Propane kits and cars


I’m looking at converting my old beater to run on propane and I have a question about the fuel tank. All the kits I’ve seen include a donut tank or a torpedo tank. Must I use those tanks? Can’t I just use a standard 20# tank like I’d use for my grill? Obviously I would have to find a way to secure it in my trunk so it didn’t roll around, but is there any special equipment a kit tank has that a standard 20# tank wouldn’t? My thought is that rather than searching for places that can fill a torpedo or donut tank, I could simply swap out my car’s tank the same way I swap out my grill’s tank.


I’m no expert, but my brother-in-law is. Back in the '70s he converted his car to run on propane (he worked as a technician for a propane company) and if I remember correctly he just had one or two tall tanks, what I think you are calling “torpedo” tanks. Those have the same connectors as a grill tank, they are just bigger. The only problem I think you’d have is a seriously short range. Those 20# tanks are not very big. It’s not hard to find places to refill a propane tank, at least not that I’ve seen, it’s also far cheaper to refill a tank than swap them, even the 20# tanks.

Thinking about it, permanently installed tanks probably have some additional plumbing so that they can remain hooked up during a refill where the 20# tanks won’t have that. You really ought to find a place that will do the refills.


You can’t use a standard 20# tank.

Propane powered engines, such as fork trucks and such, need liquid propane delivered to the vaporizer at the engine to insure sufficient fuel flow.

The standard 20# grill tanks extract propane vapor from the top of the tank, which will seriously
inhibit flow.

So basically there are two different types of tanks; those that extract vapor and those that extract liquid.


—and if you place any kind of a tank in the trunk, good luck finding a propane refill station that will refill the tank in the trunk. It’s against Federal and State laws to fully enclose a propane tank in the trunk or in the passenger’s compartment. You might get away with getting your 20# grill tanks refilled and then place them in the trunk, like at a swap-out place where you turn in your tank and buy a refilled tank. I wouldn’t try that at a propane dealer’s refill site, though. 20 lbs. of propane ain’t gonna get you too far.


Wow I am really supprised to hear that Propane Powered cars are not so well known in the States. Do your Gas powered cars use a pure Propane or do they, as they do here in Europe, a mix of Propane/Butane. Typical is a mix of 60/40 or sometimes 70/30. I have converted my Ford Duratec Motor 1,6Liter to run on the stuff. The Round tanks pull the liquid to the vaporizer where it is converted to gas Vapor. With Seq. injectors and a gas regulator computer it is injected into the intake manafold before the intake valve. Our system is built in Poland where “Autogas” has a very strong network of stations. In Holland they also have a lot of locations. With gas prices here in Germany topping ca. $9.06 (3.8liters per gallon x $1.59 to one Euro) a gallon we have a choice with the use of Autogas. Do a Google search with the word “AutoGas” and read a little about what maybe a choice for future driving.


Vehicle propane tanks are horizontal with the vapor takeoff on top and an emergency vent to the outside. They are fully enclosed in the trunk.

You can’t use regular 20# tanks unless they stand up outside and are secured on the bed of your pickup, for instance’

One drawbck of propane vehicles is they are often not allowed in underground parking garages, since propane is heavier than air and could be a fire hazard if your tank was leaking or overfilled.


You need MORE info.

CNG is Compressed Natural Gas. (CNG) these tanks are pressure cylinders. very thick, and strong.

LP is Liquid Propane. (LP) is simply cooled and in the process it turns to liquid. it is much easier to store, transport, and handle.

i think you are confused between the two.

the city buses use CNG.

it is much safer, and when it spills or leaks the gas (since it is lighter than air) disperses.

LP is heavier than air, and sinks, in holes and is easier to find a spark and explode.