Comment Re:Still.. biofuel (Score 3, Informative) 88
The issue I see is that newer VW TDIs (with the common rail system) is not designed to run on anything higher than B5 (95 Diesel/5 Bio). With my 2012 Jetta, if I use anything higher, they can void my warranty, and they are able to tell. Which sucks cause the station right near me that does Diesel does anywhere from B1 to B11, no notice as to what it is at that time. The problem here is the point in which biodiesel combusts, as compared to straight diesel. To be "clean burning", which VW Diesels are, they do a direct injection of diesel into the exhaust system to burn off the soot and other impurities that are/were common with diesel engines. Biodiesel doesnt ignite the same, leaving the impurities/soot, causing it to clog part of the exhaust system up, requiring expensive replacements.
This is to say, annoying, at the least. Now, I've heard of people having good luck with mod kits adding a second (heated) tank to use with filtered waste vegetable oil, with a cutover switch in the cabin. Start on diesel, switch over to WVO, then switch back later, but those were with pre-2010 VW Diesels.