To start recording FC for the first time:
1. Head to your favourite petrol station and top off the tank. I just let the pump attendant do it.
2. Reset your trip meter AND/OR record your odometer reading.
3. Drive, drive, drive down to say, 1/4 tank.
4. Return to your favourite petrol station, and top off the tank the same way. Note down the amount of petrol you paid for (A).
5. Note the mileage either by reading the trip meter or subtracting the previously recorded odometer reading from the current odometer reading (B).
6. Then do the math: (B)/(A) to get km/L. To repeat, start from (2) again.
7. To get lifetime average, keep a spreadsheet with all your (A) and (B) data. So lifetime FC would be (Total B)/(Total A) which is not the same as avg((B)/(A)).
* Accuracy is limited by:
- variation in pump cut-off point
- variation in ambient temperature
- variation in pump flow meter
- driveway gradients
- etc, etc...
It's addictive trying to best your previous top score for FC everytime you top off. Helps to break the monotony of a long work commute. FC hasn't been great lately because of route changes and multiple forays into the CBD area.
Bro,
Care to share how you calculate your FC. 