gas tip

rh71

No Lifer
Aug 28, 2001
52,844
1,049
126
From Geico tips:
Fill your tank in the morning and you will end up with an extra gallon of gas. This is especially true in the summer, because the gas expands in the tanks as the day grows hotter. You get less gas for your money later on in the day.
 

Shockwave

Banned
Sep 16, 2000
9,059
0
0
Its true actually. I dont know about a gallon or not, but it *is* true.
Me, well.... I have more important things to worry about in my day then the current air tempature at the time I'm pumping gas.....
 

Jzero

Lifer
Oct 10, 1999
18,834
1
0
Originally posted by: OrganizedChaos
ummm,yeahh... exactly how much warmer will the gas get 20ft. underground in an airtight tank

LOL. The gas in the CAR is warmer.
It also evaporates quicker.
But I don't think the difference is an entire gallon. In fact, I would be surprised if it was more than a few mL worth of expansion.
 

Kelemvor

Lifer
May 23, 2002
16,928
8
81
If the gas expand,s it also becomes less dense which means when it burns a set amount (volume) it's burning less gas which means a smaller explosion, less power, etc. End results is I doubt it makes any difference.
 

Calin

Diamond Member
Apr 9, 2001
3,112
0
0
It's true that the liquids grow in volume as the temperature increase. But the growth is small (in the best case). Aslo the diameter of the piping increase, so the absolute volumetric increase is somewhat compensated by the increase of the pump measuring system.
I'd say you can have at most a couple of percents for a difference in temperature normal between day and night.
Oh, and one more thing - the injection engines control the quantity of fuel injected based on the exhaust gasses, not volumetric. So it won't help.
Calin

EDIT: too late for the post to be informative...
 

zixxer

Diamond Member
Jul 6, 2001
7,326
0
0
If that were true, that means if you get gas then go like 1/4 mile to work, then your 14gallon tank is gonna have to hold 15gallons of gas.
 

jsbush

Diamond Member
Nov 13, 2000
3,871
0
76
Originally posted by: Jzero
Originally posted by: OrganizedChaos
ummm,yeahh... exactly how much warmer will the gas get 20ft. underground in an airtight tank

LOL. The gas in the CAR is warmer.
It also evaporates quicker.
But I don't think the difference is an entire gallon. In fact, I would be surprised if it was more than a few mL worth of expansion.

Even if the gas is warmer in your car, your not getting more gas at the pump. You'll just end up putting less gas in your car, becase theres less room in your tank.

So filling up in the morning or at night or whatever, doesn't change nothing except that you'll be filling up sooner in the end. But even that, if you fill your tank up completely full in the morning, then its just going to expand during the day and either spill out of the tank, or evapourate, wasting your money.
 

sxftdeep

Senior member
Feb 2, 2004
255
0
0
Originally posted by: rh71
From Geico tips:
Fill your tank in the morning and you will end up with an extra gallon of gas. This is especially true in the summer, because the gas expands in the tanks as the day grows hotter. You get less gas for your money later on in the day.

Where I come from, it doesn't matter what time of day it is when you fill up because the gas in the resevoir is always corrected to 15 degrees Celsius.
 

StageLeft

No Lifer
Sep 29, 2000
70,150
5
0
Originally posted by: Jzero
Originally posted by: OrganizedChaos
ummm,yeahh... exactly how much warmer will the gas get 20ft. underground in an airtight tank

LOL. The gas in the CAR is warmer.
It also evaporates quicker.
But I don't think the difference is an entire gallon. In fact, I would be surprised if it was more than a few mL worth of expansion.
But it pumps from well insulated reservoirs underground.

Eitherway it wouldn't be a gallon unless your gas tank was fuggin immense.
 

rh71

No Lifer
Aug 28, 2001
52,844
1,049
126
Originally posted by: ThePresence
Sounds like BS to me. Snopes doesn't have this one yet.
Do you think a company like Geico would post things they heard from email forwards that are always on snopes ? Somewhere they got this info and they were willing to put their name on the line for it. I'm sure it's at least in part true.
 

Zenmervolt

Elite member
Oct 22, 2000
24,514
44
91
Originally posted by: jsbush
Originally posted by: Jzero
Originally posted by: OrganizedChaos
ummm,yeahh... exactly how much warmer will the gas get 20ft. underground in an airtight tank

LOL. The gas in the CAR is warmer.
It also evaporates quicker.
But I don't think the difference is an entire gallon. In fact, I would be surprised if it was more than a few mL worth of expansion.
Even if the gas is warmer in your car, your not getting more gas at the pump. You'll just end up putting less gas in your car, becase theres less room in your tank.

So filling up in the morning or at night or whatever, doesn't change nothing except that you'll be filling up sooner in the end. But even that, if you fill your tank up completely full in the morning, then its just going to expand during the day and either spill out of the tank, or evapourate, wasting your money.
It won't leak out. All modern fuel systems are closed to the atmosphere. At worst, the fuel will expand and liquid gasoline will enter the charcoal filter and kill it, but even that is rare. Modern fuel systems have expansion chambers to account for this sort of thing. If you fill your tank in the morning, the expanded fuel will just get pushed into the expansion tank, where it will condense later and drain back into the regular tank. Now, if you keep going for 6 or 7 of the automatic shut offs and wait until there is fuel spilling out of the filler neck, then you'll likely overload the expansion tank and flow into the charcoal filter.

ZV
 

Zenmervolt

Elite member
Oct 22, 2000
24,514
44
91
Originally posted by: rh71
Originally posted by: ThePresence
Sounds like BS to me. Snopes doesn't have this one yet.
Do you think a company like Geico would post things they heard from email forwards that are always on snopes ? Somewhere they got this info and they were willing to put their name on the line for it. I'm sure it's at least in part true.
Geico is an insurance company. They know very little, if anything, about how cars actually work and even less about gas stations. They are simply repeating a widely-held belief that the majority of the country holds to be true without ever looking at it logically. Just because a low-end cut-rate insurance company says something, doesn't make it true.

ZV
 

Turkish

Lifer
May 26, 2003
15,547
1
81
Originally posted by: Zenmervolt
Originally posted by: rh71
Originally posted by: ThePresence
Sounds like BS to me. Snopes doesn't have this one yet.
Do you think a company like Geico would post things they heard from email forwards that are always on snopes ? Somewhere they got this info and they were willing to put their name on the line for it. I'm sure it's at least in part true.
Geico is an insurance company. They know very little, if anything, about how cars actually work and even less about gas stations. They are simply repeating a widely-held belief that the majority of the country holds to be true without ever looking at it logically. Just because a low-end cut-rate insurance company says something, doesn't make it true.

ZV

Umm yeah, Geico is just an insurance company that know nothing about cars... umm yeah :roll: