Originally Posted by arsevader
Dunno who told you this but it's baloney.
The secondary air pump is what heat the cats up upon cold starts. That flap doesn't really restrict all that much. Certainly not enough to heat up the cats. A restriction that far upstream that was enough to heat up cats would be a cause for concern.
Not that much, just 50% of the final exhaust size!
Specialized in BMW recycling, all OEM used parts
Up to 90% off new cost!!!
Most models E30 E36 E46 E90 E92 E93 E28 E34 E39 E60 E61 E32 E38 E65 E66 X3 X5 M3 M5 Z4 F30 F32
Etobicoke location now open!!!!
Call 11-8PM 416 821-2578
New inventory daily. 70+ cars in stock!