Want to modify the cat.
 

My 94 LT1 y pipe/cat was replaced a few thousand miles ago and is now rattling from the inside. I am thinking about opening up the cat from the top, removing the guts and welding it back shut. It also has a new magnaflow cat back system on it. Will this mod have a negitive effect on performance. Back pressure issues ect... When my original muffler went bad the car really ran like crap!! Engine is stock except for K/N cold air intake. Thanks Steve

Remove it, and replace with a pipe.

Gut the cat...they have random checks to ensure the cat is on there. A hefty fine by running a test pipe, so why risk it....no back pressure issues if its done properly.

No inspection worries?

If it was just replaced a few thousand miles ago is there a warranty?

Will gutted cats flip a code on that car? i don't know these cars very well

This.

Won't throw a code on a '94.

Will not throw a code on a 94 but you'll need to pass the sniffer when you go for inspection.

I gutted mine on a 94 and threw no codes. I removed clamp and smashed it out with a long screwdriver. Then started it up and took a ride open and shot all the little loose stuff out.

Right, but he was correcting an oversight on my part. You can gut it and the car will be fine, but come inspection time you will have to figure something out.

Also be aware that many people have a platinum allergy. So if you bust up the cat don't breath the powder.

Walker makes good cats if you go that route...

grazi what do you do for inspection/sniff test?

I plead the fifth.

Take it to a private shop and try to get it inspected

the key part missing there is using a shop where they know you well. I inspected cars at my shop for years and there is no way I'd help some guy I've never met. Not worth losing my inspection license and fines, the state does send setup cars.

if the car is more or less stock replace the cats, the 2hp you'll lose is a fine trade off for no hassles.

If that, and its a stock motor, what are you really gaining other than a smelly, illegal car.

Advance auto sells Magnaflow spun high flow cats, and you can use code P20 for 20% off. In the long run it's probably still cheaper than jacking around with private shops.

My old exhaust setup i had a magnaflow cat. It seperated from the housing after maybe 15k miles

That is the cheaper one. I had the same thing happen. The bullet cats don't have that problem.

No mine was the spun metalic one, cost me like 80 or 90 from summit