no state or local emissions here. remove cat during exhaust repair?

[vintagecarlover]

Heater boxes rusted out so I'm gonna be swapping out some parts. ssi or early h-e and better sounding muffler. Car is 3.0 in an SC and my big question is it good or bad to remove the cat and run a bypass pipe? Thx for any help. Also what's a cheap pipe worth?

[gamin]

That's what I did on the 3.2. M&K pre-muff with O2 sensor. Works great.

[darrin]

neither the ssis nor the early headers/heat exchangers have an interface for a cat, so you won't need to worry about a cat or a bypass pipe (or a european pre muffler) if you go that route.

[911SauCy]

Ditch the cat.

I did, car sounds great, runs great, and lost weight.

[daleflesburg]

Yes, Yes Yes and install Headers with a bung for the O2 sensor and a muffler. Mine are headers by George Narbel and Muffler by Triad. It has a deep throat, not raspy, and not too loud. Paint is by Jet Hot Coating.

[jasonlee]

i removed my cat and installed a bypass on my SC, have an O2 sensor for when when I need to tune to pass smog here in Vancouver. Runs great and sounds great

[718]

A 3.2 should be retuned (chipped). How do you do that with CIS?

[James Brown]

no chip in the CIS but the can be optimized with a engine exhaust analyzer for fuel/air settings, thats about all you can do. And ensure the cold start circuit pressures are correct

[Jack Stands]

You might want to read the chapter in Bruce Anderson's book (Porsche 911 Performance Handbook) for information on backdating to the SSI exchangers. It should give the most bang for the buck, and the heat exchangers are works of art.

[dyount]

^^^^^^^^^^^^^
Agree completely. Running SSI's w/no O2 sensor on my 83 and although a little quirky at times when it's run time it rocks!

[Jack Stands]

If they don't come with one, have an oxygen sensor bung welded in.