|
I don't have a VX and I don't have a before and after of my car either - when I got it, it had a 3inch pipe and an obnoxious muffler and I've been too cheap to replace it. Couldn't give you any numbers.
Whatever the losses are though, it's not from backpressure as is commonly thought but actually quite the opposite. The stock system is tuned to maximize "scavenging" which to my understanding is when the exhaust pulse of one cylinder travels down the pipe and causes negative pressure exactly when the valves open up on the next cylinder to fire, and actually pulls the exhaust out.
It seems the ideal pipe size is "just big enough" because it maximizes scavenging without restricting.
|