gasoline myths

[bcjammerx]

The email...
> TIPS ON PUMPING GAS

> Only buy or fill up your car or truck in the early
> morning ......
>
> When you're filling up do not squeeze the trigger of
> the nozzle to a fast mode. ......
>
> One of the most important tips is to fill up when
> your gas tank is HALF FULL or HALF EMPTY. .....
>
> 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 del ivered, 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.
>


Another email goes something like this
> Nothing is more frustrating than the feeling that
> every time I fill-up the tank, I am sending my money
> to people who are trying to kill me, my family, and
> my friends ...etc etc...


This was a reply to an email one of my sisters sent me...got me thinking and so I did some research...interesting finds.

http://www.thestreet.com/story/10393...-gasoline.html

http://www.ktvotv3.com/news/news_story.aspx?id=58945

http://www.nacsonline.com/NACS/Resou...t_gasmyths.htm

http://www.snopes.com/politics/gasoline/saudigas.asp

http://ezinearticles.com/?Why-Are-Ga...-It?&id=459508


Most of these things mentioned are actually myths.

The only one that has any shred of truth is the one about not pumping right after the store fills their tanks. I've provided links. This sounds like an ad for sunco gas to me.

Slowly pumping your gas does nothing but waste your time.

Gasing in the morning is only effective if the tanks are above ground, most places are underground and are not effected at all by temp.

Gas companies really don't have much to do about gas prices as we'd like to think...we are just looking for someone to blame...their part isn't as grand as we wished it was.

Apparently gas prices are the same in relation to income as they were in the 1950's.

Also, while not mentioned, I'll discuss a/c use. Consumer reports and another seperate company did a study of their own on a/c use. Running your a/c drops you by 1mpg...only...one mile per gallon.

Also running with the windows down has an even less negligable effect.

Also not mentioned is filling your gas tank half way vs. all the way...evidance is inconclusive but it appears you may save 1mpg by filling only halfway.

sadly, there is no way to get more outta the pump then what it tells you you're getting.

The only way to get the most bang for your buck is to watch your right foot...and maybe drive a car with a manual transmission.

If you romp on the gas everywhere you go you will drop mpg by WAY more than 1. In my honda I will go from 28mpg to 24mpg if I drive hard, and that's in a 4cyl. By driving a manual I can coast down hills and can let my engine idle down when coming to a stop.

[MikeW]

Ive heard the one about not filling up while there's a tanker present...but who knows if one was just there or if youre sucking the "gunky" gas from the bottom of the tank..? Theres no way to tell.

As for the 1/2 tank fill-up, ive never heard that, but i DO get better MPG when im OVER 1/2 tank. I can get 200(+/-) miles on a half-tank. Once it drops below half, i cant get more than 150 miles even if i try.

[owequitit]

There is actually some truth to some of these myths.

1) filling up when it is cold DOES have its advantages. For instance, even though the tanks are below ground and are LESS effected by temperature, there is still some effect.

Also, gas actually changes density just like any other liquid. 1 gallon at a lower temperature will have more fuel density than 1 gallon at a higher temperature. Since pumps in the US measure only by volume, you will get more density during the colder hours. Meaningful or not, I don't know. But hey, free gas is free gas. Also, in many countries, they have started to implement "smart pumps" which basically calculate how the density changes, and meter fuel accordingly to give you a constant amount of hydrocarbons. US companies just assume that it will average out over time.

2) There is also some merit to carrying less fuel. Airplanes do it all the time, as less weight requires less power, and thus saves fuel. I don't think it is significant in cars though. We don't have a high enough burn, and we are usually only carrying about 100lbs of fuel max. Carrying a passenger would be worse. But, still it is a valid truth.

3) A/C use can affect mileage more than 1 MPG. I come from a hot region of the country where we end up using our A/C the majority of the year. Our MPG usually goes UP in the winter, when most other regions go down. On average, the difference with A/C usage is about 2-3MPG.

The other issue is that even incremental savings eventually add up.

[bcjammerx]

All true...and I tried to say those things myself...but guess not

Indy cars use cold gas too...
the myth part comes from saying that at a gas station with underground tanks have colder gas in the morning...not true...which was why I saidd if the tanks are above ground then it might work. But again...have to be above ground.

And the a/c and half empty...well the folks say you gain 1mpg with the half tank and 1-2mpg with a/c so between the two you get 2-3mpg...mabye possibly 2-4??? that is enough to be worth it for me!

