Greetings,

Well, my recently acquired '99 has been a very expensive adventure. About two months ago, I started noticing a metal rattle/jingle coming from underneath the car when letting off on the gas after the car warmed up. Searched forums and the internet and thought it might be a lose hanger or heat shield...once those were debunked, the culprit turned out to be the catalytic converter.
Now I'm undecided whether to just pony up and have the converters replaced OEM...to the tune of about $600 or just removing them. I've read pros such as performance gains and cons such as legality and engine issues about taking them off, so that concerned me. And I can't seem to find many aftermarket hi-flow cats, either. Because if I'm tearing into my exhaust, I might as well make it better.

 

Random Technologies makes high flow cats for the corvette. I would go with a nice set of long tube headers and high flow cats and enjoy the extra power.

 

I was leaning towards this as well. Like I said, if I can replace the cats while actually gaining something, I'd like to do that. Never replaced headers before, though.

 

Get rid of the cats all together in my opinion. I cooked my stock ones and gutted them.

 

Do you have emissions in your state? that will be a big factor to remove them or replace them.
I would decide if you are going to run headers or stock manifolds. Magnaflow makes a new bolt in cat and H-pipe if you want a bolt in with high flow cats... or you can have a local shop remove the stock cats and replace with high flow cats... If you wan to spend 1000-1500 for headers with cats you will gain power and keep the air clean.. then you will want to spend the money for a tune as well to optimize it.

I have a set of 04 Z06 exhaust manifolds, stock downpipes and H-pipe (cut at the rear) if you want a upgrade over your LS1 exhaust and you dont want to spend the money for headers w/cats and tune. PM me if your intersted..

These below should all be for a 1997 model, but be sure to verify yourself if you order anything.

Magnaflow 93988 (97 C5 corvette) ~$425+free shipping from many online venders (Jegs, Summit, Amazon, ect..)
I read that it might need some welding but is a direct replacement for stock... Also might be a good time to add a X-pipe.


MagnaFlow 15479 C5 Corvette 1997-04 Cat-Less Performance H-Pipe


C5 rear X-pipe: few venders offer as well.


Magnaflow Catless DP and Xpipe together look like this: (no welding)


Hope this helps..
S

 

I'm in the same situation... I do not have emission checks where I live plus I wouldn't mind a little louder exhaust so I have to decided to replace my stock cats and H pipe with an off road x pipe and no cats.

 

I wouldn't buy these. I did and they are a nightmare. First, they don't fit.
I had to cut the center strap. Second, the pipes are only 2.5 versus the 2.75 factory pipe. The result is that they are so restrictive, I had to have a tuner pull back timing to keep it from pinging. I'm going to put my factory ones back on a have new high-flow cats welding on - with 3 inch openings.

Shame on Magnaflow.

Jon

 

After my cats clogged and started to fall apart....





All better now.

Sounds way better too

 

For what it's worth,,, GM has a 80,000 emissions warrenty so,, check into new warranty cats.

I have a big cam in my ZO6 and run the Random high flow cats. They work excellent.

Bill

 

The federally mandated emissions warranty is 8 years or 80,000miles, whichever comes first. Does GM have their own?

 

What happens if you take them in on a modded mid pipe stock section on a car with a blower? lol

 

Hey,,, the dealership these days may just not know the difference...

 

That what I'm gona do to mine one day.

 

Small sledge and a metal bar does wonders.=)

True lol

I heard a story (I think on the forum) where a service tech didnt know the ZL1 camaro was a V8. Asked the customer is it the v6 or V8 model....

I'd trust him!!

 

This might be what I end up doing. Did you just crawl under and start hacking away?

 

Mine is a '99 with 97k. So I lose on both.

 

Since your system is all stock your best bet may be to have a local shop cut out the cats and weld pipes in place.

I have long tubes and previous owner had factory cat/H pipe section cut and modified to connect to the headers...yea

When my cat/h pipe section is unbolted I have closer access to the cats and simply put a crow bar and hammer and beat them out then turned pipe over and dumped out the mess.

The problem with the stock system is I dont see how you will be able to get anything inside the front to reach the cats to beat them apart.

Anyone else have to do this on a stock system?

 

Are you sure it is the cats? There was a service bulletin about a jingling noise and it has to do with the H pipe. My understanding is the hole in the H is pretty small and the exhaust gasses make a jingling sound.

 

I have heard of that issue as well. A co-worker who is an avid Corvette owner suggested that it was a cat-related issue. When I took it to an exhaust shop, they got under the car while I revved it up and felt that they isolated it to the cats. This just randomly started one day and is very annoying. It almost sounds like I'm dragging a piece of metal when I let off on the gas. As this point, I'm thinking of taking the cats off and replacing the H pipe with a Corsa X pipe while I'm cutting this apart.

 

This is exactly what im doing. Mine started doing that one day and i've decided im gonna cut the cats out and weld in pipe