ethanol question. Any chemist out there?

[Jem]

There are several videos on You Tube showing how you can add water to E10 and the water will absorb the ethanol and you can then decant the de-ethanoled gasoline off. Are they right? Very relevant here in the UK as all our standard fuel is going E10 next month. I have one car with 10.5 compression heads (not a T!) which I have to drive 8 miles to get Premium, which will remain E5 or lower.

[TXGOAT2]

I am not a chemist. However, ethanol is hygroscopic, that is, it will mix readily with water. Gasoline will not readily mix with water. Agitating ethanol-adulterated gasoline with water will cause the ethanol fraction to pick up water and sink to the bottom of the container. It might take a while for all the ethanol/water to settle out. It might not all settle out. The problem with doing this procedure, besides the obvious dangers of handliing fuel and the issue of what to do with the toxic ethanol/water waste is that stripping the ethanol out of a typical pump gas blend containing ethanol will lower the octane equivalency of the gasoline substantially. It will also reduce the volume of the gasoline ethanol blend. There may be other additives in a typical gasoline/ethanol blend that are hygroscopic and removing them or hydrating them could be very detrimental to your fuel system and engine. Loss of octane equivalency would not likely be an issue with a Model T, but the loss of already marginal octane equivalency for fuel used in a modern engine would be a serious problem, and the risk of having residual water in the fuel would also be real. To sum up: It's not a good or practical idea, and the risks and loss of fuel quality far outweigh the problems associated with using ethanol adulerated fuel. About all you can do is make every reasonable effort to buy fresh fuel and store it properly and use it as soon as practical... and vote ethanol pushers out of public office.

[mtntee20]

Jem,

In North America ( U.S. and Canada) there is a web site "pure-gas.org" where a person can search for fuel stations selling pure gas without ethanol added. Maybe there is a sister site for the U.K. It's worth a try.

Good Luck,
Terry

[John Codman]

How will stripping Ethanol out of gasoline lower the octane rating? Ethanol contains only a little more then half of the energy that the same volume of gasoline does. Gasoline is 116,090 BTU/gallon, Ethanol is 77,000 BTU/gal. I do realize that Octane (anti-knock rating) and energy content are not the same thing. If the anti-knock chemicals are evenly mixed in the solution, the pure gasoline should be unaffected as to octane rating unless the separation process pulls the anti-knock chemicals out of the gasoline in greater proportion then the Ethanol.

[Scott_Conger]

John

Octane is related to the burn rate, not power produced. Low octane fuel ignites with a "bang" to the cylinder/piston, thus the predisposition to knocking or pinging, where higher octane fuel ignites with a (relative) "push" to the cylinder/piston.

Increased compression in engines necessarily required an octane boost throughout the development of gasoline engines as compression and thus efficiency and power increased. Stripping ethanol from today's fuels and reducing octane would be of no concern to a T.

I recently erred in advice regarding volatility of old fuel, mixing "volatility" for "octane" in my mind, and had to very quickly amend my advice as being particularly boneheaded.

[Philip]

i thought octane is a rating of how much pressure the fuel will withstand before it fires on its own like a diesel.
e84 ethanol fuel is 100 octane at sheets

[TXGOAT2]

That's essentially correct, Phillip. The "detonation" point of the fuel in an operating gasoline engine is affected by octane equivalency, and about 100 other factors, including air/fuel ratio, engine temperature, ambient temperature, elevation, humidity, throttle position, the engine's volumetric efficiency in any particular operating mode, fuel volatility, combustion chamber design, valve, and piston design, ignition timing, and more. Most any engine will run well on straight, very low octane gasoline at idle and light throttle. However, as you open the throttle, everything changes, and that's when you need a sufficiently high octane equivalency to prevent the air/fuel mix from self-igniting, which can occur before or after the spark plug fires, or without the spark plug firing at all. In some instances, the spark plug will fire the mixture, and before it has all burned, secondary ignition will occur within the unburned portion of the charge, which causes a violent pressure spike within the cylinder which can result in damage to the engine. It's a very complex subject with many variables. What the gasoline engine wants is a fuel with sufficiently high octane equivalency that it will not self ignite under any operating condition the engine encounters. Diesel engines are another matter. Combustion timing in the diesel is controlled by the injection timing. The fuel cannot burn until it is injected into the cylinder, and then only as rapidly as it is injected. In a gasoline engine, the entire fuel/air charge is in the cylinder prior to the ignition event. Diesel fuel has a low octane equivalency, similar to kerosene.

[John Codman]

...but I still don't see why stripping the Ethanol out of a gallon of Gasoline will lower the octane rating of the remaining gasoline.

