My OBD system was reading 0.84-0.86 volts at WOT in fourth gear at the time I checked it in January. When I went to the dyno with NO changes to the car, the wideband O2 sensor read 12.25:1 in the same gear and the same points. This means that for me, my O2 sensors are running 0.86 when I have an optimum AF ratio. I wouldn't expect the voltages to be the same on every car.
warmonger