pure-gas.org

[litesong]

Looking at the accurate map of ethanol-free gas stations on the website pure-gas.org, there is a tendency for larger cities NOT to have ethanol-free gas stations. Even in the southern U.S., where viewing the map from an overall distance shows a higher concentration of ethanol-free gas stations, southern larger cities, specially away from the ocean, marine & airport facilities, have few & sometimes NO ethanol-free gas stations.
It is quite obvious that 10% ethanol gasoline is the only gasoline facilities for a very large percentage of Americans, despite some states having many hundreds of ethanol-free gas stations. There are no ethanol-free gas stations in all of southern California & only a handful in northern California. No ethanol-free stations in Houston, Austin, Fort Worth, or San Antonio, TX, nearly none in Portland, OR, Seattle & Tacoma, WA, Denver, Albuquerque, Washington D.C, Baltimore, Boston, NYC, Philadelphia. In the dense ethanol-free southern states, there are no such stations in Birmingham, AL, Montgomery, or Atlanta, Georgia, Richmond, Virginia..... The list is big & continues on.

Ostensively, 10% ethanol blends are to cut imports of foreign gas into the U.S. However, if mpg from 10% blends drop 5% & higher for a large percentage of vehicles using 10% ethanol blends, the political policies to use 10% ethanol blends fail to cut imported gas stocks much at all.

There seem to be some methods which may or may not raise mpg for those people using 10% ethanol blend gasolines if your vehicle is missing the sweet spot of efficient combustion. Re-jetting the fuel injection system may help. Since ethanol has higher octane than 100% gasoline, possibly a re-timing could help. I'm sure the mechanics here will also have other ideas.

However, the best way to avoid mpg drops & the 10% ethanol blend blues is to use 100% gasoline, for which gasoline engines were made to run efficiently AND WITH WHICH the EPA RUNS ITS MPG RATINGS FOR EVERY BRAND OF GASOLINE VEHICLE.

[litesong]

i filled up on thanksgiving for 3.19/gal in pomeroy ohio.. anywhere else its 330ish

Did you fill up with ethanol-free gasoline? pure-gas.org does not have Pomeroy, OH listed for ethanol-free gas stations. If you did fill up on ethanol-free, you should list it on pure-gas.org.

If you did fill up on ethanol-free, have you run enough to determine any difference between it & 10% ethanol blend? Meanwhile, the one station in Parkersburg, WV is about 15 miles from Marietta, Ohio, roughly the same distance from a station I go to that has a good price on ethanol-free.

[getnpsi]

87 octane fuel with 10% ethanol has the same octane as 87 rated 100% gasoline. They use a lower octane fuel and add ethanol to bring the octane rating back up. You will knock the same with 87 octane no matter the blend.

[blkfordsedan]

Around here, the E10 blend is 89 octane (vs. 87 for straight unleaded). Some stations now even have premium with 10 percent Ethanol (rated at 91).

One of the reasons you can't find "pure gas" in high population areas is because ethanol fuels burn cleaner. Such areas need to control the emissions more. Fuel blends are very specific to the area and gov regulations dictate what fuel can be sold where. That's also one of the reasons gas prices fluctuate between areas and increase the overall cost for everyone. Government regulation defined.

[getnpsi]

There are three times as many cars out here then there were when i was a kid growing up. I don't remember hearing about a smog inversion or a stage 1 alert in years. I don't think its merely passenger cars or e10 that has helped the air quality versus industry and cows leaving the state, along with stricter laws on diesel burning and bunker fuels at the ports. Every little bit helps/hurt but of course as a car enthusiast i dont want to admit something i use and consume is the root of the problem, when it's all of it. CARB is a joke.

[blkfordsedan]

There are three times as many cars out here then there were when i was a kid growing up. I don't remember hearing about a smog inversion or a stage 1 alert in years. I don't think its merely passenger cars or e10 that has helped the air quality versus industry and cows leaving the state, along with stricter laws on diesel burning and bunker fuels at the ports. Every little bit helps/hurt but of course as a car enthusiast i dont want to admit something i use and consume is the root of the problem, when it's all of it. CARB is a joke.

LOL, you're trying to use logic to determine the basis and effectiveness of government regulations :nono:

[getnpsi]

Indeed. As the "little people" we just have to make do with whats available. Hypermiling techniques will offset any loss in fuel formulations. If you drive 10% less you have bought 10% less and so on.

[Darlo]

Hey, lets discuss them any way so you can use the proper terms when you attempt to, again, discuss something beyond your comprehension.
First off you need to do more research and find the difference between additives and extenders/diluents.
The additives I speak of are used to keep the fuel from polymerizing in your tank, keep things suspended into solution, keep the fluid from foaming excessively when filling your tank, keep injectors clean, and remove or keep deposits from forming, among other things.
They are used in both "pure" gas as well as the ethanol contaminated versions for the same purpose.
Again,loadings measured in PPM to maybe 1%.

