The move to official automaker support for higher blends of biodiesel has been a slow one. One important step along the way were the establishment of American Society for Testing and Materials (ASTM) standards for B20 (20 percent biodiesel mixed with 80 percent petro diesel) in the middle of 2008. Last year, General Motors announced that the new 6.6-liter Duramax V8 engine would be factory certified to run on B20 sometime this spring. That time is now. Full Story