Pure Gas vs. 10% E

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If this is a stupid question, I apologize in advance.

Is pure gas better than a top tier 10% fuel? I used to always fill with Chevron. I found a station called Cenex that sells pure gas in 93. I just never heard of Cenex. Pros and cons?? What are your thoughts on what I should be using?
 
Would you be mad if the bartender added 10% water to your 12 year old scotch?
Your car feels the same way.
 
Originally Posted By: BovineScapegoat
In my area only regular 87 is 10% E. midgrade 5% and premium is always 0% Ethanol


Not likely.
The only gas that is advertised to be ethanol free in Ontario is Shell V Power premium 91 octane.
 
If find my 5.3l Silverado hardly pings at all on pure gas, and it seems finicky on what you put in it (especially in heat). My Camry beater gives me about 3mpg better on pure gas too. But the problem for me is that it costs more than super unleaded by nearly 10 cents per gallon. So economically I just run pure gas every other tank in my truck during the hot summer months. The Camry really doesn't care on way or another.
 
Originally Posted By: PhillyJoe
Would you be mad if the bartender added 10% water to your 12 year old scotch?
Your car feels the same way.


I sure hope my fuel is not 12 years old! But I am in complete agreement.

Our fleet trucks take a big hit on 10% corn liquor, my car actually likes it for KR values but still costs me more as the mileage goes down with it.

Ever see the carb jet sizes in an alcohol fueled car at the strip? Some of the fuel pumps are like a commercial well on a farm! Takes a lot of liquor to make it work.

let's burn all our food as fuel and save the world...
 
Originally Posted By: Danno
Originally Posted By: BovineScapegoat
In my area only regular 87 is 10% E. midgrade 5% and premium is always 0% Ethanol


Not likely.
The only gas that is advertised to be ethanol free in Ontario is Shell V Power premium 91 octane.


I know that in Canada both Shell and Ultramar does the 10%, 5% and ethanol free thing with premium. Petro can and Esso say up to 10% ethanol/dont specify. I dont like the idea of ethanol but doubt it makes a difference in mileage on a tank at an up to 10% ratio.
 
I use whatever octane that the owners manual recommends. There are a couple of stations that in town that sell 100% gasoline but at a premium cost.

As far as mileage goes paying the extra price is simply not worth it in my opinion.

Keeping vehicle in tune. Keeping tires properly inflated. Adjusting driving some will = fuel savings.
 
Remember that "if" the gas actually contains 10% ethanol (my local gas contains somewhat less by my tests 4% to 7% lately) , the gas has 3% less energy content. This means that MPG will be reduced by about 3%. If you get 33MPG, you can expect to lose about 1 mile per gallon at 10% ethanol.

However, locally the gas is well less than 10% ethanol, and MPG loss is very minimal. On the order of 0.5MPG.

We have local 100% gas (90 octane) station and I can't measure any MPG improvement while using the ethanol free gas.

That's all well and good. But here is what's interesting to me. The 100% gas has been having problems with water separating out! Causing rough running and occasional fuel starvation in my equipment. Yes, we had a lot of rain lately. And I suspect the station got a touch of water in the tank.

No problems with normal pump fuels. And, when I switched back to fuel with ethanol, the water was absorbed and problems went away.
 
It's not an issue of octane. It's an issue of energy content.
Ethanol has an energy content of 26.8 MJ/kg.
Gasoline has an energy content of 43 MJ/kg.
So if you put ethanol in gasoline, the mixture will contain less energy than pure gasoline.
In the case of E10, the energy content would be 41.4 MJ/kg, or about 4% less than pure gasoline. Maybe you wouldn't notice a difference in fuel economy with this relatively small decrease in energy. But in a car that gets 25 mpg on pure gasoline, you would get 24 mpg on E10.
In the case of E85, the energy content would be 29.2 MJ/kg, or about 32% less than gasoline. You would definitely notice a decrease in fuel economy with this mix. This is why I say people shouldn't pay more than 70% of the price of gas to buy E85. In all years that E85 has been out, I've never seen it priced that low.
 
