There is increasing evidence that E10, or gas with 10% ethanol is the worst possible blend for your car. The 10% is just enough to mess with the fuel, but not enough to get the sensors to "adjust" properly. ( or the reverse, the 10% messes with the sensors to a much greater degree than is called for )

3 recent studies, one by Volvo, one by the University of North Dakota, and one by Minnesota State University all point to a "sweet spot" MPG in most cars using E30, or 30% ethanol.

In the case of the I4 2.3L Ford Fusion, this car got better MPG with 30% than with 100% gasoline. The Ford Fusion did worse than gasoline, but better than predictions based only on btu content, with 20% ethanol.
The Ford Fusion did worse than predictions at 10% ethanol, and blends over 45% ethanol.

The 2.4L Toyota Camry also did better than pure gasoline with 30% ethanol.
The 3.5L Chevy Impala did best on 40% ethanol, nearly as good as pure gas, but not quite.

It seems in modern, newer cars ( the 3 cars tested were all 2007's ) the air/fuel sensors, and fuel injectors adjust "properly" ( or at least to your advantage... the lean side of things ) at about 30-40% ethanol.

NONE of the cars tested got a "check engine" or warning lamp with less than 50% ethanol. Some "regular" cars can run on up to 65% ethanol before getting a check engine lamp. All cars "run" on E85 ( just poorly ).

So myself and some others at work are going to give this a shot.
( most people I know do not drive hybrids though )
We are going to mix our own 30% and 40% ethanol fuel.
It is easy to do if you live in an area where you can get E85.
Just "dilute" the E85 with regular gas.
( or "enrich" your gas with some E85 )

The tables below tell you exactly how to do this.
Table 1 is for E85 and plain gas.
Table 2 is for E85 and E10 gas.

If possible, allow 3 tanks for your car to fully "learn" the new mix, and to average out weather and traffic concerns that affect MPG.
However most researchers feel this adjustment period only takes 30 minutes / miles. Please report your findings. Thank You. -John

 

Cool!

I look forward to your results. However, I would probably approach it from a slightly different tack. I would prefer to mix the gas in spare cans rather than try to mix in the tank. Our variable sized bladder Prius is not the best 'mixing' container.

Bob Wilson

 

Can't you just mix the gas in your tank in the proper ratios, intentionally not filling the tank several times. Then after several iterations of doing this, top it off with a slightly out of balance ratio, if required, to get a "full" tank to calculate mileage based on the totals added.

Obviously this will have to be a manual calculation, but it should work to see the effects of Ethanol mix vs. straight gasoline

 

That's one reason why I made the table in post #1.

At first tank, I can make a 30% mix based on 15 gallons.

On second tank, I will have to "estimate" based on gauges how much "empty space" I have in my tank, and make a 30% mix based on the predicted "empty space". But not knowing exactly, I will say, need to make a mix of 13.5 gallons the second time.

If I'm about to enter an area / state where E85 is hard to find, and my tank is not "empty" there may come a time when I need just 5 gallons of 30% mix to "top off".

I have 30% in my car now, and have gone 25 miles with no caution lamps or any drivability issues. Purrs like a kitten ( so far ).

Any reason to doubt the accuracy of the ScanGauge or On-board display for MPG? ( knowing each has +/- 2 MPG error on regular gas )

 

I just ordered my Scangauge and still waiting for it yet, so I'm just going by what's advertised on their website for this. But isn't one of the trip data parameters you can track "fuel used"? Is that accurate enough to know very precisely how much room is left in your tank?

I'm thinking that if I can use that "fuel used" parameter data to keep accurate measurements of my fuel usage on each tank, I can use that to get the proportions right. Then I can just keep a couple of 5 gallon fuel cans of E85 at home so that when I get to empty I know exactly how much to put in at the station and then come home and top it off with the E85. It's a bit of a trip to get to the nearest station with E85 (about 7 miles from home in the wrong direction from my trip to work), so it'd work better for me to stock up on it and mix it at homethan to go to that station each time to fill up.

 

There are ways to adjust the SG... but I know mine always under-reports just a touch.... it is usually within 0.5 gal out of a 15 gallon tank.

Sounds like you have a really good idea.
Use the E85 for one tank while you are there,
and then take some home with you for next time!
I think they sell yellow cans for E85, but I think it is "legal" to put E85 in a red gas can.... but it may not work well in lawn-mowers, etc. so you may wish to get a yellow gas can. I think blue cans are for kerosine. IIRC.

( I put E50 in a gas generator at a construction site and it ran fine. )

I think you will find ethanol costs about 1 cent more per mile to use in your non-flex-fuel cars. Is one cent per mile worth it to you to use a home-grown, made in the U.S.A. product?

( It's cheaper price, but lower FE will still result in 1 cent extra cost, likely, but that is my guess... and each experiment will help prove/disprove this. )

It costs more per kWh to get your power from a windmill also, about 30 cents more per day, just as a comparison.
-John

 

Chuck, I like your idea too. The SGII-xgauge is very accurate when the tank fill, refill procedures in the manual are followed. If you move your SG to other vehicles, the tank values will be skewed. That's just another GOOD argument to Santa to have one for each vehicle

 

The fractionation system designed by Applied Milling Systems will separate the corn into bran (combusted as an energy source to save the ethanol plant an estimated 40 percent of its natural gas costs), germ, and endosperm (starch for ethanol) as well as other food products like corn meal. ( Word on the street is Frito Lay will buy corn meal from "food grade" ethanol plants. )

 

interesting. There is an E85 station about 30 minutes from the office....

 

I wanted to drop a line and say thanks as this is terrific information. I only wish the local fuel stations would sell anything ethanol (other than Casey's General Stores 10% blend).

Your research showed exactly what I found out a few years ago - that vehicles run poorly on a 10% ethanol mix. I found out the hard way that the fuel was 10% ethanol in the first place (didn't notice the sticker on the pump) - my Toyota 4x4 ran like it was ingesting wet gas (fuel with some water content). It took all kinds of additives off the shelf (octane booster, heet, etc.) to get the poor little 2.4L EFI motor to suck that stuff even partially through. Once it got 1/4 tank down, I topped off with Super Unleaded (93 octane out here) and it started improving. Turns out that my 3,800 pound 4 cylinder truck really did need all of it's available power to climb the hills out here.

I'm going to keep my eyes open in the near future for E85 and hope for the best. In the meantime, I hope they find a more suitable source than edible corn to produce fuel. Imagine the backwards world we live in - with people starving with little food in some areas - and the rest of us wanting to turn food into fuel for our vehicles.