Over on the GMnext blog, Coleman Jones has posted
a response to the recent push to go from E10 to E20 at regular gas pumps
in Minnesota. Jones is the Manger of Biofuels Implementation at GM Powertrain. While GM has obviously been a huge proponent of the expanded use of ethanol, they are reluctant to endorse this move toward E20. Their concern has to do with durability over the long term. Vehicles sold as E85 capable have already gone through all the durability testing necessary to ensure that the engines, including the fuel system and exhaust system, will survive the long-term use of E20 and higher concentrations of ethanol. Non flex-fuel engines haven't gone through this kind of rigorous testing and a one year test of 40 vehicles isn't considered sufficient.