[john1701a]

Don't forget about...

BLADDER EFFECT

...because it is that time of year again!

Capacity of the tank will be reduced as the temperature drops, as much as 1.5 gallons (5.7 liters) in the extreme of winter. This is because the cold causes the bladder (which significantly reduces evaporative emissions) to shrink.

 

[john1701a]

The variance over the 171 tanks (1,318 gallons) with my 2001 Prius was an overall 2.1 MPG difference.

http://john1701a.com/prius/spreadsheets/Prius-2001_MPG_Spreadsheet_Lifetime.xls ...note column "S".

The variance over the 56 tanks (454 gallons) with my 2004 Prius has been an overall 1.4 MPG difference.

http://john1701a.com/prius/spreadsheets/Prius-2004_MPG_Spreadsheet_Lifetime.xls ...note column "V".

I don't put too much stock in individual fill-up calculations since pump-error and bladder-effect have far too profound of an effect.