Please dont get Biodiesel fuel confused with a vegetable oil conversion. Biodiesel can be bought at pumps or made by mixing lye, methanol, and vegetable oil.
No conversion is needed to run on biodiesel, if your lucky and live in cali there are plenty biodiesel stations that sell it.
A veggie conversion is different. The goal is to run your engine off straight vegetable oil thus needing a conversion (second heated tank). To run on straight vegetable oil without chemically altering it into biodiesel requires you to heat it to lower the viscosity to the same as diesel or biodiesel.