First, is anyone using biodiesel? Second, if you're getting it from local restaurants, are you having any problems with contaminents in the wvo?
Had an 'oil guy' at a restaurant show try and sway me off of pursuing bioD saying that there's lots of people screwing up motors because of contaminents. Course, he's in the business of collecting WVO, so guys like me would be a competition for his raw material.
Waste vegetable oil isn't biodiesel. There is a chemical transesterification process to make it into biodiesel. There are people using filtered WVO in diesels with varying degrees of success. On the other hand, there are plenty of people processing it and making very good biodiesel and running it with no problems at all. There are some very good web sites that go through the whole process step by step, just do a search on Google.