Fuel Finder

Mixing Fuels and Calculating Octane

We often get these two questions:

  1. Can I mix fuels?
  2. What is the octane when I mix them?

The answer to #1 is easy. Yes, you can mix any of our race fuels. But remember – if your engine needs an unleaded fuel, you don’t want to mix leaded with unleaded. Doing so would make a leaded fuel which could still damage oxygen sensors and catalytic converters.

The answer to #2 requires a little math.

First you need to calculate the percentage of each fuel that will be in the final mixture. Then, use this equation to find your octane:

( [ % Fuel A ] x [ Octane of Fuel A ] ) + ( [ % Fuel B ] x [ Octane of Fuel B ] ) = Octane of Mixture

Here’s an example. Let’s say you mix 3 gallons of 110 with 2 gallons of 100 and you want to know the octane of the resulting 5 gallon mixture.

The percentage of 110 in the mix is 3/5 = 0.60 (60%).

The percentage of the 100 octane fuel in the mix is 2/5 = 0.40 ( 40%).

Plugging the information into the equation:

(0.60 x 110) + (0.40 x 100) = 66 + 40 = 106

So the octane of the resulting mixture is 106.

You can also determine the oxygen content of the mixture the same way – just use the oxygen content information we provide in place of the octane numbers.

See, that wasn’t so bad, was it? After all, it’s just math. And if you have any other questions about race fuels, don’t hesitate to contact us or call 800-RACEGAS.