The biggest story of the winter break – Mercedes’ 2026 engine solution – remains a key issue for F1’s manufacturer teams. Another reunion has been organised between engine suppliers and the FIA, with the intent of reaching a compromise.
At Mercedes, the situation is clear. The Silver Arrows believe their power unit is unequivocally within the regulations, having previously received confirmation from the FIA about their engine’s legality.
Of course, this does not stop other manufacturers from making counter-arguments. This topic is still being discussed, and with various courses of action on the table, Mercedes are ready to embroil themselves in Formula 1’s political games.
Why Mercedes are confident in engine legality
Any team with real ambition is expected to push the limits of the regulations. This reality is extremely relevant this year, when a brand new set of rules provide teams with plenty of room for aggressive interpretations.
Aston Martin’s AMR26 has offered an early glimpse into the radical aerodynamic solutions we could see in 2026.
However, it is power unit development that has proven the biggest point of disagreement over the winter.
Mercedes have spent more than a year developing a unique compression ratio innovation. In short, the German constructor is able to increase their engine’s compression ratio above the 16:1 limit.
The consensus is that Mercedes achieve this through use of thermal expansion. As a result, this process only takes place when the engine is at high temperatures and being used on track.
Crucially, when the FIA conduct static tests at normal temperatures, the compression ratio is within the 16:1 limit.
Because there is no agreed upon methodology for measuring compression ratio on track, Toto Wolff’s team can capitalise on their solution when the W17 is out and running – increasing the ratio and unlocking more horsepower.
For the time being, it is difficult to assess the lap-time value of this unique approach. Most estimates suggest a baseline improvement of three tenths per lap is possible.
With that said, depending on how effectively Mercedes’ sustainable fuel interacts with the engine, the performance benefit could be even greater. (cont. on next page)