Amid the general shock and disbelief that Mercedes, constructors’ champions of the last eight years, is not even competitive at the moment, heads have turned towards its power unit.
The Ferrari and ‘Honda’ motors in the two cars fighting over race wins at the moment are delivering stronger performance than the Mercedes PU and that is incontestable. Furthermore, the three Mercedes-engined customer cars – McLaren, Aston Martin and Williams – are uncompetitive even relative to the midfield teams around them. By contrast the two Ferrari-powered customer teams – Alfa Romeo and Haas – are clearly the fastest of the non-factory teams.
There are two main points to this.
1) The power unit is at the moment down on the best, but by nowhere near enough to account for the shortcomings of the various cars in which it is fitted.
The Mercedes power unit shortfall accounts for between 0.1-0.2sec of lap time as interpreted from GPS data, probably around 0.15sec. It’s difficult to be precise after just two races-worth of data, but definitely in that order of magnitude. But the Mercedes W13 is a full 0.7sec off the Red Bull/Ferrari pace. The fastest car from the non-factory teams is the Alfa at just under 1sec off Red Bull/Ferrari pace. Taking this as the non-factory ‘pole’, the McLaren is 0.45sec adrift of the Alfa, the Aston Martin 1.12sec adrift and the Williams 1.2sec adrift. AlphaTauri, with a competitive ‘Honda’ power unit, is within less than 0.1sec of the Alfa.
Lap time deficits to Red Bull/Ferrari pace

Even with a fully competitive power unit the Mercedes W13 would be around 0.5sec off the Ferrari/Red Bull pace. Relative to the Alfa, the McLaren would be around 0.3sec off (ie, around 1.3sec slower than the Ferrari team with which it competed hard last year), with the Aston and the Williams around 1sec slower than Alfa (ie 2sec off the ultimate pace).
So the four teams using Mercedes PUs have conceived aerodynamically-flawed cars under the new aero regulations. Ferrari and Red Bull have not – and in the case of Haas and AlphaTauri at least – the Ferrari and Red Bull customers have created cars quite similar to those of the ‘parent’ teams.
Which begs the question of whether there is something in the architecture or cooling requirements of the Mercedes power unit which has led to designs which are not aerodynamically suitable for the new regulations. Or is the fact that all four Mercedes-engined teams have produced bad chassis at the same time really nothing more than unfortunate coincidence?
Mercedes engine is down on power; is its packaging flawed too?
Florent Gooden / DPPI
2) Accepting that the biggest limitations of all the Mercedes-engined cars are aerodynamic, it remains true that the Mercedes power unit, after years of setting the standard, is a tenth or two off the pace. Why might this be so?
The challenge of the switch to E10 fuels has been significant. That 10% ethanol content represents 10% less opportunity for the chemical trickery which squeezes the best from these densely-engineered hybrid turbo motors. Has that hit at the heart of the former strength of the engines from Brixworth? Was there previously a crucial chemical advantage which has now been nullified?