|
Backpressure myth
You should read the AutomotiveForums article on the myth of backpressure. It's at the top of the Technical forum.
Chances are that the exhaust system isn't sealed and you're having flow problems due to this.
Also, going to 2.5" piping on a B17/18A is absolutely useless unless you're going to FI your engine to oblivion or redline around 9 grand. All it's going to do is lower your airflow efficiency and hurt your exhaust's ability to aid in scavenging air from the cylinders. I'd expect a noticeable loss in high-end performance (perhaps as much as 10hp) if you're working on a generally-stock engine.
|