removing or gutting cat

[RT22]

anyone done it and will it cause error codes? 1991 EXT Cab D21, any chance of it throwing ecu codes if I gut or remove and replace with straight pipe?

[seang]

I'm pretty sure your truck won't throw any codes, RT. Especially if there isn't a second o2 sensor behind the cat. I'm guessing there isn't since your truck is an obd1.

Another thing. I have no scientific proof of this, but I'm guessing that straightpipe > hollowed out cat because of turbulence(?). You could even cut your cat, place a straightpipe inside of it, and weld the housing back together on top of the new pipe if you really wanted to be tenacious.

[C-Kwik]

Another thing. I have no scientific proof of this, but I'm guessing that straightpipe > hollowed out cat because of turbulence(?). You could even cut your cat, place a straightpipe inside of it, and weld the housing back together on top of the new pipe if you really wanted to be tenacious.

I agree. But you don't necessarily need to cut your cat open. You can use a pipe that fits inside and just have the ends welded.

[RT22]

My cat is bolted on both ends so I can have a pipe welded to 2 flanges and just unbolt and rebolt, but thanks for the info.