What is your actual MPG?

[petert]

Just did a brim tio brim test and after converting km to miles etc my average over the last tankfull (794km) was 27.9 miles per imperial gallon. OBC showed 24.5 miles per US gallon (= 29.4 miles per imperial gallon) so the OBC is about 5% optimistic, pretty much what I've had on previous BMWs.
Peter T

[JCL]

Originally Posted by petert

Just did a brim tio brim test and after converting km to miles etc my average over the last tankfull (794km) was 27.9 miles per imperial gallon. OBC showed 24.5 miles per US gallon (= 29.4 miles per imperial gallon) so the OBC is about 5% optimistic, pretty much what I've had on previous BMWs.
Peter T

That is on the diesel, presumably? Winter fuel?

My OBCs have all been much closer than that. Would be interested in whether you have the same delta on summer fuel.

[boyce89976]

Originally Posted by JCL

That is on the diesel, presumably? Winter fuel?

My OBCs have all been much closer than that. Would be interested in whether you have the same delta on summer fuel.

Agreed. The OBC on my wife's 35d is always close... for example, at the last fill up I hand calculated 23.5 mpg to the OBC's 23.7.