How to properly conduct an experiment

[RunningOnFumes]

Originally Posted by WorkingOnWise

Is topping off the gas tank, up to the top of the filler neck, really a good way to be sure there is the same quantity in the tank for every test?

Right off the bat, I and anybody can be 2% off due to that.

The only way is to use an external tank and then temperature has to be taken into account for volume increases/decreases.

[Draigflag]

Yea every fuel pump is different, most overestimate how much you put in, some are slightly under. You can test this by filling a small Jerry can that you know the exact size of. 5 litres is pretty common, fill it up and I bet you a small sum of money the pump will read higher that what you've allegedly put in. Now empty it and try it again at a different station, it will be different again. Annoying but true...

[RunningOnFumes]

Even if the pumps were spot on, there are so many other factors affecting accuracy.

Having run a standards calibration lab, I have to chuckle at how some measurements are made by the general public.

[Aynjep]

I appriciate your help big time Dave.
When my masters gets published next year, I wont forget to mention your name in my thanks to list.

Again, thanks a lot.

PK