"Cutting The Cat"

[TurBoGs-T]

I'm interested in getting a 3 inch turbo back. now all i need to know is should i get a 3in high flow cat or should i just get the test pipe. Also does cutting the cat really make that big a difference?

 

[nine5raptor]

go test pipe...as long as you don't have on site (side of the street) inspections like those cali' guys

 

[BOOSTEDPSI1]

Test pipe for sure.
One of my biggest performance gains that I have experienced, plus it is cheap. You can do it yourself if you have a welder.

 

[rubbersidedown]

gutting the cat is just stupid. i think it makes a dumb noise. Just get a 3inch hi-flow cat. I think someone brought it up before but w/ the way the new cats are made today (especially a 3inch hi-flow) i don't think you'll notice too much of a difference wether you use the test pipe or the cat. So use the cat if you're concerned about emissions of course.

 

[Rob]

http://www.testpipe.com/htmlsite/Custom.asp <~~~ go here and save some time and money

 

[DSMJim]

Buy an old cat. Take a 3 inch pipe and pound it through the center of the honeycomb. It will literally cut its way through. Just put a piece of wood on the end and use a big ass hammer to pound it through. It will move an inch or so, pull it back out and clear your pipe then put it back in and pound again.

Eventually you will pound your pipe all the way through the honeycomb completly. Now you have a streight pipe with a cat and honeycomb stuck around it. Then if they tap the cat it will sound solid like a real cat does because the honey comb is still in there just that there is a pipe running through the center of it. Weld the edge of the cat to the pipe running through it and put on your flanges to the right length and voila you have a perfect solid sounding cat which is really just a test pipe.

I did that for my GTi and it was perfect it looked and when taped on sounded like a normal cat. If you looked under the car it looked just like a stock cat. Even better if you use an old piece of pipe and old cat so the pipe and cat match each other.