I've got 158,000 miles of Prius driving data using E10 that disagrees with that claim. Let's see your data. .
I use E10 when ever I can get it. I have not noticed any difference in consumption between 94RON E10 and 91RON unleaded. In Australia E10 is made using ethanol made from sugar cane which has a lower carbon footprint than corn. I have never tried E85 as it isn't available here. I switch to E10 when I was still driving my 2 litre manual Camry. Due to the higher octane rating I could use 5th gear around town without pinging and I got my average consumption to drop from 9L/100km to under 8L/100km arond town. At the same time I was paying 3 to 4 cents per litre less for 94RON E10 than I would have paid for 91RON unleaded. E10 also keeps injectors and the rest of the fuel system cleaner. If you switch an old car to E10 you should change the fuel filter after a couple of tanks.
DON'T USE E85, FOLKS!! The Prius does NOT run it. (just wanted to reiterate this fact to help people, in addition to the OP's passing comment) ZC1
Do you live in an oil producing state? I noticed when I went to Queensland (where most of Australia's sugar comes from) E10 is everywhere but in South Australia only a couple of brands sell it as we have no sugar industry at all here. I'd guess an oil producing state would have a population more resistant to ethanol than a corn growing state in the USA.
John, I've seen the charts that you posted up at the front of this thread and if I sort of fill in the "winter gaps" (we don't get that cold here for that long), it sort of looks like what I was seeing before last week (FE in the mid 50's.) OK, so what's significant about last week? Well, that's the first time that I know for sure that I've put E10 in the car. As I posted earlier in this thread, I usually get gas from places that have signs on the pumps that say the product "may" contain up to 10% ethanol. Until last week I always assumed that "may" meant "does". For a variety of reasons last week I had to get gas at a station where there is no doubt that they're selling E10 and have been selling it for months. The very first thing I noticed was that my FE dropped from the mid 50's to the high 40's. This is with other things being equal (tire pressure checked fine on Saturday, it won't be cold here for another five months, not really any hotter this week than last, no out of the ordinary long or short trips, etc.) The only thing that I see different is the gas, all of a sudden I'm starting to wonder if what I was assuming was E10 was maybe not. I do notice that the car is much less willing to enter some of the higher speed cruising modes and requires more accelerator pressure to maintain speed. With alot of nursing, I've managed to get the FE back up to about 50 mpg, but getting over that plateau looks like it's going to be tough. I'm curious to know what you and others make of this. Is this my imagination or am I seeing something that's "real"? I'm certainly not concerned that there's anything "wrong", but I am trying to get my head wrapped around whatever is going on.
