LPG Automix (50% propane 50% butane) or 100% Propane

Some will have inadvertantly used it after filling up at a country servo.....if they dont sell much gas, they only have one LPG tank and it gets used for cars aswell.......LP gas is mixed with butane, which has less calories than lpg and burns hotter...so using LPG in a car will result in less heat and therefore more power....problem is, when you cant get it, the lp gas will be out of tune....and if you get a leanout, you will get a backfire....
Andrew

How much propane is actually in the gas that you buy called propane?
I think that you will find that it is actually not 100% propane. You can call it propane if it is 80% or more pure propane and it can vary between each tanker delivery. This can account for a better power output from different retailers. If you are in a town that can get very cold then the gas supplier will want as pure propane as they can get but in a warmer place they can get away with selling a lower grade mixture.

Robnicko

Have a read en.wikipedia.org/wiki/Propane