Ok, Im back for more.

I haven't been able to get under my car yet but is it easy to remove just the stock cat? I wouldn't mind taking it out just to do a few tests. After the tests, I would like to put it back in. Is it bolt on as a stock unit?

 

You have to remove the whole downpipe. It's only 4 bolts, but they could be rusted pretty badly.

Here's what your exhaust looks like stock:

 

Ah I see. Thanks. So it would be bolts at the manifold and bolts just before the resonator, after the ubend?

 

Yes it bolts at the manifold and resonator.

 

@Chibi: Is that for a 3.4, or a 3.8L? (Your mock-up ...)

 

Keep in mind your stock cat is very recyclable too. So if you have a scrap yard or recycling center in your area you may be able to get some cash for it. My friend made $115 off hers from a stock trailblazer,

 

Chibi can correct me if I'm wrong, but I'm fairly certain that mock up is for a 3800. BUT the 3400 is not much different (the bends/dimensions on the manifolds/cross-over and DP may be a tad different on a 3400).

 

okay so i plan to replace my stock catalytic converter this weekend. this is my first major fix. ive ordered the replacement cat. its a direct fit bolt on. my landlord is going to help me, he's had experience changing them. he mentioned cutting the bolts off and said i need to buy new ones to replace them with. does anyone know what size bolts i should buy???????? thanks very much for your time guys!

 

I am very concerned with my gas mileage and the hot-rod sound that I am getting while driving. I have noticed a lot of 95 - 2000 ish GP (Grand Prix's) sound like this as well. So I wanted to know how would I know if its the converter or not? And is it an easy fix for me to "do it myself"?

 

Usually, you get a bogged down noise but if your cat is clogged, you can get a noise that sounds kind of cool but you don't see the performance that matches the sound. If you have one of those laser thermometers, get the car nice and warmed up and point it ahead and behind the cat. There shouldn't be toooo much of a difference. When my cat was really bad, I saw night and day temps after a half hour drive.

Most shops can check your cat for pretty cheap if not free.

The upgrade was very doable but I am mechanically inclined and I will always try stuff myself. It would have been way easier (and not too expensive) to take it to a shop and let them do it but I'm stubborn.