RJKK

I'm running the Fabspeed x-pipe with sport cats and am thinking about swapping out the cats with the by-pass pipes for an upcoming track weekend to try them out. For those that run the by-pass pipes instead of CATS, what have you done with the outer O2 sensor? Leave the plug in the pipe and zip tie the sensor out of the way, or install the sensor in the pipe? Since it's a track session not too concerned with throwing a CEL.

Thanks!

Jarg1

Another option is to temporarily remove the sensors.

RJKK

That's the direction I went. Left the O2 sensors in the Cats and just ran the by-pass pipes with the plugs in. Took a short test drive and no CEL.....yet. Will be interesting to see how long it takes to throw one.

The by-pass pipes with SuperCups is very loud. Good thing the tracks here don't have db restrictions.

ECU Doctors

For off-road purposes, you can program the ECU to work without these O2 sensors in the mapping.

You won't get a CEL either.

It's like a ROW conversion to the ECU and gives you better performance.

k722070

how do the after cat o2 sensors affect the mapping so that if you program them out you get better performance?

ECU Doctors

The ECU can inject more fuel without having the rear O2 sensors influence/stop whether the car needs more/less fuel in order to achieve a certain clean/emission mix.

Hence why this is only for off-road and track purposes.

k722070

thanks, that is interesting.
I thought the 2nd set of o2 sensors only checked catalytic efficiency and did not make any adjustments.
just sent a cel light when the cats didn't work.

Quadcammer

That makes basically no sense

ECU Doctors

Quadcammer,

Why do you say that?

I open to hear to what you have to say.