I believe my comparison is valid. I did have a flow meter to measure real time consumption. The meter also kept a cumulative total The comparison was done several times over hundreds of gallons of fuel. Results using the real time correlated with the tank fill ups against the cumulative total gallons consumed. For all these reasons, I am confident in the results. Of course, this is based on a 2003 engine. It does have a knock sensor, so presumably timing was advanced more with the E10 than E0, although I could not monitor this.
In the olden days, straight alcohol was used to increase power in race and dragsters before nitromethane became available along with engine modifications to use it. I have an ancient British textbook on competition engines indicating the carburetor jets must be increased considerably to use alcohol over gasoline.
This has been argued for as long as E10 has been available.
I have to disagree with your comparison............ Mainly BECAUSE your fuel flow differences are not valid. (I have one of those fuel flow meters too. they are not all that reliable) E10 will not produce huge differences in fuel flow in todays engines.
A 2% increase in fuel flow at 10 gallons per hour is 0.2 gallons! a 20% increase would result in a fuel burn of 12 gallons per hour. With ANY planing type boat powered by todays V-8 engines , it only takes a minute change in throttle position to increase the fuel flow by 2 gal/hr AND the corresponding change in speed is barely measurable!
All you would have to do is change the load (weight) and drive angle and you wouldn't get a speed increase at all.
Ethanol free fuel is available here in Wa for slightly more cost...........
If the above were true we would ALL be getting similar results. And we're not.....I have tried the same comparison and didn't see significant differences at all............. A 2% difference in energy content doesn't produce a 20% energy output difference (and corresponding throttle position increase) in any spark ignited engine. AND if you do have a knock sensor, it would likely advance (or allow advance) where it would normally retard a bit. That would also 'make-up" for a slight loss due to knock detection.
Your anecdotal "test' is not really valid because you simply cannot reproduce the same engine load every time you run the boat.
There's only one way to do it, and that's put the engine on a dyno so you can measure the torque and RPM accurately along with the fuel flow (using an accurate meter) Only then could someone produce repeatable results. and no test has shown a 20% increase using E10.
With all the political "stuff" aside of why we're being forced to "swallow" this fuel (pun intended).............The differences are not really enough to worry about. Many of us have 20+ years of experience of running it with no real problems at all. I don't even use snake oil in the fuel when I store the boat..........
Regards,
Rick