View Full Version : what is a test pipe?

11-15-2004, 12:41 PM
is a test pipe the same as a downpipe?

11-15-2004, 12:43 PM
test pipe is a pipe that goes in place of your cat...

the cat is the most restrictive piece of your exhaust, replacing it with pipe can be very beneficial, but can also cause CEL's

11-15-2004, 12:52 PM
well i just installed the awe/borla exhaust with dp. so does this mean i can't use a test pipe?

11-15-2004, 12:53 PM
yea, like Shon said, a test pipe replaces your cat. the car is the part that is directly connected to your turbo, and then the downpipe connects to the cat. A test pipe replaces the cat, and it is basically a straight through tube and usually has a couple bungs for sensors in it. It has its performance gains, but it also makes the car louder, and you'll get a check engine light from it unless you get a simulator for the sensors that plug into it.

11-15-2004, 12:54 PM
no, you can use a test pipe, because it replaces the cat, not the downpipe.

11-15-2004, 01:00 PM
is it a good idea to try to add a test pipe to my awe/borla? what since it does thow on a CEL, how does it benefit the car?

11-15-2004, 01:03 PM
well, the turbo will spool faster with a test pipe, but personally... in order to avoid getting a louder exhaust, and a check engine light, i would go with a high flow cat instead of a testpipe. i also have a borla exhaust and downpipe... same as yours.

11-15-2004, 01:17 PM
I need one bad. Who makes the best TP? Why shouldn't I just clean all the honeycomb out of the inside of the cat?

11-15-2004, 03:30 PM
Tantrumworks has test pipes, I had a test pipe with my T28 and miltek exhaust and the note got a little deeper, but not louder. I know how a test pipe with my GT28RS and no center resonator and it is loud, but very deep.


EC Motorwerks
11-15-2004, 03:39 PM
Whats better to have? A test pipe or a race cat?

11-15-2004, 04:44 PM
Originally posted by A4RobM
I need one bad. Who makes the best TP? Why shouldn't I just clean all the honeycomb out of the inside of the cat?

Coming right off your turbo especially, this will cause more turbulance and that'll do more bad then good because it'll totally disrupt the flow.