Fuel Type - Ethanol's effect on MPG

Besides energy density, which should be a 3% decrease, the engine's state of tune also comes into play. The Gen 3 was less effected than was Gen 2. Perhaps the C is more effected. If you were Bob Wilson, I would ask you to run 10 tanks of E0 and ten tanks of E10 and graph the differences.

 

Study up on all the MPG saving Prius driving techniques on here... Your technique defines your gas mileage more than any other factor... Over-inflating your tires a little helps too!

 

All of my tanks have been E10, and I get decent mileage (see Fuelly badge). I'm happy with it. But of course I don't know how much higher it could potentially be with Ethanol-free gas. Ethanol is mandated here in Oregon, and it's not worth it to me to go through of hassle of seeking out Ethanol-free gas.

 

If you want to see if you can get an extra mile or two more per gallon w/non-ethanol gas here's the list of who sells it in Oregon: Ethanol-free gas stations in the U.S. and Canada In my experience during the wettest part of the winter non-ethanol gas works way better than water-absorbing ethanol...

 

...as others have said we would expect +1 to 2 MPG for ethanol-free gaso.
Driving habits such as short trips or speeds over about 70 mph tend to reduce MPG.

 

I know, we had an old user who posted that link everytime it came up. They're all out of my way, and at least one of them requires you to drive around the back of the building to find it...not to mention it's illegal, and they might not even want to sell it to me. It's not worth it to me.

 

Some stations are selling Ethanol Free Gasoline which normally sells for about
50 cents or more per gallon in Oregon. Mostly high test gas that states "contains
no ethanol". I believe many boaters use this type of gas as 10% ethanol
has a negative effect on marine motors from what I heard.

 

I ran across an ad for 'Ethanol Defense' from Bell Performance. It is an additive. I wonder whether anyone has tried it or has encountered any positve/negative information concerning this product. I know most experts recommend staying away from additives since they accomplish little for the most part other than seperate the consumer from some money.

 

Most additives are nothing more but 21st Century "Snake Oil".

 

Tank condensation can give trouble with todays' gas, especially w/ ethanol added in. I use Seafoam in my equipment for landscaping, gardening, and snow removal. I am now experiencing zero problems with varnish buildup in the carburetors and smoother, easy starting engines.

My Prius gets a treatment 1x / month as condensation is not a problem due the fuel bladder pretty much negates this issue. I do this to minimize any moisture caught in the ethanol in the gas.

I am impressed with the use of Seafoam. I can't comment on Ethanol Defense, as I haven't tried it.

DBCassidy

 

I ran across this in further researching. It is from 2008, so some of the info concerning availability of non-ethanol gas is probably out of date.

Fact, fiction and realities of E10 fuel -

 

I recall from earlier posts that your engine control computer was replaced and your gas mileage improved. I wouldn't have expected a 14% increase from switching from E10 to E0. The real test would be to have someone else refuel your car so that you don't know if you have E10 or E0 in the tank. If the E10 always gives 15% less mileage, then perhaps there is an issue with the oxygen sensors in your engine?

For what it is worth, the 100+ heat took a toll on my fuel efficiency. My mileage is much better the last few days since the heat wave broke.


Tom

 

When I filled up with 100 % reg gas in Carson City Nevada last month I noticed
an increase of at least 3-5 mpg. It also seemed to have more power than
with 10% Ethanol Gas.

The nearest place to get Ethanol free gas here is across the Columbia River in Chinook, WA. (one way 25 miles)
But the price there is normally 30-40 cents a gallon more than gas at Costco. (11 miles away)

 

Forgive the newbie for asking, but I searched and this thread came the closest to what I wanted to ask: what grade of gas is best? 87, 89, 0r 93? I wasn't sure if there was one better than the other. I'm at the 1/4 tank mark of my first tank since bringing baby home from the dealer and realized I didn't know which gas I should use. I'm not going to track all over IL to get ethanol free.

 

Your Prius only requires 87 octane (regular gasoline). Higher octane actually
has less energy per gallon. If you can find 87 octane with no ethanol
added that would be as good as it gets for your Prius.

 

I wish no ethanol gas was even an option out here.

All my tanks have been on E10 and my MPG is just fine. However, pure gas would be nice.

 

Well, after that snarky response, I sure don't feel welcome. Of course, I completely understand how internet forum members get upset answering a repetitive question. I mean, you've got so much more important things to do than read and reply to a post on a car forum....oh, wait.

Casual criticism like what you posted certainly poisons a newbie's enthusiasm quite quickly; if you are sooooo busy being an important Prius chat contributing member <<rolling eyes>> why are you bothering to answer a question you consider redundant? What's with the need to insult others via some online chat board? Jerk + anonymity + internet forum = troll.

In answer to your post: yes, my car came with an owner's manual, and yes, I did read it. However, my post was meant to elicit advice/opinions from more experienced Prius owners in regard to the type of gas they use and their experiences. I thought perhaps I might learn something along the lines of "the manual says 87 to use octane, but I use 89 octane and get XX MPG more per tank than I did with 87 octane." I apologize if I did not elucidate enough to make that point clear, and that it was misunderstood. I'll make sure that in any future posts I use small words, or maybe draw pictures, to make sure what I'm asking is clear and easily understood.

Way to welcome a new member, PriusCamper. Thanks!