This is all nice and good... but it has REALLY strayed from the OP.
The question here is simple. For TUNING, can a NB sensor be used on its edge to help try to determine what AFR is happening right that second. Nothing more, nothing less. All this talk of running closed loop, etc has NOTHING to do with the OP. It has EVERYTHING to do with the construction of the sensor.
You guys have moved this way ass away from the OP and are now talking tuning, etc. I do NOT care if you sporty has crap for brains, Andy. It runs HALF what a BT runs in the ECM. That is NOT the question.
The question is... how close to a volt can we get in a Nernst cell and have it hold semi stable. Doesn't have to hold TRUE, just semi. The reason I say that is the ECM will work with an average. We SEE that average out of the ECM using Data tools. So, at .975 or whatever volts... can we trust the AVERAGE reporting of that nernst cell? I think that we can do so. Then the ECM reports that as a voltage, with an offset. No biggie there at all.
If we tune to that voltage, this should work OK. The biggest thing would be to TEACH members how to move a fuel line around for consistency.... consistency of an AVERAGE, at that!
Andy, you do have a tendency to move an OP off topic. Not downing you dude, I'm LOVING you! But... we all DO know each other somewhat.
So... the question is simply this: we all TRUST wide bands. We tune with Wide Bands and accept the results from doing so. Do NOT argue anything outside of that trust, Andy. This will be part of our Hypothesis. It is a GIVEN for this discussion. One can't argue the givens.
So, since we all trust our wide bands... can we also trust our Narrow bands to do a similar task? THAT, my friends is the ONLY question that was asked in the OP. All other things are a GIVEN (whether they are or not) and NOT arguable.
I know that the Wide bands and NBs use the exact same Nernst cell construction. Go look at the Bosch site. Those cells are identical. Wide bands ADD a pump into the sensor. This pump allows faster reference air and makes the sensor able to read a wider swing of AFR, and... Bosch and NTK take that ability and change the inherent output of the Nernst cell. Instead of 0-1 volt... its like 0-5 volts. ANd... there will be NO damn arguing about that 0-5, as far as can it truly read out there, etc, because 0-5 is a STANDARD in the analog industry and Bosh, etc adopted it. It could be a fact that if we over powered a WB, it COULD read further that 0-5... who knows? Do ANY of you? It just runs on a Standard set by industry.
It is MY understanding that the reference air pumping cell would 'clean out' exhaust gasses faster to allow the sensor to read variations, right?
Well, dammit, we are NOT trying to read TRUE variations, in this thread anyways. We are reading averages from an ECM. We are reading WHAT the ECM is seeing, NOT what the sensor is seeing at all. This is analog crap, NOT digital. It has ranges and not just on/off or good/bad.
Everyone here, except for Andy, will agree that the WHOLE enchilada is about.... if the ECM is 'happy', then the bike will run decently. Some here need to get over themselves and quit thinking a frigging Harley Engine needs tuned to the NTH degree. That is the bullchit some tell customers, but here, with our members, this needs to stop. A damn Harley engine will run FINE, as long as the WOT fuel line is between say... 12.5 to 13.5 AFR. ANd... as long as we tighten that up a bit, just like we use WBs for... get it roughly from 13.0 to 13.5 AFR, it runs very nicely. Also, we are not talking huge variations, after all we will be attempting to make the sensor read the damn same, right? So... reference air pumps come into just a small portion, in this OP due to that fact. It is WOT TUNING... just that. WHat is the average voltage we see when trying to make the whole damn thing read the same voltage, right? Removing reference air quickly looses its main thrust, in life, when we are TRYING to drive the sensor into its happy, non movable, spot. (FWIW... I, myself, tend to make my fuel lines at 13.0 to 12.8. Most here will agree a bit more fuel for larger builds is simply a safety margin, but... with a DIY guy doing a Stage 2-4? 13.2 AFR is MORE than fine and sufficient).
So... can we use the MV output AVERAGES from the ECM to tune DIY style our bikes for WOT?
The answer is YES, we can. Will it be dead perfect? NO! But neither are WBS or 4 gas or anything else. Simple engine, to a point, and simple solutions wurk best. Dammit... it does NOT need perfection, what it needs is for a DIYer to understand and use the info, in the same way WE trust our wide bands (with all of THEIR inconsistencies).
Nothing is perfect and all we really need to do is come up with some tables and how-tos to HELP the DIY guys and NOT argue such fine points it doesn't matter. That crap is for OTHER threads.