Originally Posted By: SteveSRT8
Originally Posted By: PhillyJoe
Would you be mad if the bartender added 10% water to your 12 year old scotch?
Your car feels the same way.


I sure hope my fuel is not 12 years old! But I am in complete agreement.

Our fleet trucks take a big hit on 10% corn liquor, my car actually likes it for KR values but still costs me more as the mileage goes down with it.

Ever see the carb jet sizes in an alcohol fueled car at the strip? Some of the fuel pumps are like a commercial well on a farm! Takes a lot of liquor to make it work.

let's burn all our food as fuel and save the world...

+1 And it will be a hungry world we save, but the "green weenies" want fewer people anyway.
 
Originally Posted By: dparm
Modern cars are tuned to run on gas containing up to 10% ethanol, FYI.
What's a "modern" car?
 
Originally Posted By: A_Harman
It's not an issue of octane. It's an issue of energy content.
Ethanol has an energy content of 26.8 MJ/kg.
Gasoline has an energy content of 43 MJ/kg.
So if you put ethanol in gasoline, the mixture will contain less energy than pure gasoline.
In the case of E10, the energy content would be 41.4 MJ/kg, or about 4% less than pure gasoline. Maybe you wouldn't notice a difference in fuel economy with this relatively small decrease in energy. But in a car that gets 25 mpg on pure gasoline, you would get 24 mpg on E10.
In the case of E85, the energy content would be 29.2 MJ/kg, or about 32% less than gasoline. You would definitely notice a decrease in fuel economy with this mix. This is why I say people shouldn't pay more than 70% of the price of gas to buy E85. In all years that E85 has been out, I've never seen it priced that low.
And just think of the money we spend on fuel stabilization...helps the economy, too!
smile.gif
 
Thanks for everyones insight. Since there is a pretty widespread difference in price, I think I'm sticking with Chevron 10% for now. I do track mileage religiously and will monitor for changes.

Thanks again all.
 
Originally Posted By: A_Harman
In all years that E85 has been out, I've never seen it priced that low.


That is why ethanol is the biggest farce ever unleashed upon America. Food for fuel, stupid. Plus it is wasting billions of gallons of water.
 
Originally Posted By: HerrStig
Originally Posted By: dparm
Modern cars are tuned to run on gas containing up to 10% ethanol, FYI.
What's a "modern" car?


That's a great question! I assume he means any OBDII vehicle...?

In our fleet the ethanol cost us more than the math would indicate. My car also took a bigger than expected hit, but I have a handheld tuner and adjusted my mixture and timing values to work properly with liquor added.

The Farm Lobby must be proud. I read here where it only cost them 33 million to push it through, and the returns have been HUGE for them. Just another example of how big money gets the perks.
 
Originally Posted By: Hermann
Originally Posted By: A_Harman
In all years that E85 has been out, I've never seen it priced that low.


That is why ethanol is the biggest farce ever unleashed upon America. Food for fuel, stupid. Plus it is wasting billions of gallons of water.


The biggest "farce" is the idea that the food supply is diminished due to biofuel production.

Sad I have to repeat this again.... and you can check all this out for yourself.

80% of the total US corn production is used for livestock feed. Also, of the total US corn production, 40% is used for ethanol production. The human consumption portion of the total corn production is NOT AFFECTED!

Of the corn that is fed to livestock, most of the starches in the corn just pass thru. Cattle use the lysine from the corn and do not digest the starches. The starches, are what is used for ethanol production. So..... why not use some of the corn production for ethanol and use the resulting Dried Distillers Grain, which is primarily lysine based protein that livestock can actually use, in livestock production. This reduces feedlot runoff wastes and provides a fuel for automotive use. There is no "waste", but in fact, there is greater utilization of the nation's corn production.

It does not "waste" billions of gallons of water. True, it uses a large amount of water, but most of it is recycled, and what does get evaporated into the atmosphere just returns to the normal water cycle that has gone on since the world began. Seems some think that the water used in biofuel production is forever lost. Sad the public school system did such a lousy job.
 
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