Does a full fuel tank affect automobile gas mileage?

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Offline Huxlly

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Automobile gas mileage. What is the reduction in gas mileage if you keep your gas tank full versus limiting the tank to one-half full. I drive mostly in town and usually short trips. I'm a Senior at Farragut TN High School.
« Last Edit: 10/11/2009 11:00:36 by chris »


Offline Don_1

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Re: Does a full fuel tank affect automobile gas mileage?
« Reply #1 on: 10/11/2009 09:11:47 »
Very little.

If your tank has a 75 ltr capacity and you do not allow it to fall below 1/4 full, the most weight saving you would make is around 50kgs.

But if you do this and ensure that your boot (trunk) is not full of unnecessary rubbish and do not engage in high acceleration, heavy braking and other bad motoring habits, well, as the saying goes, 'every little helps'.
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Offline chris

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Does a full fuel tank affect automobile gas mileage?
« Reply #2 on: 10/11/2009 11:17:41 »
The bottom line is that the more weight your car transports the more energy it needs to move and hence the more fuel it needs to consume.

A full fuel tank can weigh as much as a person, so driving with the tank permanently full is like carrying an extra passenger everywhere. The weight of this fuel needs to be accelerated by the car every time you pull away or gain speed, using fuel. It also magnifies frictional losses through bearings and other moving parts because the load is higher.

In calculating how much fuel to put in the car, you need to take into account the above as well as the amount of fuel you would consume in driving to the garage to refill the tank, which you'll need to do more often if you put less fuel in.

The best approach, for short journeys, heavy traffic or for driving around town involving lots of starts and stops, is to drive around with about 1/4 of a tank, which minimises the weight carried but without impacting on range.

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Offline litespeed

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Does a full fuel tank affect automobile gas mileage?
« Reply #3 on: 11/11/2009 15:06:15 »
Fuel Economy Tips

1) Keep tires properly inflated. This is probably the one most important economy related thing you can do with the vehicle itself.

2) Feather foot the throttle. Sort of pretend there is a single Grade A egg velcroed to the accelerator.

3) Use the highest gear practical for any given situation. This will generally be taken care of with an automatic transmission through application of step 2 above.

4) If you want to get extreme about it drive in such a manner that you use your brakes as little as possible.  For example, keep enough distance between you and the car in front of you so that you can simply coast forward if he suddenly decelerates for some reason. To make a turn for instance.  Coasting to slow down for read lights, however, sometime irritates the other drivers.

By Nature, I am hot-rod-lead-footer!  But just for the heck of it I decided to see how much difference I could attain. Sort of like a game. From lead foot to feather foot increase my fuel economy about 20 percent. Your results may vary....


Offline neilep

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Does a full fuel tank affect automobile gas mileage?
« Reply #4 on: 11/11/2009 16:05:15 »
I asked a similar kweschun !..i me me  !!
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