Is it better on money to drive with less fuel rather than more fuel in a car?

Question

Not with the gas light on but between quarter tank and half tank. Neil deGrasse Tyson said he experimented with this idea and said he saved on money. The reason why, he said, is because the less fuel you have, the lighter your vehicle weighs and thus the less fuel is required to move the car. And I know you shouldn’t drive with the gas light on because it could mess up your fuel pump. Couldn’t find the answer on google. Thanks.

Anonymous · Answer

Neil is right.  If the road is uphill all the way then you need more horsepower to move you up the hill   Try strapping a kid heavy rock to your pedal cycle and pump them. Very soon you want to cut your rock kid free because you do not have enough energy (more weight requires more energy-which equals more fuel to burn.
. This is why they are very weight conscious about what goes up into space by rocket.  There is only so much fuel and no more.  So much so that the golf club just barely made it on.  All astronauts are skinny bass turds.  Chubby ain't going for a long while yet. His Twinkies stay on Earth.
. No condensation builds up inside the tank because fuel vapor evaporates out.
. The low fuel light comes on letting you know you got about a gallon left so 25 miles flat level driving?  No where near the fuel pump damage point

a · Answer

Driving around on less than a full tank allows condensation to build up which can result in thousands in engine repairs or being towed in the winter due to fuel line freeze up.
Driving around on less than 1/4 tank will cause the fuel pump in the tank to overheat and fail early which will cost you another $1000 or so to fix

not · Answer

Most cars hold about 80lbs or 35kg of fuel. Cutting that weight to 25% but having to go refuel more often will consume fuel. I wouldn't expect a measurable difference in most cars with this small of change in weight. If the car is has more engine than nessasary to do its job then it will consume the same fuel to go the same speed while underpowered cars will see some relief from losing weight.

Things like tires, alignment, rolling resistance, aerodynamics are where to spend your efforts.

Bill · Answer

14 gals of gas only weighs 112#.  If you're driving alone that's less than the weight of 1 person.

You're better off with a full tank and filling up when it reaches 1/4 tank.

my_alias_id · Answer

Gas weighs about 9 pounds per gallon.  I have a 12 gallon tank.  So 6 gallons is only 54 pounds.  That's the weight of a small child passenger.  That really isn't enough of a weight difference to make a difference.
So I really don't see the benefit of riding around with half a tank or less.

Is it better on money to drive with less fuel rather than more fuel in a car?

5 Answers