

[e30s52]

Mine isnt that loud and its a 3in but it goes into two 2.25's.

[genocide98]

3" all the way back ;-)

If only...

I don't really mind losing out on a bit of power down low.. I could probably run it with nothing manifold back and still have more power than my M10. lol. I'm more interested in having a wider power band than peak HP, anyway.

I'm mostly concerned with keeping it quiet enough to avoid being pulled over and ticketed while keeping it as free flowing and light as possible. I figure that shouldn't be hard considering I get to take out the cat/s and install an aftermarket muffler..

plus I don't want to have to pay for another (3") exhaust.

Maybe I can nab an e36 m3 exhaust and modify it to fit the e30? Anyone tried that before? Or would I be better off going a custom 3" over that for the sake of power?

Anyone have some insight on the obd2 vs supersprint reps? I don't mind the shoddy fitment I can torch up the pipes and bend them to fit, just so long as I don't have to do that to all of them.

Sorry about all the ????'s but I had never decided on my motor situation so I had never researched the exhaust.

You guys are pretty helpful so far. Thanks!

[FredK]

I just swapped to a 5x11x22 3.0" Magnaflow muffler yesterday, from the cat back. The muffler is not much louder than the 2.5" muffler of the same size. If I want to quiet it down further I believe a center muffler will quiet things down nicely. There is a little more drone at around 2700 rpm, that disappears at 2900 rpm.

I hate loud exhausts, so this one hits the spot for me. I don't fear getting pulled over.

If I knew I was going to eventually install a turbo, I would just go 3.0" from the get go. Stainless pipework is pricey!

[JRKOUPE]

I ran a 2.5" Magnaflow 5x11x22 muffler with a cat and Aero Turbine AR25 resonator with mandrel bent tubing that I welded together. It is reasonably quiet at idle and fairly manageable on the highway. At 3000 rpm it isn't that obtrusive. At 4000 rpm (highway cruising) it gets a little louder / higher pitched.

If you want to quiet the exhaust down more, install a turbo. :razz:

Fred...pm sent

[Mr Two]

Dual 2.5" + UUC System U + Raceland euro SS reps. Then supercharge it down the road!

[flyboyx]

If only...

I don't really mind losing out on a bit of power down low.. I could probably run it with nothing manifold back and still have more power than my M10. lol. I'm more interested in having a wider power band than peak HP, anyway.

I'm mostly concerned with keeping it quiet enough to avoid being pulled over and ticketed while keeping it as free flowing and light as possible. I figure that shouldn't be hard considering I get to take out the cat/s and install an aftermarket muffler..

plus I don't want to have to pay for another (3") exhaust.

Maybe I can nab an e36 m3 exhaust and modify it to fit the e30? Anyone tried that before? Or would I be better off going a custom 3" over that for the sake of power?

Anyone have some insight on the obd2 vs supersprint reps? I don't mind the shoddy fitment I can torch up the pipes and bend them to fit, just so long as I don't have to do that to all of them.

Sorry about all the ????'s but I had never decided on my motor situation so I had never researched the exhaust.

You guys are pretty helpful so far. Thanks!

i am using the front half of the stock exhaust from an mz3. my purposes may be a little different than yours, however. i want to run all 4 o2 sensors so my emissions work correctly among other things.

in addition to the included cats, it also comes with a really nice set of resonators directly behind them.

i need to get this "mid" section modified to make it fit my car however, because it sure as hell won't fit stock. some people say it will, but i can tell you from trying to line it up under my car myself that it certainly won't.

coming off the stock manifold for cylinders 1-3, it will hit the cross member and the sway bar a bit. the pipe coming from cylinders 4-6 will hit the control arm bushing on the passenger side of the car. i purchased the treehouse bushings to alleviate this issue. from here the pipes swing around toward the center of the car but they are about 2 or 3 inches too long after this bend. they miss the heat shield and will have to be shortened a couple of inches in this location as well. i know you said above that you don't intend to run cats, but for those reading this thread the rear o2 sensors in their stock location will need to be adjusted a bit also because they interfere with the heat shield. other than that, i guess it fits perfect. just a few things for you to keep in mind if you do decide to go that route.

[e30polak]

My old 3" setup: stock manifolds > 3" piping > 3" high flow cat > 3" piping > 26" Accelerator Truck series muffler (it was big) > 3" piping > 3" Vibrant Turbo series muffler.

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

My current 2.5" set-up: ebay headers > flowmaster y-pipe > 2.5" piping > Borla generic mullfer > 2.5" piping > Vibrant turbo muffler (piping is 2.5" all the way to the muffler)

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

Fun on the dyno rollers

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

Both systems are loud, bu the 2.5" has way less drone, and a better tone. I like my exhaust loud! :D