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Wednesday, October 24, 2007

Get The Most When Pumping Gas

I received this information via email, recently, and thought I would share. Considering the amount of money we are all paying at the gas pumps, nationwide, anything to maximize our dollars is extremely welcome. I had heard of some of these recommendations before, but not others, and although I have been unable to confirm whether this legit or not, most of it makes sense.


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 pipeline; 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 vapor, 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’.

14 comments:

Renegade Eye said...

That was quite interesting.

Pat Jenkins said...

huh. well i will try them all.

John said...

Thanks for the tips!

Frasypoo said...

Great tips,I know hubby follows 2 and 3.!

Strawberry said...

Interesting - I never thought about any of those things.

Panhandle Poet said...

And just how much gasoline will this save me in a year???

I think #2 is an excellent comment. A clogged fuel filter hurts performance and efficiency.

Incognito said...

REN: Thanks.. I thought it was...

PAT J: Me too. Never can tell.

JOHN: You are very welcome.

FRASY: Smart hubby. I had no idea about some of them.

STRAWB: Me neither.. glad there are people out there looking out for the rest of us.

PAN: Heh. Well.. anything helps at almost $3.oo a gallon.

WomanHonorThyself said...

thanks Incog..and I didnt mean to include YOU in the Hollywood lefty rant I wrote hun..lol..;)

Incognito said...

Glad to hear that, Angel.. :-)

Reign of Reason said...

This is more urban legend...

I'm an engineer -- the difference in density between gas at say 40deg F and 70deg F is almost not measurable.

Besides,
1- given the large volume of gas in an underground tank, it would take a considerable amount of time for a temp gradient to permeate the tank (i.e. change the temp of the gas significantly).
2- the ground temp is relatively constant day-night once you get 10 or so inches underground...
3- etc. etc. etc.

Besides, gas pumps deliver fuel by mass ... even with a density changed, flow is regulated not by volume, but mass (i.e. quantity of molecules).

This is one of the many many stories that "sounds good" on the surface, but when you analyze it, its full of holes.

Incognito said...

REIGN: Thanks for edifying me. I checked on Snopes and other sites to see if this was an Urban Legend or not.. and couldn't find anything. I figured the recommendations could do no harm.

Frankly, I think most people just pump gas and have done with it.

Reign of Reason said...

Very true...

Being in aviation I've had occasion to look at the 'weight' of avgas as it varies with temp. That's the basis of my experience.

Anonymous said...

Here is one I read on the internet about a week ago. When you finish filling your car turn off the pump turn the nozzle upside down and pull the trigger and it releases the gas still in the hose. They say it doesn't work on all pumps, but I tried it on my next fill up and it worked on that pump. It wasn't a great amount of gas but at today's prices every little bit helps and after all if it is in the hose it has already been metered and you are paying for it.

Incognito said...

ANON: thank you so much for that tip.. will try and figure out what you mean... next time i fill up.