I bought a obx hight flow cat on ebay for a gst that said 3inlet and outlet but its only 2.25. Well I already have a 3in gst cat back on and the flanges on the cat are straight and the flange on the exhaust that connect to the cat is at a angle. What cat will work on my car? Also will hollowing out my cat be just as effective?

holy cow...this is like the 4th thread I've read in like 10 minutes about your exhaust :-o


i'm sure one of your posts will be answered :thumbsup

do a test pipe cat and the resistor mod to the rear o2 sensor. much better money and performance....

there was also definetly a post about this within the last month too, the gst/gsx cat is not the same as the rs/gs cat. where it bolts up to the cat-back should match up but where it bolts to the downpipe shouldn't. If your looking for an actual cat, I know you can get one from CI but i don't know where else

Originally posted by tim97rs
do a test pipe cat and the resistor mod to the rear o2 sensor. much better money and performance....

X2

Shawn, get under the car, remove your cat (you might pick up some PB Blaster at Autozone and spray those bolts really good the night before so you don't break them), get your measurements, pick up your flanges and pipe, then have a muffler shop weld it together for you. Shouldn't be too much. Pick up new bolts from ACE and new gaskets from Autozone, then put the cat in a box and the pipe on the car. Being turbo, I'm thinking you'll notice a difference.

When it's time for emissions, swap the cat back in place and go test. You should be good to go.