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Mike and zwede, you are failing to consider a couple of things when stating that 10% ethanol cannot result in a greater than 10% loss of fuel economy.
1. All modern engines possess the ability to retard the ignition timing when it senses ping.
Ethanol burns hotter than gasoline.
If, due to engine design, ethanol puts the engine closer to detonation then the computer is going to sense this and retard the ignition timing.
This results in less power. That can translate into less fuel economy.
2. Ethanol absorbs water. Not only does the water take up volume in your fuel tank it also is inert in the combustion process to produce power and is a loss of power in addition to the loss due to the ethanol.
The loss of fuel economy due to water absorbtion is therefor two fold.
In my 2008 Mazda 3, I experience a 12% loss of fuel economy.
In my 2008 Mercury milan I experience a 13% loss of fuel economy.
In my 1994 F-150 I experience a 10% loss of fuel economy.
A co-worker of mine has a 2013 Toyota Corolla.
He gets 38 MPG with ethanol blended 87 octane.
But only gets about 30 MPG on straight 85 octane gasoline.
And on blended 91 octane 40 MPG.
So it would appear that his engine approaches detonation on both 85 straight gas and the blended 87 octane and his timing is being retarded on both those fuels, more so on the 85 straight gas.
I don't see how else you can experience a 21% loss in fuel economy on 85 gas vs the blended 87.
According to Mike and zwede's own data/ computations, the loss should be from the blended 87 due to the ethanol content and not from the straight 85 octane gasoline.
Each year when the winter blend hits the pumps I experience a similar loss of about 8% in fuel economy in my Mazda 3 with straight gas due to the lighter fuel being used combined with the enrichment circuit being active for a longer period of time due to a cold engine.
Mike and zwede, you are failing to consider a couple of things when stating that 10% ethanol cannot result in a greater than 10% loss of fuel economy.
1. All modern engines possess the ability to retard the ignition timing when it senses ping.
Ethanol burns hotter than gasoline.
If, due to engine design, ethanol puts the engine closer to detonation then the computer is going to sense this and retard the ignition timing.
This results in less power. That can translate into less fuel economy.
2. Ethanol absorbs water. Not only does the water take up volume in your fuel tank it also is inert in the combustion process to produce power and is a loss of power in addition to the loss due to the ethanol.
The loss of fuel economy due to water absorbtion is therefor two fold.
In my 2008 Mazda 3, I experience a 12% loss of fuel economy.
In my 2008 Mercury milan I experience a 13% loss of fuel economy.
In my 1994 F-150 I experience a 10% loss of fuel economy.
A co-worker of mine has a 2013 Toyota Corolla.
He gets 38 MPG with ethanol blended 87 octane.
But only gets about 30 MPG on straight 85 octane gasoline.
And on blended 91 octane 40 MPG.
So it would appear that his engine approaches detonation on both 85 straight gas and the blended 87 octane and his timing is being retarded on both those fuels, more so on the 85 straight gas.
I don't see how else you can experience a 21% loss in fuel economy on 85 gas vs the blended 87.
According to Mike and zwede's own data/ computations, the loss should be from the blended 87 due to the ethanol content and not from the straight 85 octane gasoline.
Each year when the winter blend hits the pumps I experience a similar loss of about 8% in fuel economy in my Mazda 3 with straight gas due to the lighter fuel being used combined with the enrichment circuit being active for a longer period of time due to a cold engine.
I drive a 2010 Honda Insight as my commuter car. Summer Blend 44-45 mpg with normal driving and up to 50 mpg if I am trying.
Winter Blend at best 43 mpg and typically 40-41. The reduction is immediate.
The insight has 233k miles on it so this is a pretty good snapshot having gone through 4 winters.
My pop was a meticulous SOB.
I saw his data.
If he said 10% between gasohol and pure gasoline, it was 10%.
Pop may have told fish stories now and again, but he didn't mess around when it came to numbers.
Mech. Engineer
Worked in and with the oil industry all his professional life.
I saw, talked about, and believe his research. He didn't get into evaluating seasonal blends, but I bet he could have told you some things about them.
You could say I'm biased 'cause it was my Pop I'm talking about.
You wouldn't be off in that.
Again, I saw the numbers.
I had let my car sit with a mostly full tank of 10% ethanol gas for almost a year. After I started driving it again I was having a hard time keeping the car running during idle. Noticed fuel pouring out of the rear vent tube. Took off the rear float bowl and saw this
The rubber turned to mush when I touched it. I ended up siphoning all of the gas out and replacing all the rubber fuel lines. No more ethanol gas for my vette or lawn mower
The rubber turned to mush when I touched it. I ended up siphoning all of the gas out and replacing all the rubber fuel lines. No more ethanol gas for my vette or lawn mower
That's why you replace them with hoses made for ethanol blended fuels. This is not an insurmountable problem.
And if you replaced the hoses odds are the new ones are ethanol compatible.