[Scott_Conger]

Since the ethanol is not an inert addition to the fuel, and the gasoline it is mixed with is not "just gas", but a hydrocarbon fuel comprising hydrocarbons, blending agents, and additives specifically formulated to be mixed to a particular ratio of ethanol, another additive, you are losing an important part of the blend. It is simply a scientific fact that ethanol is an octane enhancer and based on that fact, reasoning concludes that removing it from a particular volume of blended fuel, will thus reduce octane in that batch of modified fuel. There are other methods of boosting octane, but the world has decided to burn some of it's food rather than eat it. I think it is safe to say that the remaining gasoline did not "lose" octane, but simply reverted back to it's lower, pre-ethanol state. Not only that, but as the ethanol as an additive with certain properties, simply stripping it out of fuel does not necessarily leave an ideal fuel for combustion engines as the other combustion aspects that ethanol brings to that blend are now missing and have not been made up for in the resulting blend.

There are other chemicals which can be used to increase octane, as well, but ostensibly, ethanol was chosen to reduce tailpipe emissions. The fact that ethanol contains less energy, and thus reduces mileage in automobiles, and requires more fuel to be burned, or the unaccounted cost for damage that it can and does to vehicles, or the environmental damage that even the EPA has documented, it's use poses a number of valid questions, but for another time and venue. Good luck finding THAT venue.

Ask a baker, why does bread rise?
He/She would say "because it contains yeast", and maybe some information regarding the fact that gas bubbles form.
That's the level of answer you'd get in any bakery or baking forum around the world
If I wanted to know the exact chemical reaction that would NOT occur if yeast was left out, then like you, I'd ask a chemist, also...I just would not look to find lots of them on a Model T forum.

I do hope you get the answer you're seeking.

[John Codman]

So I gather that Ethanol inherently has a higher anti-knock (octane) rating then gasoline?

[Scott_Conger]

It slows the combustion down and reduces the predisposition of the fuel to self ignite under higher pressures and temperatures. These two issues became more and more of a problem as compression rose in general automobiles.

This is why AV-Gas is such a high octane and automobiles require a lesser octane. Different compression, different heat ranges, etc.

Folks who run AV-Gas in their T's with very high octane may be deriving benefits from the different additives in the fuel, but they are not making the car run "better" because of the increased octane rating. In general, higher octane of the fuel is wasted on a 4:1 low compression T. AV-Gas uses lead instead of ethanol to reduce knocks (pre-ignition) and as such, it is the lead which is effectively increasing the octane. Tetra-ethyl lead was a known "bad guy" from nearly the very beginning of it's use, and if one is prone to engaging conspiracy theories, this would be a good one to obsess over. How it remained in such extensive use for so long is a remarkable feat of hiding the truth. Av-Gas, though used by many folks in their old automobiles, it's use is, I'd suspect, is absolutely illegal for that purpose in many if not most or all places.

[TXGOAT2]

Ethanol has a high octane equivalency. Removing it from a typical pump gasoline blend will lower the octane equivalency of the blend. A number of combustible fluids have a higher octane equivalency than typical straight gasoline. Some are suitable for use as octane enhancers in motor fuel. Some aren't. Ethanol isn't suitable, for several reasons, one being its low BTU content. Water has a very high octane equivalency, and it reduces tailpipe emissions to zero. Fillerup! As far as that goes, engine exhaust has a high octane equivalency...

[Jeff5015]

OK, I've read the whole thread and can understand most of it.

I have one question. There is gas sold around here (Florida gulf-coast) that is labeled "Marine Gas", and marketed as ethanol free.

At 93 octane, is this better for a Model T engine or a 1950's era 292ci Y-block?

I was advised to run marine gas in my Model T.

Thanks,

Jeff

[FreighTer Jim]

Just glad I drive a diesel truck ….


FJ

[TXGOAT2]

Using the ethanol-free gasoline will eliminate the issues associated with the comparitively rapid and destructive decay of ethanol adulterated gasoline, especially in warm and humid environments. I know of no other advantage it would offer when used in a Model T. Unless you have a very high compression 292, the same would apply. There have been warnings issued about valve seat recession in older V8 engines with cast iron valve seats when using any unleaded fuel. I believe these issues only develop in higher-output engines that are run very hard for many thousands of miles. I wouldn't worry about unleaded fuel harming a typical 292 Ford under any normal conditions of use, other than the problem of ethanol adulterated gasoline's well known propensity to decay into a destructive crud in a relatively short time. I've seen a few FE Ford V8 heads with severe exhaust valve seat recession, but I don't know exactly what caused it. I suspect that long extended and very hard use with unleaded fuel may have played a role.

[TXGOAT2]

Beware the Black Goop diesel curse!

