Fuel saving or myth??

[AJA]

I received a mail that reads -

I don't know what you guys are paying for gasoline.... but 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.

Opinions please.

[Ste]

Temp, agreed lower temp will mean more dense and therefore more MASS of fuel per unit volume
Vapour, UK pumps don't have vapour return like some US pumps do
Sure petrol evaporate in your tank, it has to. It will reach an equilibrium when the air saturate at whatever vapour pressure and temp of air / fuel gas is.
Muck being stirred up in the storage tank means less fuel for you if you pump some in your car, but just about ALL cars have fuel pick up strainers anyway nowadays - so no chance of sucking into your fuel system

[Dwabo]

deffo on the temp thing...always fill up at night or when very cold as you get more in!!..

[MalcGSI]

Only the first one applies here, quick fill up now it's bl00dy cold outside.

[GazVXLINE170]

And along with the temp thing:

- No harsh braking or accelerating; keep constant speed
- Use gears wisely; no late up shift and no early down shift, as laboring does waste fuel.
- Let the car slow down of its own accord hence use the gears as the fuel cut-off will operate above 1200rpm, so do not coast or depress the clutch.
- Keep car washed (apparently) as dirt can change the aerodynamics of the car causing more resistance.
- Make sure there are no dents.
- Keep windows up unless necessary to have them down.
- Keep all un-necessary eletrical items off - heated seats, radio, DVD players

There are apparently more and I can confirm from personal experience they will increase the range of your tank - only trouble is that it gets quite boring!!!!

Gazza4

[yorkshireborn]

Im sure the savings if any are very very minimal prob somthing like 1p in a £100.

[Brocks]

It does make sense.....However.....I know customs and excise pay visits to garages and check that the number of litres on the pump match what they draw.

I have seen this process and they use copper/Brass containers that are exactly a certain volume. They fill to the brim and if there is an error on the pump, then the garage is questioned. If they did this in the morning, and again in the evening they'd get incosisitant results wouldn't they?

[AJA]

I normally fill up early in the morning but I'm sure the saving isn't that great.

[SignumPhil]

As far as temperature goes, storage tanks that are underground tend to be at a steady temperature, so that makes no odds.
Quote, "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. "
This is just gibberish. No matter how full or empty your tank, it will still evaporate via the tank breather.

Phil

[Duncan]

If they did this in the morning, and again in the evening they'd get incosisitant results wouldn't they?

No, the pump would still deliver the same volume of fuel. What the temperature affects, albeit maybe insignificantly, is the density of the fuel, so you'll have a greater mass of fuel in that same volume of fuel.