Originally Posted by labedra
My bimmer sounds louder now after over 2 weeks of driving with the valve open, I guess the left side of the exhaust has to break in a little if the valve was mostly closed before. It sounds the best when driving in a tunnel as the noise get amplified. Here is my bimmer and stock exhaust sound 800 - 3000 rpm rev. It also sounds much deeper when you are driving since the engine has to work harder.
why would the engine have to work harder? if you reduce the exhaust restriction, what do you think happens to the engine?