The MGU-H electric turbocharger on the Porsche 992.2 GTS

Porsche is breaking new ground once again with its 2025 GTS model, integrating an MGU-H electric turbocharger unit into its 3.6 T-Hybrid engine. Unlike the traditional configuration where excess energy is directed to the battery, Porsche has chosen to connect the MGU-H to the traction motor, the MGU-K, when it is in power mode.

When the turbocharger generates more electrical energy from the exhaust gases, this energy is transferred directly to the MGU-K unit for more efficient use of propulsion, rather than being stored in the battery. This active approach promotes vehicle efficiency and performance. Although Porsche considered redirecting the energy from the MGU-H to the battery, they ultimately opted to modulate this energy to the MGU-K.

Porsche is at a technological crossroads in having to develop instant power. The brand claims to use both instantaneous revving via the turbocharger's electric motor and torque compensation via the electric drive unit (MGU-K). This means that the battery powers both the turbocharger and the MGU-K, but there is no mention of the turbocharger's electric motor recharging the battery.

Once the turbo lag is eliminated, the challenge lies in the transition of the electrical unit from supplying power to turn the compressor wheel to a reverse action, where the turbocharger electric motor becomes a generator. It seems that this transition could cause a loss of power, but Porsche has managed to eliminate it.

According to the Porsche press release:

The 911 GTS uses a newly developed electric turbocharger. An integrated electric motor, positioned between the compressor wheel and the turbine wheel, rapidly accelerates the turbocharger to develop supercharging. This electric motor also functions as a generator, producing up to 11 kW from the exhaust gas flow. The electric turbocharger is not fitted with a pressure relief valve, allowing only one turbocharger to be used compared with the two previously used, while simultaneously improving throttle response and performance.

The electric turbocharger and the electric motor housed in the transmission are combined with a lightweight, compact high-voltage battery. It is comparable in size and weight to a conventional 12-volt AGM starter battery, but can hold up to 1.9 kWh of energy (gross) and operates at 400 volts. It is located under the front bonnet, where the 12-volt battery used to be. To optimise weight distribution, the 12-volt battery is a lightweight lithium-ion battery located behind the rear parcel shelf.

Although the press release does not explicitly mention that the MGU-H is used to turn the turbocharger and simultaneously supply instantaneous power via the electric drive unit, this was explained in a press video in which Thomas Brandl, Director of Software and OBD for internal combustion engines and hybrids at Porsche, explains how it works.

Conclusion

With this cutting-edge technology, Porsche is once again demonstrating the ability of its research and development team to innovate beyond the competition's standards. The sophistication of this system, which combines performance and weight control, is crucial to Porsche's desire to preserve the legendary agility of the 911. By way of comparison, the AMG GT 63 S E-Performance, also equipped with a hybrid system, exceeds two tonnes, while the GTS remains under 1.5 tonnes, a remarkable feat and an argument of ... weight.

For WOT, this breakthrough represents a unique opportunity. The mastery of new technologies, such as the MGU-H electric turbo-compressor unit, opens the way to new possibilities for optimising performance while complying with homologation standards. At WOT, we are ready to incorporate these innovations to offer our customers engine reprogramming solutions that are ever more effective and reliable.