I don't think the temperature of the undergorund tanks will change through the day. They are underground where the temp is stable. The trucks bringing the fuel will change that a little, but it is hard to know when they arrive, and in the winter it would be an advantage as they would add somewhat colder gas.
And why would you lose more gas to vapor when you run the gas faster? I'm not sure where that vapor comes from anyway ... where is this vapor release? It would seem better to pump faster if anything ... less time the column of water is exposed to air ...
I'm not sure about the running on the top half or bottom half of the tank ... the tanks have a cap that won't let out a lot of fumes, if any. And no matter how much gas is in fumes, only the gas fumes that escapes would matter ... A eight gallon volume of fumes is not much, as long as it is not constantly escaping.
I guess big trucks unloading might stir up sediment ... maybe ... but there are probably filters.
The miniscule difference in the density of cold vs. warm gasoline will probably not justify trying to gas up in the early morning. (Fewer cars in line, though!) When the price of gas is dropping, it's better to wait until you're almost empty to fill up; when the price is rising, filling up more often saves money (though perhaps not time). A full gas tank (20 gal) weighs about as much as a passenger (140 lb), so you probably get better mileage driving almost on empty.
I can see what he means by the gas evaporating inside the tank, and keeping it full so less evaporates. Altho' the gas that evaporates is still inside the tank, you can't use it as the evaporation doesn't make it thru the fuel line to burn. And, unlike water, gasoline does not recondense back into liquid. At least not nearly as readily or as much as water.
A similar principle applies to when you're pumping gas. Unless you're not sticking the hose inside the tank entrance, there is nowhere but back thru the vapor return, where it does go back into the stations storage tanks.
By the way, I used to work at a few gas stations/convenience stores about 20 or so years ago, so I found out a few facts about gas pumping and such, and this article makes sense. (Thanks Roy! ) Also, while the ground does not vary in temperature as much as the air above it, it does vary. How much it helps tho' is open for debate.
Another tidbit. Since a full tank contains more weight in fuel, I think that it would make sense that it would exert additional pressure on gas going towards the fuel pump, thus giving you additional mileage. Correct me if I'm wrong on that, tho'.
I can see what he means by the gas evaporating inside the tank, and keeping it full so less evaporates. Altho' the gas that evaporates is still inside the tank, you can't use it as the evaporation doesn't make it thru the fuel line to burn. And, unlike water, gasoline does not recondense back into liquid. At least not nearly as readily or as much as water.
True, when you fill up, you will lose the vapors in the tank ... but if you fill up just the top half, say 8 gallons, you lose 8 gallons worth of vapor, instead of 16, but you have to fill up twice as often, so it is a wash.
I don't see why the speed of the pump matters, and the extra weight that George mentioned is probably the overriding factor ... so better to drive on the bottom half, for efficiency sake. The extra driving and time to fill up more often may be another factor.
Also, while the ground does not vary in temperature as much as the air above it, it does vary. How much it helps tho' is open for debate.
With such a large volume even just a few feet below ground, I can't see any change from just daytime heating ... I'd bet less than a tenth of a degree ... but I wouldn't bet much ...
Another tidbit. Since a full tank contains more weight in fuel, I think that it would make sense that it would exert additional pressure on gas going towards the fuel pump, thus giving you additional mileage. Correct me if I'm wrong on that, tho'.
I'm no mechanic, but even in the old carburator days, I'm not sure more pressure would help pump more gas ... nor would pushing extra gas through make for more efficiency ... if it was too rich it would waste fuel and pollute more.
But especially with today's electronic fuel injection, all that is very precisely controlled.
If you use premium, I'd stay away from the mom & pop stores. Many times I see where the driver wrote that they were instructed by the store to drop some regular in the premium tank. I've noticed some pumps are confusing with the regular in the middle or on the right, so you'll grab the wrong one. I'm sure that's not intentional, ha ha ha...
Also midgrade is actually 2/3 regular and 1/3 premium. It's not in the middle, although the price usually is.
And don't use premium or midgrade if you don't need it. It's not 'better' gas; it just has more octane for engines that need it.
I see lots of pickup trucks with their tailgates down. That doesn't improve mileage. There's a bubble of air over a moving pickup bed, so the air doesn't really push against a closed tailgate. You can Google that.
I think people get a bit irrational with gas. A couple cents price or a tiny change in the temperature isn't really that significant on a fill-up, imo. I think you can save more by simply driving slower and smarter.
