Tech Talk: Mercedes engine advantage explained

Mercedes have an obvious advantage over their rivals in the power unit department thanks to a clever design innovation which has been widely discussed.

As you can see in our power unit diagram of the Mercedes V6 above, they have split the turbo. The 'turbo cool' (charge air) is located at the front of the engine near the driver, whereas the 'turbo hot' is at the back of the engine toward the exhaust outlet.

This is unique to the Mercedes power unit. The reason for this is to keep the charge air (blue) as cool as possible. As you can see on the Renault V6 diagram below, the French manufacturer has followed the traditional route of placing the compressor and turbine together.

The heat generated by the red turbo transfers to the blue, reducing its efficiency. Despite some heat shielding between the two, heat transfer still occurs. To make matters worse, the MGU-H to the left creates additional heat.

Mercedes have circumnavigated this problem. A shaft running through the 'V' of the engine block keeps the turbo connected, but keeps the cooler element away from the heat generated by the MGU-H and the turbo heat.

A cooler charge air increases the efficiency of the turbo and thus increases the power from the engine. It also means Mercedes have to run less cooling pipework. That has other tangible benefits such as saving weight, allowing them to run a smaller intercooler which reduces the need for large sidepods which increases airflow to the diffuser, making it more efficient.

Another bonus comes from the fact that the MGU-H is located in the middle. This could allow Mercedes to have either or both sides working through one-way clutches, making the complete unit more efficient.

The way in which this system generates electrical power, feeding the MGU-K, again increases power and reduces turbo-lag, providing immediate power the driver.