Well, there is a way to cheat. To avoid the titration, etc. you need to filter and settle it well, then cut it with either regular unleaded gas, or kerosene to make it run well through the lines. Like other diesels, it will gel in winter time, so it is not a great idea when it is cold. If I had a ready supply, I would be pimpin' a 1983 Mercedes Benz 300D about now. It's the best car for it as the injection system is more robust than newer diesels. It lacks any electronics and everything runs off a vacuum pump or some other mechanical means.
If you do your WVO to biodiesel conversion wrong, it will destroy your injection pump. This happens when there is too much methanol in the fuel. In fact, the BBC show Top Gear did just that when they tried to go endurance racing in a BMW Diesel 3 series on biodiesel, and killed the whole fuel injection system. You can also end up making a big batch of soap too, as lye and animal fat are the key ingredients in both soap and biodiesel. Don't kid yourself, it is a dangerous process! Lye will burn you, but it will kill your nerve cells at the same time so you are unaware of the bad chemical burn that is taking place. That's why I would probably just mix the filtered and settled oil with some kerosene instead of going through the process of making BD.
