I just finished installing my DP (yay). The problem is, I found out that the flange on my cat is bent away from the DP flange, creating a large gap that my exhaust likes to spew out.

I still need to pass emissions (a new thing for me coming from Washington State), so a nice 3" midpipe is out of the question.

What I want to know is what are my options? Aftermarket cat (expensive), another OEM cat? Will it line up, as the DP is 3" and the stock cat is smaller (2.5" maybe)? I know the STIs have an exhaust gasket that transitions from 3" to a 2.5" pipe, would that work?

Magnaflow sells a direct fit cat for under 100 dollars, while the high flows are around 350-400.

Any advice?

Thanks, just trying to not look (and sound) like the Hondas that drive around base with their 4" fart cans...

 

The stock piping it actually about 2.25", so trying to mate a 3" pipe to it will almost definitely leak. But if you can find some sort of reducer gasket like you mentioned, it could work. Otherwise a 3" aftermarket cat will be the route to go. Also, stock main cat length is about 17.5" from end to end for reference.

 

Thanks. Does anyone know of a 3" cat that has an air pump hookup as well as being 17.5 inches long? What cats are people using with their DP and catback exhaust systems?

 

Would something like this http://cygnusperformance.com/cart.ph...ategory_id=161 work with an OEM replacement cat?

 

rx7.com has good quality cats that last and fit well.