trying to work out the most economical speeds for my GL II

if i drive economically i don't seem to get enough exhaust temperature and get active regen with waste of fuel and it really hits the MPG

if i drive faster i get passive regen but due to drag / windresistance i get carp MPG

sweet spot seems to be engine revs between 1800-2300 to keep exhaust temp hot enough so soot don't build up in the dpf

so somewhere around 56-65mph in 5th, 45-55 mph in 4th is the rev range i am looking for

anyone narrow it down any more

if i drive at 50 in 5th i get great mpg, until it goes into active regen, had it twice in two days so i know this is not enough heat for passive regen

I don't think you can pin it down to a set speed / rpm.

There are too many other variables, ambient temperature, fuel quality etc.

also seems to deend on distance of the journey, if i do a 60 mile trip 56-60 seems to be the speed for best economy without active regen, but the heat take a while to build up, on a slighty shorter run (25 mile trip to work ) 60-62 seems to be better

just wondering how this fitted with what others were seeing

done 10k with the car and still trying to work out the best way to drive it to get the balance of speed v economy