exhaust options

[JeffRR]

OK i did the s52 and used the stock headers.. we heated the back down pipe and bent it in about 1/4in so it would clear the sway bar.. the front down pipe we hade to make a custom pipe off the flange because of the control arm.. So i did dual pipes and made a x pipe right after the down pipe.. (fall-line told me this would make the sound deeper and make more power). So after the x pipe dauls into the stock 2 cats from a m3 e36 and then duals from their into the B&B triflow.. We had to do the exhaust 3 times before doing it this way and getting it right.. now is sounds sweet and nice and low with very little rasp.. the bill was 200 the first time but after redoing it 2 more times the grand total was 400.00 the car sound great!! If you do true dual and no x pipe the car will sound like a 80hp ricer. thats how it was the first time.. the chambers need to mix before the muffler.. so a xpipe / h pipe will give you the great sound and power.. also i used 2.5in pipe

Do you have any pics of you exhaust with the X-pipe, I'm thinking of going this route. I really don't like the raspy sound of the single 3" no-resanator set-up.

[tonytony]

i'm running obd2 midpipes to a single 2.5 all the way back, is that too small? seems like people are running dual 2inch or more?

[MR 325]

I'm thinking about doing this... [S50]

-ebay shorty headers
-catless midsection
-IE E30 catback

Wonder how that would sound.

[Mot]

loud with rasp.

[static]

I'm thinking about doing this... [S50]

-ebay shorty headers
-catless midsection
-IE E30 catback

Wonder how that would sound.

it WILL sound terrible: S50 is one noisy MOFO and E30 chassis is not the best braced chassis - i.e noisy and droney

My best advice on a custom exhaust would be the following: stock S/M52 mani, custom downpipes, hiflow cat, at least 16" straight through muffler right after cat (in the middle), another 18+ straight at the end.
I heard this configuration in an S52 e30 and it's great with no drone and not too loud at all.
My current one with 24"long 4" round resonator and 16" dynomax muffler sounds like shite when cruizing (drone), not so bad when just accelerating.

So i slowly but surely come to conclusion that to cut down on highway drone, one needs a fullsized mid-mounted muffler (not just a thin res)
I am installing a 22" 5x11 magnaflow at the back for now, so i'll update with soundclips

i have mandrel 2.5 ss piping btw

Alex

[FredK]

FredK – Are you planning on doing the entire exhaust yourself?

OK, hilarity hasn't ensued YET, but it will in the next month. I bought a welder, some mandrel bends, some pipe, and some mufflers. How has a year already passed?!

I'm going to prototype a 2.25" system with the following:

Cast iron manifolds
Stock OBD-1 downpipes, mated to a 2.25" section
2.25" I/O 18" glasspack muffler
2.25" I/O center/offset Walker Super Turbo muffler

If the glasspack sucks balls, no problem. It only cost $21. It's going on an M50 swap vehicle, eventually. I plan on honing, um, make that learning, welding skills on this aluminzed steel beauty.

It can't be much more annoying than a 5x11x18" generic muffler hooked up to a stock M42 system. At least there will be sexy six cylinder noises. If the sound bothers me that much I'll just swap to a S2.79. J/k.

[matt]

OK, hilarity hasn't ensued YET, but it will in the next month. I bought a welder, some mandrel bends, some pipe, and some mufflers. How has a year already passed?!

I'm going to prototype a 2.25" system with the following:

Cast iron manifolds
Stock OBD-1 downpipes, mated to a 2.25" section
2.25" I/O 18" glasspack muffler
2.25" I/O center/offset Walker Super Turbo muffler

If the glasspack sucks balls, no problem. It only cost $21. It's going on an M50 swap vehicle, eventually. I plan on honing, um, make that learning, welding skills on this aluminzed steel beauty.

It can't be much more annoying than a 5x11x18" generic muffler hooked up to a stock M42 system. At least there will be sexy six cylinder noises. If the sound bothers me that much I'll just swap to a S2.79. J/k.

Good plan. 2.25 is the proper size for pretty much everybody, but nobody actually runs it. It's hard to find good mufflers and such in 2.25.

Mine is 2.5, in anticipation of running the same exhaust with the turbo.

I do prefer the stock OBDII headers. Very pretty and much lighter than the cast ones. I will have a set for sale this summer some time. :pimp:

[FredK]

Yeah, I have a set of the OBD-II headers. I am sort of trying to figure out how to most effectively plug them up. I figured I'd just make a small weld in the air injection channel, right next to each port, then somehow surface them down flush to the same level as the rest of the flange.

Alas I don't have a belt sander, so I guess I'm gonna just use the cast-iron units for now... LOL at having a set for sale in the summer.

What surprised me was how big 2.25" OD really is. The stock OBD-II pipes are pretty dang small, they only look fat because of the double layered pipe. Internally they can't be more than 1 3/4" OD each!

[matt]

Welcome to the few, the proud... the ones that pay attention.

For the o2 sensor holes, you can use BMW K-bike oil drain plugs. I can get you a part number if you want.

I have a set of plates techno550 made for me to block off the EGR stuff. Pretty simple with some 1/4" steel plate and a bench grinder.

[asubimmer]

I already have some obII headers and I was planning on running a single 2.5" all the way back w/ a glasspack where the cat goes and a dynomax where the muffler goes. Seem like a good or bad plan?

[matt]

I already have some obII headers and I was planning on running a single 2.5" all the way back w/ a glasspack where the cat goes and a dynomax where the muffler goes. Seem like a good or bad plan?

Good if you like loud.

These motors really need two real mufflers, IMO.

[asubimmer]

hmm...

how loud are we talkin? The glasspack is a hooker red hot and the dynomax is just one of the generic super turbo's.

How much should it help to run dual 2.5" to the back, one glasspack on each w/ an X pipe and then come into something like this flowmaster...

[matt]

Dual 2.5 won't help at all. Way too much pipe.

Just run a smallish muffler right behind the cat and the biggest one you can fit next to the spare tire well. Single 2.5 all the way. If I were doing it again, I would also change the collector on the secondaries and raise them up a little for ground clearance.

[dougsic]

OK, hilarity hasn't ensued YET, but it will in the next month. I bought a welder, some mandrel bends, some pipe, and some mufflers. How has a year already passed?!

I'm going to prototype a 2.25" system with the following:

Cast iron manifolds
Stock OBD-1 downpipes, mated to a 2.25" section
2.25" I/O 18" glasspack muffler
2.25" I/O center/offset Walker Super Turbo muffler

If the glasspack sucks balls, no problem. It only cost $21. It's going on an M50 swap vehicle, eventually. I plan on honing, um, make that learning, welding skills on this aluminzed steel beauty.

Fred,

May I make a suggestion?

At a minimum, get yourself a die grinder and a cutoff tool. The Chinese ones from Harbor Freight will work fine for now. The cheapo grinding discs wear out really quickly but they will make you appreciate the brand name ones when you move up to them.

You'll love welding as it's a lot of fun.

Good luck and enjoy it!

[e30polak]

I'm running an ebay SS turbo manifold, to forget about any restriction problems. I had one of the local exhaust gods setup a 3" down-pipe perfectly down to a 3" vibrant high-flow cat. Then i continue to a 3" borla race muffler (as a resonator), and finally to a 3" vibrant street power - turbo series muffler. The exhaust is by far the nicest 6 cylinder note I've ever heard, but it gets a little loud after 4 grand :shock:, the neighbors hate it. Total was a little under $900.