O2 sensor-cat pipe

[ChevelleSSLS6]

I have a 2000 Se v6, and I was wondering, when I finally get a real catback, if I should get a bigger "downpipe". How much of a gain is there with that over just a catback?

I'm thinking 2.5" diameter pipes.

[car audio dave]

if your cat-back pipes match then itll be nice to have. you will still be restricted by your exhaust manifolds tho. just keep looking back in the system, once all of the restrictions are taken care of then youll get your optimum setup.

the only downpipe thats meant for our cars is the one from random tech...not sure that you can even get one tho, they had a problem with them. PFYC pulled them off their site shortly after i had the problems with mine. now random tech doesnt even have it on their site anymore.

[PhunkAssassin]

I have a 2000 SE V6 as well, ad i just had the pipe from the O2 sensor replaced when i got a catback exhaust. I'm not sure how much of a hp gain there is since i got it all done at the same time, but the pipe that comes stock is apparently very restrictive (after talking to several muffler/custom exhaust shops). If you wanna get it done it should only be $40-50, and a local shop can probly put a custom one in like they did mine.

[schweppe23]

the stock downpipe is pretty restrictive so i'd get a bigger one and i'd also get a highflow cat to go with it.

.02

[ChevelleSSLS6]

I have heard repeatedly that the 99-up cats flow quite well. Those of you with the 3100s, they are sucky cork-in-the-pipe cats.