first off I'm curious the piping size of the stock prelude exhaust. I'm thinking around 1.75" to 2". Honda is pretty balanced when they design something, for back pressure etc.. My question is why is it that every exhaust sold for a prelude is 2.5" inch instead of a probably better size of 2.25". wouldn't that be better than going too big and getting crappy back pressure??

 

Stock is 2.0" piping. You definitely need to research back pressure, exhaust velocity, etc.

 

2.5" is not to much by any means.

H22's make power off 3" Piping.

What do you think Honda designed the Engine/Car for? Performance or Economy?
Sure it can do more, but they only go to a certain point before they feel it's not worth the Economy factor.

 

cost to the auto manufacturer plays a large role. a larger exhaust is more expensive, not just for the piping, but for the cat and muffler in particular.