Cat removal OR not on a 83' SC

[911 tweaks]

I have a client that is considering for me to remove his catalytic converter from his ALL original 1983 911 SC car...

A couple of q's come to mind:

1. we all know about the weak oe metal used as valve guides...so...how long can an original engine last in the original configuration w/ working a/c and the cat remaining on the engine...?? car has about 120k miles on it and never been opened up or had any internal repairs as far as we know & it runs great now... (this kind of has us feeling that we maybe should not fix something that is not broken kind of thinking...)

2. if cat removed, would you recommend to go with just using a cat bypass pipe or pull the oe h/e's & install ssi's & which muffler...?? I ask this question from a car's value stand point...= the guy is not planning on showing the car, but, I would like to hear from you all what is recommended...(I do understand that the ssi/sport 2in/1out muffler is better for the engine & some consider this a value adder to the car & help to the engine, but, do the purist frown on changing out the oe exhaust as the car will not be original there after...??)

Thx, Bob

[OldTee]

Pitch the cat, or gut it. Probably not doing anything anyway. I put cat-by passes on all my cars. For a 83 you need one with a O2 bung. At that age you will most likely have to cut off the bolts. All new gaskets.

[911 tweaks]

Thx OT...I forgot about breaking out the ceramic center = great idea...your idea is the least $$ :-)
I guess I can explain it this way as your idea being the least $$ and tell the guy everything else will cost more $$ and be further away from oe looking = ssi or ssi/sport muffler will breath easier allowing a few more HP at the cost of $1500 +...
Thank you...
Bob

[millhaus]

Cut the cat!

[shrtshck]

Knock the guts out of the cat and put the shell back on, will retain the stock look but gain a little hp through less back pressure.
It is a messy job and the ceramic is pretty tough, I used a long screw driver and hammer to break it up.

[hcoles]

I think I'm missing something. Why gut the cat? If the cat works save it for the next owner who might live in a state that requires a cat during inspection. Install a good quality bypass pipe. People have been known to wrap the pipe to keep heat off the tire and nearby parts. I think the cat has a heat shield in stock setup.

[ben parrish]

Leave the cat...just put mine back on after years without it and I couldn't be happier. The exhaust really smelled bad to me with the cat off; seems to be worse with fuel/etheanol. I can't tell any differance in power with the cat back on.

[911 tweaks]

Thx guys for all of your inputs...looks like we have a full spectrum of possible answers as your suggestions...I guess there is no clear cut majority choice in this area for the 911's w/ a cat...

My biggest & main concern is the heat that the cats generate...maybe I will install one of those heat shield products...has anyone used one and what do you think of it...??

[enzo1]

Heat Sheet?

[304065]

Remove the entire original exhaust system, clean it to perfection and store it in cosmoline.

Replace with SSI and sport muffler.

[LakeCleElum]

I have a By-pass pipe I would sell.....Has the O2 bung.