E10 vs E0 MPG study

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I did the MPG study in my 2003 corolla with 10% ethanol in BP gas vs 0% in Chevron gas.

9 tankfulls, 100% city driving, alternating between BP and chevron gas.

There was a slight difference in means (E10=28.1 MPG; E0=28.64 MPG) but it was not statistically significant (p=0.56).

This was in contrast to the first impression when I got 26.4 MPG with E10 and it went up to 27.7 with E0.

The lesson is, changes bases on a single tankful can be misleading.

BTW, the range was 26.4 to 29.8. Both the highest and lowest was with E10.
 
One engineer wrote a letter to the editor in Automotive Engineering Sept '09 issue on this matter. He ran many tankfuls of E10 and E0 in his 2008 Nissan Rogue. The bottom line was that he got 7.8% better mileage with E0 over E10, even though E10 has only 3.3% less BTU content. Using the widely accepted basis that it takes 75% of its energy in gasoline to produce ethanol, it can be argued that he was actually burning more gasoline with E10 than if he ran 100% gasoline. E10 does not reduce our dependence on foreign oil!
 
I think this is because most cars are calibrated for E10 and not "E0" as you called it, fuels.

Using E0 fuels in place of E10 will change the mileage somewhat as the engines computer adjusts the fuel mixture to compensate based on 02 sensor readings but the timing is still retarded for the E10 as set by the OEM, and doesn't change if the car isn't equipped with a knock-sensor based on the fuel that is used.

If the car has a knock-sensor the fuel economy should be much better with a E0 fuel versus an E10.

Now using a E0 fuel even at a higher cost is better IMO because you generally get the best or more additives from the company you purchase it from, a better octane rating, leading to lowering of NOX readings which is good for the oil and engine life due to decreased cylinder temperatures, and you have the benefit of not having all that ethanol in your system possibly wearing your fuel system components down faster than with an E0 fuel.

Most cars will never see a problem running E10 fuels but those of us that want superior life out of our components should consider running an E0 gasoline all the time.
wink.gif


Now you could get a tuner and reprogram your ECM's spark timing so that it is setup for a higher octane fuel and you can see the mileage benefit.
 
Originally Posted By: StevieC
I think this is because most cars are calibrated for E10 and not "E0" as you called it, fuels.


Almost any vehicle made since the late 90s SHOULD be able to trim its tables enough to burn E10 close to optimally, I would think. However, the real test would be to run a comparison using a FlexFuel rated engine, which can run optimally on anything up to and including E80.
 
It's a crying shame that automakers can't or won't design all cars to run optimally on both fuels... especially considering the Herculean efforts used to meet CAFE.

The choice to run 100% gasoline has been taken away from us.
 
Originally Posted By: Kestas
It's a crying shame that automakers can't or won't design all cars to run optimally on both fuels... especially considering the Herculean efforts used to meet CAFE.

The choice to run 100% gasoline has been taken away from us.
+1
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I completely agree... They should not have removed the choice.
 
I consistently loose 2 MPG (from 14 to 12) when I fill-up with E10 in my Axiom. This year am running MMO in every tank, and so far, my E0 mileage has been 15.5-16 MPG. I just started using E10 (mandatory winter mix in AK), but so far it has been right around 14.1 MPG. We'll see what happens later in winter.
 
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1. Doubt if there is any difference between the amount of ethanol in those two brands, sold in the same area. It could be different IF the Chevron stations advertise that they are 100% gas, and no ethanol. Otherwise, just because you THINK there is no ethanol in the Chevron gas, does not make it so.

2. ALTERNATING between the two brands is not a good test. What you are doing is mixing the two brands on each fill-up. A better test would have been to run 9 tankfulls of one, then 9 tankfulls of the other.

In my case, my former car (MKZ), plus my Continental gets between 10% to 20% WORSE on E10. Matter of fact, when Florida switched to E10, I had a good comparison. In addition, whenever I go to Western New York, I use Hess from one station that is 100% gas, and my milage goes up by 10% to 20%, with those two cars. Last year, with the MKZ, I fulled up at that Hess Station, then drove South, and made it to North Carolina before I needed gas (running on fumes). I could never do that filling up on E10 while up there. Just returned from the same trip with the Continental, and again, my gas milage was much better than when using the E10.

My Genesis is a different story. Almost all I can get is E10. I get GREAT gas milage with this car, however there is one place near where I live in Central Florida, that advertises they have 100% gas, no ethanol. Their price is normally 35 to 40 cents a gallon more than the other stations. OK, When the price of gas fell down to the $2.30 range, I started to use the no ethanol gas. I used two or three tank fulls. No Change. Could be that the Genesis is tuned for E10, don't know, but I do know that there was no difference with the Genesis but a big difference with the former MKZ and present Continental.
 
