Ah smart!! Thanks
Because I run lean, more O2 will be in the mixture (both pre/post-cat) and thus also the post-cat will also be lean (0V). So then I need to return 1V always if I'm in lean-burn for post-cat converter (can be narrow-band), to tell the ECU all O2 is bound (e.g. N2O). Nice idea.
I'll change it then to a full AFR map, including all values to have more control (including WOT). Ignition timing is not possible for me now I do not want to mess with ECU yet..
Do you perhaps have a guess-timate how much % fuel only the AFR map would save, and separately how much the ignition timing would ? Makes it easier for me where to put the priority on. Thanks!!