i recently bought a custom exhaust from a guy parting his hatch out. in the deal, i got:

-DC headers
-downpipe (or whatever its called that is between the cat and headers)
-the pipe that is between the cat and muffler
-aftermarket muffler

so in short, i got everything but the cat. i measured the diameter on the pipes and it appears to be a 2" system. i'm assuming my stock cat will not work and would like to know what you guys recommend for me in that department. this is strictly an autocross car that is being built for the STC class so i'm not expecting to be putting out a ton of power. basically will eventually be built and maxed out for that class...again not putting out a ton of power or anything.

should i go catless? (i will have no problem passing inspection because i'm emissions exempt and i work for a dealer that will look the other way during the visual inspection). or should i go with a high flow cat or a stock spec 2" cat?

my other concern is where do i find the header gaskets and pipe couplers that will fit and join it all together?

i'm used to going to advance auto, telling them i need all the stock hardware for a stock exhaust and throwing it on in the driveway. with this custom system thats 2" opposed to the stock diameter has me a bit thrown off and over thinking things

anyone have any tips? attached is some pics of the pipe ends to see what kind of gaskets i will need.

thank you!

 

Straight pipe FTW

 

so will i have to have one fabricated or does anyone sell a straight pipe that will fit in the place of where the cat would go?

 

It's called a test pipe
you can make one, or buy one.

 

would this work for me?

also, should i go with the OEM header gasket or would a rock auto one work?

 

If you are not required to have a cat, then it is to your advantage to not use one.

 

you need a cat to be legal in STC. run a high flow cat.

 

thanks...i wasnt sure about class rules on that one.

 

edit:

well after measuring again, it appears to be a 1 3/4 inch system, so maybe the stock cat would work....

my dumb *** wasnt measuring the inside diameter of the pipes