I see lots of pickup trucks with their tailgates down. That doesn't improve mileage. There's a bubble of air over a moving pickup bed, so the air doesn't really push against a closed tailgate. You can Google that.
Mythbusters experimented on that one, and showed the air-bubble by simulating it underwater.
Both the Mythbusters and I were quite surprised the tailgates up didn't lower mileage.
I see lots of pickup trucks with their tailgates down. That doesn't improve mileage. There's a bubble of air over a moving pickup bed, so the air doesn't really push against a closed tailgate. You can Google that.
Good info outintexas ...
I looked into the tailgate down thing ... mythbusters did tests that showed what you said is true ... but they did a later test that showed using one of those mesh tailgates with the heavy tailgate removed saved 5%.
I suppose it maintains the aerodynamics mostly, perhpas improves them a little, but reduces weight by some 75 pounds. Not driving a truck or large vehicle unless you really need it saves even more ... :)
Get a kick out of fuel prices as well, then. In the UK petrol (gasoline) is now a stunning £1.07-£1.10 or thereabouts per litre (that's a non-London price). It just went up. I think that's about US$7 per US gallon. You see why we prefer smaller less thirsty cars over here...
I just filled up - in a snowstorm. This is April - huh?
Get a kick out of fuel prices as well, then. In the UK petrol (gasoline) is now a stunning £1.07-£1.10 or thereabouts per litre (that's a non-London price). It just went up. I think that's about US$7 per US gallon. You see why we prefer smaller less thirsty cars over here...
I just filled up - in a snowstorm. This is April - huh?
I'm showing one pound is about 2 US dollars ... so I don't know what is up wit dat ... gas in europe used to be much higher ...
but much of the rise in gas price is due to weakness in the US dollar ...
That's the trick in England (and probably other countries in Europe). The price looks reasonable to an American, until you realize it's the price per LITER. $2/liter ~ $7.60/gallon.
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coolchef
roy thanks for shareing
peace
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RottieGrrrl
I'm driving a real gas guzzler so thanx for the tips :)
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dmiller
Hey there Roy. :)
Thanks for sharing this here. I heard these facts on talk radio a week or so ago.
Makes sense to me. Saving some pennies here and there quickly translates into $$$.
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rhino
I don't think the temperature of the undergorund tanks will change through the day. They are underground where the temp is stable. The trucks bringing the fuel will change that a little, but it is hard to know when they arrive, and in the winter it would be an advantage as they would add somewhat colder gas.
And why would you lose more gas to vapor when you run the gas faster? I'm not sure where that vapor comes from anyway ... where is this vapor release? It would seem better to pump faster if anything ... less time the column of water is exposed to air ...
I'm not sure about the running on the top half or bottom half of the tank ... the tanks have a cap that won't let out a lot of fumes, if any. And no matter how much gas is in fumes, only the gas fumes that escapes would matter ... A eight gallon volume of fumes is not much, as long as it is not constantly escaping.
I guess big trucks unloading might stir up sediment ... maybe ... but there are probably filters.
Anyway ... that's how I see it ... :)
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waysider
Drive downhill-----Both ways.
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GeorgeStGeorge
The miniscule difference in the density of cold vs. warm gasoline will probably not justify trying to gas up in the early morning. (Fewer cars in line, though!) When the price of gas is dropping, it's better to wait until you're almost empty to fill up; when the price is rising, filling up more often saves money (though perhaps not time). A full gas tank (20 gal) weighs about as much as a passenger (140 lb), so you probably get better mileage driving almost on empty.
George
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Shellon
Thanks Roy! We can use all the tips and ideas we can get huh?
Appreciate you!
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GarthP2000
Rhino,
I can see what he means by the gas evaporating inside the tank, and keeping it full so less evaporates. Altho' the gas that evaporates is still inside the tank, you can't use it as the evaporation doesn't make it thru the fuel line to burn. And, unlike water, gasoline does not recondense back into liquid. At least not nearly as readily or as much as water.
A similar principle applies to when you're pumping gas. Unless you're not sticking the hose inside the tank entrance, there is nowhere but back thru the vapor return, where it does go back into the stations storage tanks.
By the way, I used to work at a few gas stations/convenience stores about 20 or so years ago, so I found out a few facts about gas pumping and such, and this article makes sense. (Thanks Roy! ) Also, while the ground does not vary in temperature as much as the air above it, it does vary. How much it helps tho' is open for debate.
