Originally Posted by Diesel2
As someone out here has stated that sulfur is not a lubricant is incorrect as it is a very good lubricant and when it was some 5000 ppm years ago in diesel fuel it was great at stopping wear. When they started to remove it along with it they removed the BTU'S of the diesel. The BTU's gives you power and also fuel mileage. When it dropped down to some 500ppm of sulphur max.,diesel owners started having problems with their fuel injection systems and injectors, big problems as they started failing in no time. Oil companys had a big problem for a time because of it too.
Very true. VW sent new car owners a pamphlet on why they should buy this bottle of "diesel fuel lubricant" when the ulsd came out.
As far as milage, in 2007 the emission controls added to the diesels to make them pass the more stringent rules is what cut the milage. (from 20% egr to about 60% among other things) If you pull the dpf off and recalibrate the computor to reduce the egr settings (and mod the inj pulse,blah,blah,blah) you can jump from 14mpg in a 08 f-250 to 21mpg. (don't ask how I know) hehehe