Symptoms of a bad cat on an e30?

[Stanley Rockefeller]

I had my chutch and slave cyl. replaced recently. Car works better than it ever has in the past 7 years I've owned it!

Ever since I picked up the car from the shop, the exhaust sounds noisier than before. The cat on this car is so old that the heat shield on it is starting to rust away. The resut of the exhaust is fine as the PO replaced the muffler with an OEM one at one point.

Also, ever since replacing the clutch, the check engine light is on.

The last cars I've had that had the Cats fail, the following occured:
1) the performance went to shit!- not the case on my e30 as it has no problem with accelerating or idling correctly.
2) the added exhaust noise

any thoughts?

[troman]

If they dropped the exhaust at all to do the installation, they may have left the nuts a little loose that connect the exhaust to the exhaust manifold. That could add some noise, and maybe disrupt the O2 sensor in a way that would throw a code? (not sure about the last part)

[Danny]

I'll sell you a catalytic converter.

[lolcantturn]

Run just headers. problem solved.

[Danny]

Run just headers. problem solved.

Explain to me how this would remedy the situation.

[e30huh]

gut that shit

[lolcantturn]

Explain to me how this would remedy the situation.

It wouldn't.

[Danny]

It wouldn't.

Don't post bullshit in the technical forums.

[nando]

gut that shit

gutted cats are a far bigger flow hinderance than a properly working one.

there's no reason not to run a cat on a street car, either..

but generally a clogged cat will get really hot and make the engine totally gutless. E30 cats are pretty bulletproof, usually the insides don't fail, but the case eventually gets a hole in it and then it rusts from the inside out.