I know NBO2's are unreliable, BUT WTF
05-30-2006, 11:00 AM
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I know NBO2's are unreliable, BUT WTF From a dig, I floor it...AFR is 11.5:1 and the NB's are at 940 and 950. By 100MPH my WB is at 11.01:1 (testing meth/water injection, expected rich scenario) and my NB's are at 890 and 870.
With me going about .5 richer on the WB shouldn't I "ASSUME" the NB's would go richer as well. Or are they just that unreliable.
My WB is located in my Y-Pipe(So I should be reading a combined Bank 1 & 2 stream). My CATS are gutted.
With me going about .5 richer on the WB shouldn't I "ASSUME" the NB's would go richer as well. Or are they just that unreliable.
My WB is located in my Y-Pipe(So I should be reading a combined Bank 1 & 2 stream). My CATS are gutted.
05-30-2006, 11:08 AM
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The thing that makes them unreliable is, the output
voltage moves more with temperature than mixture
when you are up on the rich region flat-top. So you
start to cook and the output goes down. You would
need a close-coupled EGT probe to have any hope of
mapping the output voltage to AFR. And in fact that
is kind of how the WBO2s work, they -control- the
sense element temperature so they can get a stable
voltage vs AFR output.
voltage moves more with temperature than mixture
when you are up on the rich region flat-top. So you
start to cook and the output goes down. You would
need a close-coupled EGT probe to have any hope of
mapping the output voltage to AFR. And in fact that
is kind of how the WBO2s work, they -control- the
sense element temperature so they can get a stable
voltage vs AFR output.
05-30-2006, 11:10 AM
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If you look at the signal curve for the NB, the answer will be obvious. I don't have a diagram handy or I'd post it. Basically, the signal is very accurate at stoich (14.7) or .457 volts. Outside of this value, the signal is definately not linear. 
05-30-2006, 11:49 AM
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Ahhhh. I do have an egt sensor. This all makes sense. Thanx! I guess I was just worried to see such a drop in the NB's, .060 and .070 seemed like alot.
