I don’t check percentages. I don’t really care. I tuned for what I think is the highest percentage of ethanol, 85%. If it ends up with more gasoline, then i end up with a more rich air fuel ratio and no damage is done. I don’t run on a razors edge of detonation where a slight mistake in calculations or a fuel control error would become catastrophic. I’m not going for a win in races.
I do have fuel maps that I can easily upload if I feel the fueling is too rich, too lean and it’ll change the entire spectrum 1 % at a time.
