Thread: racing fuel

The gas station that I use near the field for mogas also sells "Racing Fuel" listed at 100 octane. It costs 6.75/g rather than 3.20/g for the supreme unleaded. Does anyone know if this is a good choice or offers any benefits for the Rotax 912? It seems a little pointless since the 91 octane works perfectly, but I was just curious.

All would depend as to what s in this fuel. Quite oftn you will find much higher percentages of ethanol and you know the issues with that.

It may just be 100LL. Unless you know what it is and whether or not Rotax approves it in writing, I'd not use it.

Originally Posted by BasinFlyer

The gas station that I use near the field for mogas also sells "Racing Fuel" listed at 100 octane. It costs 6.75/g rather than 3.20/g for the supreme unleaded. Does anyone know if this is a good choice or offers any benefits for the Rotax 912? It seems a little pointless since the 91 octane works perfectly, but I was just curious.

Not all racing fuels are ethanol free. Most pilot shops sell a simple ethanol fuel tester that you can use to test the fuel. I got mine from California Pilot Center at Long Beach, next to Rainbow Aviation. There are some companies that do sell an unleaded 100 octane racing fuel. The extra cost of the fuel does not seem justified when most 91 octane I have purchased tests at no more than 5% ethanol. Getting an unleaded aviation fuel without ethanol is difficult now, but a lot of work is being done to resolve it. We may have a solution by next year. In the mean time, I just test any mogas for ethanol content, and always add Decalin when using 100LL.