Gas-pumping tricks to max your money's worth

[Ino]

I received the following in an email. I don't know the science behind it, but it won't hurt to try. Every little bit helps!
_______________

From a person in the Industry

I've been in petroleum pipeline business for about 31 years, currently working for the Kinder-Morgan Pipeline here in San Jose , CA . We
deliver about 4 million gallons in a 24-hour period from the pipe line; one day it's diesel, the next day it's jet fuel and gasoline. We
have 34 storage tanks here with a total capacity of 16,800,000 gallons.

Here are some tricks to help you get your money's worth:

1. Fill up your car or truck in the morning when the temperature is still cool. Remember that all service stations have their storage
tanks buried below ground; and the colder the ground, the denser the gasoline.

When it gets warmer gasoline expands, so if you're filling up in the afternoon or in the evening, what should be a gallon is not exactly a
gallon. In the petroleum business, the specific gravity and temperature of the fuel (gasoline, diesel, jet fuel, ethanol and other petroleum products) are significant.

Every truckload that we load is temperature-compensated so that the indicated gallonage is actually the amount pumped.

A one-degree rise in temperature is a big deal for businesses, but service stations don't have temperature compensation at their pumps.

2. If a tanker truck is filling the station's tank at the time you want to buy gas, do not fill up; most likely dirt and sludge in the tank is being stirred up when gas is being delivered, and you might be transferring that dirt from the bottom of their tank into your car's tank.

3. Fill up when your gas tank is half-full (or half-empty), because the more gas you have in your tank the less air there is and gasoline evaporates rapidly, especially when it's warm. (Gasoline storage tanks have an internal floating 'roof' membrane to act as a barrier between the gas and the atmosphere, thereby minimizing evaporation.)

4. If you look at the trigger you'll see that it has three delivery settings: slow, medium and high. When you're filling up do not squeeze the trigger of the nozzle to the high setting. You should be pumping at the slow setting, thereby minimizing vapors created while you are pumping. Hoses at the pump are corrugated; the corrugations act as a return path for vapor recovery from gas that already has been metered. If you are pumping at the high setting, the agitated gasoline contains more vapors, which is being sucked back into the underground tank, so you're getting less gas for your money.

Hope this will help ease your 'pain at the pump'.

[hlthe2b]

1. I almost didn't read this, thinking there would not be anything "new"

I knew about the cold versus heat expansion issue, but I hadn't thought of the other issues. thanks

On edit, I do look forward to the day when I no longer pump petro based fuel, although I admittedly do like something about the smell of gasoline, however toxic. I know, I know, it is bad and I don't intentionally inhale the fumes.

[tridim]

6. Old leaded regular smelled the best

I used to love going to the gas station when I was a kid, just to smell the fumes.
Ahhh, memories. :crazy:

[MadinMo]

14. and combine the smell of regular gas with the smell of lake water

and to me it was the smell of heaven. I know --- an ecological nightmare. Still smelled wonderful to me --- great memories there.

[underpants]

2. Posting to see what our resident experts say on this

DU is such a fantastic resource for stuff like this

[karlrschneider]

3. Technically true, but the temp of underground tanks changes very little from day to night.

One other thing - if you aren't going to drive a fair distance, don't fill the tank clear to the brim! If you don't use some, it can expand right out the filler and be wasted.

[ProfessorGAC]

4. One Note On #1 and #2

The tanks are buried sufficiently low that ambient temperature diffences of a few degrees won't matter. Yeah, th edifference between summer and winter will be significant, but the difference between 20F in the morning and 28F in the afternoon won't matter to a measurable degree. The tank will take a very long time to equilibrate, given the lack of mixing.

#2 is questionable. Highly reputable gas stations use water and sludge sensors. And, since tanks are now polymeric, rather than metal, the old sludge problem is far less than it used to be. If the tanks show water on the sensors, they have a legal su(at least in Illinois), to have the tank sucked clean and new gas put in. So this isn't the problem it used to be.

3 and 4, i like.
The Professor

[piedmont]

5. At least a couple of them are pretty dumb.

1. The tanks are buried below ground far enough that the soil acts as a temperature buffer. It won't change temperature from morning to afternoon.

3. The evap system on most modern cars sucks the gas tank vapors into the engine's air intake, and the vapors get burned anyway.


Numbers 2 and 4 seem fishy, too.

[yellowcanine]

7. The "fill up in the morning" thing is mostly bs. As stated here, the tanks are underground.

Therefore the gasoline in them is influenced very little by air temperature. The amount of exposure to air temperature during the pumping process is minimal also, so the change in density is going to be minimal as well. You are going to save more by filling up at a gas station on your daily commute that gives you the best price per gallon, regardless of what time of the day you do it. So stick to the routine that allows you to fill up for the cheapest price.

[Highway61]

8. One more

I use a Citi American Express dividend card to fill up and get 3% off gas and food.

[trotsky]

9. One tip will save more than all of these put together, even if they're true.

Keep your tires properly inflated.

[piedmont]

10. And drive slower. And keep your car properly maintained. nt

[Highway61]

12. BINGO!

I forgot to mention that...good one

[tridim]

15. And use thinner oil in the winter..

and don't let your heater warm up for 10 minutes before driving.

Coast down hills.
Don't use drive-thrus.
Stop accelerating if you see a red light ahead.
Remove spoilers and window flags.
Don't brake when taking corners (If it's safe).
Use the vent instead of rolling down your windows.
Don't use the AC unless absolutely necessary.
Screw the cops, roll through stop signs if there are no other cars present.

[underpants]

16. Avoid left hand turns

I read this in an outdoor magazine about tips for the enviroment. Basically the time you spend sitting waiting to get across traffic is useless. Of course you may not be able to complete avoid them but do what you can-it saves gas.

[PVnRT]

11. Another note about #1

In general, any piping or other equipment buried below ground must be below the "freeze line", i.e., a depth where the freezing point of water is never reached. For one, this prevents water from freezing inside pipes, which very easily can blow them out; you can make an "ice grenade" using this principle. Two, once below the freeze line, the temperature tends to stay fairly constant, which reduces stress on metal components constantly expanding and contracting. Above-ground piping is usually insulated or heat-traced to avoid this very problem.

In short, there should not be a significant difference in density because of temperature differences in underground tanks. There will, however, be fewer vapors when you fuel up at lower temperatures, since vapor pressure (how much evaporates) decreases with temperature.

[SIMPLYB1980]

13. One more trick.

When the pump turns off hold open the nozzel and lift the tube to get the last of the gas out of it. Not much but if you don't it just evaporates.