On 06/01/17 00:27, Dave Plowman (News) wrote:
In article ,
Jeff Layman wrote:
I checked my average for last year, and the Jazz's displayed mpg average
was 50.3 (Honest John's real mpg figure is 49.6). My calculated average
figure (trip meter mileage divided by petrol pump reading when pump
automatically stops) was 46.3.

How many tanks did you do this over? One isn't enough. You can't guarantee
you started and ended with the same amount of fuel in the tank.

A total of 18 tankfuls over last year (I do around only 5500 miles a
year). The tank is filled every 300 miles - give or take - and to when
the pump automatically clicks off; I never try to drip-feed it to the
top. So although I can't guarantee everything is equal (different pumps,
slightly different amounts of petrol), I think it's a pretty accurate
average.

FWIW, the figures for 2014 and 2015 for my Mk1 Jazz we
2014 - Real 42.1 Honda 43.2 (n = 17)
2015 - Real 43.2 Honda 43.9 (n = 22)
So much closer together. That's why I am suspicious of Honda's displayed
consumption figures for my MkIII Jazz - never mind the "official" figures.

--

Jeff