'92 S13 Stock cat converter i.d. pipe size

[VA240]

I'm getting ready to purchase a BRM 2.5" exhaust for my S13 and I want to get a new converter to go with it. The direct fit Catco cat 4087 shows a diameter of 2.5" but I don't know if that is i.d, o.d., or flange size.

What is the inner diameter of the stock cat piping? I'm guessing it's smaller than 2.5"

Thanks,-VA240

[nissandrift]

i beleive its 2".

[onosqv]

well if you are getting a 2.5" brm exhaust, you mite as well get the 2.5" hi flow cat, will flow better.

That is the piping size. the flange will just hook up around it. And make sure they make the one that "spins" around and not welded into the cat. Taht way you can spin it around and have it fit the headers and exhaust perfectly.

While your under the car, mite as well replace the headers if you haven't. I did and it's sweeeetttttt. .

[VA240]

I just received my BRM exhaust and Random Technology high flow cat yesterday.

The 2.5" RT cat mates up with the 2.5" BRM exhaust perfectly.

-VA240