Just wondering...see a lot of people say they get better MPGs with biodiesel. I just ordered a few hundred gallons of 5% here from the coop to go in my 1,000 tank here at the farm. I have been running 11% (tax break above 10% in IL) in the tractors and in my old 7.3 NA Ford farm truck and didn't notice much difference in operation. Can anyone comment?

 

I've read just the opposite, that it lowers your mileage just a tad because it doesn't have the same BTU content. If I could get it here locally, I would still run it because whatever we buy of that keeps that much from coming across the pond and keeps our people working too.

 

Yeah I always thought it was lower in BTUs as well...I suppose the added lubricity is nice on things in these 3rd gens. It is more expensive but we get lower taxes on blends below 10% and no sales tax at all on blends over 10%. 5% costs a little more than regular diesel yet, but after losing the sales tax on 11%, it is actually about the same exact price as plain ol' diesel. I didn't want that high of a blend because of pumpability issues in the winter here, and potential issues with cummins...

 

and NO this is NOT dyed fuel

 

From the studies I've read lower percentage blends (~2%) can actually help increase fuel efficiency (depends on the engine and driving conditions), but when you get to the 10-20% and above it starts going down. At smaller % the extra oxygen in the biodiesel improves combustion efficiency more than the reduced BTU content of the blended fuel. At around 20% and above the improved combustion efficiency starts getting swamped out by the reduced BTU's of the overall blend. The Cummins studies I've read showed that B100 gave about 5% lower mpg even though the total BTU's were 10% lower than petro diesel.

 

Strjock81 - I've run more than 4000 gals thru my vehicles of bio since 2001 - I can definitely tell you , it won't increase your mpg in any blend. Studies shmuddies, lower btu=lower mpg period. As for operational differences - you likely won't notice a major difference until you get to b20 or higher. At b20 you finally start to notice a difference in smell, and quieter/smoother idle quality. Either way you are doing your engine a favor with increased lubricity and zero sulfur, the environment a favor with lower emissions, and the country a favor by supporting domestically produced fuel. I applaud your efforts! Try increasing your blend to 20%, I think you'll like it. I never noticed a major drop in mpg till about b50-60.

 

Lightman, I respectfully disagree that BTU's are the only influence on mpg. The combustion event is a very complex, interdependent phenomena that has a large number of variables that determine the amount of heat energy produced from the combustion event. For example, with the advent of high pressure injection systems we are able to get better atomization of fuel giving a better mixture with the incoming air allowing for a more complete combustion of the fuel. This higher efficiency at converting the BTUs in the fuel into useable heat energy increased the power and fuel efficiency of modern diesel engines over their predecessors. Due to all these interdependencies it's not possible to make a blanket statement that X% of biodiesel blend will lower your mpg Y%. Each engine and driving condition is different. I myself have been using biodiesel for 4 years in my VW, and have seen a correlation with better mpg with B2-B5 than with no biodiesel or higher % of biodiesel (I've ran from B0 to B100 over the life of the car). This trend has also shown to hold true in the Cummins (I've ran B0 to B35 so far).

As an extreme example of how biodiesel can produce more power than petroleum diesel (even with lower BTUs per unit volume) see
http://www.biodiesel.org/resources/3...rld_record.pdf

 

i don't get any better fuel economy running B20... and right now the winter blend is coming in too, so fuel economy is going down [i need to learn to keep foot out of throttle]

 

I got this bulk in now because I wanted to get fuel before they "winterized" it with D1 or something. That way I have summer fuel and just add the high rate of White Power Service to the entire mix. It has gotten pretty cold now a few times and have had no issues. Guess I will see when it gets down to -15 F.

 

There are not many Bio-diesel stations around here in S.Michigan.Question?? do they or can they run a winter blend Bio-diesel fuel,without the gelling problems.Thanks,coobie

 

Coobie, the one B20 pump by me (I'm nearly an equal latitude 1/2 way between Milwaukee and Chicago), last winter at least, they just quit selling it.

I've not checked yet this winter as it's a good ways out of my way...but it appears it's still for sale.

http://forums.biodieselnow.com/topic.asp?TOPIC_ID=2711

FWIW, I've not noticed a real hit in my MPG. Then again I find it hard to find trends in MPG as my driving varies, traffic varies depending on when I go to/from work, and the range is just too darn long.

 

The possibility of better mileage with Biodiesel is from the higher cetane. It lights better. I saw no loss in mileage using bio up to 20-25 %. May a slight increase. As stated, it is a complex picture.

 

I've heard all of the arguments for years. Some think the higher cetane of bio might offset the lower btu's, however that's just not the case for me. Maybe you folks that use the regular 40-42 cetane garbage truck diesel that's commonly served could see a tiny performance gain due to better combustion with the higher cetane of biodiesel. I am lucky enough to have access to 50 cetane minimum BP Diesel Supreme so the cetane benefit of biodiesel isn't a factor for me. No matter what blend I've used, bio has not improved mpg. It hasn't noticeably taken away from mpg until I get above b20.