A friend of mine had this question too on his mind, he told me that here in my country, Enya is not popular it is used mostly in europe or in cold countries, my city gets pretty hot in summer, scorching hot, Im not expert but my common sense tells me that atmospheric temperature does effect on your engine, but what if the ground temperature which is hot, and when plane goes higher like 2,000 feet or more, upper atmospheric temperature is much cooler, but engine still seems to run good? Irvine its british engine, its not popular here. Here in my city people prefer, TT, O.S. Magnum & ASP, magnum and ASP are my favorite. in 4 strokes they prefer O.S. and YS, not saito I wonder why but Im sure somebody would come up with better answer than mine.

Mody