...well you knew I couldn't resist this one...! CoachGeo makes a good point about the lack of sulfur in biodiesel. No sulfur = no sulfer dioxide in the exhaust = no contribution to acid rain. The sulfur serves as a lubricant, which is good, and I can understand adding some to make current low sulfur fuels a better match for an older diesel. Vegetable oil and/or biodiesel are both better lubricating fuels, so one might just throw in a gallon of new vegetable oil as a lubricity additive...won't hurt, and might work just as well or better than sulfur.

Another great thing about bio diesel is that it doesn't put more carbon (as carbon dioxide) back into the environment. The carbon in fossil fuel is essentially out of circulation until we dig or pump it up and throw it into the air from our exhaust. Using bio-diesel or vegetable oil takes carbon that was already in circulation (in the recently grown plants) and puts it in the air where the same amount can be re-absorbed by new plants.

I know, blah blah blah, and I just wanna drive, too, but this stuff is really simple when you think about it. Alternative fuels have to happen, and we've all got a head start with our "old" engines!

...excuse me while I climb down off my soap box...!