[X3BMW]

The X3 has 2 tail pipes but I have noticed that on a cold day smoke only comes out of one. Is one tail pipe just for show and not even connected to muffler?

[Barbera335]

Originally Posted by X3BMW

The X3 has 2 tail pipes but I have noticed that on a cold day smoke only comes out of one. Is one tail pipe just for show and not even connected to muffler?

There is a vacuum actuated exhaust flap installed on the muffler. If you look under the back of the car you can see it. It remains closed at idle and under light load and will open at wide open throttle or heavy load. It is there to make the car quieter at idle and light load.

[Tjalle]

And then there is.........

M Performance Klappenshalldämpfer- dual mode: legal - illegal. Operated by driver.

For X4 35i M, but could be installed on X3 35i M, but not perfect fit.

[ianfp]

Originally Posted by Tjalle

And then there is.........

M Performance Klappenshalldämpfer- dual mode: legal - illegal. Operated by driver.

For X4 35i M, but could be installed on X3 35i M, but not perfect fit.

This looks fantastic and I bet it sounds fantastic too!

[Tjalle]

There is a thread on X4 forum with a video/sound of a 360bhp/600nm Russian X4 being dynotested with Klappen.