Propane vs. EFI: Which Is a Better Conversion?
Q I have a 1984 Toyota XtraCab 4x4 manual with a 22R four-cylinder in it. I have 5.29:1 gears, a spool in the rear, ARB Air Locker in the front, 39.5-inch IROKs and chrome-moly Birfield eliminator in the front; it also has a flatbed and 14-inch-travel Bilstein shocks.
I want to ditch the carb and go propane or fuel injection. It is 99-percent off-road driven. Which would be better to do? I live in Montana and I've heard elevation can affect the propane. Is that true? If propane is the better choice, who makes a good conversion kit for it? Will it make enough power to wheel comfortably?
A Elevation has the same effect on an engine being powered by either gasoline or propane. It's not so much the fuel, but the lack of oxygen. Compare hiking at sea level and at 6,000 feet. It's a lot more difficult due to the lack of oxygen.
Now, I know the next question is going to be about the cold.
Well, I also live in Montana, and most of the houses around me heat with propane. However, the lower the temperature, the less vapor pressure there is available to push the gas down the line. While I know little about propane as a motor fuel, I believe that the regulators used on a vehicle are designed to handle the proper amount of flow, no matter what the air temperature is.
There is a company called Got Propane in Tempe, Arizona, (www.gotpropane.com) that has propane kits designed for Toyotas like yours. They claim no loss of power.
Most likely the EFI conversion will make more horsepower, but will be a bit more troublesome to do. Guess the best bet would be to pull the entire system and wiring harness off of a later-model vehicle and hope you're good at wiring.