Zeppelin

I just returned home from vacationing in Orlando with my family for the last 9 days and I found something quite curious. (BTW, I drove our van).

Before leaving, I filled(completely topped off as I always do) with kroger(Ohio) gas and we set off. I drove until I had about an eighth of a tank and topped off once again in Northern Georgia at a speedtrac station.. After checking my mileage, I found it to be 25.9 mpg at about 4 miles over the speed limit on Interstate 75(with Kroger gas).

After topping off in Northern Georgia at Speedtrac I continue on. Again, I run the same speed and stopped with an eighth of a tank in Valdosta, Georgia where I fill at another speedtrac. Upon checking my mileage, I found out I got 18.2 mpg(with speedtrac gas). I wondered about the big diff, but chalked it up to different conditions, even though I did not know what had changed.

Drove to Orlando and filled at yet another speedtrac(I'm not a fast learner). Again, from Valdosta to Orlando, 17.9 mpg. Now I was really wondering. Driving to both coasts from Orlando, I ran the final Speedtrac gas out to 18.9 mpg.

After wondering what the heck was going on, before leaving for home this morning(Sat) I filled at a shell station. I ran the shell gas almost to Atlanta. With the shell gas, 27.2 mpg. Filled at another shell, 27.6 mpg. I am now home and still have shell gas from my last fill and it appears I am getting similar mileage in the 27's.

To sum it up, Speedtrac gas, 17-18 mpg.


Kroger gas, 25.9 mpg.


Shell gas, 27 mpg.


My question, what in the heck is going on with speedtrac? I will never, ever get gas from them again. They were about 4 cents cheaper per gallon, but I sure did pay it all back plus some in mileage. Any of you have experiences like this?

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mac7769

Sounds like you found the E-85 pumps.

LI Sound Grunt

Gasoline - 115,000 BTUs per gal

Ethanol = 75,000 BTUs per gallon

E85 is about 78,000, or 35% less than gasoline - or 9 mpg's less - isn't that what you found? SURPRISE!

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Zeppelin

I cannot say for sure that I didn't, but I think I remember pushing the 87 octane as I always do.

BTW, it was "Racetrac" that I filled at and not Speedtrac. I don't even remember seeing E85 pumps.......? I'm 99.9% sure I did not put the wrong fuel in.

If I did somehow put E85 in my vehicle, will it hurt the engine? My van is not an E85 vehicle. I probably drove 1500 miles on the Racetrac crap.

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"Man who walks through airport turnstyle sideways, is going to Bangkok."

Chinese Proverb

tommyr904

racetrac is 20% plus e-10 fuel.

billinstuart

Interesting. Grunt is correct about BTU content affecting mileage..diesel has about 130,000 btu's, which combined with more efficient cycle (higher compression) results in better fuel mileage. If the apparent octane was lower, the knock sensor could have been bumping the timing back also.

Any other observations about fuel mileage variation?

Zeppelin

??? I don't know what that means in comparison to the fuel I typically use (Kroger).

__________________
"Man who walks through airport turnstyle sideways, is going to Bangkok."

Chinese Proverb

Zeppelin

Is that something I would have heard/felt?

__________________
"Man who walks through airport turnstyle sideways, is going to Bangkok."

Chinese Proverb

LI Sound Grunt

I disn't even know this E85 was out yet - we just have E10 and that Seems to Be a good 10% penalty (more than the chemistry/math would indicate). Why would anybody buy the E85 if it doesn't cost 40% less? I suppose its high octane but you can't advance your timing that much. And they environmental effects are now considered to be same as gasoline or negative. Look what it did to food prices. I guess its just an energy independence thing?

I hope they get some real experts on board and listen to scientists and engineers before they move on to the next generation (pun intended) fuel/power systems. I suspect that just putting more effort into bring down the production costs the cost of current technology photovoltaic cells could do alot (for home power and electric cars). A cheaper battery wold help - seems they have taht down too- just a matter of cost - between engineering production costs and economies of mass production I also suspect electric cars could become viable. I mean the distribution infrastructure is already here - expecially compared to hydrogen, compressed NG or Liquid NG or these other exotic systems....I really think that is the way we will get out of this - now if the financial guys here can just tell me which companies are going to make money on this.......

And Zep - Bill is right - I think the whole knock sensor system would be transparent to you. It automatically advances/retards the timing as much as needed to give the most power/lowest emissions/best fuel economy without knocking. So no, you wouldn't have heard anything if everything was working right. But I think that ethanol is pretty hi octane stuff - but just doesn't have the energy of the petroleum fuels.

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billinstuart

Remember the event at Indy a couple decades ago..Swede Savage and the fireball on the track? After that, Indy cars ran ethanol. It does have high effective octane rating, but takes more way fuel to produce similar power. The safety issue..it's much less volatile, but when it does burn, the flames are colorless. You can put the flame out with water, though.

I've heard that the percentage of ethanol is very inconsistent in fuel now, and the retailer has no control over this content. Often the ethanol is added to the tanker before delivery, and mixing, if it occurs, takes place during transportation.

We are just now seeing the tip of the iceberg on this ethanol issue. It's gonna get worse.

This is what happens when politicians like Teddy Kennedy consume too much ethanol before making laws about adding ethanol to fuel!

Monterey10

This is a common situation in California. Our unique blend of eco fuel results in terrible mileage. Mmmm, I wonder how that effects smog?

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jeffro22

I have seen some reports that ethanol is inaccuretaly measured sometimes when added to fuel. It is possible that even though you used the regular 87 octane fuel pump that it had more than 10% ethanol. I think this is more common with the cheaper or discount fuels. I remember seeing that ethanol is added by the driver and not done at the refinery. This would leave some question as to the drivers accuracy of adding the correct amount of ethanol or the gas stations integrity of making sure you get the fuel you pay for. I woudl stay with a Known brand fuel as oppposed to the cheapest discount fuel available

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