I heard E85 has a much higher octane rating than gasoline 87, a few stations here sell E10 and its octane rating is 90. How can engines take advantage of this if it ran exclusively on E85? I wonder how high the octane rating will be? I had a friend who put E10 in his TSX and he said his engine did not knock, since it required premium fuel (octane 91).

Any attest to the science?

i got around 20 km a liter when i drove a civic 5 spd using advanced hypermiler techniques
and now I drive a salvage nwh20 prius that gets almost to 25 km/l with 195,000 km to date.