Ive heard of people burning oil as fuel in there cars?

I think that’s only for hybrids.

only a diesel engine can burn the vegetable oil. it can be a mix called bio-diesel. part vegetable oil, part diesel fuel. and they also have conversion to run on pure vegetable oil. look at greasecar.com

It is vegetable oil. You need a diesel engine. The problem is that type of oil becomes thick and won’t run in colder climates or even overnight. You can get a tank heater to fix that problem.

Make sure you strain the oil to get out the food particulates.

If you can find restaurants to give it to you free, well then it is free (minus your time collecting and straining it).

What you are referring to is known as Bio Diesel and can be used to power conventional diesel engines. It will not work on gasoline engines. Bio Diesel is thicker than regular diesel and either has to be pre heated or mixed with regular diesel to be used. If a person had their own source of oil for bio diesel then the savings would be substantial. It is environmentally friendly since the oil is from natural plant sources.

Used cooking oil (usually vegetable-based oil) can be used to power a diesel car.

This was proved on the show “Mythbusters” where they rigged a supply of used cooking oil to run directly into the fuel system of a diesel car. They didn’t modify the engine in any way, either.

It’s more environmentally friendly that regular diesel fuel. Especially because there is less harzardous material involved in the refinement process.

The savings aren’t that great, but vegetable oil is renewable, oil is not.

Your spelling is excused, this time

EDIT:
Thanks to the other posters, I forgot about how the veg-oil can perform poorly in the cold conditions.

A mixture of diesel fuel and veggy oil can be burned in a diesel engine. Plus, the exhaust smells like french fries! Minus – all the dogs and fast food junkies in your area will be following you around.