Question - how many Btu/gallon is your fuel?
 

Here in the UK pump diesel (#2 diesel) is between 135,000 and 140,000 Btu/gallon.

I'm wondering if your yank diesel is different, esp summer / winter fuels?

Apart from the 1.2:1 ratio of gallons, which will mean a 1.2:1 ratio of MPG (while is why kilometres per litre is a better method) a difference in fuel quality will also affect MPG, or kilometres per litre.

Biodiesel (B100 or 100%) is around 127,500 Btu/gallon, so obviously running on bio will also drop your MPG.

#4 diesel is basically home heating oil.

ULSD (ultra-low sulfur diesel) in USA has about 1% less BTU per gallon than LSD. Source: http://fleetowner.com/mag/fleet_abcs_ulsd/

I think EU diesel is ULSD (<15ppm sulfur content) as well, no?

So they should be BTU equivalent.

Yup, we've had ULSD for yonks, also had unleaded for yonks...

what we don't get (in *this* area) is #1 diesel.

#1 diesel = kerosene for purpose of energy content

Kero is 135k BTU / US Gallon.
Diesel #2 is 130k BTU/ US Gallon

Its about the same. Kero is added locally here for anti-gel in the cold.

The heating value (BTU/pound) is fairly constant for #2 diesel, the major variation is in the density which affects the volumetric heat rate (BTU/gallon).

I don't have the numbers in front of me, but #2 diesel should have a higher volumetric heating value than kerosine (#1 fuel oil).

'Like the Article,BUT...
 

"WILL I NEED TO USE A FUEL ADDITIVE?

Like low-sulfur diesel, ULSD fuel requires good lubricity and corrosion inhibitors to prevent unacceptable engine wear. As necessary, additives to increase lubricity and to inhibit corrosion will be added to ULSD prior to its retail sale. With these additives, ULSD is expected to perform as well as low-sulfur diesel."

The following excerpt Is a Tale of Fairies:

"As necessary, additives to increase lubricity and to inhibit corrosion will be added to ULSD prior to its retail sale. "

'Ain't No Refiner/Jobber/Etc. in CONUS "adding" anything to ULSD.