Ditto, Jon! I ran the maintenance shop for a sand & gravel company that ran a lot of their equipment on propane. The fuel conversion was a pretty primitive affair that used a liquid-to-vapor converter, and ran the vapor through a conventional carburetor housing. Displacing enough air to get sufficient fuel vapor through the venturi was responsible for the power loss.
Propane is 104 octane, so an engine can be boosted to 11.5:1 compression or higher, but that kills the dual-fuel capability. If someone could design a system to inject liquid propane at the intake port, a lot of the power loss could be avoided, but the cooling effect of -70 degree fuel evaporation would turn the intake manifold into a block of ice. Besides- - - -it's still a byproduct of petroleum refining, so where's the cost savings with $100.00+/barrel oil?
Jerry
