On Thu, 20 Jul 2017 18:08:32 -0400, wrote:

On Thu, 20 Jul 2017 17:22:06 -0400, wrote:

On Thu, 20 Jul 2017 11:58:39 -0400, wrote:

On Thu, 20 Jul 2017 12:08:33 -0000 (UTC), Mad Roger
wrote:

What is a realistic accuracy & precision of typical MPG measurements when
measured by the consumer using the typical method of dividing their
tripmeter miles by the gas-pump gallons during fillup?


This thread reminded me to run-the-numbers from my car's log book.
I record each fill-up and a few times a year I'll plug the numbers
into a home-made spreadsheet.
I'm not sure if my car even has a built-in calculator - I'll have to
check .. my brother's Buick will always show about 1 mpg
better than reality.
in liters per 100 km my last 10 fill-ups are :
6.5 8.0 7.3 7.9 7.0 7.4 7.4 7.4 7.3 7.4 avg = 7.36
The adjacent high/low values indicate that the fill-up was
filled-to-the-brim or not-quite-full due to the pump sensivity.
Interesting to compare winter driving with winter tires :
8.3 8.7 8.2 7.9 7.7 8.0 8.5 8.3 8.0 8.0 avg = 8.16
2015 Kia Rondo 6 speed auto ; 2 liter gas ;
rated 10.6 / 7.6 city/highway at Natural Resources Canada
http://oee.nrcan.gc.ca/fcr-rcf/public/index-e.cfm
John T.


That is a combination of snow tires, sloppy roads and cold weather -
not just tires


Yep - warming up in the driveway while I scrape the windows ..
also I'll run the winter tires just a pound or two soft.
John T.
and the engine runs richer with low intake air temps too. Amd the
bearings and gears are stiffer in the cold, and you are pushing slush
aside or crawling over snow - all of which takes more power and fuel.