GUTTING OUT THE CAT!!!!

[cab83_750]

I strongly recall B. Anderson's comment about 'no gain' removing the catalytic converter.

Do you all agree on this?

Has anyone gutted out the cat and still pass the 'sniff' smog? Any HP gain?

I am 'earth' friendly. However, based on input read off this BBS, it sounds like we do not pollute that much anyway! Somebody even wrote about how the sound got better once internal collapse occurred.

How about you guys with SSI's, etc.? I think I can safely assume that the 'swap tango' dance is done every other year! Any input? Any ticket from 'surprise' smog cops? What was the $$? Leniency/warning ticket/fix-it, maybe?

Let me know so I can start using my air compressor/drill/disc, etc.

[Doug Zielke]

Unless you are *sure* your cat is non-functioning, spare the dear thing it's life. They are expensive. What you want to do is put on a test-pipe, saving the cat for future inspections by the smog police.
If you remove the cat, and it rattles when you shake it, and/or material falls out, then yours is probably NFG.

As far as power gains....
If your cat was melted down inside like mine was, yes. And if you combine a test-pipe with a free-flowing muffler, you might find upwards of 10 hp. You may also notice a broader spread of torque than offered by the stock system.

You would gain more power from a set of SSI's, but then you cannot easily revert to the cat for smog testing. That is the main reason I did not use SSI's on my car.

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Doug
'81 SC Coupe (aka: "Blue Bomber")
Canada West Region PCA
members.home.net/zielke/911SC.htm

[This message has been edited by Doug Zielke (edited 06-09-2001).]

[Wayne 962]

A new, free-flowing cat doesn't generate too much resistance at all. It's when they get clogged that they degrade performance. The 911 Cat is also a good design. I would tend to agree with Bruce that there is little gain to be had from removing the CAT.

Don't forget that the engine is also tuned and designed to be used with it's original exhaust. Changing backpressure, etc. can sometimes actually hurt performance...

-Wayne

[Superman]

Funny you should ask. Two weeks ago my 3 year old CAT began rattling. I asked some questions and then removed it. The looseness was near the curved pipes so I know there was no hope of salvage or repair. As it turns out, it is easy for SCs to meet emissions tests without a functioning CAT.

So I (ahem) ported the CAT. for track use only, of course. Anyway, I can report much cooler sound. Interestingly, every improvement I make to the car increases its performance and horsepower. Washing it, for example. Washing seems to add about 6-7 horsepower. Hard to say exactly without scientific instruments.

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'83 SC