[FreighTer Jim]

My 7.3 PSD has over 400K on it.
Clean oil = clean injectors = long engine life


FJ

[Kaiser]

Well when you mix water in your gas olene, you end up with a water and alcohol mix and on top of that pure gas olene....
This is a win-win !! you get beter gas for your T and ... Gin is basicaly a water-alcohol mix , right ?
I'd say the gas companies are gonna make bootlegging a thing of the past, the money made on selling the "Happy Sally" are more than covering the gas bill

[TRDxB2]

Model T gas tanks are vented through the gas cap to allow gravity flow (siphoning) of fuel to the carburetor. As a result a small amount of moisture will accumulate in a gas tank due to condensation, independent of the fuel formula. The Model T fuel filter (aka potato) is designed to capture heavy than gas liquids to some degree. Needs to be flushed from time to time.
Question: Lets say that the condensed moisture results in 2 teaspoons of water. So which fuel blend (at 8 gallons each) will deposit water to the bottom of the tank?

Running Ethanol Blended Gas

Ethanol is hygroscopic – it attracts moisture from humid air. Phase separation is when ethanol in the fuel absorbs too much water, and separates from gasoline by dropping to the bottom of the tank since the ethanol and water mixture that results from phase separation is heavier than gasoline. May happen naturally in 3 months if unused & left in the gas tank. As an example, at 60 degrees F, water can be absorbed by a blend of 90% gasoline and 10% ethanol up to a content of 0.5 volume percent before it will phase separate. This means that approximately 3.8 teaspoons of water can be dissolved per gallon of the fuel before the water will begin to phase separate (8galons x 3.8 = 30.4 teaspoons capacity - 2 teaspoons of water = no separation, no water in the bottom of the tank and being able to accommodate 4.7 more oz of water))

Running Ethanol Free Gas
Condensed moisture in the tank will settle to the bottom of the tank since there is nothing to absorb the water - water is heavier than gasoline
One gallon of 100% gasoline can dissolve only 0.15 teaspoons water at at 60 degrees F. (8gallons x .15 = 1.2 teaspoons capacity - 2 teaspoons of water = .8 teaspoons of water in the bottom of the tank)

From https://www.epa.gov/sites/default/files ... terphs.pdf

[Art M]

I thought that alcohol can absorb water at a rate10 percent of its volume before there is separation of the two liquids. Maybe that applies to another type of alcohol. Been 60 years since I studied chemistry. Alcohol mixed with gasoline might change this whole absorption rate.
Art Mirtes

[TXGOAT2]

MTBE is not ethanol. It is methyl tertiary butyl ether, which is a uselsess, poisonous substance that has a great affinity for water. As far as I know, you can blend most any amount of water with ethanol or isopropyl alchohol. Beer, wine, and liquor are blends of ethyl alcohol, which is ethanol, and water, with small amouts of other substances. As I understand it, 100 proof liquor is 50% alcohol, or very close to it. Beer runs about 6 % alcohol. Everclear is 100% ethyl alcohol at 200 proof. I have been able to get a 1 1/2 horsepower John Deere E to start and run on rubbing alcohol, which is 70% isopropyl alcohol and 30% water. That doesn't make it a good fuel.

[TXGOAT2]

There are branded products, such as HEET, sold for the purpose of getting water out of fuel systems while preventing cold weather freeze ups. I believe that HEET consists of isopropyl alcohol. In theory, fresh, anhydrous gasohol would be able to remove small amounts of moisture from a fuel system and prevent fuel line freeze up.

[TRDxB2]

MTBE is not ethanol. It is methyl tertiary butyl ether, which is a uselsess, poisonous substance that has a great affinity for water. As far as I know, you can blend most any amount of water with ethanol or isopropyl alchohol. Beer, wine, and liquor are blends of ethyl alcohol, which is ethanol, and water, with small amouts of other substances. As I understand it, 100 proof liquor is 50% alcohol, or very close to it. Beer runs about 6 % alcohol. Everclear is 100% ethyl alcohol at 200 proof. I have been able to get a 1 1/2 horsepower John Deere E to start and run on rubbing alcohol, which is 70% isopropyl alcohol and 30% water. That doesn't make it a good fuel.

Thanks for noting the diff of MTBE & ethanol. I didn't realize that I had copied the wrong #'s from the link. Whiskey on the rocks
also MTBE is now banned or limited in several states. MTBE is also used in small amounts as a laboratory solvent and for some medical applications.

[TRDxB2]

There are branded products, such as HEET, sold for the purpose of getting water out of fuel systems while preventing cold weather freeze ups. I believe that HEET consists of isopropyl alcohol. In theory, fresh, anhydrous gasohol would be able to remove small amounts of moisture from a fuel system and prevent fuel line freeze up.

https://www.goldeagle.com/product/heet- ... r-remover/
HEET® brand contains a special fuel additive and methanol. When HEET® brand is added to the gas tank, it sinks to the bottom and mixes with any water. Since both HEET® brand and water are heavier than gasoline, they go to the bottom of the gas tank. HEET® brand absorbs water and keeps it from freezing, and blocking the flow of gasoline through the gas line and fuel pump. When the vehicle is started, the additives, methanol, water, and gasoline are consumed during combustion inside the engine.

So just like the rest When the vehicle is started, the additives, water, and gasoline are consumed during combustion inside the engine