Originally Posted By: ctrcbob
It could be different IF the Chevron stations advertise that they are 100% gas, and no ethanol. Otherwise, just because you THINK there is no ethanol in the Chevron gas, does not make it so.


If you get Chevron gas that comes from the Pascagoula refinery, it doesn't contain any ethanol.

And most of the e10s you are getting aren't a full 10% of ethanol either. "Up to"...being the key words there.
 
Yes, chevron in my area advertises "100% gas" and "no ethanol" is stated on the pumps.

As for the BP, you are correct, "up to 10% ethanol"
 
Originally Posted By: ctrcbob
1. Doubt if there is any difference between the amount of ethanol in those two brands, sold in the same area. It could be different IF the Chevron stations advertise that they are 100% gas, and no ethanol. Otherwise, just because you THINK there is no ethanol in the Chevron gas, does not make it so.

2. ALTERNATING between the two brands is not a good test. What you are doing is mixing the two brands on each fill-up. A better test would have been to run 9 tankfulls of one, then 9 tankfulls of the other.


#1 is addressed in the post above.

#2 the alternating is clearly a better design due to control for weather and ambient temps. When I started the study, the temps averaged 90F and AC was used 100% of time. MPG was about 27 at that time. By the time I finished, temps were near 60F and heater was used at times. MPG is about 29 now. So, your design would lead to wrong conclusions. Yes, there was some mixing, but I refilled with 1-2 gallons left from the max 13.5.
 
Originally Posted By: StevieC
I think this is because most cars are calibrated for E10 and not "E0" as you called it, fuels.


No! The automakers import E0 from way far away to run their CAFE tests. IIRC it was chevron too.
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The feedback fuel systems can more than handle this, even the stupid carbs of the early 80s.
 
Originally Posted By: eljefino
Originally Posted By: StevieC
I think this is because most cars are calibrated for E10 and not "E0" as you called it, fuels.


No! The automakers import E0 from way far away to run their CAFE tests. IIRC it was chevron too.
wink.gif


The feedback fuel systems can more than handle this, even the stupid carbs of the early 80s.
So how does my engine without a knock sensor know there is premium fuel in the engine and advance the timing?

How does a carb engine do so without a manual retune?

Please fill me in...
 
Originally Posted By: friendly_jacek

#2 the alternating is clearly a better design due to control for weather and ambient temps.


That is MORE than offset by the fact that every tank is actually a mixture of gasolines. Your "E10" tank is always less than 10% ethanol, and your "E0" tank is always more than 0%.
 
Originally Posted By: StevieC
[/quote] So how does my engine without a knock sensor know there is premium fuel in the engine and advance the timing?


It doesn't, but then most current E10 regular-grade blends are not actually higher octane than the non-ethanol regular grade blends. They simply use ethanol to achieve the same octane that was previously achieved with other additives such as MTBE.

Originally Posted By: StevieC

How does a carb engine do so without a manual retune?

Please fill me in...


70s and 80's feedback carbs (eg. Chrysler Lean Burn, Ford VVC, etc) could skew the mixture over a rather wide range using the varible-duty-cycle enrichment solenoid under computer control. That's why those cars had 02 sensors and computers, after all.
 
I have done a few "test" between E10 and E0 on 2 of my cars. I averaged about 1-1.5 mpg more on E0 but the cost of the E0 is 15-30 cents higher in my state, so in actuallity is its cheaper to run E10.

Ethenol is a joke, it cost so much to produce. There was a National news story about my state (Nebraska) we have the lowest unemployment rate in the country right now. They contribute it to corn production and the money made by selling corn and turning it into Ethenol and Food Products. After all Nebraska is the #1 corn producer in the country, perhaps the world.

While that should make me a fan of Ethenol I am not. The famers get paid the most to grow corn and to use it for ethenol, they get tens of billions from the government in subsudies to do so. Look at jst about any food stuff today, corn is a huge ingredient, since the corn is going to ethenol it raises food costs.

I can understand the government wanting to use ethenol to not have to buy foreign oil, and that money stays in the country. It is a great theory but in actuality I think it sucks and doent work.

Some gas stations here ONLY sell 89 E-10 which sucks for me because I have 2 motocycles, a car and an ATV which will ping like creazy unless I use 91 octane. That choice is being forced on us weather we like it or not. Even the 87 E0 cost 15-30 cents MORE than the midgrade 89 E10. We can always "vote with our dollar" but in this case nothing would change and the gas companies get rich off the choice.
 
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