Why does it work so well?

Propane's 104 pump octane rating and low carbon and oil contamination characteristics can result in documented engine life of 2 to 3 times that of gasoline. This is one of the prime reasons for propane's popularity in delivery fleets, taxis, buses and industrial engines. Since the propane is a gas and not a liquid, it's said to burn cleaner while in the combustion chamber. There is virtually no residue, and the time between oil changes is much greater. The propane does burn hotter than gasoline, so the oil will be become more viscous over the course of time. Intervals on the oil change is every 15,000 km as opposed to every 5,000 to 8,000 km