Costco now using ethanol Blend in Huntsville Al

[remax]

My millage has fallen from around 50-52 to approx 44 mpg. I could not figure out what was going on. When I went for gas yesterday I found out that costco had switched to a ethanol blend. Is this bad for the Prius? I know my wifes maxima manual states not to use ethanol. I am very disapointed w/Costco. The attendant said they have had several complaints and 1 man was starting a petition.

[lefat1]

as far as i know, most gas is now a blend of up to 10% ethanol. there are a couple threads on this already

[Highly ImPriused]

E10 is not going to cause your mileage to drop like that. You would maybe see a 2% decrease (about 1 MPG if you normally get 50), but definitely not 10%+ like you are saying. It's also not going to harm your car in the least and it reduces air pollution.

E85 on the other hand you would not want to put into a regular car (Prius included) unless it has been modified for it. That is probably what the warning in your wife's car manual is about.

[Jiipa]

We really don't have any choice here as all the gas is E-10. The only exception is at the marinas due to the problem with ethanol desolving the plastic gas tanks on the boats and ruining their engines.

I don't think that E-10 should have caused that much of a drop in your mpg, perhaps there is another problem. I have used E-10 since I bought my Prius and am getting between 55 and 56 mpg without trying to hypermile, just slowed down to the speed limit plus 5 and using the cruise control when possible.

[CEguru]

We have E10 here in our metro area, but the ocean resort areas 150 miles east aren't required to sell an ethanol blend. On my non-hybrid fuel guzzler I see about a 10% MPG increase on the return trip (filled up with non-Ethanol gas). Sure, there could be other variables, but it's pretty consistently about 10%. In the two years I've had the Prius I haven't ever filled it with anything but E10, so I would be interested to see if the 10% economy increase carried over to it as well. If so, that's about 5mpg difference. Not insignificant.

[rfred]

An ethanol blend will not be as efficient a fuel as non-ethanol blend. But as others have pointed out a 10% ethanol blend should not affect your mileage that much.

Caveat emptor.

[Flying White Dutchman]

Originally Posted by Jiipa

We really don't have any choice here as all the gas is E-10. The only exception is at the marinas due to the problem with ethanol desolving the plastic gas tanks on the boats and ruining their engines.

I don't think that E-10 should have caused that much of a drop in your mpg, perhaps there is another problem. I have used E-10 since I bought my Prius and am getting between 55 and 56 mpg without trying to hypermile, just slowed down to the speed limit plus 5 and using the cruise control when possible.

the prius got a plastic tank or not?

[fcc]

i was always a conserved driver... and i can only easily get E10 gas.
no matter how hard I try, getting above 50 MPG is tough!

I am averaging around 47-48 MPG with E10 gas.. and would really like to
try a tankful of non ethanol gas.

people who get better mileage with E10 really have to consider if their typical
driving route is the cause for better mileage then the rest of us. After all I live
in NH and this is hilly compared to lets say an OH or what not.

But you should be able to do better then 45 without even trying hard with E10...
Also keep in mind I have a touring which is supposed to get slightly less MPG then
a normal prius.

[Highly ImPriused]

There was a thread on here where somebody showed the energy calculation. I can't remember it exactly, but it was pretty straightforward. Think about it though, 10% ethanol can't reduce fuel economy by 10%. That would be the case only if ethanol provided zero energy, which clearly isn't true. E10 results in about 2 or 3% lower fuel econcomy if I'm remembering right. I'm sure someone can provide the details.

[dwdean]

Originally Posted by remax

My millage has fallen from around 50-52 to approx 44 mpg. I could not figure out what was going on. When I went for gas yesterday I found out that costco had switched to a ethanol blend. Is this bad for the Prius? I know my wifes maxima manual states not to use ethanol. I am very disapointed w/Costco. The attendant said they have had several complaints and 1 man was starting a petition.

I'd hope that you're Costco is like the one here....the sign on the pump says that the product may contain up to 10% ethanol. I've been told that they'll get "straight gas" if they can, but they buy according to the cheapest price they can get. That means that some of what goes in their storage tank is E10. I'd imagine as we move further into summer and oil gets more expensive, there'll be more and more E10.

I also know that someone else pointed out that the energy content of E10 isn't that much less than straight gasoline. The reality is apparently something like 3%.

With that background, I can say that I know I've had one tank where I know the whole thing was E10 (bought from an independent station that's been selling E10 for a long time.)

I did see an FE drop with the E10, and it was fairly dramatic. However, I finally figured out that what happened was that the different fuel was causing the car to respond differently to accelerator inputs. In other words, the E10 generally seemed to take a "lighter foot" than the straight gasoline.

I'm not at all sure that I understand the whys and wherefores of that, I'm just repeating the empirical observation I made. When I drove with that lighter foot, my FE on the E10 got noticeably better. On the next tank, which was from Costco, and which I believe was basically straight gas, the car went back to what I call "normal" accelerator input (i.e., I had to drive with slightly heavier foot.)

While that's all very loosey-goosey, hopefully it'll help a little. I'd really like to try and do some tests with this, but haven't found the time and am not quite sure how I'd source the fuels (at least the "pure gasoline" part) and/or where I'd get another Prius driver crazy enough to try it with me...