At 10%, or more, ethanol is hardly an additive.

I suspect your extraordinary MPG is likely caused by an improper fill, more so than an under sized tires.
FYI, mile markers suck when it comes to estimating a proper distance.
Stick with the GPS.
You might even want to use fuelly.
Darlo, a member here, has a pretty high MPG over many tank fulls.
The difference here is, I trust his number way more than yours!

Its too bad I didnt catch this sooner.........

Ok, now listen up........ Ethanol is 66% as efficient when compared to gasoline (energy per volume), so you might look at this and say “Holy crap, I will get only 66% the gas mileage!”, but you would be very wrong.
When fuel contains 10% Ethanol and 90% gasoline, you are actually only losing 3.4% mpg!
This can be easily proven  (0.1)(0.66)+(0.9)(1.00) = .966 = 96.6% efficiency


Now for the variability in your measurements. I have 60 fuel ups now with my Festiva, and have seen some “weird” fills, but only between 41.4mpg and 52.5mpg. The fact that (the thread author) got 57mpg on one fill and then 47mpg on the next…….Something is causing this beyond additives. Most likely he clicked off the fill nozzle too early thus causing there to be a false increase in mpg for that fill.

Everyone needs to FORGET about filling “at the same pump at the same station at the same time of day at the same temperature…..etc”. These variables are small potatoes compared to driving style, tire pressure, driving temp, weather, city/hwy, etc. Think of it this way, if you were stabbed by 3 things, a pin, a steak knife, and a samurai sword, where to you think the doctor would start when stopping the bleeding? NOT at the pin or the steak knife, because they are causing WAY less danger than the giant sword! In the same way, you cant worry about things like fuel additives, and gas station elevation (etc), when you should be worrying about driving perfectly and keeping your tires inflated. (oh and by the way, your city driving mpg would increase significantly if you simply turn your car off at lights that would be longer than 15 seconds.)

Now a little stats…….

The smaller of an effect something has on an outcome, the more trials it takes to determine whether that variable is statistically significant. What this means can be understood by a simple example.
If I wanted to find out the relationship between tire pressure and mpg, I could reduce my tire pressure to 20psi and drive for 5 fills, and then switch back to my regular 45psi. Now I would have say 15 fills to work with (5 before, 5 during, 5 after), and say I got numbers like 46,45,42,47,45 ---- 41,39,42,45,40 ---- 45,44,48,46,47. (They average 45mpg before, 41.4 during, and 46 after) You could be pretty confident that the lower mpg that occurred during the (trial period) was due to the lower tire pressure. This would still need to be proven by calculating the standard deviation of each set of numbers, and then applying a 95% confidence interval, and all that, but I will save you from this, lol…….
The point is this, if I now did something that had less of an effect on gas mileage (like say, a Kamm-back), where I am only looking to increase my mpg by 3%, I would need to fill up 40 times with the kamm on to see if there is any statistically significant difference.

All summed up, the smaller the effect of a variable on an outcome, the more trials you need to do to prove that the effect you are seeing is not simply a natural variation caused by other variables.
BTW….I love stats….



Ps. Pu241, you are doing very well with your gas mileage!

[Pu241]

Darlo, think you covered some good points!

The style/type of driving is very important.
For me, I do a lot of long distance/minimal stop driving.
But, because I have to run at near highway speeds (60-65 MPH) to keep from becoming a statistic my MPG suffers.

And with your Kamm-back your only estimating a 3% gain, but as you and I have discussed you rarely exceed 50MPH so yes it's going to be a smaller effect.
Where as if I had the same setup I should see a larger effect, purely due to the my average speed being higher and my Coefficient of drag being higher at the higher speed.

Yeah my is MPG OK, but this is my Fall/Winter/Early Spring Car so I have to pull out the log and get my Fuelly updated. I expect the average to fall when all the data is in!

[Darlo]

And with your Kamm-back your only estimating a 3% gain, but as you and I have discussed you rarely exceed 50MPH so yes it's going to be a smaller effect.
Where as if I had the same setup I should see a larger effect, purely due to the my average speed being higher and my Coefficient of drag being higher at the higher speed.
(

You are incorrect about the coefficient of drag changing with speed. As well as you seeing more effect than me. Here is why:

The total drag increases D = (0.5)(p)((v)^2)(A)(Cd)

D = total drag
p = density of air
v = Velocity of car
A = frontal area of car
Cd = coefficient of drag

So you can see, by reducing Cd by 3%, you will decrease your total drag by 3% given everything else is constant.

