The gel point of B100 is higher than petroleum diesel although it is dependent on the feedstock used. Rule of thumb is that WVO biodiesel will gel before SVO biodiesel and that non-vegetable oil biodiesel will gel before biodiesel make from vegetable based oils. It is not recommended for use B100 without treatment, blending or heating below freezing no matter the feedstock used to produce the fuel.
That said, biodiesel is a better option for vehicles than using straight vegetable oil in an unconverted or converted diesel. I'll probably catch some grief, but unprocessed veggie oils will coke the cylinders and injectors ... biodiesel will combust much more cleanly.
