Gasoline has the same exact energy content regardless of the octane rating. Octane has nothing to do with the energy content of gas, it only relates to its resistent to burning upon compression. If you put in a higher grade than you car was designed for and requires, you will accomplish nothing. Next time you feel the need to put higher octane in your car than it needs, you might as well put the correct grade gas in and burn the extra dollar or two you saved in a fireplace. The end result will be the same.

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Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record