I have a 93 Accord LX. I have stepped the pipe up to 2.5 from the cat back and I intend on getting headers this month. Would it benefit me to get the Cat also or is it a waste? I heard that the Hi-Flow cat is for top end and would hurt my low end. Is it true?

 

Well, unless it's forced induction, you're only going to lose HP. Modern engines are designed for some amount of backpressure. If you remove it all, you'll find that you actually lose power.

 

:werd:

 

didn't mean to re-post again but i haven't really seen a high-flow cat do that much, IMO

 

How would a hi flow cat remove ALL the backpressure?

First off, your piping is too big, 2.5" piping is too large for a 4th gen LX w/ minor mods. Add the hi flow to that and you will lose even more backpressure, making you low end torque suffer worse than it has. Your decision though?

 

So, step the pipe down to 2 1/4, keep the stock cat and get 4-2-1 headers. I guess I really didn't think about .25" being such a big deal. Should I go as low as 2" or just 2.25

 

2.25" will be just fine.