how to choose exhaust size
How do you decide which exhaust pipe size will be best for the application?
I read that probably the smallest diameter that can handle the cfm will be best for performance.
For example my 450hp GTO would need a dual 2,5" (the size I use at the moment).
But there are other opinios that say "bigger is better" and a 3" dual would be best.
Is there a way to determine what size is best for performance?
The formula I got says that you need 2,2cfm for each hp. That is 990cfm for my engine. A 2,5" has a total flow of 510cfm, a 3" a total of 750cfm and a 2,25" has 410cfm. So a 2,5" (2x510=1020cfm) would be best. What do you think?