exhaust options

[matt]

Ben's car didn't use the stock cat. It went from an AA track pipe collector to 2.5" pipe (you could put a highflow cat here) then it split to 2x 2" with a flowmaster Y-pipe then connected that to the stock 99 M3 catback with a pair of stock flanges off my old exhaust. Hangers were all custom AFAIK.

It hung a little low, but it was cool.

[///Mpressive]

Ben's car didn't use the stock cat. It went from an AA track pipe collector to 2.5" pipe (you could put a highflow cat here) then it split to 2x 2" with a flowmaster Y-pipe then connected that to the stock 99 M3 catback with a pair of stock flanges off my old exhaust. Hangers were all custom AFAIK.

It hung a little low, but it was cool.

That's just a big, heavy muffler. It had maybe 1/2 inch clearance above the muffler, it was a tight perfect fit. It would be okay on a plastic bumper car with some type of rear valence to hide it, but you would still be able to see it a little.

I miss that car.

[e30_kid89]

hey guys, im running a ENTIRE stock m20 exhaust system from the modified down pipes back on a M50TU. my only mods i plan on doing are basically the bolt-on's - 3.5 HFM, s50 cams and maybe a properly done CAI along with software of course....but for now its stock. is my exhaust good for now or restrictive? will it be restrive with those mods?

[static]

hey guys, im running a ENTIRE stock m20 exhaust system from the modified down pipes back on a M50TU. my only mods i plan on doing are basically the bolt-on's - 3.5 HFM, s50 cams and maybe a properly done CAI along with software of course....but for now its stock. is my exhaust good for now or restrictive? will it be restrive with those mods?

stock exhaust should be fine for a 2.5, i don't imagine you'd see much gains by opening up the exhaust.
3.5 HFM is totally unnecesary on a 2.5 IMO. Think about it, they used the same 3.0 MAF on all of the M/S5X. So if it was reasonable for 3.2 S52, i'd think it's enough for 2.5L m50. So save your cash for cams and upgrade the retainers when installing cams. Also make some kind of decent heatshield or cold air box. In the summer, you'd see more gain from this than from HFM+exhaust.

[FredK]

OK, I started my 2.25" exhaust for an M50 swap.

I started by getting the placement of the rear muffler (A Dynomax Super Turbo) centered in the rear valance cutout, and getting the height and depth correct for an exhaust tip. I haven't installed the tip yet, as it'll be one of the last steps.



I then guesstimated a good angle to cut off a mandrel J-bend, then prepped both ends of the tube, and hung it off the muffler.

I screwed around with a protractor and some graph paper to get a feeling for how much tubing I'd need to cut. Fortunately, I got a decent first ballpark. I then placed the glasspack muffler where I thought would leave enough room for a catalytic converter, should I decide to weld one in.



I then used two longer legs of two J-bends to connect the glasspack to the rear muffler.



I tacked everything together using a MIG welder.



Here's a closeup of the rear bends and the tack welds holding it together:



I still have to attach the front downpipe to the exhaust manifold flanges. I guess I need a 5mm spacer to make the downpipes clear the exhaust manifolds. The 2.25" tubing matches the OD of the downpipe merge pipe probably close enough to weld it.

That will need another section of the J-bend, and a short piece of straight pipe. I also need to weld in that $$$$$6.99 O2 sensor bung on the straight pipe.

[matt]

Good work. Looks a lot like mine, but I have a Magnaflow. My tip is just a little bend/turndown sprayed black. Very subtle until I start it up.

[FredK]

Thanks!

I considered just attaching a piece of SS pipe that I'd sand and polish, but then I figured, nah, I'll make it look RAZE with a rolled edge tip. It might take the focus off the rust on the license plate lights. :mrgreen:

[FredK]

OK, I'm pretty much done with the exhaust. I just have to weld on 2 more hangers. Here's a pic of the downpipe:



Closeup of downpipe.


Downpipe, after installation.


I used around 3/8" of washers to space up the passenger side engine mount. Here's the resulting clearance.


I started it up, and it's pretty quiet at idle, and revs pretty aggressively. I'll eventually post up some sound clips. Maybe in another year.
:drink:

[matt]

That's going to be pretty low...

[FredK]

Yeah, the midpipe does sit low. SCRAAAAAAAAAAAAAAAAAPE! J/k.

It won't sit as low as pictured, because the rear section was not supported in its final position. Also, the picture is canted, making the O2 sensor look like some kind of tree branch magnet.

[matt]

Lol. OK.

Mine scrapes all the time. Then again, my car is dumped.

[iwantone]

i have a non vanos m50
it has ebay shorty headers
to X-pipe
magnaflow cat converter
dual pipe back to hollow dtm muffler

WAY too loud for my tastes, mostly because of the hollow muffler
so, i was going to get an ebay catback system for and e36 m3:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=020&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=300100528790&rd=1,1

i think itll look good and hopefully sound and perform good as well

[static]

I started it up, and it's pretty quiet at idle, and revs pretty aggressively. I'll eventually post up some sound clips. Maybe in another year.
:drink:

if you are not running cat (i don't see it on pics, is that a res in the middle?) your dynamax will burn its guts out in no time (ask me how i know) then it's gonna sound like shite
I have a very similar system now

[FredK]

No cat. I might eventually add a cat, but the car it's going on won't have to be inspected for another year. I don't expect the Dynomax to last long anyway, seeing as it's a $45 muffler! I don't want to rape the environment, so I'll probably end up installing one of those $65 cat converters.

[DEV0 E30]

Bumping this because when I pull the M50 to go S50 I want new exhaust.

Current is OBD I manifolds, downpipes that rub on the swaybar ( I think ) to an h-pipe that really doesn't quite it down to dual 2.5 all the way back with magnaflow cats, to a dual in dual out magnaflow muffler.

Way too loud, way too raspy, and drones way too much. With the S50 I'd like it to be quiet in comparison. What do you guys suggest? I was thinking single 2.5 with some sort of muffler that sounds sexy and quiet. E36 M3 sound but with an early model it would stick out like a sore thumb and it's heavy.