Octane Boosters

[neville]

For my 912iS I mix 4 gal 92 mogas with 1 gal 100LL. The local Rotax shop
recommended this with the comment that Rotax engines like a little 100LL.
The mix is well below the operators manual point for requiring Decalin and more frequent oil changes.

[Paul Z]

For my 912iS I mix 4 gal 92 mogas with 1 gal 100LL. The local Rotax shop
recommended this with the comment that Rotax engines like a little 100LL.
The mix is well below the operators manual point for requiring Decalin and more frequent oil changes.

That should be 90.4 octane, I like the idea of changing oil less than every 25 hours.

[Av8r_Sed]

I worked the bulk of my career for a refining technology company. I've worked on online octane analyzers and on a team dedicated to octane analysis for refinery blending operations. I can assure you that octane number cannot be predicted accurately as a linear function of two components.

The good news is that the ratios being discussed of 88 unleaded to 100LL will most likely result in a higher octane boost than the average calculations would indicate. Anyone following this advise should be good to go. They just won't know their exact octane number.