On Apr 19, 4:10 pm, pittss1c wrote:


I believe changing from 7:1 to 8.5:1 gives you 10 HP
I would hope for something like a 15 to 25 hp improvement over the 7:1.- Hide quoted text -

- Show quoted text -

Detonation will be the biggest limiting factor. At 10:1
100LL or even straight 100 probably won't cut it. There used to be a
115/145 fuel (purple) for the old high-output engines used in piston-
pounder airliners and so on. Dunno if it's available anymore, but the
guys who use old airliners for firebombing might know.
If you get detonation in an O-320, that engine won't last long at
all. You'll either burn holes in the pistons or blow the heads off the
cylinders. Cylinder bases have also been noted to pull right off the
case.

Dan