Restrictive Stock 323Ti exhaust: Options without going Aftermarket

[MTRD3]

Perfekter sound! klingt einfach geil Stefan

I actually would like it if the car produced just a slightly more aggressive sound, but as an extension of the motor, as opposed to just from an aftermarket exhaust amplifying it. So how your car sounds is just right for what I would like. Will have to keep my eye out for the 328 & Z3 parts.

[vesku]

Hi,
I have the same project going on, 328i exhaust under my 323ti compact. Just bought a complete used 328i sedan exhaust from manifolds to the end, with some unknown stainless silencer.

If you have some experience already, will appreciate. I have to shorten the pipes about 8 inches from somewhere and I'm wondering welding of stainless with my Kemppi inverter MIG. Stainless wire is not a problem, but probably pure Argon would be better than 25% Argon and 75% Co2 I have now in my bottle.

I also see the two fat 76mm outputs quite ugly (I'm too old :-) ) and wonder if I have to cut them away and put two 2,5" stainless pipes with single core instead.

[stefan323ti]

I think one big problem will be the pipes between the exhaust and the catalyst.

The pipes will bump again the rear axle carrier.

[vesku]

Probably yes, there will be several problems to overcome. Some new curves have to be done. Where to find 2" stainless pipe curves, that's one problem. A lot of work anyway.

[vesku]

Finally I've got the exhaust done to my 323ti. Front with dual cats from 328i and selfmade catback with 2 x 2" in and 2 x 2" out silencer from A-Alt.Avgassystem AB in Sweden. Otherwise good but too noisy at low rpm's and some load. At highway the sound does not really disturb, but at lower speed yes. I modified the rear ends of the 328i part also, targeting more distance to the petrol tank.

Where to find a bigger 2 x 2" in and 2 x 2" out silencer from??

[vesku]

I made one's again a new revision. Now it is like it should have always been, in all 323ti's from the manufacturer! 2 x 2" tubes from the beginning to the end, downpipes and cats from 328i, rear muffler from Z3 3.0. some handmade curves between. Quite silent, maybe a little bit too silent but ok. BUT! one problem still exists. When the pipes heat up, the end turns a little bit left, almost 1 inch. Might be a difficult task with double pipes without an additional support to the end. I think I have to make an additional support somewhere in the end to keep it in right position.

Many thank's for Stefan323ti for the idea of Z3 silencer!

[vsonix]

Originally Posted by MTRD3

Perfekter sound! klingt einfach geil Stefan

I actually would like it if the car produced just a slightly more aggressive sound, but as an extension of the motor, as opposed to just from an aftermarket exhaust amplifying it. So how your car sounds is just right for what I would like. Will have to keep my eye out for the 328 & Z3 parts.

Since the engine is an M52 I am assuming the airbox is the same as on my 328is; by removing the baffle inside the airbox, you get a little more induction noise, by removing the snorkel from the front of the airbox the effect sonically is almost comparable to fitting a cone filter or similar. Run some ducting from the brake duct or front grill to the front of the airbox and you have a nice cold air feed straight to the stock airbox giving you better flow, nicer noise and the engine protection of the OEM paper filter. Combine that with the 'golf tee' mod (forcing open flap in exhaust) and the M52 starts to sound really fruity!

basic how-to here...

jury's out as to if it robs any HP or not.

[MTRD3]

Originally Posted by vesku

I made one's again a new revision. Now it is like it should have always been, in all 323ti's from the manufacturer! 2 x 2" tubes from the beginning to the end, downpipes and cats from 328i, rear muffler from Z3 3.0. some handmade curves between. Quite silent, maybe a little bit too silent but ok. BUT! one problem still exists. When the pipes heat up, the end turns a little bit left, almost 1 inch. Might be a difficult task with double pipes without an additional support to the end. I think I have to make an additional support somewhere in the end to keep it in right position. Many thank's for Stefan323ti for the idea of Z3 silencer!

Nice work Vesku! Nice pics as well, everything looks nice and clean under there Have you noticed any immediate difference in the way the car drives (or should I say "breathes") or throttle response? Power?

I'm really glad to see this thread has turned out to be quite useful to members, especially thanks to the input from Stefan. I might be in luck this week as I found a gentleman with a clean Z3 2.2 who is changing to an aftermarket exhaust meaning I should be able to buy his OEM unit from him and get started on my complete OEM dual pipe system as well. As Vesku said "the way it should be"

VSonix, thanks for adding some tips, during my M50 manifold install, the manifold was installed so that my car has the same thing that others do with the "Golf Tee" mod, and it definately makes the motor sound "nicer" at idle and through the revs. I'm considering the "Fogging" idea you've eluded to with the ducting, I'd seen a few threads about that on-line as well. I actually have a pretty much new Dinan CF intake for the E36 which just sits on a shelf in my garage because although I was in love with the sound it made on my E36 M3 in Canada, here in Germany our TÜV (same as MOT in the UK I believe) is very strict, as Stefan mentioned in a earlier post, and normally will not approve or allow cars with A/M parts that are not tested/approved in Germany.

[vesku]

Originally Posted by MTRD3

Nice work Vesku! Nice pics as well, everything looks nice and clean under there Have you noticed any immediate difference in the way the car drives (or should I say "breathes") or throttle response? Power?

Thank's! Sound is ok, a little bit silent but ok in long run. Difficult to say anything exact about power. My feeling is, that some torque moved from low revs to 4000-6000 range. A single measurement of acceleration 80-120 km/h by 3th gear (racechrono software in handy + external GPS) at the same place shows now 0,3 sec better time = 4,2 sec (4,5 sec when 100% stock). Mods: twin exhaust, inner tube removed from air filter, Intake tube to airfilter box buffed a little bit with two pieces of 4mm threaded rod.
If 0,3sec improvement is true, I've got 10hp more(in average between 4000-6000rpm)!

By the way, the biggest reason to the movement sideways was my selfmade support before backbox, which prevented longitudinal movements. The pipe gets 5mm longer when hot!