I would appreciate if someone more knowledgeable would let me know if my understanding of ethanol fuels related to tuning is correct or not.
The tuner that I am working with says that his tune file is safe to run on mixtures between E30-E40. The rest of what is said in this post is from me and me alone.
The more ethanol content in the fuel that one uses, then the greater the volume of fuel that is required to create energy. This is in part due to the greater evaporation rate of ethanol fuels.
Once past E40, stock fuel systems (pumps, injectors, fuel rails) might not be able to support the increased fueling demands that higher content ethanol fuel requires.
A tune that will run on E30-E40 will not give greater power output just because E40 is utilized over E30, but fuel efficiency might suffer if E40 is utilized on a tune that would work just as well on E30.
Although fuel efficiency might suffer when utilizing E40 on a E30 optimized tune, the higher content ethanol fuel will help to cool the intake charge and overall engine performance BETTER, and due to the greater evaporation rate of the higher content ethanol fuel. Perhaps run E40 on track days to have a better cooling effect?
In short, there is no need to run higher than E30 on a tune file that can operate in the range of E30 to E40. Am I mostly correct with my assumptions, or off base? Trying to understand how ethanol and the various mixtures of ethanol play together when tuning.