MPG changes due to 10%Ethanol mandate?

I was noticing in the last few weeks my MPG in my cars & bike seem to be drifting lower. Then I noticed on the Fuel pumps the gas stations are now adding up to 10% Ethanol to all blends.

So I called a representative at American Petroleum Institute and he said there is a gov't mandate to put 10% Ethanol in all blends by June 2008. He mentioned this WILL reduce Gas Mileage (about 10%) and not really assist with the reduction of Green House Gases.

This probably from "Renewable Fuels Standard (RFS) in the Energy Policy Act of 2005" where "Ethanol has recently become the oxygenate most widely used in reformulated gasoline. This is in part due to the fact that the other commonly used oxygenate, MTBE, has been banned in 25 states. While ethanol has been blended in gasoline at levels of 5.7% and 7.7% by volume, it has been more frequently blended at the 10% by volume level to take maximum

advantage of available tax credits." Source https://www.api.org/aboutoilgas/otherfuels/...05_07_final.pdf

So if you are seeing a change in your MPG, this may be the reason. I hope it does not damage our fuel system for vehicles not designed for Ethanol usage... only time will tell.

Admins- I tried to post in NPRT but was not possible for some reason.

Actually, I think 10% ethanol would be about a 6% to 7% drop in mileage. Ethanol has 67% of the energy content of straight gasoline by volume. (67% x 10% = 6.7% drop)

And I think the 10% rate is common for "winter" gas blends. We would more likely get used to winter blend year-round.

And the point about NEPRT...is that one should aspire to not post in NEPRT. If it gets moved.....you probably should have looked for an existing thread to add on to.

However, you've got a slightly new angle on an old topic...and as long as it doesn't devolve and somebody start a political rant...it's fine here.

These ethanol mixtures aren't something new either. They've been around for a while with E5, E7, and E10 running in anything built the past several decades is going to be fine.

Ignacio said:

These ethanol mixtures aren't something new either. They've been around for a while with E5, E7, and E10 running in anything built the past several decades is going to be fine.

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I first used ethanol laced gasoline in the early 1980s, in South Dakota -- in a fuel injected Honda motorcycle. At the time there was a pretty common hue and cry that it would ruin just about everything.... Worked fine in my bike then -- and has worked fine in everything I've ridden/driven ever since, afaik.

I admit to not comparing gas mileage -- but, figures don't lie....... :huh:

does the adition of ethenal drop the octain rating.

There was a discusion about this at work and I reall don't have a clue on this part.

I know that the octain rating seems to be the same at the pump but that could be caused by additional work at the refinery to keep the octain rating at the proper reading.

we've been using the 10 percent solution ethanol in Houston for the past three years and I average 45 mpg every day on my '05 FJR.

All those dire warnings of reduced mpg don't seem to hold true for my bikes or cars.

Just as a data point, I get about 48-49 mpg commuting on normal regular and it drops to about 45-46 when using the 10% ethanol.

while riding at SFO i had my first experience with 10% ethanol in my FJR. it may be me but it seemed like my FJR didn't run as good on it. since i've come home and have put a tank of non-ethanol in it seems to run better again :huh:

could just be me i dunno

Thanks for everyone's input. This helps me get an understanding on what to expect out of Ethanol gas from other's experience.

There is a Difference from the real thing and wanted to let others know about these subtle changes.

So, what's the point of putting in 10% ethanol if you're going to burn 10% more fuel? You do the same distance as yuo would if you weren't using Ethanol for any given volume of 'pure' gasoline. In fact 10% more 'stuff' will come out of the tailpipe because of the reduced overall fuel efficiency.

It doesn't save 'gasoline' (in quotes because it is now only 90% gas). It does make food more expensive.

bramfrank said:

So, what's the point of putting in 10% ethanol if you're going to burn 10% more fuel?

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That's what people say when they're looking for a boggeyman to blame, but the typical mileage drop is simply in proportion to the 1/3 reduction in energy content in the 10% of gasoline you're replacing with ethanol. Do the math and it's a percent or two, although I'm sure it varies from vehicle to vehicle a bit.

- Mark

vandy said:

does the adition of ethenal drop the octain rating.

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Nope -- on the contrary.... the addition of ethanol raises octane.

In some states where ethanol production and use in gasoline is subsidized by state taxpayers (like Iowa, for instance) -- higher octane regular is actually cheaper (at the pump) than lower octane regular (regular without ethanol).

