Quote:
Originally Posted by jeremyc74
No, the flap is open for a while after the car is started. There's a VERY obvious change in tone when it closes on my car. I've got catless DPs and I park in a garage, and there's no mistaking when the valve closes.
The valve is vacuum actuated, but it's controlled by the ECU through a valve that's mounted in the trunk. Pulling the wire off the valve will do the same thing as unhooking the vacuum line and plugging it.
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This is
correct, in fact, above the amp in the left side of the trunk you can find the solenoid that the ECU uses to control the exhaust valve position. If you disconnect the solenoid as I did the valve stays open, no zip ties, no golf tee and no CEL.
The valve is in no way related to performance, it is only there for sound. Also, the reason why the engine is louder after a cold start is obviously in part due to the valve being open, but
most importantly due to the engine using massive valve overlap to warm up the first bank of catalytic converters.