I did not see a thread that specifically covered this. Also it is more of a vent than anything. I don't believe there's a reasonable solution and I didn't want to clutter up anyone else's thread. On the "wait list". Using the ScangaugeII on our Avalon while waiting for our Prius. Have been able to bring the Avalon's average mpg around town up a couple of MPG by monitoring the GPH & HPR gauges. Brought average around town from 17-19 MPG up to 19-21 MPG. Switched to Mobil1 on last oil change and increased tire psi from 34/32 to 42/40. Looked like we were going to pick up another MPG or so. Mileage began to fluctuate. Figured it was inconsistant driving habits. Then on last two fillups noticed this label on the gas pump for the first time, metro Atlanta area. "May contain up to 10% ethanol". I do not want to make this a pro vs con ethanol thread. My concern is the "May....". I assume that means that what I am pumping into my cars can contain anything from no ethanol to "up to 10%" ethanol, depending on what was delivered by the last tanker and what was previously in the station tanks. It's just a pain. Just when we were trying to get a handle on how different driving habits, maint., etc affect MPG, they make the energy per gallon variable by tankful. And no, I don't want an ethanol gauge to measure the % ethanol. Besides, if I remember correctly, the gauges accuracy or margin of error is greater than the ethanol's effect would be @ <= 10%. It's just frustrating. I just thought there could be a remote possibility that someone out there might have a suggestion since I believe that Prius owners must represent the largest concentration of people that actually track their MPG. Thank you for letting me vent. I don't expext this thread to last long.
In some places, it's actually the law that requires the gasoline to contain 10% ethanol as an oxygenator to cut down on smog-forming emissions. Where I am here in New York for instance, it's state law that requires ALL gasoline sold here to contain at least 10% ethanol.
Perhaps I need to further clarify my concern. I don't care if it's 0% or 10%, or somewhere in between. I just what to know what it is so that I can keep meaninful mileage records. I knew about the 10% and that's fine if it's going to be 10%. But how are you going to make any sense out of your effort to track your mileage if you don't know what your burning? It's the "May contain up to......" that I have the problem with. Not the "10% ethanol". Perhaps it's just a temporary label during changing over to 10% ethanol. How do the states handle it that change over between summer and winter? How do you know what you're burning. Thanks for the reply!
here in the EU 10% is already a fact. thats maybe way i can not get the US mpg's that prius owners get over there
Thank you for your replies. I am aware of the E10 issues. My concern was "is it or isn't it or where in between is it" for this fillup? How do you know if what your doing is better or worse for your MPG if you don't know the mixture? However, it seems like the issue may go way till October, when they switch back, maybe! If they're filling the station tanks with E10, consistantly, then after a few tanker deliveries, the mixture should become stable. My concern was non-E10 one fillup and E10 on the next would make it difficult to interpret MPG data. Thanks Again !
I don't think that is the reason, the gas I buy always has 10% Ethanol in it and I am still getting great mpg I am averaging 55-58mpg depending on where I go.
I have pumped 3,439 gallons of E10 into my Prius tanks and can tell you that its mixture content influence is much smaller than other factors that can affect MPG. Just drive it. .
I can tell you right now that if you buy your gas from any of the Major national brands its going to be E10 nearly every time. BP, Texaco, Chevron, Exxon, Shell all have to sell a government mandated 9 Billion Gallons of Ethanol this year. Which means 90 Billion gallons of E-10 must be sold. As a country we consume about 1 Billion Gallons of fuel every 3 days (122 Billion gallons in a year)
Has there been testing done to make sure that we're not being given more than E10, either accidentally or intentionally? Who, if anyone, polices this?
I'm just confounded by this as well. Added a bottle of Textron not long ago and it seemed to help BUT... Last couple of tanks, bought shell and struggled to get over 48. Today bought some Exxon- drove 70 miles well over 50!!! that's more like it! Think we all need to get on the bandwagon and CALL and WRITE our senators and congresspersons to END the ethanol mandate. It makes no sense... add this and your milage drops so you use more......?!?!?!
I understand the question that you're asking, but for the life of me I'm trying to figure out why it would matter unless you were trying to calculate CO2 output to a fairly high degree of accuracy. My confusion stems from the fact that mpg, by definition, is simply a measure of distance traveled per gallon of fuel. There's nothing there that says what the fuel is, just how many miles were traveled, on average, per gallon of fuel. Living in Florida, I too buy and use E10. I too noticed a small mpg "hit" when I first started putting it in the car. But I also learned how the Prius responds to this fuel and simply adjusted*. After getting up the learning curve (one tank), my MPG average is back to where it was before. I've not had the time or energy to test the supposition that the car reacts differently to E10 vs. straight gasoline. I'm not sure that I'll get the chance as it seems that most commercial gas will be E10 year 'round. If I remember correctly, there's a movement in Minnesota (or was it Wisconsin) to mandate a higher percentage of EtOH in automobile gasoline. While I understand that there are varying viewpoints on use of EtOH as a fuel centering around production methods and food supplies, it is important to remember that putting larger amounts of EtOH in gasoline as a "filler" is going to make alot of sense to the oil companies.
Evidently my question is still not clear. However, if we are going to E10 that's fine. My post tried to explain that E10 is not the issue. "May contain up to 10% Ethanol" meant an undefined percentage of Ethanol and ethanol does not contain the same amount of energy as gasoline. Ergo, the percentage of ethanol will affect your mileage accordingly. I was trying to test different driving habits, changing to a full synthetic, increasing the psi in the tires, etc. it would help if the fuel mixture was consistant so that I any changes in mpg from tank to tank would be a result of my testing, not variations in the fuel mixture. Hopefully is just temorary during the change over to E10. Then I can go back to fine tuning my driving habits. Thank you for your input. E10 is fine with me.
