​The FIA guarantees customer Formula 1 teams access to the same power unit specification as the works outfit, but the growing complexity of the 2026 systems has placed experience at the forefront. This is evident in the McLaren-Mercedes partnership, where the real difference now lies not in hardware itself but in how effectively that hardware is exploited. Throughout Formula 1’s history, being a works team has conferred advantages, yet there have been moments when customer squads have triumphed: McLaren in the recent years, Brawn in 2009, and Red Bull during its Renault-powered title run. In the hybrid power-unit era, the FIA introduced a regulation mandating that manufacturers supply customer teams with the same engine specification used by the works outfit, ensuring equal treatment in terms of hardware and the potential for performance. In past years, that rule has rarely sparked controversy. As development matured, power units became nearly transparent within the overall performance equation, with technical evolution narrowing the gaps between manufacturers to a minimum.
However, the arrival of the new technical era has reshaped the landscape — not only across different engine suppliers but also in the relationship between manufacturers and their customer teams. The heightened significance of the MGU-K has elevated energy management to a decisive performance factor, relying on software systems far more sophisticated than those employed up to last season. The framework for engine supply remains unchanged. Each customer team still benefits from manufacturer engineers embedded in its garage, but the responsibility for optimizing the power unit lies with the team itself. A supplier can respond to technical questions and provide support, but it cannot guide the customer in pursuing performance the way it would within a factory team.
McLaren has become the clearest example of this new dynamic, with performance also being influenced by gearbox ratio selection, an area Mercedes has consistently highlighted and McLaren has not attempted to hide. Yet it should be remembered that the gearbox ratios chosen last winter were tuned around the power curve of the engine specification available at that time. According to McLaren’s team principal, Andrea Stella, there is more to the story than that, and he believes the deficit their team currently faces cannot be attributed solely to the car itself.
Speaking at Silverstone during last weekend’s British Grand Prix, Stella described a circuit where energy starvation and the exploitation of the power unit are particularly important. He emphasized that, while he has spoken before about the challenges, the current situation involves more than a straightforward analysis of car performance. The relationship between customer teams and engine suppliers has evolved, and the success of a modern F1 program now hinges heavily on how effectively a team can manage and optimize the power unit’s energy and performance within the current regulatory and technical framework.