Just days before the start of the 2026 season and the new regulatory era, the FIA has officially announced a major technical change regarding the measurement of the compression ratio of power units, at the heart of a controversy involving Mercedes during the off-season.
A “grey area” exploited by Mercedes
With the arrival of the new 2026 hybrid engines, more focused on electric and 100% sustainable fuels, engine manufacturers have explored every detail of the regulations. Mercedes Benz It would thus have designed a powertrain capable of displaying a compression ratio conforming to 16:1 when stationary as required by regulations, while reaching a higher level once in operation, thanks to different thermal conditions.
An ingenious interpretation of the rules which, according to some estimates in the paddock, could represent a significant performance gain, potentially several tenths of a second per lap. This approach quickly raised questions among competitors and reignited the debate on how the FIA needed to control this key parameter of the internal combustion engine.
The FIA is urgently amending the regulations
Faced with growing tensions between the five engine manufacturers involved (Mercedes, Ferrari, Red Bull Powertrains, Honda and Audi)A vote was held to clarify the compression ratio measurement protocol. With the required majority obtained, the federation published a revised version of the technical regulations before the Australian Grand Prix, the season's opening round.
The new framework provides for a phased implementation:
- Until May 31, 2026: compression ratio measurement only at ambient temperature
- From June 1st, 2026: measurement also at operating temperature, around 130°C
In practical terms, this means that the current Mercedes engine design remains compliant at the start of the season, but any solution exploiting the gap between a cold and hot engine will have to be abandoned from the middle of the championship, possibly as early as the Monaco weekend.
A direct impact on the 2026 hierarchy
During the winter, Mercedes Benz It was often presented as the technical benchmark for the new engine regulations, particularly thanks to this innovative interpretation. But the regulatory adjustments could reshuffle the deck as the season progresses.
Especially since pre-season testing has shown particularly fierce competition, with Classic Ferrari for sale very competitive, while Red Bull and McLaren should also play leading roles depending on the circuits.
By implementing this change as early as 2026, ahead of a full harmonization planned for 2027 with systematic checks at operating temperature, FIA The primary aim is to avoid technological dominance stemming from a regulatory loophole. This strategic decision could prevent a decisive competitive advantage from solidifying the hierarchy from the outset of this new technological era.
