Higher octane = higher resistance to igniting. So I don't know how it could release more power per se.

 

octane is C8H18 and hexane is C6H14, so one mol of octane will combine with more oxygen to burn when compared to hexane, hence more kila-Joules of energy per mol. (btw I have a BS in chem)

 

Ah that hurt my head

 

fuel type MJ/L BTU/imp gal BTU/US gal RON
gasoline 29.01 125,000 104,000 87-98
LPG 22.16 95,475 79,500 110
diesel fuel oil 32.19 138,690 115,480 5-20
residential heating oil 34.74 149,690 124,640
ethanol 19.59 84,400 70,300 129
methanol 14.57 62,800 52,300 150
gasohol (10% ethanol + 90% gasoline) 28.06 120,900 100,700


http://en.wikipedia.org/wiki/Gasoline

Interesting that in my area they use gasohol which has less energy than the typical gasoline, that sucks. sorry the graph is messed up, align the numbers under the colums or check the web page.

 

but you were right about the octane # and the resistance to predetonation, I've read differently in my chem books before.

 

I get the big bottle because I put it in my tank and oil fill. It used to be lik4 bucks for that bottle and now its like 8, double the price in less than a year, I say whats up with that?