well for why?

what higher oct. does is inprove gas's ability to resist detonation. the higher the resistance to det. the hotter you can run..heat= power. the more heat the fuel can produce the more air you need for the combustion =more boost.. the lower the oct level. the easier is detonates...combustion at a lower heat.

the highest oct. is 100. anything after that is a preformance point above 100 110 is 1.0 above. these fuels are for high compression high air volume engines.. you can tell what fuel you have by the color..100 115 is a blueish color...higher is a purple (race acft fuel)

doesnt it also burn more efficently?

not exactly..if you put it in a car like a hondah the don't have forced induction or some really high compression it will actually be bad for preformance. because the engine don't produce enough heat to burn all the fuel being injected into cylinder.

It would only add performance in a car that is meant to use it. If you put low octane in that car, the knock sensor will cause the ECU to retard timing and lose power.



Theoretically you should make more power with low octane fuel, as it will burn faster. Unless your high octane fuel is oxygenated, but that's cheating! https://www.nopistons.com/forums/pub...#>/biggrin.png

In a N/A rotary you'd want to run a lower octane fuel.

why? race gas is worth a couple of hp, in a pro/spec7 car

I think mike is just screwing with us. HE KNOWS!

higher octane = more power because you can make your combustion process more efficent.



Advancing your timming is one dynamic way of changing the amount of power/efficieny of an engine.



Static ways of increaseing are increasing compression ratios. The more you compress a gas, the more power it will give you when you expand it. However the more you compress the more it will heat up.



PV=nRT



To compress air + fuel you are heating the mixture. It is compressed 10:1 or greater at times, which increases the temperature dramatically over a very very short time. To prevent the fuel from being ignited before it is suppose to, octane (hydrocarbon chains with 8 branches) are added to normal gasoline inorder prevent teh air/fuel to ignite before the piston/rotor reaches Top Dead Centre. This also allows you to slow the progration of the flame in the combustion chamber.



By slowing down the flame you can ignite it earlier and have it travel through out the cylinder at the exact point where the piston reaches Top dead centre to increase the flow of intake and exhaust gases out of the engine.

is this for a carb'd car or fuel injection? if it is fuel injection i would say the computer is not detecting any knocking and is advancing the timming.



Else race fuel has a higher BTU value, so more energy is stored per mole of race fuel.



Did u know diesel has a btu value 3 times higher then gasoline?