Exhaust question

#1

As I understand it, everything on the exhaust from the cat back can be changed. The exhaust on my car has the small crossover and then a large stepped in size resonator or cat. There is no fittings between the crossover and the next piece. Do you just cut the pipe behind the crossover? Is this not the typical stock system? The only flanges are after this big thing.

Next, can the charcoal canister be removed or must it be functioning? If it has to stay, is there anyway to make sure it is not clogged?

Thanks,

Michael

#2

There’s no bolted flange between the cross-over and the cat–it’s all one piece, stock. To remove the cat, you can un-bolt it at the rear, but you’ll have to Sawzall it off at the front between the cat and the cross-over.

Sasha

#3

ilateapex wrote:

[quote]

Next, can the charcoal canister be removed or must it be functioning? If it has to stay, is there anyway to make sure it is not clogged?

Thanks,

Michael[/quote]

Michael:

As with other parts of the car (and this is good to keep in the back of your mind while building the car), unless the charcoal canister is specifically mentioned in the Spec E30 Rules, it must be left as it came from the factory.

As to it’s condition, I’ve never delt with one so I can’t help there. Maybe someone else can…

Carter

#4

Thanks. I am definitally keeping that in my mind. I have looked all over the rules and am just trying to be sure. I just thought that maybe somewhere down the line it may be considered part of the exhaust system.

Michael

#5

If I understand the function of the charcoal canister, I would classify it as part of the emissions system, not the exhaust system. I suppose that’s a meaningless distinction, however, since Carter said you need to keep it.

Sasha

#6

I noticed while I was dealing with a PS hose leak that the bottom of my charcoal cannister is missing - I can poke the foam - don’t think that one is plugged up … B)

#7

I’ve been looking into a exhaust solution, here is what I found. The stock exhaust on an original "i" car was a dual exhaust off the manifold to the cat, then dual pipes to the muffler. The first section before the cat the two pipes meet together for the O2 sensor, then go back into two pipes. Several options I have come up with. 1. Just cut the cat out and replace with straight pipes, leave the rest as original. Only way to disconnect is at the manifold or end of cat, beginning of one piece muffler. 2. Cars without factory exhaust, like mine had the cat cut out and a y pipe installed for a single pipe all cat back. Only was to disconnect is to unbolt from manifold. I found that BMW sells new pipes for non cat cars. It’s two parts, and I can’t seem to find a place for the O2 sensor. That most likely would be a problem. I believe that I will do the option 1. That leaves the ability to drop the exhaust later.

#8

pre cat exhaust

#9

no cat pipes

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#10

option 1 is good, because you have to have the stock parts before the Cat - the non-cat exhaust is not likely a north american version.
cheers,
bruce