HI Jan K-- We americans are spoiled with nitro cost/availability here in the states!!! I have noticed that a lot of european motor manufacturers recommend 5-10% nitro. It is my belief that if they recommended 20-25% nitro they wouldn't sell motors because of the prohibitive cost of fuel over there.

Anyway I digress--I run 20/20 because I have various engines to feed --OS 46,61,91,1.08 and three mokis. If my understanding is correct the higher the nitro content,the lower the heat of combustion. If indeed preignition is my problem, my line of thinking follows that more nitro=less heat=less preignition...

My Moki documentation says 10% nitro max and no all- synthetic fuels-- I tried it on Byron's 10% and it ran ok-- I popped in a OS #8 glowplug, 20/20 fuel and those engines KICK ASS!! That kind of demonstrated for me the power of NITRO!!! If indeed Moki's concerns are justified and their bearings go away, I am prepaired to put Boca ceramics in them and fly on !!