Quote:
Originally Posted by Old Mechanic
Then what does?
regards
Mech
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Nothing by itself, you can have an inefficient motor running on an energy dense fuel compared to an efficient motor running on a low density fuel and have the answer end up moot or even in favor of the lense dense fuel. You can even run the same motor on different fuels and due to complex engine management and odd behaviors of the fuel mix itself end up with the same fuel economy or better than expected comparitively.
There were peer reviewed papers on this subject of how ethanol blends commonly get better than expected fuel economy due to vapor pressure phantoms AKA the mix did not have the expected volitility.
There are also situations like comparing my fathers 1985 Yugo to my 010 cobalt. My cobalt is over 1000's heavier, has double the motor runs on e10 and get 15mpg better than the Yugo did on the real gas available in the late 80's and early 90's.
I would also estimate if his yugo was on the road (its in the garage with a frozen brake and rotten hoses) it would get this 20% worse economy on e10, yet my cobalt gets better on 89 octane e10 than it does on 87 octane e5ish.
All antidotal in this case but a million monkeys can't all be wrong.