# Thread: High Octane Fuel

1. ## High Octane Fuel

This week i will be taking out my ski with a buddy of mines who has a couple gallons of 110 octane unleaded & 118 octane leaded sitting in his garage. I was wondering if anyone have any feedback/suggestions on these higher octane fuel in the GP1300R 150psi? Thanks in advance

2. its a waste unless you have high compression

3. The way it was explained to me:

11 gallons of 93 octane gas + 1 gallon of 110 octane

11 gallons x 93 octane / gallon = 1023 octane + 110 octane = 1133 octane

1133 octane divided by 12 gallons (total) = 94.47 octane/gallon

It might have a little more zing at 94.5 octane and 150 psig, but more than a gallon in a full tank is a waste.

4. "octane" =/= power

Higher octane fuel has less energy per unit volume. Octane is a measure of a fuels ability to resist pre-ignition (detonation, ping, etc.). Higher octane fuel is less volatile. If you run 93 octane in something built for 87 octane, you will make less power.

5. Yup, no need in a 150psi single pipe ski. My triple pipe boat actually started gaining RPM when I started mixing less and less race fuel in it. I keep it at about 10% still, just for the safety factor.

6. Thanks for the feedback guys. I figure i asked since my buddy has couple gallons just laying around. But good to know its not needed. Im just going to stick to 91 Octane

7. Also, depending on what kind of "race gas" you're running, you may have to jet richer. Methanol and Ethanol have to be run much richer to achieve a stoichiometric air/fuel ratio. Just switching over to "race gas" that includes a high quantity of alcohol (methanol is typical in race fuel) may cause you to run leaner. But, alcohol burns cooler, too, so that might not cause a problem.