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Discussion Starter · #1 ·
Alright so Ive been following a post about a CF member whos building a propane setup. I was curious what or if anything exciting would happen if I ran propane with biodiesel? From what I understand propane helps in mileage....I think? Would that or could that compensate for the decrease in mileage from biodiesel?

Or would the two compounds just not work at all?

I havent read anything about this at all.:thumbsup
 

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I see no reason why they would not blend. I ran propane on my 93 Dodge and loved it. I don't know much about bio as I dont run it. But it should work the same on bio and traditional diesel.

Brian
 

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I run it now on my 2nd gen 12v. Im not really that impressed
 

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I run it now on my 2nd gen 12v. Im not really that impressed
I guess propane is like a lot of other toys for our trucks...either you love it or you don't.
 

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Mopar1973Man.Com
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I don't see how you getting a improvement in MPG by using more fuel? Here in Idaho propane is closing in at $4.00 bucks a gallon... Diesel is $5.00 bucks a gallon... So at 35 gallons your pumping $175 bucks of diesel and another $20 bucks worth of propane (at a total of $195) to what gain 1-2 MPGs...:rof

I do that now without the propane...:w: Just a Edge comp and a small shot of 2 cycle oil in the tank... (Only $60 bucks a half year) :rof
 

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Diesel fuel is injected in a dense stream near the center of the cylinder. In order for it to burn, the fuel molecules must migrate towards the air molecules on the outskirts of the cylinder, and vice versa. Traditionally, it has been difficult for Diesel's to burn all of the injected fuel; it would be insufficiently atomized and you'd get haze.

Gas engines can burn fuel faster and more completely, because by the time of ignition the fuel is dispersed homogenously with the air throughout the cylinder.

If you're doing it right, the propane is going to be evenly disbursed throughout the cylinder when it is ignited by the injected Diesel.

The theory behind propane injection is that even burning of the propane will allow for a more complete burn of the injected Diesel. How that happens is largely a subject of conjecture; combustion dynamics are really, really complicated and hard to figure out. It's debatable whether it happens at all, and some people have seen results and other's haven't.

Today's common rails are also a holy-crap bunch more efficient at atomizing injected fuel than anything in the past; injection pressures on my truck are 13k PSI and common rails are twice that. So any benefits that propane does have is a lot lower on newer vehicles.

The above is only the logic for using propane to achieve a higher thermodynamic efficiency, by burning more of the injected Diesel. That logic is a lot shakier than the logic of using propane for high performance.

In the case of using propane for power... Diesel engines have traditionally been limited by their injection technology. The pistons on a gas engine act as their own fuel delivery pumps; the faster the pistons go, the faster gas is drawn in, and that gas is automatically dispersed evenly with the air in the cylinder. But on a Diesel, you need to rely on an injection pump system that pressurizes each little bit of fuel.

The exponentially increasing difficulty of an injection pump to deliver fuel at RPM is one of the reasons why Diesels have traditionally been regulated to low RPM. Propane, or any fumigated fuel, is an easy way to circumvent restrictions of an injection system.

My truck, for instance, can only inject 400 HP worth of fuel. If I want to add more fuel than that, I either need a bigger injection system, or I go the easy route and add a lot of gaseous fumigated fuel into the air intake; I can flow as much fuel as I want into the intake for virtually free. Only problem there is that the fumigated fuel isn't 1000 octane, so it is going to start preigniting at a point and will take out my bottom end.
 

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Well said. Also explains the diff. between people using on Gen. 1 vs. 2's and 3's.
 

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Mopar1973Man.Com
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Nice explaination Begle1...:thumbsup

But today with rising cost of fuels (Diesel, gasoline, propane, etc.) it it actually worth the added expense of the propane vs. the gain in MPG's???

I can see it as a added booster in performance apps. But not as a MPG boosters...:w:
 

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Discussion Starter · #9 ·
:lol3:
Diesel fuel is injected in a dense stream near the center of the cylinder. In order for it to burn, the fuel molecules must migrate towards the air molecules on the outskirts of the cylinder, and vice versa. Traditionally, it has been difficult for Diesel's to burn all of the injected fuel; it would be insufficiently atomized and you'd get haze.

Gas engines can burn fuel faster and more completely, because by the time of ignition the fuel is dispersed homogenously with the air throughout the cylinder.

If you're doing it right, the propane is going to be evenly disbursed throughout the cylinder when it is ignited by the injected Diesel.

The theory behind propane injection is that even burning of the propane will allow for a more complete burn of the injected Diesel. How that happens is largely a subject of conjecture; combustion dynamics are really, really complicated and hard to figure out. It's debatable whether it happens at all, and some people have seen results and other's haven't.

Today's common rails are also a holy-crap bunch more efficient at atomizing injected fuel than anything in the past; injection pressures on my truck are 13k PSI and common rails are twice that. So any benefits that propane does have is a lot lower on newer vehicles.

The above is only the logic for using propane to achieve a higher thermodynamic efficiency, by burning more of the injected Diesel. That logic is a lot shakier than the logic of using propane for high performance.

In the case of using propane for power... Diesel engines have traditionally been limited by their injection technology. The pistons on a gas engine act as their own fuel delivery pumps; the faster the pistons go, the faster gas is drawn in, and that gas is automatically dispersed evenly with the air in the cylinder. But on a Diesel, you need to rely on an injection pump system that pressurizes each little bit of fuel.

The exponentially increasing difficulty of an injection pump to deliver fuel at RPM is one of the reasons why Diesels have traditionally been regulated to low RPM. Propane, or any fumigated fuel, is an easy way to circumvent restrictions of an injection system.

My truck, for instance, can only inject 400 HP worth of fuel. If I want to add more fuel than that, I either need a bigger injection system, or I go the easy route and add a lot of gaseous fumigated fuel into the air intake; I can flow as much fuel as I want into the intake for virtually free. Only problem there is that the fumigated fuel isn't 1000 octane, so it is going to start preigniting at a point and will take out my bottom end.
very good explination, I also like the very technical "holy-crap bunch more efficient" part
:lol3:

Has anyone run bio with propane? Lets take the fuel costs and diesel out of it. Im curious if building and paying the cost of propane will have any negative consequenses or anything?
 

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Well I have ~$70 total in my propane injection setup(it is done correctly based on boost) and have seen a 8mpg average increase, and a 12mpg peak increase in fuel economy. My kit paid itself off in 2 tanks. I get propane for $10 a 20lb tank so my propane cost is very low. I am very pleased with propane. Dont know about it with Bio though, it should do the same thing.
 
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