Originally Posted by janebrink
I've tried to find these flaps on www.realoem.com
after selecting my 335d 04/2007, but I can't seem to find any?! So are u sure that 335d even has any? I'll look at my manifold tomorrow to see if I can spot any.
This is the part - no.1 - you'll see it says with flap control.
There are two inlets per cylinder; the upper and lower - the lower is what part 11 fits in. I think the flaps are only in the lower inlet, and are vacuum controlled, you can't really see any of this in the diagram.
The original design from 1998ish had flap spindles that could fail due to fatigue, probably compounded by deposits in the inlet affecting the motion of the flap and hence increasing loads on the parts.
I've still not seen any reported e9x failures - yet. I suspect the beefed up design from around 2005 has avoided the issue.