Bio diesel is basically a fuel you make on your own. The main ingrediants are corn oil, lye, and methanol. It costs you roughly 70 cents to a dollar to make. But I've seen people get the cost down to as low as 50 cents a gallon. The expensive part of making it, is getting your own processing unit. You can buy one for around 3 grand, or make your own for around $800 or so. The only real disadvantage to bio-diesel is it doesn't like cold weather, during the winter, you need to mix it w/ regular diesel, or figure out a way to keep the fuel warm while in the tank. Biodiesel is actually better for your engine, and gives you more performance. And here's the real kicker, whatever was fried in the oil, is what your exhaust smells like, LOL. So most likely the exhaust gonna smell like fries, lol.
I'll try to find the website that I like on it...
And ratzo, you don't need to mix it w/ regular diesel unless in cold weather, and even then you don't need to do 80% regular diesel. During the warm parts of the year, you can use 100% biodiesel just fine.