Quote:
Originally Posted by oshiri
as 42pilot said, if you open up the other one, it will reduce back pressure on the exhaust system. this may cause it to feel more sluggish and less powerful in the lower rev range. this is particularly applicable to turbo'd cars.
its for the same reason that ricers, when they modify their hondas to have louder exhausts by replacing the exhaust system with pipes of wider diametre, lose power and torque despite improved flow.
im not sure how restrictive the stock exhaust is on the 35i and how much of a difference opening that valve would make on the performanec of the 35i, but i dont think its worth it. could also risk having exhaust drone since the resonance at the lower revs will change from what the stock mufflers were designed to be compatible with. |
I agree it is due to back pressure for the turbos. I think the back pressure is needed to help spool the turbo at low rpm's.