After my DPF replace and EGR replace took a solo drive from salt lake city to portland. or. have that 60 gal replacement tank and went almost non stop. . even over 2 mountain ranges and valleys, and 839 miles later, the overhead showed 20 mpg even. I know it is not that much but it is cool. . i also have a 17 gal tank in the bed as well as 2 , 5 gal cans... should make another half tank.