This group dedicated to vehicles that run directly off vegetable oil (aka: vov, grease car, wvo, waste vegetable oil, svo, straight vegetable oil).
A petition process is used to block spammers.

Two types of conversions are a "Single Tank," and a "Dual Tank or Two (2) Tank" system. Single tank converstions are better used where the climate if warm most of the year.
A diesel vehicle with a dual tank kit is put through a conversion using a system to start on diesel. Then after it is at optimal temperature, it is switched from diesel to run directly off vegetable oil. Conversion kits can be purchased from a few companies.

Sources for vegetable oil are fast food, Asian, or middle eastern resturants that use vegetable oil to fry food. It is generally a good idea to contact target sources for waste vegetable oil and create an arrangement so you can call ahead to pick it up. It's good for them because they usually have to pay to get rid of their waste vegetable oil.

The oil is filtered to remove contaminants, and then put in a separate tank in the converted vehicle for a dual system, and into the vehicles main fuel tank in a single system.

This group is not for bio-diesel which is different and there are plenty of biodiesel discussion groups.