Apparently? A win-win situation (unless you're the one paying for the inefficacious processes?) (or, like to eat corn?). :blink:

03HiYoSilver said:

I hope it does not damage our fuel system for vehicles not designed for Ethanol usage... only time will tell.

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There was a bit in a recent issue of the AMA rag where they mentioned they were fighting legislation to allow more than 10% ethanol on the grounds that current bikes are approved only to a max of 10% ethanol.

What pisses me off is what about non-current bikes? Is my RZ-350 going to have a problem? I gather the major issue is rubber swelling or cracking in seals and hoses, and it's not like old bikes need any help with that!

markjenn said:

Do the math and it's a percent or two, although I'm sure it varies from vehicle to vehicle a bit.

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No, actually it's 6.7%.

bramfrank said:

So, what's the point of putting in 10% ethanol if you're going to burn 10% more fuel? You do the same distance as yuo would if you weren't using Ethanol for any given volume of 'pure' gasoline. In fact 10% more 'stuff' will come out of the tailpipe because of the reduced overall fuel efficiency.
It doesn't save 'gasoline' (in quotes because it is now only 90% gas). It does make food more expensive.

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Again, you're not going to burn 10% more fuel...you're going to burn 6.7% more by volume. That theoretically means you'd be getting a 3.3% delta....and that delta is where environmental improvements are. It's certainly not a huge amount, but it is the current state of our domestic fuel source discussion. Reduced carbon output which gets into a discussion FAR larger and potentially more divisive than the subject that the thread starter started.

vandy said:

does the adition of ethenal drop the octain rating.

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It would if nothing else were changed. However often when they add the ethanol they then compensate by using lower octane gasoline than usual and still maintain the octane rating listed on the pump.

Ignacio said:

markjenn said:

Do the math and it's a percent or two, although I'm sure it varies from vehicle to vehicle a bit.

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No, actually it's 6.7%.

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We're both wrong.

If the ethanol has 67% of the energy density of gasoline and you mix it at 10% of the total, then the resulting energy density is given by the following equation:

(1-.1) x 1 + (.1) x .67 = .967 or 96.7%

So the decrease in energy density of the mix is 1 - .967 = 0.033 or 3.3%

And I just noted someone else got the same number above so it must be right! ;-)

- Mark

markjenn said:

So the decrease in energy density of the mix is 1 - .967 = 0.033 or 3.3%
- Mark

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You're right. My math skills of the 1 - didn't come through. It is 3.3%...not my wrongly stated 6.7% or the 10% stated elsewhere.

the amount of noticeable smog in the air in Houston, particularly on a cold morning, is much less now than before we started using the 10 percent ethanol mixture.

And we don't have to worry about MTBE contaminating everything it comes in contact with.

Back in the late 80's they started putting alcohol(ethanol?) into the gas. I unknowingly put some into my '87 FJ1200 and it destroyed the rubber in the carburetors. I wonder if vintage bikes are going to have a problem.

I've occasionally put ethanol laced gasoline into my FJR and haven't had any problems. I'm glad to hear that others haven't either.

r1byker said:

Back in the late 80's they started putting alcohol(ethanol?) into the gas. I unknowingly put some into my '87 FJ1200 and it destroyed the rubber in the carburetors. I wonder if vintage bikes are going to have a problem.

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Yep with bikes that old. Rebuild kits tend to include alcohol resistant materials. It's a problem most people restoring or running vintage equipment know...or have learned.

03HiYoSilver said:

I hope it does not damage our fuel system for vehicles not designed for Ethanol usage... only time will tell.

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Well, it is already starting.....

From the article: "Just as boats may sit and the separation of the gas and ethanol in the tanks can lead to problems, there are reports that homeowners are facing similar problems with their lawn equipment.

A second issue with ethanol is that it cleans everything it has contact with, from whatever point it is mixed in with gas at the refinery or tanker and it carries all those contaminants to a boat’s fuel tank, said Rush of San Carlos Marine. Those contaminants can clog fuel filters and the injection system.

“You will limp in if you can even get home,” Rush said.

“A lot of the repair bills come from the intrusion of water and contaminants in the water,” said Kaestner of Matanzas Marine.

There also are reports that ethanol can cause polyester resin in older fiberglass fuel tanks to degrade to create a gunk that clogs the fuel system."

https://www.naplesnews.com/news/2008/nov/22...say-ethanol-ha/ (For the Full Article)

There have been reports of Engines having to be replaced since the Water drawn in by the Ethanol has Rusted the Pistons/Cylinder walls.

Keep very careful watch with your engines this year.