Do you get less gas when paying before you pump?

Discussion in 'Archived Threads 2001-2004' started by Chris Knox, Mar 10, 2002.

  1. Chris Knox

    Chris Knox Stunt Coordinator

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    You know the deal...

    You pay prior to pumping gas and the pumps go into slowdown and trickle mode somwhere around 20 cents before the amount you paid is reached. Comparing that with when you pump your gas BEFORE you pay and it is full throttle right up to the end (providing you know how to work the pump).

    Surly you must lose something when you prepay? Certainly a considerable amount considering we (most men) will tap the nozzle to get that extra bit before reseating the nozzle back into the pump.

    Any body heard of this before? Have there been comparisons made?

    Chris
     
  2. Frank Anderson

    Frank Anderson Cinematographer

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    My only suggestion is buy/pump it when it is coolest outside. Gas expands less when it's cool. Could get a few extra drops in your tank. But for all I know it probably makes no difference to what ever measures the amount coming out of the hose. So I guess my suggestion is worthless.
     
  3. Mike OConnell

    Mike OConnell Second Unit

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    Assuming you are using the same pump, you get the same amount.

    Depending on what state you are in, most states departments of transporation have a yearly calibration check on each pump and they are required to be within certain tolerances.

    The one thing you should NEVER do is try to force as much fuel into your gas tank as possible. It is bad for your vehicle. I wish I knew exactly why, but it has something to do with relationship between the tank overflow canister and the pressure situation within the tank.

    I wish I had a link to the website that I found this out on, but alas I don't.

    Good Day!

    Mike
     
  4. Paul W

    Paul W Second Unit

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    [​IMG][​IMG][​IMG][​IMG][​IMG][​IMG][​IMG][​IMG][​IMG]
    Be careful when buying gas in Lake Tahoe in the winter and driving down to Sacramento (especially if you have a fuel efficient car).
    A cow-orker of mine did this and gasoline started pouring out of the fill spout as it expanded.
     
  5. Philip_G

    Philip_G Producer

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  6. Jason Handy

    Jason Handy Second Unit

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    My naive understading about the topping off issue is two-fold:

    1) Filling up too much may cause an overflow situation if the temperature increases dramatically (i.e. morning to afternoon)

    2) The vapor pressure of the fuel in the tank is important for maintaining correct operation. If you fill too much, then the fuel can not establish proper vapor equilibrium in the tank and some bad things can happen.

    I may be wrong, but these are two possible explanations. Are there any automobile design engineers in the house?

    Jason
     

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