I have this rattling noise coming from in or around my converter. At first I thought it was a loose fitting on my exhaust somewhere, but today when leaving work it was louder. I narrowed it down to the catalytic converter (or the surrounding area) and I was wondering what could be causing it?

 

Its either the heat shield on the converter making noise or the cat has broken up inside. Take a big screwdiver and hit the cat and listen for noise from the inside to tell if there are broken pieces. I would just gut it if you can and then you can take the heat shield off.

 

what he said

 

Would gutting the cat, so that it doesnt function anymore, adversely affect the way the car runs (other than helping exhaust flow), if so, how? If it doesn't affect the car, what is a good way to gut the cat (run a drill bit through, stab at it, etc.)?

 

Wouldn't affect drivability. You'd probably see little torque lost But a small increase of HP. Best way to gut it. Cut 3 sides around the cat. Pry it open, Chisel away, and Weld it back up.

 

Hell no, take the cat and ypipe down from the exhaust system and take a pry bar and hammer and break up the insides of it and dump it out. Take ya about 20 minutes and make sure you dont breath the dust from it. And you will notice a pretty big increase in power once its gutted. Least i did.

 

Why would you gut it and put it back on instead of just removing it all together?

 

or you could get higher flowing cats

~Kevin

 

LMAO. The cats are welded to the y pipe! If he takes the y pipe down tell me what "Pry Bar" is he going to use to break up the insides If it has a curve? On an Ls1 with dual cats. The cat on the driver side has flanges it can unbolt from the y pipe. That cat can be gutting like you described. However the passenger side can't be gutted that way because its one with the y pipe and the curve gives you no access. I believe this design goes for lt1 OBD II cars as well if im not mistaken.

 

You laughed your *** off, really? Its not that funny if you dont know what your talking about, or your trying to make your self sound smarter by making me sound wrong. First of all, since he was posting in the LT1 section i was assuming thats what motor he had, so therefore who gives a damn about an the exhaust setup on an LS1. My only mistake was assuming that he had a single cat setup, but given the way he spoke about "noise from the cat" not noise from the cats, or noise from the left or right cat, i thought it was a pretty safe assumption. Therefore, on a 93-95 SINGLE CAT SETUP, he CAN unbolt the Ypipe from the manifold, unbolt the cat from the intermediate pipe, take the cat and ypipe off the exhaust and then take a prybar and break up whats inside. And of course the cat is welded to the ypipe, thats why you take it down in all one piece, and gut the cat through the BIG OUTLET HOLE. I simplified it as much as i could for you. So please tell me what part of what i just said is wrong. Jackass.

 

That way it saves you the cost of an offroad pipe, and the time to put it on. Also incase you ever get pulled and the cops for any reason look under the car you still have a cat in place. In a lot of states if you illegally gut the cat that can lead to big fines. And high flow cats still do not flow as well as a gutted cat, i dont care what you say.

 

Thanks for all the info guys. because of the potential fines and emission test problems, gutting it doesn't look like a viable option, so a high flow cat looks to be the way to go.

I have a 97 LT1, so do I have 2 cats? The one that is bad is the one located under the front passenger seat. Can I just replace that one and leave the other alone?

Also, I have seen people mention the carsounds cats on ebay. Is this the cat they are referring to? $60 bucks shipped

http://cgi.ebay.com/ebaymotors/ws/eB...941864000&rd=1

I need the 3" cat right?

 

I have a noise like this as well. I thought it was coming from around the shifter. It makes the noise at lower RPMs. I thought my shifter was loose so I tightened it on real good. It is coming from the right side of the tranny, so I suppose it could be my cat making the noise, guess I will have to take a screwdriver to it...I was going to gut it anyway.

 

My cat's doing the same rattelling. IT definatly sounds like the cat or something very close to it. It started doing it ever since my new Cat install :/ Wish i could find a way to fix it.

 

yup u have two cats , one tuck up on teh left side (driver) that looks like a coffee can and the other is down lower inder the passenger side seating area looks like a normal catt,.