Cooler combustion temp at all levels stoich or other (around 200*F cooler) and it also has a higher volume of gaseous expansion and a quicker flame front. I ran mine right at .81-.82 lambda I think it was at peak power...equates to 12.0 on the wideband. (Yes I leave it in gasoline mode and just look at the gasoline AFR I want to hit...easier for me in that manner). That is on my summer tune. That way if it richens up if a station goes to a different blend, I am ok and it is not STUPID rich, just a bit more and I can switch to winter blend tune.