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I'v heard about a rumer that says if at a half tank of gass. you top off again. you'll be gettign better mpg. the reasoning behind this is that the lower half of the tank gets smaller in size to focus the fuel toward the line intake. then there's all the bs about gravity and the rate at wich the gass is sucked into the line, etc... any truth to this?

now i'm testing it out right now to see for my self but what have you guys heard and figured out?

(currently waiting on half tank. normaly i get 200 miles at the half tank mark. then hit the 300 mark with the left-over bottom half of the tank. so i figure if i top off at every half tank. then i should be gettign about 200 for every 6 gallons or 200 miles for about $20. and man would that be great!! ^_^ )
 

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I have a 2000 Dodge Trepid, with the 2.7L and I just got back from a trip that was all highway miles..on a full tank of gas, I got 335 miles

Dan
 

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I'v heard about a rumer that says if at a half tank of gass. you top off again. you'll be gettign better mpg. the reasoning behind this is that the lower half of the tank gets smaller in size to focus the fuel toward the line intake. then there's all the bs about gravity and the rate at wich the gass is sucked into the line, etc... any truth to this?

now i'm testing it out right now to see for my self but what have you guys heard and figured out?

(currently waiting on half tank. normaly i get 200 miles at the half tank mark. then hit the 300 mark with the left-over bottom half of the tank. so i figure if i top off at every half tank. then i should be gettign about 200 for every 6 gallons or 200 miles for about $20. and man would that be great!! ^_^ )
Impossible. The fuel pressure is maintained by the fuel system (pump and FPR), not the gravity of the fluid in the fuel tank. The fuel pump is there to sling the fuel to the rail. You'd need to have something going pretty far downstream to build up enough pressure for gravity to carry it horizontally towards the engine.
 

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Discussion Starter #6
now this rumer has been around for quite some time so the newer style cars/trucks might be built better/defferent.
 

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Impossible. The fuel pressure is maintained by the fuel system (pump and FPR), not the gravity of the fluid in the fuel tank. The fuel pump is there to sling the fuel to the rail. You'd need to have something going pretty far downstream to build up enough pressure for gravity to carry it horizontally towards the engine.
Correct, and even the older cars had a pump, so none going back to at least the 30s were gravity fed, so don't worry about it.

In fact, if you really wanted to be 100% correct, you'd get better mileage as the tank empties, since you are moving less weight.:biggrin:
 

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If there was a difference I'd bet running from 1/2 to empty would be the best mileage due to weight. If so you would not measure it in mpg but in inches because that's all you'd gain.

For convienience and time the best is to fill it and drive to the pin. This is the least number of fill ups. Trips to the station. Opening and closing the gas cap. Sticking the nozzle into the car. Go inside to pay and maybe buy yourself a treat.
 

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Impossible. The fuel pressure is maintained by the fuel system (pump and FPR), not the gravity of the fluid in the fuel tank. The fuel pump is there to sling the fuel to the rail. You'd need to have something going pretty far downstream to build up enough pressure for gravity to carry it horizontally towards the engine.
Agree, you would have to get another pump to force it into the fuel pump to make that kind of pressure and it probably still wouldnt do anything to your fuel mileage. Driving habits and car condition are the biggest things that affect your mileage.

I get about 220 on average from full to half, then about 130 from half to empty; if I run it until the OTIS says less than 20 miles remaining till empty.
 
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