| > Somewhere I read that the commercial fuel quoted percentages are by weight
| > rather than by volume. I don't know how big the difference is.
| Volume changes with temperature. Weight does not.
Of course, and I imagine that Marlowe knows that.
It's more likely that alcohol, nitromethane and oil (whatever sort)
have different densities, and a difference would come from that. If
the densities differ signifigantly, then the difference between `20%
by volume' and `20% by weight' WILL become signifigant.
Of course, I can look all this up ...
nitromethane, 1.138 g/cm^3
methane, 0.792 g/cm^3
castor oil, I can't look up, but it's probably less than 1 g/cm^3
So, it looks like it does make a signifigant difference, though when
you're just adding oil to your fuel, you're probably just eyeballing
it anyways and a 20% error probably isn't signifigant.
As for changing with temperature, all of the components of your fuel
are likely to change volumes similarly (not exactly, but similarly)
with temperature, so the percentages by volume probably won't change
signifigantly even with large changes in temperature.
Doug McLaren, firstname.lastname@example.org
"Don't tell me I'm burning the candle at both ends -- tell me where to
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