GenVibe - Community for Pontiac Vibe Enthusiasts

I'm going to have a custom downpipe done and I'm going to get a Magnaflow High-Flow Cat. The question I have is can I just put one cat on it or do I have to have both the pre and post cat? If I can just use one do I have it before the o2 sensor then, which is in the middle of them now, correct? Thanks!

turbo?the stock Vibes only have one cat...

I was always under the assumption that there were two cats. One was the pre-cat, then the o2 sensor, then the post-cat. Did you do a custom downpipe and verify this? That inlet should I get for a cat?

I have a slight off-topic question:Next summer I am going with the Magnaflow cat-back and DC headers, should I consider a custom downpipe? Is it worth my trouble?

I think if you're doing exhaust upgrades you should do it all. If you don't, it's like having a 2" in diameter hose going to a .5" hose for a couple feet, then back to normal again. It really hinders the performance if it's not upgraded all the way.

im pretty sure it was only the AWD that had the pre-cat

when I put the magnaflow on my car... I only saw one cat.

I had 2 cat's on mine (base auto). Could be different for a number of reasons. Or just because your's is Canadian. Petrucci, You should be able to get away with only one cat. You should have 2 O2 sensors. On should go in the collector of the header (exhaust manifold), the other should be just after the cat.Let me know where you get it done. I've been having a hard time finding anyone to build the exhaust I want without having to pay $500 or have them tell me thay can't do anything other than OEM design. Even though they advertise "We build custom exhaust". I'm so unhappy with what I have now. Don't try anyone here in Appleton. I've asked them all!Also, the biggest problem I had was trying to find just the flanges to connect to the end of the header and the axle-back exhaust.

Is the 2nd "cat" really just a resonator? I was reading throught the installalation manual for the magnaflow system for the base (US) model and they call that catlooking thing a resonator...

did some say custom down pie?.....group buy if its successful?

I did the magnaflow upgrade. And i have tought of the highflow cat... But it didnt seems to be very popular around here... And wasnt sure about the law and regulation about this mod here in Quebec... so i let it go. Any one have dyno sheet or info to show the real difference it makes. I agree with the idea that you have a new bottleneck with the cat but i tought that he was less restrictive than the stock muffler... If not.. why bother change to the magnaflow except for the sound...?