Fuel Question

Octane boosters only provide a low percentage of additional octane, regardless of the advertisements. For example, A 16-ounce bottle of 104+ Maximum Octane Boost to 20 gallons of 91-octane fuel will elevate octane levels to only 91.03 octane (give or take). Essentially, octane boosters are a waste of money.

We suggest you use 92 octane with 10% ethanol available. This is unless your aircraft fuel tanks are not compatible with ethanol. The Rotax 912ULS engine is allowed to operate with 10% ethanol-blended fuel.

Thank you.  Definitely answers the question.

One option is to mix with with 20% 100 LL should bring 89 up to 91+ 

Dagfinn Gangsaas wrote:

One option is to mix with with 20% 100 LL should bring 89 up to 91+ 

Yeah!  but adds lead, .

Right but better than straight 100 LL.  Maybe Rotax has some guidance on 20% 100 LL vs 10 % ethanol