Hi, has anyone ever used a hi-flow cat (I guess it might not be legal in Cali) on a GSR? Did you like it? What about my O2 sensor, do I need to drill a hole or can I just run without it? I heard you only need one sensor, either on the header or on the cat. Any info would be appreciated.

 

i'm not sure if they make any street legal high flow cats. but test pipes work really well on your car, but its also really loud, depending what catback you had too of course.
i'm not sure about the CEL coming up for the sensor. I have a WRX w/2 out of 3 cats on in my car, There is a sensor on my cat now and i still get a CEL.
that is until i got a bypass from ponyexpress.com.

 

they can't tell the cat is a highflow cat.. the purpose of a high flow cat is to be carb legal btw.. I would double check this with a muffler shop but I really think its legal

 

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ditto...a test pipe is highly illegal to have in california...i think the fine for having one is like $250+ and they send you to the state ref. I've had one on my car for the past year and a half, no hassles yet, probably because i stay away from the cities that crack down on imports. Most high flow cats are carb legal...i actually have one for sale. Its a Random Tech High flow cat for 94+ GSR's..has 2 o2 bungs so you dont need to drill anything. Let me know if you would be interested

 

holley makes a high flow cat for the GSR -- here in GA we get fined for no cats and test pipes too if they find out during an emission test.
Jackson racing also sells one for a bit more but its the exact same thing as the holley (actually made by holley)

 

i heard carsound cats are great. You can find universal applications on ebay for about 50 dollars. Check it out yourself and i've read posts where people have passed smog with their high flow cats.

 

only thing w/ the carsound cats on ebay are that you have to drill in an o2 bung, and have to take it to the muffler shop to have it welded to fit your application

 

i haven't gone to inspect my car with my high-flow cat, but i'm more than positive that i'll pass because my cat was manufactured in may of 2003, the only thing about it is that it really stinks up everything around the car when it's on

 

A cat is a cat.. high flowing or not .. its going to restrict you more than w/out a cat.. so it really doesn't matter which "high flow cat" you get.. just get one when u go to the muffler shop (call first) .. and get a generic one.. (make sure all the heat shields are welded to the cat or taken off.. cause the will rattle on most any setup eventually