So for fun today on the last hour of 4 hours of driving today, and after I shot my trip average mpg with 3-4 busts to triples passing on rural highways, I decided 325 miles into 375 mile trip I would see what I could do to bring my average up from the relatively dismal 22.8 (usually get 24+ highway).
I knew I waited to long to get up to 24 so I reset the trip odometer to see what the maximum I could pull off including driving though downtown Milwaukee on the last 50 miles.
There were plenty of hills but I never got lower than 28 average and pulled off this:
I was still a way to go but the average after driving through town was exactly 29.0.
I usually get 21.5 on mostly highway mixed driving. 29/21.5=35% better!
5.50/1.35=4.07 means effectively turned $5.50 gas into $4.07 gas. I will definitely be exploring this a little more thoroughly. It was more difficult to pull off due to a fair number of long hills and construction.
A few times I lost as much as 6-7 mph up hills but I would normally have been able to start at a higher speed to start with more kinetic energy before the KE > PE transfer going up the hills.
On Wednesday I did a similar experiment for 20 miles and netted 27 mpg.
(Typically shedding about 4mph from 76 > 72 up hills, and gaining them back on the way down).
The faster I start the less I have to drop and the construction and traffic held me back and I still pulled off 29.
When I've done the same in my 3.0 e53, the best I've achieved was 23.0. 29/23=1.26. That's pretty awesome.
So I made ≈ 450 mi. trip with 53 distance to empty! Quite happy with that.