I don't know how they are in the Beehive state about enforcing vehicle stuff, but doing it your self doesn't make it any less illegal. I missed why you are doing this, the cat is gone bad and plugged up or you think you will gain performance(You will not)? That rotten egg smell you sometimes notice out on the road is what a bad or absent cat smells like. BTW, here they would just impound your car if you happened to get pulled over and they looked under there

 

here is what you do to get around the visual inspection in the case a cop would pull you over AND get under your car. first if your car is lowered, i doubt the'll take the time to jack it up and look under there but anyways.

go to the junk yard and get a random cat. then gut everything out of it. then run your test pipe THROUGH the empty cat. so when they look, they will see the cat there and can't tell the diff. all you have to do is cut the ends of the stock cat to the size of your piping and have it welded.

i was thinking about doing this but then i just bought a carsound 2.5" high flow cat. gonna install it when i put my turbo on though. do what you want, thats just an idea you could do.

 

C'mon Chanc... running a test pipe is actually seriously messed up for the environment. It's bad and you know better.

Your car was designed to run with a cat, and so why try to cut corners and save money very little hp gain? Do it right, man...

Unless the car is a dragstrip only racer, Test pipes cheapen the car... you can smell and hear the difference... but you can't feel the difference...

 

hey man 2 of my friends have test pipes (one in a mustang and one in a teg) and im gonna put one on mine too i think. they smelled and sounded kinda funny for like 2 weeks. now no smell at all and they both sound awesome.

 

You might have just got use to it, its all in the brain

 

:slap: They sound like ass and they do incredible harm to the environment... Get a real High-Flow cat!

 

:happysad: just get a highflow cat :happysad:

 

Back from teh dead :eek3:. I trust the guys opinion about a high-flow, test pipe or nothin for me .

 

Bah!

On a stock motor you don't need a test pipe.

On a modded motor you run a 2.5" system from the header back, with a high flow cat.

That is all.

Now as penance for even considering being a gross polluter, you must hug five different trees and tell them how it's so nice of them to convert harmful greenhouse gasses into lovely, breathable, oxygen.

 

You're welcome to trust his opinion, but he's honestly just incorrect. The flow numbers of Carsound high-flow cats are such that there will be virtually no appreciable difference in gains between them and test pipes. 20 years of experience or not, the simple fact is that a test pipe that flows ~400 cfm isn't going to perform any better than a cat with roughly the same flow figures.