05 Silverado - Drive on top half of tank?

Question

Okay I've heard people say countless times driving on the top half of the tank is crazy. The extra weight makes your MPG go down.

Just thinking about the logic I completely agree.

Yest why does the top half of my tank seem to last almost twice as long as the bottom half?

I've noticed this on long road tips and locally where my schedule and driving distances doesn't really vary.

I thought maybe my fuel gauge wasn't right. But what I put in seems to pretty much match the fuel gauge. As much as a floating ball in my tank can lol

Any comments?

Answer 1

I work at a plant that made tanks and fuel level senders for your truck.

The bottom of the tank actually is smaller than the top.  It's not a square, or rectangle.  The top "half" of the tank holds more than the bottom "half".

But, the fuel level sender measures linearly.  

This results in the gage reading that the top "half" takes longer to use.

Answer 2

The only explanation is that your fuel gauge is not linear....

If you have a 20 gallon tank, the weight of the gas in it will be 80kg.  That is no more than an average adult.  Half of tank is about the weight of a child.  While weight makes some difference, it won't be noticeable.

Remember, when your guage shows EMPTY, you still have few gallons.  My *guess* is, while top half of your tank may correlate to half reading on your gas guage fairly accurately, the bottom half isn't.  Therefore, they move faster on the bottom half.

Answer 3

the guage doesnt' necessarily reflect 'half' the fuel in the car.  what you really need is to find after the first 10 gallons i drove 180 miles.  then the next 10 gallons i drove 170 miles, or 185 or whatever.  but based on teh fuel guage really means nothing.