[DonC]

I was suprised to see vaper exiting out of the right outlet the other day. I put my hand over the left outlet and there was no air coming out. I had thought that my X3 3.5i had duel outlets. I heard about flapper valves but am having a hard time finding infomation. So what's up with the stock exhaust?

[02420X3]

Yes, that's normal. The left side is active, but only opens under load. See http://x3.xbimmers.com/forums/showth...ht=35i+exhaust

Basically, there's a butterfly valve and a vacuum line that control the left side. A throatier exhaust note is added when the left side opens. Some have done a "golf tee mod" by pulling and plugging the vacuum line at the muffler, which keeps the left side open all of the time. Some have achieved the same thing by disconnecting a plug in the right rear access panel.

RealOEM.com has a nice depiction of the exhaust. See http://realoem.com/bmw/showparts.do?...24&hg=18&fg=20

[DonC]

Thank you.

[02420X3]

You're welcome. Should you want to play around, here's a link to a Golf Tee Mod thread. http://x3.xbimmers.com/forums/showthread.php?t=570532