I use a cetane boost fairly regularly in my truck, every 5 fills or so. The thread here on the board about gas mileage got me to some reading today and I found this thread on the diesel place forum.
I never really thought much about what the lower sulfur content fuel, ULSD, 15ppm, did versus the older 'LSD' or low sulfur diesel, 50ppm.
I know for a fact that my fuel mileage has suffered drastically over the last few years losing around 20% per tank on my mileage compared to using the LSD prior to '06.
From reading a bunch today I've discover that it's a possible result of a loss of lubricity that the ULSD causes in older vehicles like mine.
Anyone use Opti-Lube XPD or any additives in their diesel engines and noticed notable improvement in mileage?