Alternative fuels question. Propane vs Gasoline

[XXSpiralXX]

   Ive seen a few cars with this conversion and im told they get better fuel economy and can run higher compression because of the propanes 104 octane rating.
   What I want to know is how much more efficiently does the propane burn?  How does one bbq tank equate to a full gas tank? Whats the gallon to lb ratio? I cant find the right formula for it( I dont know if im looking hard enough ).
  If it turns out that propane is better I might consider doing a conversion. I never travel in tunnels anyway.

[BMC440]

LP gas weighs 4.24 pounds per gallon....Your 20 pound grill tank holds4.72 gallons

[Arthu®]

It is cheaper, is somewhat more fuel efficient. But I don't know what kind of car you are looking at installing this in, but you should think about the toll this is going to cost in the long way.

Arthur

[70charginglizard]

The 1999 dodge charger concept car was supose to have a compressed natural gas concept incorporated into it.  

The 1999 Dodge Charger R/T pays homage to the original muscle-era car but updates it for the future. One of the most obvious changes in the concept sports car include its transformation to a four-door sedan. Harder to detect is its use of Compressed Natural Gas (CNG) rather than traditional petroleum-based gasoline to power the 4.7-liter, supercharged V-8 engine.

[Arthu®]

http://www.cse.polyu.edu.hk/~activi/BAQ2002/BAQ2002_files/Proceedings/Subworkshop4/sw4b-3Chan_Final.pdf

read and learn, some pretty good info in there, even though it makes more of a point considering the heavy duty applications like busses and trucks.

Arthur

[Drop Top]

I don't know who is blowing smoke up your butt. But Propane doesn't get better milage its much worse.

Growing up I lived on a very large farm that was owned by my father. We had converted many of the trucks to run on propane and some that would run on eather. The propane trucks would be very low on power and the mileage was about 1/2 of what it was on gas. In other words if the truck would get 10 MPG on gas, it would get 5 MPG on propane. Then it wouldn't have enough power to get out of its own way. The propane was at that time about 1/2 the cost per gal. of gas, but in the long run it wasn't any cheaper seeing as how it would take twice as much propane to get to where you needed to go. The reason we used propane was to keep the fuel in the trucks. When we ran gas the tanks always seemed to be empty. So for us it was still cheaper to use propane.

I was going up the infamous Grapevine with a 35 ft goose neck stock trailer. It was loaded with cattle. We where taking them to the L.A. Fairplex for their cattle show. I started out on propane. As I started going up I was loosing ground so bad the big trucks was going around me like I was on stands. I changed over to gas and it was like a whole new engine. The power came right back up and I started to pass all those trucks. This was in a then new 86 Chevy 1 ton with a 454. It was no slouch.

I did allot of research on running propane. If all your going to do is burn propane you will need to rebuild the motor with at the least 12 to 1. Put in a very hot thermostat. Run the distributor very advanced. It is a very high octane fuel. It burns very clean but it also burns cold. On very cold mornings it would sometimes ice up and you would have to pore warm water over the lines to get any fuel. I'm sure that they have come along way since I quit using it (1990). But For my money stick with gas. With the cost of the convertion the weight of the new tanks and the room you will loose with the tanks. You wont be happy with the power loss. It will be hard to find it on the road compared to gas. Its just got more negatives then positives.