Widebands after high flow cats? Shoot me straight.

[Mo-finkle]

I?ve seen tuners put widebands at the end of tailpipes for tuning and people shove them into stock cats or bango them next to o2s1 narrow bands. I?ve read mixed reviews where people say it?ll only change it by .1-.2 stoich lean going after cats in normal cruise and accel if that but will be accurate at WOT.. other people saying it?ll make everything be in accurate..

I really don?t have room to install it next to my narrowband on my long tube collectors and I really really don?t wanna remove the headers. My rear 02 sensors are just taking up space.

Shoot me straight, can a person really put a wideband after a dinky high flow cat and have correct readings?

[5FDP]

My opinion is that it's not going to make a huge difference with a high flow cat. The widebands we use aren't lab grade either but overall they work pretty darn good.

I run a wideband after my stock cat on my truck and for the medium to full throttle stuff is pretty darn close to when it's before the cat. So for me close enough is good enough for the stuff I do. I use the fuel trims to do other parts of the tune.

[HaasExp]

Shoot me straight, can a person really put a wideband after a dinky high flow cat and have correct readings?

Yes you can.
If anything they add to the safety margin as they will read a slightly leaner post cat than precat. For example: if you tune to lambda 0.85 with the WB after the cat, it would actually read maybe 0.84 if you moved your WB before the cat with the same tune.
Therefore, the actual lambda coming out of the heads will always be ever so slightly richer than what you are tuning to or "see" after the cats with your WB.
Note that this all assumes you do not has any exhaust leaks upstream of your WB sensor