Hi,
this is my first post here. I have been building my own chart since I bought this car (2010 Mercedes C200 CDI diesel estate, manual gearbox). What I am presenting is a series of values I sometimes gather during my highway trips. Each point represents 50 km (30 miles) of travel. Some trips have 250km, other are shorter (say, 50km) and therefore longer trips results have a bigger weight on the definition of the regression curve (made with Excel with standard parameters). Speeds are retrieved from the computer, which is very accurate in this respect. MPG data are also from the computer, which is, in average, 6% optimistic in relation to tank fill data. The car is absolutely stock and is using Michelin Energy Saver 205/55 R 16. I live in Portugal, so please apologize my English!