I know it effects me because when LSD (Low Sulfur Diesel) was in the pumps i got at lease 23 to 25 mpg that's with out additives but with additives i got at lease 2 mpg improvement. But when ULSD Rolls in Oct, i started to see my mpg drop to 19 to 22 that is without additives, if i added additives i got better mpg say around 21-24 mpg. I know there is no fuel leaks because i send my car to dealer for fuel leak inspection...

anyways what do you guys think.....

Ps
It was done on a 300SD....

__________________
Current Garage
2008 Mercedes GL320 CDI 188k mi Repair/Work in progress
1994 S350 160k mi Garage Queen & prepping for repairs
2005 E320 CDI 203k mi Healthy & Daily Driver
1994 S350 357k mi Retried as parts car
1984 300TD 214k mi Blown OM617 Poss OM603 Swap??

Sold
1987 300SDL 200K+
1994 S320 181K mi
2008 E320 Bluetec 127k mi
1999 S420 130K mi
1980 240D 360k mi
15+ Others that has come, stay and gone

GONE, BUT NOT FORGOTTEN
1995 E320 SE 220k mi
1984 300SD 350k mi

ULSD has a minimal effect on mileage, less than 2%.

I saw no change with the transition to ULSD. Are you sure you're not talking about the transition to winterized diesel? That would make more sense. ULSD is a year-round fuel. Cold weather may cause a mileage drop as well.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

DOE says 12%.

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Gone to the dark side

- Jeff

I would really like to see that reference, I have worked with about a dozen nuclear power plants that have reevaluated their emergency diesel generator capacities based on less than 2% reduction in energy content:

http://www.nrc.gov/reading-rm/doc-collections/gen-comm/info-notices/2006/in200622.pdf

In reality, some testing that I have seen shows no decrease in energy content.

Hey, there's the PDF I've posted here so many times, ...

__________________

Gone to the dark side

- Jeff

The pdf I linked quotes a value of 1.2 %.

Even if the energy content of ULSD is within 2% of the LSD there is still a difference in the lubricity of ULSD and LSD. The additives effect lubricity and this may be why you are seeing the mileage go back up.

I rarely burn diesel by itself, but I do know that biodiesel has significant lubricity advantages and that even though it has less energy content the mileage is similar even at 100% because of it, not to mention that better lubrication is better for you engine.

Some truckers, who purchased new trucks in 2007 and 2008, like to run 2-5% biodiesel or lubricity additive so they don't have to overhaul their engines as much.

__________________
1991 350SD (updated rods)
Biodiesel B100 when I can find it.
Dino when really cold outside

I've been chasing declining MPG since 2005. My MPG was excellent between 2002-2005, it slipped a little in 2006, and most noticeably declined in 2007 and 2008. I've been thinking something is wrong with my car. If it turns out to be crappy fuel, bow howdy, I'll be madder than a skunk dipped in perfume.

Anyone got a link to documents with the 12% info? All I've seen is the 1-2% claim. Maybe that was a typo with the hyphen left out...?

__________________
Dave
Boise, ID
Check out my website photos, documents, and movies!

really i dont see a 1.2% in reduction its more like 12% really my 300SD used to give way better mpg when LSD was on the market, with a full tank of Low Sulfer Diesel i can go from Tulsa to OKC round trip (200 miles) and still have at lease half tank of diesel left, now with full tank of ULSD i only get quarter tank of diesel, now that is not a 1.2% reduction its more of 12%, maybe its time that i should add some biodiesel and i bet its way cheaper than buying additives.....

__________________
Current Garage
2008 Mercedes GL320 CDI 188k mi Repair/Work in progress
1994 S350 160k mi Garage Queen & prepping for repairs
2005 E320 CDI 203k mi Healthy & Daily Driver
1994 S350 357k mi Retried as parts car
1984 300TD 214k mi Blown OM617 Poss OM603 Swap??

Sold
1987 300SDL 200K+
1994 S320 181K mi
2008 E320 Bluetec 127k mi
1999 S420 130K mi
1980 240D 360k mi
15+ Others that has come, stay and gone

GONE, BUT NOT FORGOTTEN
1995 E320 SE 220k mi
1984 300SD 350k mi

Trust me, I've read enough diesel fuel test reports to know it's not 12%, actually it's often 0% depending on the process used to reduce the sulfur content. Lubricity has nothing to do with mileage, but if you are concerned about excessive fuel system wear use additives (personally, I think they are a waste of money but you should do what makes you comfortable).

If you are really seeing a significant decrease in fuel mileage you should do some basic troubleshooting and find the real problem; valve adjustment, IP timing, injector condition, timing chain stretch, compression, etc.

Im sure the difference varies widely based on all kinds of factors. Craig, from what you said it sounds like youre talking about ULSD in huge power backup generators, thats ALOT different than an old diesel benz on the highway. its a much bigger engine running at constant rpms.

But i also seriously doubt that %12 lower mileage is possible when all we have is anecdotal evidence. I also get alot lower milage on the highways than i did a few years ago, but i think a more likely cause is me having to speed up and slow down all the time because of all the people driving slower because of the high fuel prices!

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1991 300 D 2.5 Turbo, 220k
also in the family:
1981 240 D 185k
1991 350 SD 185k
2006 S 500
2005 SLK 350

There is also a significant variation in the energy content of D2 due to it's density. The ASTM spec allows a significant range in density (about 5% I think) that is independent of the sulfur content. It is also possible that the current D2 available at the pumps is at the low end of that range.

The tests I was referring to were just laboratory tests of the fuel's energy content.

Thanks for the NRC white paper!
(I cannot remember if I've seen that one before or not.)

BUT,In the paragraph on METALS it mentions copper as being one of the
metals that react in a harmful manner with USLD.

Are not the "sealing rings" inside the Delivery Valve holder COPPER?

'Wonder how much of a problem that will cause?

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'84 300SD sold
124.128

I am also in NE Oklahoma and am probably using just about the same #2 diesel fuel that you are. Although I'm not sure when we actually started using the ULSD around here, I have seen essentially no change in mileage over the last several years. There is of course the winter drop of a couple of mpg due to the winterized fuel, but that is really all.

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150