As for lawn equipment: I put stabil & MMO in the gas. I don't drain the tanks for winter. Both my lawn mower and trimmer starts right up in the spring. The lawn mower is 11 years old and has run E10 since new. It runs perfectly.
That's why you replace them with hoses made for ethanol blended fuels. This is not an insurmountable problem.
And if you replaced the hoses odds are the new ones are ethanol compatible.
Correct. Ethanol compatible materials have been available for 30+ years and used in all cars for at least 20. Shame on Holley for selling the poster a non-compatible float.
Strictly speaking ethanol does not burn hotter. It burns cooler than gasoline. I just put it that way for simplicity.
The Stoichiometric ratio for Ethanol is 6.4:1.
The Stoichiometric ratio for gasoline is 14.7:1
So if ethanol is introduced into the gasoline and no correction in fuel mixture is made then you have a lean running engine. This increases the combustion temperatures and can lead to detonation if left uncorrected.
In our carbed Corvettes that would require an enrichment of the air fuel ratio (larger jets or other adjustments) to offset the ethanol mixture to get back to a correct Stoichiometric ratio. This decreases the fuel economy in addition to the loss of energy due to the ethanol content in the fuel. So a two-fold loss.
In modern timing adjustable and close loop fuel injected systems the system will sense the lean condition and command a richer fuel ratio, but only after it have sensed it.
Prior to that, the immediate condition at throttle application is a lean one.
If ping developes then the timing will be retarded.
So depending on the required mixture ratio and the immediate conditions demanded, either enrichment will occur or timing retardation will occur and maybe both. Both strive to correct the lean/hot condition in the cylinder just for different reasons.
One of the more respected Corvette restorers here was having a hard time getting an old fuelie to run well. On a hunch, they put some ethanol free gas in it and it started running better. So they decided to test some of the local gas stations.
They went out and bought a gallon of gas from 6 or so stations including name brands.
Some were 11% ethanol, and the rest varied all the way up to one sample was 30% ethanol. That particular gallon came from a Texaco mini-mart station.
So if ethanol is introduced into the gasoline and no correction in fuel mixture is made then you have a lean running engine.
Except that no production carbed engine came off the line jetted spot-on. Not possible to do in a production environment, so they deliberately jetted them rich. If anything, a 3% shift to lean by using E10 would improve performance in this respect, not cause the sky to fall as you're predicted.
That's two posts you've started using a false premise to bolster an incorrect theory.
We use pump gas in our race cars and measure every time we buy fuel for the ethanol content. I can't say for winter blends, but summer blends we have never seen over 3% ethanol, while the pumps say can contain up to 10%, doesn't mean they do. Last fuel I bought was around 1%.
Except that no production carbed engine came off the line jetted spot-on. Not possible to do in a production environment, so they deliberately jetted them rich. If anything, a 3% shift to lean by using E10 would improve performance in this respect, not cause the sky to fall as you're predicted.
That's two posts you've started using a false premise to bolster an incorrect theory.
Lol what was I thinking? I have actual facts and you have your opinions. How could I possibly dispute the opinions of the almighty mike ward. He knows all. Stupid me.
If you care to actually back any of your assertions with some kind of factual data we can have a healthy debate over the facts based on data, not your personal opinions.
OK, have it your way. Show me proof that cars were jetted spot on and that going 3% lean would cause the sky to fall as you've asserted. Onus is on you.
OEMs made hundreds of squillions of cars with carbs. E10 has been around since the 70s. Not one car I've ever heard of has suffered the horrible fate you've predicted.
In modern timing adjustable and close loop fuel injected systems the system will sense the lean condition and command a richer fuel ratio, but only after it have sensed it.
Correct.
Prior to that, the immediate condition at throttle application is a lean one.
Incorrect. The factory calibration is rich, just like a carb car used to be. The computer learns how much leaner it can go by monitoring the O2 sensor. The resulting fuel trim is stored in a map. The map has rpm and load is the axis (it's a 2D map). Next time the engine hits that load & rpm it will start with the learned trim.
If ping developes then the timing will be retarded.
The engine will not ping due to E10. If you fill up with straight gas and then with E10 the computer will need a few miles to re-learn the trim table. After that you won't notice a difference. The initial slightly lean situation (after you fill up with E10) is not enough to ping. The computer is extremely fast at correcting.
The tank in my '69 rusted through from the inside out. Tank always kept full, stored in the garage in California. Ethanol is hygroscopic, weakly bonded to gasoline and falls to bottom carrying water with it and rusting the metal. The Corvette Center in Colorado Springs said they have been seeing a lot more of these issues since the prevalence of ethanol blended gasoline.
Furthermore ethanol blended gasoline is a ridiculous politically driven policy. We mine hydrocarbons for fuels, grow food to eat, not put in our gas tanks. Our posterity in a couple of hundred years will wonder how we could have been so stupid.
