andy levy wrote:
>
> I won't bore the list (first time for everything) with my thoughts, as
> I've been talking to Tom a lot about this (had a slow day at work). But
> more to consider:
>
> Tom's tires are nearly bald. His truck is calibrated for new tires.
> Thus the odometer and everything attached to it will read high,
> artificially increasing MPG.
Blah - no argument about that - but then again unless we have controlled
conditions with precise measurements - we can never get a highly
accurate figure for fuel economy. Yeah - miles driven divided by gals
of gas burned - but unless we have some more precise way of figuring
fuel burned, aside from just filling up the gas tank and not knowing
exactly how much fuel is in the tank... we wont get precise.
Speedo calibration vs tire wear is an unavoidable problem. Unless we
had a system to constantly adjust for tire wear - to make that part of
the equation is irrelevant. Remember what the polls always say?
Accurate +/- X% - that's how I look at the entire process of figuring
fuel economy - take it all with a few grains of salt.
>
> Tom never made any scientific measurements on the real amount of gas
> used at the beginning.
>
No - never said I did - I based the 19.7 MPG number on estimated
figures. I know I drove an approximate amount of 255 miles. And the
gauge read half full on the tank - specs say I have a 26 gal tank. It
is very unscientific and imprecise to assume that because the gauge read
halfway - that I had exactly 13 gal of gas left and that I had burned 13
gal of gas. It was an educated guess. And a somewhat fairly accurate
guess to make given the circumstances.
> I tend to see better gas mileage on the first half of a tank than the
> second. Which I know makes no sense, as it's an electric fuel pump, and
> thus shouldn't be affected by the amount of gas pushing down on all the
> gas going into the inlet.
I would be more inclined to think the "better-MPG-when-half-full" theory
has more to do with the accuracy of the fuel tank sending units - and
the mysterious and ever unknown amount of "reserve" that may or may not
exist
in the fuel tank.
I am planning to do a controlled and much more precise experiment
regarding the fuel economy of my truck at the posted speed limits vs my
lead foot driving style.
-- -------------------------------------------------------------- ***** Countdown to 2004 DML BBQ (69) Days Left! *****Terrible Tom -- AIM & Yahoo Name: SilverEightynine http://members.aol.com/silvereightynine/
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