I am not saying that running a higher octane fuel in a car engineered for regular octane will give you better fuel milage. Fuel economy is determined by a number of variables, including the energy content of the fuel and the condition of your vehicle, neither one of which have anything to do with the octane level of the fuel. Two fuels of identical octane could have different energy content due to a difference in composition and therefore can give you different results.
I do know that for whatever reason in a couple of cars I have owned, in particular a 93 probe gt (which required reg fuel) 'seemed' to run better on the higher octane.
In the z, I adjust the timing with a switch (MSD) when a higher octane isn't available (it is built to run on 94). Retarded timing equals less power, and less available power equals more pedal....
Also the lower the octane number, the more explosive power it has. High-octane fuels burn slower, so a cooler burn. Cooler burning fuels mean less pinging and fewer emissions.
Using high-octane fuel in a vehicle that doesn't need it is just a waste of money....that's the bottom line.
