Converting to LP gas?

You have to price the LP in your area against the cost of gasoline. Then you have to see what the energy quotient is -- will you still get 20mpg, or will it be better or worse? If worse and it costs less, then you want to look at the cost per mile -- divide the price for a gallon by the mpg. If better and costs less, then it's starting to look good. If worse and costs more, then your question is answered.

My instinct is that while the city that burns through hundreds of thousands of gallons of gas per year, making the change to LP makes sense. But you will find that you cannot drive the car long enough to recover the cost of conversion. Then, along with your inability to recover the cost of conversion, you have to find LP gas when it might not be convenient to look, and when you need it, it might not be convenient to find. So, not only do you have overhead costs associated with the conversion, you have acquisition issues every few days. Personally, I think it is looking bad.

We all know where they sell LP in our neighborhood, but we are not always in our neighborhood when we want to get more gas. The place that fills BBQ bottles might or might not be able to deal with the fittings in an automobile, and fewer and fewer places fill BBQ tanks anymore because Home Depot, Lowes, the corner gas station, all keep a storage bin full of bottles on hand, and you simply drop one off and grab another one and drag it home and hook it up to the BBQ. Certainly the tank for a BBQ is not the tank that they will put into your car.

Only if you don't have to pay for the conversion. LP requires special tanks, engines valves and some other internal and external parts. It is expensive to convert from gasoline to LP.

Jeff

While I LOVE Propane as a motor fuel it is not financially viable to convert a vehicle, especially an EFI one. A carbureted one could be done easily, but not EFI, and here is why:

Propane does not require much of any cold engine mixture enrichment because it vaporizes at such a low temperature What little it does need is taken care of by the vaporizer being heated by the engine coolant, as the engine warms up the warmer vapor becomes less dense. For an EFI car unless it has a cold start injector you would either have to reprogram the ECU or for dual fuel run a piggyback module.

You have to use dual fuel unless your tank has separate vapor and liquid taps as you can't start on liquid propane with a cold vaporizer, you must either start on gasoline or propane vapor with the engine cold, if single fuel you must also remember to switch back to vapor a few miles from home to clear the lines of any residual liquid.

All of this assumes a vaporizer/converter and mixer. Vapor injection requires special injectors that can handle dry firing and liquid injection requires super high pressure injectors and lines as there is a pump in the tank that must keep the lines under the hood at a pressure high enough that the propane doesn't boil due to the heat.

For best performance you also need either forced induction like super or turbocharging or need to boost the engine's compression ratio.

Cars with

Once properly done it does work well, I use an old IH Farmall 450 LP tractor that has separate liquid and vapor valves with manual hand knobs. The LP version has more horsepower than the gasoline and diesel versions of the same tractor because it has a higher compression head and a cold intake manifold, the gasoline versions of old tractors have the intake and exhaust manifolds cast as a single piece so that the exhaust heat can help vaporize the gasoline, since the propane is already a vapor this isn't needed and so the manifolds are separate and a colder intake means a denser charge hence more power.