So for me driving at 55mph, say I get 50mpg without the kamm, I should see 51.5 with the kamm (3% increase)

For you, if you drive 65mpg say you get 45mpg without the kamm, you should see 46.35mpg with the kamm (also 3% increase).

In actual fact, I gain more mpg by adding the kamm than you would, BECAUSE I drive at the slower speed.

Isnt math fun, lol......


Ps. Check out this site! http://www.atmosphere.mpg.de/enid/In..._drag_507.html
.
.

[Pu241]

You are incorrect about the coefficient of drag changing with speed. As well as you seeing more effect than me.

You are correct!
I concede the math!:notworthy:

[Darlo]

You are correct!
I concede the math!:notworthy:

HAHA, indeed.........:p

[nitrofarm]

Zoom Zoom,

litesong is a bit sloppy in his use of terms.

And now he pulls the term "non-energy producing additives"out of another orifice.
Typically, gasoline will have add packs in it even before it arrives on the barrage to the distribution centers. At the distribution centers more adds, specific to a brand, and others, are added to the gasoline when loaded on to bulk tanker and transported to your local station. Incidentally, they all burn and they all produce energy. Additives are typically in the ppm to 1% or so level from AO's, anti-foaming, suspension agents, and anti-fouling agents and others.

So litesong, what "non-energy producing additives" were you trying to exclude?

He said ORIFICE,thats Kewl !

[litesong]

pure-gas.org shows that 100% gasoline stations have increased by 100 over 4 months to somewhat under 5000. With the end of ethanol subsidies at the end of last year, there is no rush for gas stations to sell 100% pure gasoline.

At the end of autumn 2011, I switched to 100% pure gasoline. As winter took hold(not a good time for mpg increases in northern states), our 3 cars increased their mpg over 10% ethanol blend by 7-8% for a 1988 Ford Festiva, 7-8% for a 2007 Dodge Caliber, & 6% for a 2008 Hyundai Accent. As the spring warmed, our 3 cars' mpg compared to 10% ethanol was 8% for the Festiva, & remained unchanged for the Caliber & Accent.

[Darlo]

pure-gas.org shows that 100% gasoline stations have increased by 100 over 4 months to somewhat under 5000. With the end of ethanol subsidies at the end of last year, there is no rush for gas stations to sell 100% pure gasoline.

At the end of autumn 2011, I switched to 100% pure gasoline. As winter took hold(not a good time for mpg increases in northern states), our 3 cars increased their mpg over 10% ethanol blend by 7-8% for a 1988 Ford Festiva, 7-8% for a 2007 Dodge Caliber, & 6% for a 2008 Hyundai Accent. As the spring warmed, our 3 cars' mpg compared to 10% ethanol was 8% for the Festiva, & remained unchanged for the Caliber & Accent.

To get better results for comparison, you must alternate fills between the variables you are changing. This way, other variables (temp, rain, time between oil change, etc) will not be playing nearly as much of a role in the variability of the mpg data........

If you would like, if you have recorded all the controllable variables (aka date of fill, ethanol content, A/C usage etc.), I can take your data and run a proper statistical model to see the actual effect of the ethanol.

I went for an entire year recording several variables and this is the formula that accounted for about 93% of my gas mileage variability :

MPG =
378 - 0.000033 Aggressive cubed + 0.00430 Aggressive squared
- 0.158 Aggressive % - 0.000401 A/C squared
+ 1.39 Cutting engine at lights - 0.000882 city X aggressive
- 0.647 Fills since oil change + 0.0372 fills since oil change squared
- 0.000063 pounds of gas cubed + 0.0335 pounds of gas squared
- 5.85 pounds of gas on average

I have the variables:
% Aggressive driving in a given tank(then squared and cubed of variable)
% A/C use in a given tank (then squared too)
Tanks of gas that I turned off the car at lights
# of fills since last oil change (average fill is 400 miles)
pounds of gas in my tank on average in a given tank (squared and cubed)

I also have a X product in there as well (city X aggressive) which takes my %city driving and multiplies the % of time in that same tank that I drove aggressively.

I had 23 data points (23 fills over the course of the past few months).
This regression model gives a R-squared value of 92.9%. (which means that 92.9% of the variability in my gas mileage is accounted for in this equation.)

Oh and the reason I added the pounds of gas in the tank is due to the debate over whether getting gas too often (aka when you still have half a tank) will hinder your mileage. And it does indeed seem to.

(All percentage values were multiplied by 100)

As for aggressive driving, I defined it as the percent of the miles driven that I
a) would speed (to a maximum of 10 mph above the limit)
b) purposely accelerate and brake needlessly (aka in the city in between lights)
c) drive in a lower gear (aka higher revs for same speed)
And this percentage may be off by 5% or so either way, but as per the large "n" normality in the data's variation would indeed even out.,

I just started a new thread about this, lol