My experience suggests that the volitility of 100LL is not always less then
mogas.

I have seen 100LL 'fizz' like champagne in a drain test container when mogas
from an airplane parked next to mine showed no volitility at all. This as
at Albuquerque on a 100+ degree afternoon. He departed with no problems.
My fizzing 100LL scared me enough that I stayed overnight and left in the
early morning with cool fuel.

Bill Daniels


"Kyle Boatright" wrote in message
. ..
My understanding is that 100LL has a relatively low volatility to reduce
the chance of vapor lock. Whereas Mogas often has a higher volatility.

With this in mind, what happens to the volatility if I mix 50% 100LL with
50% Mogas? Is the volatility of the mix the straight average of the two
fuels, or is the net volatility higher than the straight average?

Why do I ask? I'm considering running a "mix" in the RV-6 to save a few
bucks. The FBO at my home field charges about $2.00/gallon more for 100ll
than the nearby station charges for 93 octane, so a couple of 5 gallon
tanks worth of fuel will save me $20 bucks.