Re: Propane carbs/injection
[Re: dthemi]
#173248
12/23/08 02:19 AM
12/23/08 02:19 AM
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Joined: Feb 2003
Posts: 21,318 Manitoba, Canada
DaytonaTurbo
Too Many Posts
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Too Many Posts
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
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Can't tune propane carbs(mixers) worth a crap. They do not run at ideal a/f ratios at full throttle. A propane injection system would be the way to go, but propane injectors are not cheap.
Propane has a lot of octane but produces less BTUs of energy than gasoline when burned. So you build to a higher compression ratio to use the extra octane, but produce no more power on the dyno because of the lower btu rating.
Some people are making great power on propane, but for most, the cost and headache of it all is just not worth the trouble. I calculated it out, and back when gas prices were high, it was not THAT much cheaper to run on propane than gas. You would have to be a delivery driver or do a ton of driving to make that investment back.
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Re: Propane carbs/injection
[Re: dthemi]
#173250
12/23/08 02:26 AM
12/23/08 02:26 AM
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Joined: Aug 2003
Posts: 43,129 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,129
Bend,OR USA
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I have had two vehicles, one car hauler a one ton Dodge truck with a 318 Poly motor and a class A motorhome. I added the propane dual fuel conversion to the car hauler in the late 1970s due to the gas crunch, not being able to buy gasoline in some towns at night and the propane tank held 82 gallons of fuel. Propane does not have as much latent energy that gasoline does so you have to use more propane to make the same HP, just like alcholol The motor home was a pig on propane so I switch it back to gasoline only, the truck burnt two exhaust valves shortly after the conversion so it was not as good as I had hope for There was a 1968 or 1969 Charger that ran at the Winternationals around 1973-76 as a exhibition car on Saturdays severl years in a row, but it was not a class car and didn't really run very fast, high 11 s to mid 11s if I remember correctly. I'm sure it was Hemi powered, it may have been a school car project for one of the SO CA junior colleges Maybe someone with a better memory or someone that was involved with the car will chime in I have heard that some of the deisel truck guys use propane injection for a power adder , or maybe to cool the inlet air down
Last edited by Cab_Burge; 12/23/08 02:38 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Propane carbs/injection
[Re: schwep]
#173258
12/23/08 02:40 PM
12/23/08 02:40 PM
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Joined: Aug 2003
Posts: 43,129 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,129
Bend,OR USA
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Shwep, I think your sourse of informatin is in error, the charts I have seen show LNG around 58000 BTU, Propane around 57000 BTU and Butane at 55000 BTU, way less than any type of alcholol. Edit, I'm not sure of how much propane in liquid form turns into as a gas but as I already said that old Dodge truck averaged right at 7.5 MPG on the cheap regualr gasoline and 6.0 MPG on propane. Propane was way cheaper per gallon than gasoline then so it was a little cheaper to run for the same distance as gasoline so it was a advantage except for killing the exhaust valves.
Last edited by Cab_Burge; 12/23/08 02:44 PM.
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Re: Propane carbs/injection
[Re: schwep]
#173262
12/24/08 12:52 AM
12/24/08 12:52 AM
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Joined: Oct 2005
Posts: 162 Centerville, MN
schwep
member
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member
Joined: Oct 2005
Posts: 162
Centerville, MN
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Quote:
BTU's Per gallon:
Regualr Gasoline = 114,100 Ethanol (E85) = 81,800 Propane = 91,600
1. Note: BTU value of gases is based on density at one atmosphere at 60 degrees Fahrenheit.
2. Sources: a. North American Combustion Handbook, 3rd Edition b. Automotive Fuels Handbook, SAE
Work in the propane industry myself in design/sales of propane cargo tanks and pumping systems. I have some experience with LP as an alternative fuel in Medium Duty chassis but very limited.
So these are just facts that I thought might be beneficial to the post. Obviously as stated by others there are many more factors other than btu's to be considered.
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