Exhaust issues.. idea?

[r4esh]

Just finishing up with my m52/e30 swap.
So in all of the research I've done, I've read that some of you guys were able to use the stock e36 exhaust without modification and i don't believe it. I've manhandled the shit out of it now and have declared it impossible. with enough "power dents" you can get it to clear the sway bar no problem, after removing the heat-shield around the first cat clearance is easier... i managed to get the driver-side pipe on the manifold, but there is no way the passenger would fit without rotating it about 20 degrees or so... which you cant do. I went as far as dropping the sway bar + denting the side where the control arm is to make sure it wasn't rubbing, but still can't get it.
I'm not experienced with welding, and don't really have the cash to pay someone to do it right now.. Anyway i can make this work? if i do end up haing to cut it up / weld a new setup, at that point I should probably just do it right ya? At that point what should i salvage from the stock e36 obd2 exhaust from a 328is? Should i use those stock resonators + ditch the first set of cats + use the second set? or what?
also, which o2 sensors should i use for this swap (still unclear there now that it has been conerted obd1). Thanks guys.

[lennon]

if the motor is obd1, you use only 1 o2 sensor.

someone else will help with exhaust, ive never tried e36 exhaust on e30s.

[87e30]

I have an m52 with obd2 e36 exhaust manifold... I couldn't make it clear the subframe either. I tried for a long time as well.

I had someone cut and weld the exit flanges and a bit of an angle so that it would clear. Then repeat on the rest of the e36 exhaust. Problem I'm having is the exhaust is huge and it hangs wayyyy too low. Gotta figure this out at some point...

[sharky]

I run OBD2 headers mated to a modified E36 OBD2 mid section ( front tubes cut and custom ones made to mate up to headers) and then to a euro E36 Tubi catback. It all fits but it takes a bit of fabrication. Mine also sits too low but I will address that in the spring.

[hoveringuy]

I have OBD2 headers--> OBD2 cats ---> M3 OBD2 muffler.

Each took a little bit of cutting and welding.

On the headers I needed to cut about 3/8" of pipe away at the flange to raise it up enough to clear the subframe.

It takes a little bit of work, but so does a custom exhaust. The result is a quiet exhaust with great sound.

[matt]

I have OBD2 headers--> OBD2 cats ---> M3 OBD2 muffler.

Each took a little bit of cutting and welding.

On the headers I needed to cut about 3/8" of pipe away at the flange to raise it up enough to clear the subframe.

It takes a little bit of work, but so does a custom exhaust. The result is a quiet exhaust with great sound.

I have a non-modified version of this setup on my 328is (e36) and I have to say it's perfect for me. I like to hear the radio when I drive, but it still has a nice tone if you get on it.

[sharky]

hoveringuy do you have any pics of the stock M3 catback on your car? I really love my Tubi but kinda want something quiet.

[87e30]

I have a non-modified version of this setup on my 328is (e36) and I have to say it's perfect for me. I like to hear the radio when I drive, but it still has a nice tone if you get on it.

Matt,

What did you do about the rear 02s sticking up? They seem to rob A LOT of ground clearance forcing the midsection to sit a lot lower...

My exhaust is only 50% done and I have the front custom cut/welded to make the obd2 e36 part fit, but I dont' have an axle back yet and the whole thing sits about 1/2 an inch off the ground. Very annoying.

[matt]

On an e36, they fit fine.

[hoveringuy]

hoveringuy do you have any pics of the stock M3 catback on your car? I really love my Tubi but kinda want something quiet.

OBD2 exhaust (left) e30 exhaust (right) e30 exhaust has M50 downpipes grafted to it. The OBD2 cat section only needed a few adjustments to fit. The biggest trick was the passenger side downpipe is rotated so that it was closer to the other pipe which let it clear everything nicely. The fat part downstream from the weld is double-wall.



fitment at swaybar



tips need to be cut and welded at a different angle to fit e30 rear valence. Flying Spaghetti Monster!



the muffler needs to be shortened an inch or so. You can see the welds were it was cut and joined near the rear subframe.



Finished product is a slightly heavy, but awesome sounding exhaust. I'm tempted to go with headers if I can find the right one...

[87e30]

On an e36, they fit fine.

Oh, dur. That would explain it.

Was there someone else in here running obd2 mid pipes? They seem huge compared to what really fits under there...

[sharky]

you arnt running a headshield huh? Did you gain alot more clearance without it? I have one on mine and my pipes sit too low.

[r4esh]

Thanks for information everyone.
After starting to chop the obd2 stock exhaust and reading a bit more, I decided I "cooould" do this.. but not right.. and not the way it should be done. So I'm forking over the money to get it done right.
And on that note... I'm going to pay to do this right one time and one time only. (sorta). I'm thinking of 2.25'' or 2.5'' pipe from the downpipes, then right after they clear the control arm / sway bar mess -> X pipe or H pipe (which is better?) -> to stock obd2 resonator/cats -> stock obd2 muffler for now (depending on how much they qute me), trying to maintain the larger pipe size where I can.
If things arn't too pricey I'll do a different muffler. (fingers crossed)
I don't want the end result to be TOO loud, but some volume and def tone is the goal. This WILL be my daily driver. I had a 95 e36 M3 with Borla muffler on it and it sounded awesome.

Oh yeah, so since I converted everything to obd1 I only need 1 o2 sensor? Where are you guys putting it? In the stock obd2 position? then just pluging/welding the other hole? The position of the obd2 o2 sensor as other people have mentioned before sucks, has anyone had luck moving it? If so to where?

Thanks,
Dillon

[Mossman]

ideally you want to sample the exhaust for the single o2 someplace that's fed for both pipes. I have obd2 headers, modified obd1 downpipes (cut/welded/hammered/flex pipe added) that merge to a single pipel, where the 95 m3 they came off had its o2 sensor, and it fits great there without any interference. From there back its all custom 2.5" single on mine but I would definitely just remove the rear o2's from an obd2 rear section and install plugs

[99em1]

My OBD2 mid has the post cat O2's chilling in there with 6 inches or so of wire where it was cut. Can I just snip the wires and leave the O2's in there? Or do I have to use plugs.