I was on a trip last week and got off I-81 in Virginia to fuel up and the pump at the station read "Bio Diesel" I filled up and proceeded to drive 400 miles before my next fill up and noticed a loss of power and when I filled up I got 4 mpg less than I normally do. after filling up with Pilot which I normally do my power returned and at the next fuel up so did my milage.
My question is this is this normal for Bio Diesel ?

Yes, a few miles/gal is normal. Biodiesel has something like 7% less power in it than petro diesel. So I wouldn't be suprised if the lower milage was due to biodiesel, assuming MPH, in town/highway, hills/flat, etc.. were all the same.

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rdanz,
What blend of biodiesel did you use and what model of Merc is this?
I ran B100 in my 1985 300D and 1999 E300 from May through October of 2005. I do not remeber my exact milage, but the drop was less than 1.5mpg for both cars.

perhaps the power drop off was due to gunk in filter? 1 tank of biodiesel will clean up alot of stuff in the tank.

But the gunk would still be in the filter affecting performance when the petro was put in so I would say it wasn't a clogged filter. But rdanz, you might take a look anyway just to see.

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That does raise some interesting questions about locally brewed biodiesel, though. Who knows the actual quality of the stuff? I know some places give better petro than others. Bio seems like it could be even more of a crap shoot.

I typically see a 2 MPG drop in fuel economy when running pure B100. The engine also seems to be slightly down on torque, it kind of feels like the A/C is compressor is engaged.

B20 use results in no observable drop in mileage or performance.

The place I get mine from supplied the state DOT, so I'll wager its pretty decent. Wouldnt the label of B100 have some garuntees?

You would think, but you would also think petro would come with some kind of guaranty too, but a few months ago a station here in Boise got some bad diesel and caused all kinds of ruckus here.

They only test so much of biodiesel and petro, they can't test it all. So it's possible that some bad stuff gets through.

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My vo gives me about 25 mpg vs 27 at 75mph.

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82 300D....went to MB heaven
90 350 SDL....excercising con rods

it has 10-12% less power than dino. the reason it is so clean emission wise is that it has all that plant oxygen in it*. this hampers power although the cetane rating is 50 vs 40 for std pump dino and 45-50 for the prem bp dino.


*from biodiesel:growing a new fuel economy-greg pahl

page 57 and i paraphrase(but not plagerize)..... On the downside, the energy content of bio d is 10-12% less than dino.(about 121k for bio d and 135K btu for dino) The oxygen allows favorable emissions but has a reduced energy content. Although there is this slight reduction it is offset by a 7% avg increase in combustio efficiency. Generally speaking the use of bio d results in 5% decrease in torque and fuel efficiency in a diesel engine. However, most people will not notice the difference in their automobiles.

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currently
[1981 300 td tdidi 165500 dark brown/palamino-Brownie-mine-3k miles of ownership
1983 240d 162+++ Anthricite grey w/ henna red interior and hella lights-wifes car-Red

the above two cars are for sale
and can be seen on the cars for sale thread here. pix also available.


240d-144+ Manilla Yellow w/ palmino interior-greasecar kit-Blondie-the college kids car

23" gt 21 speed still on original tires-still got the nubs
21" khs tandem

What does the cetane rating matter if it is lower in power and economy.

Most people will not notice it in the automobile but probably sooner or later in the wallet.

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

With the passat TDI it doesnt loose a drop of power when on B100. Although it does drop in mpg (45mpg hwy) but thats better mpg then the benz anyway.

Its still peppy in the city and flys down the hwy with no hesitation. My mom actually said the only real difference was that the engine was quieter.

On our trip to LA she drove to LA on B99 and she didnt notice any differnce in power. On the way back we filled up on B99.9 and i drove the whole way back home and myself didnt notice any power loss. And ive driven it on pure diesel before. So the power is the same on these cars.

On the 300SD when i run test batches of biodiesel in it i only notice a faster idle pace. im assuming its because of the higher cetane. I never pay attention to mpg's so cant really say anything on that but i assume it less then if it was on diesel. When the SD is on diesel it seems to have a little more power but not a major differnce overall.

But the biodiesel gives the car more power in city then when on wvo.

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Current:
05 E320 CDI
07 GL320 CDI
08 Sprinter
05 Dodge Cummins
01 Dodge Cummins

Previous
2004 E55 AMG
2002 C32 AMG (#2)
1995 E300
1978 300D
1987 300D
2002 C32 AMG(blown motor :[
1981 300SD
1983 300SD
1987 300SDL
2002 Jetta TDI
1996 S420
1995 S500
1993 190E 2.6
1992 190E 2.3
1985 190E 2.3 5-Speed

If it has less energy per unit, how can it not have less power? Maybe you don't notice it but the dyno might.

Without a dyno and duplicating the conditions you cannot know. People notice a difference in their car after they put a mod on via the Butt-O-Dyno.

Why would it give more power in the city or highway? How is that possible?

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

Biodiesel would have to be about 10% cheaper to make itself worthwhile since it is 10% less in energy if I am reading the above posts correctly

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow