A guy I work with has a Chevy truck, mid 2000's year. He has shorty headers with exhaust that dumps in front of the rear tires. He also has NO cats. He just passed emissions here in Illinois. He said his guy that tunes has the o2's off, but set it so the monitor says they're "ok". He just went through emissions, and sure enough has no cats. Has anyone heard of this, or know a tuner that has done this. He said its basically a setting that tells the computer that they plug into the vehicle, that all monitors are ok. Kind of got me curious before I spend the coin on headers with cats.....

 

Spend the coin on the cats please, here are 2 reasons:

1. Cuts back on the amount of fuel smell you get from running a richer tune.

2. Cuts down on the raspiness of the exhaust.

From personal experience, here in GA, I tried getting my emissions with the rear o2's turned off and I couldn't. The monitors for the o2's were in a "not ready status".

I finally had to double-stack non-foulers on each side and screw my o2's into them to be able to get it to pass with the monitors on.

 

Tell you friend to ask on a proper Chevy forum, lol!
J/k. It's all solvable.

Not uncommon to turn-off rear o2 sensors. Depends on local inspection criteria.

 

I've heard that there are emission-friendly tunes but I'd call AM or Brenspeed and see what they say.

 

Yea Nuke, that's what I was thinking.

Raspiness of the tone was another thing I was worried about with no cats. According to him, his tuner told him he was able to set it so the monitors said "Ready" for the o2's. It all sounded kinda strange, but he did pass, and he definitely doesn't have cats. I think I'll stick with cats......

 

No real reason not to have them. We beat on the environment enough. Do it this one lil favor.