Hi, I have a hollowed out cat in place, I put the sensor right after the cat. It has been working out very good. I am still tuning, it helps alot.Ray

 

The disadvantage of locating the wide-band sensor after the "Y" is that you don't know how each bank of the engine is running, and that's the way the PCM controls the fueling - by individual, independant banks. You could have one bank running rich, and one bank running lean, and you would never know it because the sensor is reading the combined exhaust of two banks.

 

Ok I see so Injuneer would you recommend putting a bung/plug in each collector then and this way you can log and tune with info from both sides?
I have a Innovate LC-1 btw don't know if this makes a difference.

 

I answered that above.