Gas pump accuracy?

If you're looking for the "golden" pump, you probably won't find it in the sun. The sun's heat makes gasoline volume expand, so you actually get a little less than you would pay for if you bought your gasoline during the hours of darkness, when it's usually cooler. It's not a big thing, but it could make a small difference in your calculated mileage figures.

It's the temperature of the gas when it goes through the mechanism that measure the volume, not the nozzle. Gasoline when it comes out of the ground is a more or less temp because the ground is a much more constant temp than the air. So changing the time of day that you get gas doesn't matter. The only thing you don't want to do is get the gas right after the tanks are filled, so that the dirt in the tank is not stirred up.

The angle at which your car sits, the speed of fuel going into the tank, when the the nozzle kicks off and how the tank it topped off are going to make more of a difference about how much gas gets into your car's tank at a particular fill-up. Over the long haul, though, it will even out.

The other thing I do know is that it is possible to adjust the volume of fuel going into the tank according to the temperature at the volume measuring device in the pump. Except in Alaska and Canada and other Northern parts of North America, it is rarely done on continent. In fact, in some states OPW, which is a company that makes the device won't even sell it. I guess the oil companies don't want people to get that finally 1% of gas that they pay for.

Jeff

Either way if he is lucky, in four or five years, the mileage he is getting will help him recover some of the premium price he paid to by the Prius.

mike

You cannot use the Prius gas tank capacity from fillup to fillup as any indicator of how much fuel you actually used.

This is a fact. It's because of the bladder inside the tank, primarily. It stretches or not to differing degrees, depending on a whole host of factors. The result is a bladder that takes more or less fuel each time, and virtually never the same amount--even filling from the same pump.

If you want to do all the fuss then you can buy a 10 gallon fuel container. At the gas pump fill it up to 10 gallons and check if it match the proper level. After that you pour the gas to your tank.

The states do that already to make sure that the pumps are accurate and consumers not ripped off.

The states are supposed to use values that aren't even, say 3.56 gal, to keep the vendors honest.

I know it is hard to believe, but there are some vendors who will try to rip people off.

Jeff

But then you have to check the fuel level in the 10g container because the Prius holds only about 8.5G.

Not to mention, that most gas cans are 5 gallons. However, considering that the Prius tanks are 8.5 gallons, I think I see a solution.

Jeff

Hopefully some day they will re-institute fuel rationing. Then you will have no argument. You will be happy to have received your 2 allocated gallons of fuel. You will not question it, because there will be 20 people behind you waiting and it will be back to the end of the line for you after you get finished complaining.

but gas mileage can change depending on how and where you drive your car...

for example if one trip across town reuquires more uphill driving, it isnt going to give you the same read out...

i am sure you knew that but i am just saying...

i usually top off.. add another dollar of gas to the car after the automatic click..

Except the Prius (an average of 22 to 25 thousand) is not anymore expensive than many cars and still gives great gas mileage. So if youre driving an SUV which usually cost around the same price or more. You are typically paying

Mike, seriously... remove your head from your ass and your dream world...

You're the kind of hick, that at the dinner table, yells, "ITS DEM COMMIES WHO ARE TRYING TO GET US TO BUY DEM HYBRIDS."

Signed, a non hybrid driver...a Yaris owner. Douglas

I don't disbelieve that... but vendors already get ripped off as it is... It really goes up to the gas company...

That is a bad habit to get in to. Besides the risk of spills, there is a chance, albeit small, that you can contaminate the charcoal canister from constant overfilling. When the pump clicks off, I just round up to the nearest nickel or dime.

GOOOOD advice Ray. I see so many trying to top it off and then spilling, wasting fuel, not to mention the flash fire danger. There ought to be a law......

And do you think that there aren't vendors, who, given the chance, will rip off costumers, even if they are already making a tidy profit?

Jeff

"Most" gas cans are 5 gallons?

So, how big are most trash bins?

LOL....you yanked the words right out of my mouth!

That's what caused Engine Check light to come on in my 99 Camry--trying to get every last drop in caused P type error codes to activate the Engine Check Light. Once I stopped putting fuel in after the automatic gas pump cut off, I stopped getting those bogus engine check lights.