Thanks Bill ~

A gutted cat paired with stock mufflers seems to meet my needs.
Roto-rootering the cat start's now!

 

TA12 ~ you might just have a piont. The cat was removed today and its h-e-a-v-y.

 

With OBD2 you'll probably get a check engine light for cat efficiency bad, or something like that. It checks the readings of the upstream and downstream O2 sensors to see if the cat is working. I assume people have figured out a way around this if they are using bypass pipes.

 

Yes, as you mention the four 02 sensors are in a classic input / output comparitor curcuit arrangement. My thoughts exactly as to "how to over ride" the check engine light. Oops. Maybe I should put this cat back on so-to-speak.

 

What model year 993 are you refering to? If the vehicle is ODB II equipped was there an issue with the O2 sensors and the use of a bypass pipe?

 

The Cat Bypass pipes....your CEL will go on sooner or later. Fabspeed Cat By Pass an Robin Sun's mufflers, great sound...well over 95 db. I had them, I know this

Fabspeed Super Cups with stock cats provide a great sound and are smog legal...you will be deaf after a while, but you will enjoy the sounds in the process of losing your hearing. I had these too

I am now back to my stock cats and RSR mufflers. They sound great outside the car, very mellow inside the car.

I suspect that a great "fix" may be the DACH sport cats and mufflers. I don't have these but would love to have them.

However if it all comes down to $, then I suppose a gutted cat would be OK...it will be a problem when it is time to sell the car, at least in Cali where the car must pass a smog test.

 

As someone who is getting the DACH sport cats, let me caution you against gutting your stock cats. There's one problem not yet discussed.

Your car will stink. Everyone will think there's something wrong with your car. Your friends will tell you to get a tune-up. Your wife and/or girlfriend will not ride with you. Eventually you'll get sick of it, too.

Add that to fact that you won't be able to sell the car to people in most states, you'll get a CEL, a stock cat is worth money (just go and try to buy one), you won't be "green" . And you never know what your own state legislature is going to do next year or the next. You may need that cat!

Although almost never done due to cost, I am a fan of using cats in place of mufflers on vintage cars that don't require cats or never had them.

 

Thanks Bruce and others ~ I've jettison the gut the cat notion. What a bitch as the exhaust system is now in pieces. New exhaust hdwr. is on its way from Suncoast. Oh well.