2.0 6 cylinder rear exhaust muffler valve.

[ANDREW HUGHES]

Hello everyone.

I have a 1999 2.0 6 cylinder z3 it has two tail pipes at the rear.
One has a vacuum valve sitting on it.
I believe it opens and closes as and when the engine rpm rises.
Giving a better flow through when required.

Try as I might I cannot find any detail about this valve and nobody seems to have them fitted ?
I cannot belive I am the only one ?
Do people take them off when the exhaust is replaced?
Are they really needed ?
What happens to the vacuum pipe feeding it , if it is no longer there ?

Mine seems loose and is swivelling round of its own accord opening and closing the paddle in the exhaust as it does it and not as required ?

I would like to know how it is held in place ?

Anyone who has one I would like a photo of it - simply to see if something has broken/dropped off to hold it in place ?

Cheers

Andrew

 

[ANDREW HUGHES]

 

[Dino D]

They are common across e36 and e46.
I believe it cuts down on some low rev bass notes. I couldn’t tell much difference on an e46.
They often get stuck shut which of course will restrict the exhaust at high revs.

 

[Chrisr1949]

Yep I got one on my 2000 2L, do know if it's working though, next time I jack it up ill check it.

 

[Eddie Zedder]

I have one one mine. I believe they were fitted to M52TUB twin vanos variants only (facelift 2.0L and 2.8L). Totally unnecessary, but I love the change in exhaust tone when it opens up at 2500rpm .

 

[Chrisr1949]

Ah, I'll have to listen out for that

 

[Devon Z]

Left mine disconnected when I did my M54 manifold conversion, so it’s open all the time.

 

[NZ00Z3]

I have one on my 2.0L Z3. It runs closed and opens around 2,500 to 3,000 rpm depending on engine load. Less bass when closed for when you're running around town and not disturbing the locals, not that its loud when open. There is a controller in the left rear sump in the trunk. If you disconnect the flap, remember to plug the vacuum hose with something.

 

[buze]

From my research, it's called the "golf T mod" to remove the vacuum line, close it with the golf T or a screw, and leave that second pipe open all the time. I can clearly hear the difference in noise at 2500rpm on mine. Might close the vacuum line next time I'm under the car, been wishing to disturb the locals for a while

 

[Dino D]

If you guys are going to disturb the locals do it right:

View: https://youtu.be/kCIGcjwFVao