F1 power unit controversy: How Mercedes turned politics into performance. Mercedes has reportedly won the political battle over F1 engine regulations.

F1 | Engine case: Mercedes wins big, when the truth differs from the narrative

Mercedes has won the political battle. The PUAC (Power Unit Advisory Committee) is expected to vote early next week on a proposal to introduce, from August, an additional test to verify the 16:1 compression ratio under hot conditions, specifically at a temperature of 130°C.

The regulation is likely to be approved unanimously by the manufacturers. The FIA would therefore have found a way to put a definitive end to an issue that has been… overheating the paddock during the winter months.

Some may have assumed that the Silver Arrows would be forced to redesign their engine before August to comply. However, from March 1 the homologation of the power units comes into force, meaning no changes can be made without FIA approval.

The measure must therefore be interpreted for what it truly represents: there will be no need to update the Mercedes F1 M17 E Performance V6, because the Brixworth-built unit already complies with the compression ratio limit at the “hot” temperature of 130°C. It is worth recalling that last week a preventive check was carried out at 115°C, and the FIA technical delegates led by Jo Bauer were able to verify at HPP headquarters that the internal combustion engine — featuring a dual micro-chamber in each cylinder — was fully compliant.

Only at higher temperatures (or rather, higher combustion chamber pressures) does the small passage that fills the secondary 2cc chamber become obstructed, allowing the unit to operate with an 18:1 compression ratio.

The analysis, therefore, must be turned on its head. If Mercedes is already compliant, it is their rivals who may need to react. Other manufacturers will have the opportunity to intervene on their cylinder heads by invoking the ADUO (Additional Development and Upgrade Opportunities), the FIA system that allows engine suppliers to modify their six-cylinder internal combustion engines after the Miami Grand Prix, when the Federation will assess the actual power outputs of the power units.

If a performance gap of 2% is identified, an upgrade package may be authorized, financed outside the cost cap. In other words, it will be up to the other manufacturers to invest additional resources in order to realign themselves with Mercedes’ engine performance levels.

The choice of August for the new checks is therefore far from random: in theory, it gives the chasing manufacturers time to update their power units if they choose to do so.

There is another aspect that does not fall directly within the technical analysis but could prove crucial in the search for performance. We have previously reported that Petronas has not yet received homologation for its e-fuel; most likely, they were waiting for the outcome of the engine case before deciding which specification to introduce in Australia.

In this tactical battle, Toto Wolff has been highly skillful in extracting the maximum advantage from the situation.

With the power unit confirmed as compliant, it is easy to imagine Mercedes focusing on a fuel that can fully exploit the calorific potential of an 18:1 compression ratio. The advantage? More power with lower fuel consumption, meaning less fuel needs to be carried at the start of the race. A lighter car could, in turn, prove beneficial for tyre management over the course of a long run — a potentially decisive factor across a Grand Prix distance.

While the new 130-degree verification test was initially seen as a hurdle for Mercedes, the team’s existing compliance means they can now focus on optimizing their e-fuel integration for the 18:1 compression ratio, leaving their rivals to rely on the ADUO system to close a significant performance and efficiency gap before the August deadline.