Will gutted cats effect O2 sensors? '93 corvette

[jay72]

I have a '93 corvette, when I bought it one cat was broken up and in the muffler. So I just hollowed out the other cat.
Problem is it has, what I would consier, weird O2 sensor readings. The O2's are less than 12" away from the center of the cat, and the cat is one hollow chamber that it seems wouldn't hold a hot exhaust as well as a pipe.

It also has shorty headers because I couldn't find any stock manifolds that were not cracked.
The O2's read from the 900's to zero, fairly fast. The sweep shouldn't be that wide should it?

Anyone think getting rid of a hollow can approx 6-7" in diameter and 8" long and converting to heated O2's will help?

[RobertISaar]

O2 signal sounds fine. that's how a narrowband sensor acts.

as for the hollowed cats, the exhaust wave slows down when it encounters a pipe with a larger cross-section than the area it was just in. when it transitions back to the smaller pipe after the cat, it speeds up again, so you may have a weird resonance happen at a seemingly random RPM.

[jay72]

Ok, thanks, I'll leave that stuff as is (for now).
FWIW I'm using your $DA3-16159278-V2.1 ADX, best one I've found for TunerPro.

[RobertISaar]

that title sounds like someone else worked on it after I pushed out the complete, basic version of it. if it works, it works.

[billygraves]

...........

[jay72]

How does it run not looking @ the O2 readings? If you look at anything, where are the Block Learn and integrator along with knock signal? Meaning lean with spark knock.
It's your engine. I've hollowed out cats and had no errors.....

It ran ok.
I just changed the cam (only) and got a mail order tune for the cam change.
The BLM's seem normal, theres no spark knock. I just want to make sure everything is good so I can send an accurate log file to the tuner so he can make changes if needed.


I have done some tuning on LS1 engines and the 02 readings seem to have a tighter swing (IIRC) This LT1's O2's definatly hit zero and 900. If thats normal I'll make a log file and send it, maybe later I'll get rid of the cats and convert the O2's.