wide band location

Can I mount the wide band 02 sensor after the cat in the rear 02 sensor location and will be accurate or do it need mounted befor the cat? Thanks

pre-cat

I have mine post-cat in factory 02 spot. I was told by Allen, that's he's tried all locations, pre/post/at tailpipe, and as long as it's not RIGHT at the exit, all the readings were the same (for all arguments sake)

Obviously, if you can easily put it pre-cat, go for it, otherwise, wouldn't sweat too much.

I've found multiple threads that say post cat is normally .3-.5 richer than pre-cat. I know mine read richer when I had it post cat, but I don't remember how much. It wasn't an insane amount.

it'll go pre cat when I finally get my headers on.... but don't tell me that


I'm reading 13.6 cruising and 12.6 WOT now....post cat. Maybe I'll just leave my fuel solenoid off and run a dry shot lol.

That wont do any good. The maf wont read it and it'll lean out like a mother.


I run 12.7 WOT and its dead on. I need to check my WOT on the bottle now though.

I hope allen would chime in on this.

i'm no expert at widebands or locations, all I can tell you is, my avalanche has about 5 o2 bungs, all the way up and down the exhaust, the wb reading reads pretty much the same in all locations.

Allen have any of the reading taken after the cat?

From "Designing and Tuning High-Performance Fuel Injection Systems" by Greg Banish:

In a section talking about locating the sensor away from pressure areas he says "Factory Catalysts can be another obstacle altogether....If the converters are the source of the restriction, it's best to either take pressure measurements for Lambda correction or measure WOT mixtures downstream of them and accept the signal latency."

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That suggests to me that there is a delay in the readings when located post-cat. Maybe not enough to be a problem, but seems like pre-cat is a better choice when you can use it.

Allen, interesting info there too.