Hi Richard -
I guess that likely was me. I just didn't realize I was talking to the same person in two different places - many months apart.
Less than three weeks
In both cases I wanted to make certain we were comparing apples to apples. Folks are very focused on getting the best mileage they can. If they are hearing mileages that are not going to be possible with their vehicle's specifications this is just going to confuse the issue further.
Sounds like we can assume that you are doing the math right to convert volumes and distances properly.
We do know that your Sprinter has both a different engine and a different transmission (that are not available in North America). Both of these could have a big impact on fuel mileage.
You would be right to assume there would be a difference, in engine and auto configurations, but it should be no more than say three miles to the gallon less TOPS ranging in engines from the 308 through to the 616 CDi on the current Sprinters not the new one 2006 onwards.
I also have seen the following repeatedly (admittedly in a very un-scientific survey):
1. Folks that drive at lower highway speeds (60 mph or even lower - goal is to keep engine rev's down at least below 3000 rpm) are consistently getting better mileage.
This is not rocket science it's a proven fact! If one drives within this range you will have up to a 25 to 30% saving in fuel consumption, If you think about it, whilst in this mode your engine is running under almost zero strain it's as good as idle.
2. Folks that accelerate cautiously and manage to keep the turbo from kicking in as much as possible on acceleration are consistently getting better mileage.
Agree; If you can avoid excessive acceleration fuel being pumped into the engine will not require as much fuel to feed the higher RPM output a further saving on fuel, and less wear and tear on the engine management system.
3. Folks that try to maintain as steady a speed as possible (minimize deceleration and, therefore, re-acceleration) are consistently getting better mileage.
Now your seeing the big picture starting to emerge
Case in point: my wife and I both drive our Sprinter and our Mini. I get roughly 1 to 5 (difference is more dramatic in the Mini) mpg more than my wife does. I'm convinced that the difference is due to #'s 3, 2, and then 1, in that order of importance for us.
Proves your above point! different strokes for different Folks
It would be interesting to have some of the mileage champs trade Sprinters with some of the folks who are getting lower mileage. I am pretty convinced that, on average, the mileage figures would follow the drivers more so than the vehicles.