Catalytic Converter

[davery]

Theoretically would the removal of the converter increase performance on a FI car? If so, could the same performance increase be achieved by removing the innards of a catalytic converter and reinstalling? Not that I would ever do such a thing........

[RRoller123]

Banging out the innards with a long rod has been suggested, but for track use, off road only, of course. Illegal for street use.

[klweimer]

Depending on how the cat was made, banging the guts out is a big PITA. I did it on mine, but would not do it again, I would buy a "test pipe" instead.
Kirk

[joelittel]

I think it was Midwest Bayless that used to sell the flanges used to make a test pipe. Fuel Injected spiders use the four bolt flange.

[davery]

Depending on how the cat was made, banging the guts out is a big PITA. I did it on mine, but would not do it again, I would buy a "test pipe" instead.
Kirk

Yes, but a test pipe would not pass a visual inspection (if one was inclined to do this).

[joelittel]

Ahhhhh the ol' visual inspection dilemma.

There is a post where someone described just how difficult it was to bang out the insides of their cat. It sounded like an all day affair.

[ORFORD2004]

You will pass a eye inspection but fail a smog test. Use test pipe and keep the converter just in case

[davery]

You will pass a eye inspection but fail a smog test. Use test pipe and keep the converter just in case

Well IF I was going to do this, I would probably try and find an inoperable converter. And we no longer have smog tests in Ohio.

[joelittel]

Could you cut a converter open to make clearing it out easier, then weld it back together again?

If it were me I'd swap between the two, but if you don't have smog testing in Ohio do you really need to worry about the visual test?

[RRoller123]

The "test pipe" and retaining the Cat seems to make the most sense. The pipe would give smoother flow through the exhaust system, and there is value in the Cat either for future regulatory use or in the precious metals inside it.

[Nanonevol]

And what about the OP's original question, "Would it increase performance?"

[RRoller123]

Well, we would have to hear from people who have done this.

[ORFORD2004]

When I remove mine, I put a test pipe that I made. It was too loud for me so I replace the test pipe with a resonator.

[RRoller123]

Did the Resonator provide improved performance over the CAT?

[joelittel]

I'd bet the test pipe would add to the performance of the car simply because the original cat is bound to be full of junk and somewhat restricting.