I thought the below may be of interest to some people.
Last spring I was doing a regular daily run on the same stretch of motorway (abroad) with light trafic. I decided to monitor the fuel consumption at different constant speeds.
For each run I had a target speed, which I did not go above. If traffic meant that I had to slow down, I slowly accelerated back up to the target speed when the traffic cleared.
The runs were on the same 20 mile stretch of road.
I cannot remember what fuel I was using, but it would have been "super" of one grade or another.
Any run which had heavy traffic, I omitted from the results.
You get a much better graph (and the figures are much more meaningful) if you plot (look at) actual speed against consumption rather than target speed.
Obviously, this could be considered as "pacemaking" which may not be covered under some insurance policys, but obviously, I had proper insurance cover in place.
The results are from the on board computer which I reset at the start of each run. I have no idea how accurate this is, and for the fuel comparison trial I am currently doing, I am not using it. Speeds are in MPH and consumption is in MPG
The speeds are according to the car speedometer, not my GPS, which suggests the car speedometer over reads by quite a bit.
As (I suspect like most Brabus owners) I normaly like to "make good progress", the lower speed runs were a real test of disciplin......
target speed actual speed Consumption
85 80 29.4
80 78 30
80 77 30.7
85 71 33.6
75 73 33.4
60 60 44.8
50 50 51.3
70 70 39.2
55 55 47.8
85 80 29.4
75 75 34.8
60 60 43.4
65 65 39.7
55 55 50.4
85 77 31
60 57 44.8
60 60 40.9
