Interesting. Sorry to get too detailed.
E10 has 2% less energy than a standard gallon of petrol. Petrol is also mixed differently from summer to winter and the difference in energy per gallon is about 3% between them. If you want to get more miles per gallon fill up in the early morning and in cold weather. The fuel is denser so you get a very slightly more energy per gallon. Oh, and there is less ethanol in high octane fuel so more energy.
I still run my cars on higher octane fuel, and octane improver as well, for some!
Out of curiosity I did the sums. Health warning - I am careless according to teachers . Anyway, with today's temperature difference of 5 deg C and assuming a 50 litre fill up, you would get the equivalent of an extra 0.2375 litres of petrol ( in reality 180 grams) in return for getting up at 0600 hours. But thats forgetting that the tanks are buried in the ground where the temperature will barely vary at all.
Changing the subject a bit, the reason that drug trials are done on a double blind system is the human ability to discover the precise effects they expected to discover. I am sure its the same with the effects or non effects of different fuels. The views are subjective
