As promised last month we are going to examine our fuel economy data in more detail, particularly looking at how different manufacturers perform.
Of the 459 vehicles included in this study, spread across 26 manufacturers, the average real-world mpg by OEM ranges from 31 to 54mpg, with a mean of 44mpg. The deficit from the official figures ranges from 7% to 23%, with the average 22% below NEDC.
The graph, which ranks manufacturers (excluding manufacturers where we have tested fewer than five of their vehicles) according to the extent of their variance from official figures, reveals some interesting observations. Three of the OEMs towards the right of the graph with lower mpg are performance-car-only manufacturers, specifically OEMs 19, 23 and 26. If we exclude these, then the range of real-world mpg shrinks to 40 to 54mpg. By comparison the NEDC figures for these vehicles range from 50 to 63mpg, almost the same spread but 20% higher.
There is then one outlier that does worse than average (OEM 10) and two that are significantly better (OEMs 21 and 25). These manufacturers may have a model range which causes this skewing effect, for instance if they have few big cars in their model mix their average mpg could appear better than other manufacturers. When these three OEMs are also removed from the analysis, the miles per gallon narrows even more from 42 to 49mpg.
So, despite the remaining 20 manufacturers representing a variety of nationalities, technology types and target audiences, their vehicles have surprisingly similar performances in the real world. However, the variance from the official figures still ranges from -13% to -24%.
Although I promised to keep this anonymous, I feel confident that the top performer won’t mind being mentioned. Therefore, I can reveal that OEM 26, which has the smallest variance from the official combined mpg, is Porsche. It also has the second lowest absolute performance, perhaps not surprising given its model line up.
Our consultancy service allows OEMs to see their vehicles in direct relation to their competitors. Contact us if you would like to find out more.