Offline
Another Google search:
Or:
[3] Harwood, Richard; Coates, Christopher; Talbot, Christopher (2015-07-31). Chemistry for the IB Diploma. Hodder Education. ISBN9781471829222., https://en.wikipedia.org/wiki/Octane_ratingOctane ratings are not indicators of the energy content of fuels. (See Effects below and Heat of combustion). They are only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner.[SUP][3][/SUP] Where the octane number is raised by blending in ethanol, energy content per volume is reduced. Ethanol BTUs can be compared with gasoline BTUs in heat of combustion tables.
Or:
https://www.bellperformance.com/blog/bid/101182/What-Does-Octane-Do-In-Gasoline-Octane-RatingsSo, octane does not enhance the explosion in the cylinder like most people think. What does octane do? It just prevents the air-fuel mixture from igniting before the spark plug does it. Firing the air-fuel mixture at the proper time gives you the maximum power your engine was designed to get. Using higher-octane gasoline than your engine is designed to utilize is only wasting your money.