my neighbour makes his own bio-fuel and he runs 100% in his focus with no problems, but he does change fuel filter every 4 weeks, but the preperation and time involved it's not really worth it, it's ok for him he's a chef and knows where to get plenty of waste oil and his grandfather has a farm so he can run 2/3 tanks at a time but the chemicles are expensive to start with. i think he make about 200lts a day.
tezzer