I got this email forwarded to me. Thought I’d share, not because I think the tips are worth a damn, but as it could make for good discussion. Or at least some bickering.
>Tricks to get your money’s worth
>
>TIPS ON PUMPING GAS–GOOD INFO
>I don’t know what you guys are paying for gasoline…Here in
>California we are also paying higher, up to $3.50 per gallon. But 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. In slow mode you should be pumping on
>low speed, 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 or HALF EMPTY. 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…
>
>Hope this will help you get the most value for your money.
>
>
>
>DO SHARE THESE TIPS WITH OTHERS…
The tips are pretty much worthless, let me put on my Julie math hat
the tanks are underground, so the temp variance will be minimal even on a hot day. You can feel this by when you pump the gas the handle will become cooler. In addition this variance is pretty small in quantities under 20 gallons. For a couple thousand gallons it would add up, but in our cars the amount against the loss of convenience would not really make it a factor.
These are the numbers that I found as defined by US gov.
231 Cubic inches at 60 degrees = 1 gallon gas
234 cubic inches at 80 degrees = 1 gallon gas
I would doubt that gas would change outside that variance in underground tanks, but here is the math at 3 dollars a gallon.
(3/231)*100 = Percentage of difference about 1.3%
20 gallons of gas at 3 dollars = $60
601.013 = 60.78 or a potential savings of 78 cents. So assuming you fill up 2 times a week you would save at most .7852*2 or $54.78 a year. Wow that is 31,000 miles a year at 15mpg… so lets half that and call it $26 bucks a year assuming the gas is measured at 231 ci/g and is pumped at 80Degrees F every day. which I doubt would happen all year round. So realistic savings would be more like 10 bucks a year at most.
Hmm a little larger then I thought but the math works out, yes it is a difference but even in the extreme I do not see it as more then a $10 savings a year if you drive 15k miles a year.
The problem with the temperature theory is that liquids don’t tend to have much of a thermal expansion coefficient. A quick google search turned up 950x10^-6 cubic ANGSTROMS per degree C. AKA nothing.
As for pumping more slowly… Again liquids aren’t compressible so having the nozzle half open will result with a higher volume but at the same velocity so I don’t really see a lot extra being vaporized. Maybe from turbulence in the tank lowering surface tension, but still.
“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. In slow mode you should be pumping on
>low speed, 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.”
There is no fucking way in hell I’m standing outside in sub freezing temps pumping my gas on low to save next to nothing.
