My 300SDL has the two tank conversion. Running on waste vegetable oil is basically free. Restaurants have to pay someone to haul the used vegetable oil away and most will gladly give it to you for free. Take it home, filter it, and put it your second tank. I just drove from DC to Atlanta and back for pretty much free.DarkOneSK said:biodiesels. I just don't get it. isn't vegetable oil more expensive than diesel? Learn me.