W212 best speed for MPG

[paul3408]

Hi all

I'm of on my yearly trip to see friends and family in Poland, Holland, Germany,
I done this trip in a 1998 C Class 250 td auto in summer with ac on all the way and managed 37 mpg round trip covering 3000 miles
W204 2007 220cdi auto ac on same mileage doing 50 mpg
W212 2012 220 blue efficiency auto again same miles returning 53 mpg, all of these trips the speed was 70mph, is this the best speed for max mpg ?
I'm thinking of 80mph this time.

Your thinking please

Thanks Paul

 

[rascalmaster]

my 211 gives 65 mpg when driven at a steady 54.25 mph...



especially on this day of the year!