Like he said early in the thread, Propane has about 10% less BTU per/gal as gas. As E85 has about 30% less BTU per/gal. So respectively, you would see about those kind of decreases in MPG when compared to gas in an equivalent setup. The only way you might see less then those loses, is with some lean cruise type tuning. With his price difference between 93oct gas and propane, propane is the cheaper fuel per $/mile.

 

Propane and other gas-based fuels have other benefits to somewhat accommodate the lack of chemical energy in the fuel. A gas homogenizes with another gas much easier than an atomized liquid homogenizes with a gas, so fuel distribution in the cylinder is much more uniform. This results in a more stable combustion event and allows more power to be made. Lean cruise plays nicely with that attribute of the fuel as well

 

Some more info to help clarify, Propane has the third highest energy density by weight losing only to Natural Gas and Hydrogen. Was frustrated that i couldn't find the link to a handy chart I found last year so I went out and found the info again. I get questions like this all the time so I should probably know the answer if i am going to be "that propane guy"

From the table at energy.gov

Fuel---weight (lbs/gal)----BTU/LB (higher value)--BTU/Gallon (higher value)

Propane---4.22-------------21,594-------------91,420

Gasoline---6-6.5------------20,004-------------124,340

Diesel---7.079--------------19,673-------------137,380

Ethanol---6.61--------------12,830------------84,530

Methanol---6.63------------9,837--------------65,200



I don't know how to do the math to compare propane cost to gasoline with octane compensation but when you compare high octane race gas to equivalent octane propane the cost difference is at least double or triple in favor of propane. 87 octane gas is cheaper than race gas but not a true cost comparison since you have a hard time burning it at 15-20 lbs boost without melting pistons or pushing water.

I am told this guy is running 40 lbs boost? Either way he is haulin the mail, wait til 2:05 to see what motor he is running! He just got it into the 8's this summer.

 

Inline 6 cylinder!! ******* cool!! Not familiar with who makes that engine though. Thing is seriously hauling the mail too!

 

it's an australian ford engine. they also built some pretty cool windsor V8's down there that we didn't get.

 

Didn't ford have that in a lot of their vehicles? I had a 1990 F-150 as my first vehicle that had a straight 6 300ci.

Zero top speed but torque for days.

 

There was a 36' Chevy pickup at the LS1Truck.com Track day last feb that had a turbo inline 6. Look like a normal street rod pickup but had a wheelie bar and chute on the back of it. I thought it must just be for show till I watched him bust off a 8.xx!!!

 

Very cool!!

 

Really cool build. In Arkansas when i was a kid lots of people ran propane setup on their truck. My dad did in the 80's so did my grandpa. Again congrats. Oh and we never blew up. lol

 

I noticed today, that the county south of mine, their sheriff's office has some cars that are fueled with propane. Shows that it must be just fine as far as safety goes or else they wouldnt put it in a cop car that at somepoint is going to get beat up lol.