Another tidbit. Since a full tank contains more weight in fuel, I think that it would make sense that it would exert additional pressure on gas going towards the fuel pump, thus giving you additional mileage. Correct me if I'm wrong on that, tho'.
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rhino
True, when you fill up, you will lose the vapors in the tank ... but if you fill up just the top half, say 8 gallons, you lose 8 gallons worth of vapor, instead of 16, but you have to fill up twice as often, so it is a wash.
I don't see why the speed of the pump matters, and the extra weight that George mentioned is probably the overriding factor ... so better to drive on the bottom half, for efficiency sake. The extra driving and time to fill up more often may be another factor.
With such a large volume even just a few feet below ground, I can't see any change from just daytime heating ... I'd bet less than a tenth of a degree ... but I wouldn't bet much ...I'm no mechanic, but even in the old carburator days, I'm not sure more pressure would help pump more gas ... nor would pushing extra gas through make for more efficiency ... if it was too rich it would waste fuel and pollute more.
But especially with today's electronic fuel injection, all that is very precisely controlled.
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WordWolf
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outintexas
I work in the fuel business, too.
If you use premium, I'd stay away from the mom & pop stores. Many times I see where the driver wrote that they were instructed by the store to drop some regular in the premium tank. I've noticed some pumps are confusing with the regular in the middle or on the right, so you'll grab the wrong one. I'm sure that's not intentional, ha ha ha...
Also midgrade is actually 2/3 regular and 1/3 premium. It's not in the middle, although the price usually is.
And don't use premium or midgrade if you don't need it. It's not 'better' gas; it just has more octane for engines that need it.
I see lots of pickup trucks with their tailgates down. That doesn't improve mileage. There's a bubble of air over a moving pickup bed, so the air doesn't really push against a closed tailgate. You can Google that.
I think people get a bit irrational with gas. A couple cents price or a tiny change in the temperature isn't really that significant on a fill-up, imo. I think you can save more by simply driving slower and smarter.
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WordWolf
Mythbusters experimented on that one, and showed the air-bubble by simulating it underwater.
Both the Mythbusters and I were quite surprised the tailgates up didn't lower mileage.
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year2027
God first
Beloved coolchef, RottieGrrrl, dmiller, rhino, waysider, GeorgeStGeorge, Shellon, GarthP2000, WordWolf , and outintexas
God loves you my dear friends
coolchef - your welcome and yes peace
RottieGrrrl - your welcome
dmiller - your welcome and yes lets save anyway we can $$$
rhino - thanks - yes I just do not know one way or another for sure
waysider - thanks "Drive downhill-----Both ways"
GeorgeStGeorge - thanks my friend
Shellon - your welcome and we Appreciate you my friend
GarthP2000 - thanks and hi and yes your welcome
WordWolf - thanks for the link - it looks like a good report - thanks
outintexas - I like that "simply driving slower and smarter" thanks
thank you
with love and a holy kiss blowing your way Roy
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rhino
Good info outintexas ...
I looked into the tailgate down thing ... mythbusters did tests that showed what you said is true ... but they did a later test that showed using one of those mesh tailgates with the heavy tailgate removed saved 5%.
I suppose it maintains the aerodynamics mostly, perhpas improves them a little, but reduces weight by some 75 pounds. Not driving a truck or large vehicle unless you really need it saves even more ... :)
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outintexas
I didn't see that episode, but yeah I saw the same thing about the mesh tailgate on their website. Love that show.
As a Yankee transplant in Texas I get a kick out of all the pickups here. Just part of the culture.
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Twinky
Get a kick out of fuel prices as well, then. In the UK petrol (gasoline) is now a stunning £1.07-£1.10 or thereabouts per litre (that's a non-London price). It just went up. I think that's about US$7 per US gallon. You see why we prefer smaller less thirsty cars over here...
I just filled up - in a snowstorm. This is April - huh?
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rhino
I'm showing one pound is about 2 US dollars ... so I don't know what is up wit dat ... gas in europe used to be much higher ...
but much of the rise in gas price is due to weakness in the US dollar ...
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waysider
A liter is just slightly larger than a quart.
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GeorgeStGeorge
That's the trick in England (and probably other countries in Europe). The price looks reasonable to an American, until you realize it's the price per LITER. $2/liter ~ $7.60/gallon.
George
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rhino
oh ... duh .. I missed the "per litre" part ...
But England is so tiny ... and they can just run around in those tiny little cars ...
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