cat or test pipe?
 

Catalytic converter recently began making the little 'rattling sound' at certain rpms. So... I assume it is about time for its replacement. However, should I replace it or swap it out with a test pipe? I believe the price for each is about the same, so I guess my main question is, is there any difference?

a test pipe is just a straight through pipe, it just bypasses the cat and runs normal, pipe where the cat usually is, i have heard people say they get huge HP gains with test pipes on turbo cars, i bought a high flow cat off ebay for 40 bucks which is a step in between a restrictive cat converter and a test pipe, just get one of those, good luck

john

Sweet, my CAT was doing that to, making a rattling noise at 3200rpms. Dude, you have an NA 944, you have to get a CAT becuase if you dont you WILL NOT pass inspection. Get a free flow CAT, they are pretty good. I got mine from amhet for like a 100 bucks. I was blowing rings of steam out the back when I first started the car up:)

yah buy a high flow, but try to spend less than 50 bucks! Go on ebay and buy a carsound high flow cat, they are great, thats what i have it cost 41 dollars shipped!

I have a test pipe and I think it hurts low end torque while improving high end RPM power...I like it, my car sounds just a bit more throaty without being too loud! It depends on where you live...No inspections here in cold Indy...:)

You can just gut the cat, and reinstall it. Make sure to use a mask and gloves. You probably wont pass a smog test. Poblem with a test pipe is you wont even pass the inspection. Even if there is no smog test it is illeagle to remove smog equipment.