I have a 1990 iroc and just purchased a set of headers for it. I am now trying to locate an aftermarket set of pipes that goes from the header collector to the cats. My problem is that I have dual cats. I can find all kinds of Y-pipes, but those are all for single cat systems. I can have these custom made locally, but they want way to much for them. Does anyone know of anybody that sells these already made up?

 

Why don't you just switch it over to a single cat system, it's a better system then the double cat system.

 

From everything that I have read they went to a dual cat system for more HP. Two pipes has got to be better than a Y-pipe?

 

I've seen them in "JEGS", I know Edlebrock makes some, and maybe Headman?, I don't have my catalog in front of me but I have seen 2 makers offering them...and NO a single cat system is not better, cheaper but not better.

 

How can the dual cat system be better? It seems to just be more restriction, and all the exhaust ends up going through one pipe anyway (in the end). I'm not saying you're wrong, you probably know more about this than I do, but I just don't know why the dual cat setup is better.

 

GM rates the dual cat f-bodies 5-10HP higher than the single cat cars, so there must be less restriction in there.

 

How would it make it more restrictive running all of the air through 2 pipes and that cat as opposed to running all of the air into a single pipe (major difference right there) then forcing twice as much air through a single cat.

And it does make a difference if your just slightly alter the stock setup and run true dual, just toss in some chambered mufflers and youre more or less good to go

 

A single 3 or 3.5" exhaust flows just as well as dual 2.5" from what I have read on this board. There is no need to retain the dual cat setup if you are modifying the exhaust. The dual cats freed up a little more of the restriction and resulted in a marginal gain in hp. Get a single BIG pipe exhaust and never look back man.