300 mile club

[MBrown1003]

Originally Posted by MTROIS

{SNIP}

BTW, how do you guys calculate your MPGs??? Do you trust what your odometer is saying or do you do the calculation each time you fill up your tank?

I record a bunch of data at each fillup, then put it on a spreadsheet, so I compare actual values with calculated values. I also calculate overall consumption by taking the current odometer, subtracting off miles at delivery (about 150 in my case), and dividing that by the total number of gallons I've put thru the car.

IIRC, the OBC error (compared to calculated values) has been about 1% - 2% on my Bimmers. Interestingly, the two Volkswagen GTIs I had (2000 and 2003, both of which were VR6s, and both of which had trip computers) were more accurate than the BMWs.

My tracking spreadsheet has the following columns:
* date
* odometer
* trip odometer
* MPG from OBC
* avg MPH from OBC
* gallons
* $/gal
* total

...plus several calculations, such as calculated MPG and percentage difference between the calculation and the OBC reading.