I drive a 2008 F450 with 6.4l powerstroke diesel power. Between the size, weight, and low gear ratios this unit is a fuel hog. Since buying the truck used I have brought the maintenance up to a higher standard and on the recommendation of my mechanic started using Stanadyne diesel fuel additive. Between improved maintenance and using Stanadyne I have improved fuel consumption from 22 l/100 Km to 17 l/100 Km and the truck is running great. Because I made so many changes I can’t attribute improvements directly to Stanadyne but it seems to be a good part of my overall vehicle maintenance plan. I will start using it in my BMW X5 335d to see what difference just using Stanadyne makes.