Why SVO instead of biodiesel?
Vegetable oil is completely chemical free, requires no production process, is non-corrosive (so it wont harm the rubber in your engine as biodiesel can), is free to those who seek it out at the restaurants (or even better, you can get paid to take it sometimes, as typically they pay around $40/ month to get it hauled off), and has the benefit of redundant fuel systems when installed with the recommended two-tank kit.
