Removing Cats from 2002 Silverado!

LeeS · March 18, 2002

I have a 2002 Silverado, and I live in West Virginia, we don't have emission testing. I was wondering if anyone knows where I can find off road pipes, which are the pipes from the exhaust manifold to the stock muffler flange. I need this pipe but without the catalytic converters? Anyone know where I can find such.

Thanks Lee

silverado man · March 18, 2002

I dont think you can take the cats off because there are sensors in the cats, and that will trigger the computer to give an error. I could be wrong on this though. ???

GoFaSSter · March 18, 2002

I do not understand why you would take them off. Do you have some proof that they will give you more power? Is there something about your cats that is particularly restricting you? My budy is running a 502 with dual exhaust and dual Catco brand Cats and the difference on the dyno, with and without exhaust (mufflers and all) is 2.3 hp. This truck is built for racing and has some serious flow. Unless you have some pretty serious mods, I doubt the cats are hurting you. To each his own.

obyone · March 19, 2002

Your best bet would be to cut the cats out and replace with the same sized piping. Don't think you're going to find a direct replacement. While you're at it you might consider setting it up for true duals.

On the downside, you have 4 - O2 sensors before and after each cat. The trucks computer monitors the emmisions before and after the cats. If there isn't a reduction in emissions between the forward and rear O2 sensors, you will get an error code. That will require reprogramming the truck for not having the cats.

c4boom · March 21, 2002

keep them on but use the biggest hole saw that will fit in the pipe then go to town

2000 GMC · March 21, 2002

If it's a 2002 you shouldn't mess with them, it might void the warranty. I asked my dealer about dual exhaust for my truck he said as long as I don't mess with the cat's, it wouldn't void the warranty.

Yont283 · March 22, 2002

I took my coverters off a while ago but my mom made me put them back on. You do need cheater boxes for the rear O2 sensors so it does not set off a code. My truck ran fine with these cheater boxes. I still have them if you want to buy them or you can get them Casper electronics. Just e-mail me if you have any questions.

sincityZ71 · March 22, 2002

Also, by taking cats off of newer vehicles you are breaking federal law, doesn't matter if your state doesn't have emissions, your still breaking a federal EPA regulation which trumps all state laws, therefore you still must abide by that law. If you run across a police officer (any officer can enforce this law, not just federal) who has a good eye or ear or is very picky, he will find out and the fine for removing cats, and the fine is at least $5000. Maybe no one in WV will care, but if you ever travel out of state, they do. The cats are the only thing that clean-up emissions at all, that is why they are required. So remove at your own risk.

01z71 · March 22, 2002

Yeah, I don't see much point in doing this other than voiding your warranty. If it was an older vehicle it might be worth doing if you had a problem with the converter but otherwise there is not much benefit to doing it. Also, try to find a repait shop willing to take the risk.

GoFaSSter · March 22, 2002

Catalytic convertors got a bad rap back when they were the old pellet style. They had a tendency to plug up and did not flow well even when new. I still have this style on my '90 Chev. The newer style monolithic cats are very efficient and cause very little loss if any. GM started using these in 1991 on their truck line. When they go bad they do not flow as well and make a terrible rattling noise.

I guess the general consensus on this board is to leave them alone. I would still like to see the dyno chrts where someone proves they rob all this horsepower on a mild street truck.

BDBWTE · April 30, 2002

The cats on your truck are as free flowing as they come. I wouldn't take them off unless you felt you needed too. If you do however take them off you can buy a relay that will trick the Post Cat O2 sensor into thinking that everything is all right. It will make the truck quite louder and not to mention free up some horsepower, but it will hurt your gas mileage, just because the truck's computer which controls air/fuel mixture will be getting a constain single and not adjust to less fuel when it is not needed.