Exhaust

[Rich328]

i've noticed that on my 328i the exhaust seems to have a flap/valve attached/in the right hand side pipe....... anyone know what this does?

I've also noticed that the person who had it before me has had it tied open..... will this effect anything?

[Furious]

it creates backpressure for better performance in the low end. it usually stays closed untiill you get going then, opens.

[BaLAnCe17]

ya i noticed that too. i just replaced my stock one w/ the uuc tse. (alot louder now) any ways. its a valve that is closed at idle so it will be quieter and opens later like furious said. after i put the uuc on i stuck a gold tee in the line and put it behind the heat shield becuase i wont be needing it anymore. later