Tips on pumping gas

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dustermaniac

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I read this on the web this morning and thought I would share this:

I don't know what you guys are paying for gasoline.... but here in California we are paying up to $3.75 to $4.10 per gallon. My line of work is in petroleum for about 31 years now, so here are some tricks to get more of your money's worth for every gallon:
Here at the Kinder Morgan Pipeline where I work in San Jose , CA we deliver about 4 million gallons in a 24-hour period thru the pipeline.. One day is diesel the next day is jet fuel, and gasoline, regular and premium grades. We have 34-storage tanks here with a total capacity of 16,800,000 gallons.
Only buy or fill up your car or truck in the early morning when the ground temperature is still cold. Remember that all service stations have their storage tanks buried below ground. The colder the ground the more dense the gasoline, when it gets warmer gasoline expands, so buying in the afternoon or in the evening....your gallon is not exactly a gallon. In the petroleum business, the specific gravity and the temperature of the gasoline, diesel and jet fuel, ethanol and other petroleum products plays an important role.
A 1-degree rise in temperature is a big deal for this business. But the service stations do not have temperature compensation at the pumps.
When you're filling up do not squeeze the trigger of the nozzle to a fast mode If you look you will see that the trigger has three (3) stages: low, middle, and high. You should be pumping on low mode, thereby minimizing the vapors that are created while you are pumping. All hoses at the pump have a vapor return. If you are pumping on the fast rate, some of the liquid that goes to your tank becomes vapor. Those vapors are being sucked up and back into the underground storage tank so you're getting less worth for your money.
One of the most important tips is to fill up when your gas tank is HALF FULL. The reason for this is the more gas you have in your tank the less air occupying its empty space. Gasoline evaporates faster than you can imagine. Gasoline storage tanks have an internal floating roof. This roof serves as zero clearance between the gas and the atmosphere, so it minimizes the evaporation. Unlike service stations, here where I work, every truck that we load is temperature compensated so that every gallon is actually the exact amount.
Another reminder, if there is a gasoline truck pumping into the storage tanks when you stop to buy gas, DO NOT fill up; most likely the gasoline is being stirred up as the gas is being delivered, and you might pick up some of the dirt that normally settles on the bottom.
 
Thank you for the great advice and spreading the word dustermaniac.. :coffee2:
 
Do you really think there is a difference in ground temp where the tanks are buried? I would think the temp would stay pretty constant.
 
Do you really think there is a difference in ground temp where the tanks are buried? I would think the temp would stay pretty constant.
X2
I was thinking the same thing, thanks for letting us know.
 
The temperature deep in the ground takes weeks to change (summer to winter)
Even though it is spring now ,it will be awhile before the underground frost is gone.
dustermaniac I know you are the messenger , but how much savings per month?


Darryl
 
The temperature deep in the ground takes weeks to change (summer to winter)
Even though it is spring now ,it will be awhile before the underground frost is gone.
dustermaniac I know you are the messenger , but how much savings per month?


Darryl

That I do not have the answer to.... sorry.
 
Do you really think there is a difference in ground temp where the tanks are buried? I would think the temp would stay pretty constant.

The real difference in tempature change has to do with the tankers making the fuel dump. If ambient temp is hot/cold when the fuel is dumped then it will change the temp of what is in the storage tank no matter the time of the day. Over a period of time the fuel will return to the ground temp. Anyone have a geothermal heat pump? The earth has an underground temp of approximately 55* year round at the level that the geothermal system feild is installed.

Buying while they are dumping fuel or have just dumped fuel does stir up any trash in the tanks. I will never buy gas where I see the tanker dumping.
 
Thanks for posting this, dustermaniac. I heard some of this years ago and have pumped gas accordingly.
I fill up at half-tank for the reason stated in your post but also because it "hurts" less with the lower total price. I know I'm only fooling myself because I have to fill up twice as often, but it still isn't as much of a shock to the wallet each time.

 
From what I understand, new pumps dispense based on weight and are temp adjusted. So it shouldn't matter. If you found a station with pumps from the 70's or earlier, never updated, you might have something.

Also the ground at just 6' below surface stays a pretty constant temp year round, IIRC ~ 72*, go deeper a bit deeper, gets cooler until you start hitting core related heat sources.

Note the advice says "temperature compensated" when loading the trucks. I'll bet that's using a pounds/gallon formula. Same deal when it goes into the tanks and comes back out through the nozzle to your car.
 
The reference temperature for gasoline volume measurement is 60°F or 15°C. Ten gallons of gasoline at that temperature expands to about 10.15 US gal (38.4 L; 8.5 imp gal) at 85 °F (29 °C) and contracts to about 9.83 US gal (37.2 L; 8.2 imp gal) at 30 °F (−1 °C).

If you are buying fuel from a non temp compensated location with above ground tanks, then filling when it's cold out could be valid.

BUT...

In the United States, the National Institute of Standards and Technology (NIST) specifies the accuracy of the measurements in Handbook 44. Table 3.30 specifies the accuracy at 0.3% meaning that a 10-US-gallon (37.9 L; 8.3 imp gal) purchase could vary between 9.97 US gal (37.7 L; 8.3 imp gal) and 10.03 US gal (38.0 L; 8.4 imp gal) as to the actual amounts at the delivery temperature of the gasoline.
 
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