Testing MPG over a short distance

[JQmile]

So I thought instead of doing a super-long mpg test till the tank is dry, why not to a series of 4 to 5 fill ups over say, 30 miles each. If there is air in the tank or the pump stops differently, you'd get a reading that was waaaay off. Kind of maximizing errors instead of minimizing them. I did this with my Chevette a while back and got readings all between 57 and 59 mpg. I would think if I had a test discrepancy, one of the readings would have been like 70, or 40. Any thoughts? Sorry if this is a repost.

[ATaylorRacing]

The longer the trip the more correct your mpg will be...and more so if you refill at the same pump, same wether conditions, etc. I used to let the pump go on the lowest speed until it clicked off, but there is a large difference in the pumps. On one 100 mile trip the pump would not even stay on since I used so little amount of gas, but the same trip at other pumps always took under 2 gallons to fill normally, and a couple of times they only clicked off after 1 gallon....using those last two pumps would have given me a inaccurate mpg average of 100 mpg..WAY NOT RIGHT. The only way I can think of to eliminate this problem is to install a 4 or 5 gallon fuel cell and fill it up to the same spot every time. The extra 5.5-6.5 gallons of gas that I will not be carrying around when full is worth about .4 mpg better FE.

[thatguitarguy]

Check out this thread:

Accurate fuel measuring

It is definitely not good to top off your tank every 30 miles.