But i don't have a/c so I'de only get a gain of maybe 1mpg...

BUT I do that anyway...some crazy theory I have about averaging out to spending less on gas (with all the price changes that is...which I will never care to try and prove )

[starchland]

i think the one about stirring up the tank is bullshit...sure 50 years ago when they didnt have filters on the pumps.

[texasvtak]

The only way to get the most bang for your buck is to watch your right foot...and maybe drive a car with a manual transmission.

Absolutely. Ive been driving my moms civic for the past couple weeks and Ive been seeing amazing mpg numbers. 36 in the city and 41 on the highway...

Ive heard the one about not filling up while there's a tanker present...but who knows if one was just there or if youre sucking the "gunky" gas from the bottom of the tank..? Theres no way to tell.

As for the 1/2 tank fill-up, ive never heard that, but i DO get better MPG when im OVER 1/2 tank. I can get 200(+/-) miles on a half-tank. Once it drops below half, i cant get more than 150 miles even if i try.

Thats because the gas tank isnt a perfect geometric shape and fuel gauges dont calculate for this fact. The bottom of the tank is smaller than the top. I usually see 250 or so when my gauge reads half, but I usually dont see more than 400-450 on E.

[owequitit]

All true...and I tried to say those things myself...but guess not

Indy cars use cold gas too...
the myth part comes from saying that at a gas station with underground tanks have colder gas in the morning...not true...which was why I saidd if the tanks are above ground then it might work. But again...have to be above ground.

And the a/c and half empty...well the folks say you gain 1mpg with the half tank and 1-2mpg with a/c so between the two you get 2-3mpg...mabye possibly 2-4??? that is enough to be worth it for me!

But i don't have a/c so I'de only get a gain of maybe 1mpg...

BUT I do that anyway...some crazy theory I have about averaging out to spending less on gas (with all the price changes that is...which I will never care to try and prove )

I saw the part about underground. Gas tanks aren't buried deep enough to be 100% independent from the effects of solar radiation though, so during the day, they will heat up slightly. Like I said, it may not be significant, but it is there.

[verothacamaro]

"Gas companies really don't have much to do about gas prices as we'd like to think...we are just looking for someone to blame...their part isn't as grand as we wished it was."

heheheheh

Hopefully you meant oil companies....

[JoshM]

Only buy or fill up your car or truck in the early morning ......

Please take my advise and don't do this. I did that last week around 9am. By about 4pm the gas expanded so much in my gas tank that it began leaking from the spout.

[ZeRoCooLCB7R]

Another myth you will save a little bit more gas with your AC on and windows up on a hot day cruising the wayways.
Windows down + more wind resistence = more ft lbs on gas pedals

[bcjammerx]

Please take my advise and don't do this. I did that last week around 9am. By about 4pm the gas expanded so much in my gas tank that it began leaking from the spout.

I don't advise it but only because doing so will not benefit you any. I don't think that is what caused your tank to overflow.

Another myth you will save a little bit more gas with your AC on and windows up on a hot day cruising the wayways.
Windows down + more wind resistence = more ft lbs on gas pedals

huh? You will most likely save gas by running with the windows down, I think it was mythbusters who said they didn't find a significant increase in fuel consumption while the windows were down. But they did find a 1mpg (my buddy always had 2mpg in his 91 accord) drop with a/c on.

Sooo...eh...you may suck a little more gas down with the wind resistance from the windows being down but it won't be much...

going over 55 causes much more resistance than rolling those windows down.


I think one of those sites said that at a some mph...like 70?...50% of your engine's energy is going towards fighting wind resistance? I forget...anyway I'm supposed to be pricing replacing my woman's headgasket not posting HA HA


ANY WAY...point being...if its DAMN hot I don't think that 1-2mpg reduction is gonna cause a dent in your wallet, and it'd be worth it

BUT if you're like me...with no a/c...windows rolled down won't suck the mpg down enough to really notice.

Course you can always just barely roll them down too.

[MikeW]

Yes, it was tested on MB's. They proved its better to run with windows down above or below a certain speed, Vice Versa for the A/C.

I dont know about you other ppl but the midwest see's some pretty nasty humidty. So even when im doing 70mph down the highway, the wind may be blowing but it aint cool.

[bcjammerx]

yeah it's like that here in North East Texas too...the humidity is killer...if only I had a/c...oh well