As a reply to all of the above. We ahve used B99 for 3 years now in many brands of engines, and have worked with engine manufacturers in sharing results. We use app. 25-30,000 gal. of Bio per year. In the winter in over the road trucks in Colorado we have run B50 without any problems whatsoever. As some realize there can be a huge difference between Bio and WVO, and SVO. I would not run much WVO or SVO in the newer Teir III emission engines w/o extensive lab work. In older (mechanical Injection) engines you are fine if the purity issues are addressed properly. Bio is the same as diesel in that poor quality causes problems. The main reason that WVO or SVO will gell at higher temps., is that it contains glycerin, which has a much higher cloud point. Commercial bio has the glycerin removed through a chemical process. If you want to try this to see there is much info. on it but you use lye and methanol to seperate the glycerin from the SVO. Work now is being done to leave the glycerin in the bio, as it is energy. Our testing, and of others familiar with this show app. 6% decrease in B100 vs. #2 ULSD, and a 4% increase from bio SVO over #2 ULSD. When you mix the unleaded you are mixing at levels (80-20) which also has worked well. The unleaded serves only to bring the viscosity to levels matching #2 diesel. The glycerin is still in the VO. In years past with mechanical injected engines, common practice in the trucking industry was to add unleaded to the fuel to lower the cloud point. You must be careful to keep that level to where pre-ignition and "drying" of the fuel did not cause lubricity problems. Today, I would be cautious of this practice in a Teir III engine due to split injection cycles, higher temps etc.. ULSD is severly lacking in lubricity, hence changes in additive packages, oil recomendations, etc. Hence one of the reasons that bio, done correctly is a good fit with most new engines. CNH just announced FULL engine warranty with B100. Others we have tested with will announce when all testing is finalized.
CAUTION: Remember, WVO, and SVO are NOT the same as lab verified B100, so BE SURE of what you are using. FILTRATION is critical. Many hear of horror stories, often involving WVO-SVO and do not recognize why there can be a difference. Good Luck