I've looked back through the E85 topics that have appeared before, and I've read the (somewhat chaotic) Creed Project report, but I haven't seen anything that looked definitive. Has anyone else tested this? Can a standard 2005 Prius really use E85 fuel without ill effect? This fuel has recently become more widely available in my area (Missouri), and it would great to think that I was not only getting better mileage in my Prius, but using only 15% oil-based fuel to do so. If a standard car would have trouble, are their well-known modifications that would allow this? Ultimately, I would love to be driving a plug-in version of the Prius burning E85 as my fuel. A vehicle like that would be a very light touch on the oil supply.