The FIA has released its findings from the second period of the ADUO review process, confirming no new homologations have been granted to any power unit manufacturer.
ADUO, which stands for Additional Development and Upgrade Opportunities, is a new mechanism introduced to Formula 1 in 2026 to help close the competitive gap between engine suppliers.
The system works by comparing each manufacturer’s internal combustion engine performance against the best-performing unit on the grid, with a 2% deficit triggering eligibility for additional upgrades.
Manufacturers falling between two and four per cent behind the benchmark earn one upgrade in the current season and one further upgrade in 2027.
Those more than four per cent behind the leading engine receive two upgrades in 2026 and two additional ones in 2027, giving them a more substantial opportunity to close the gap.
The first ADUO analysis period, covering races from the Australian Grand Prix through to the Canadian Grand Prix, controversially identified Red Bull Powertrains as the benchmark engine, with Mercedes ranked second despite their strong on-track performance.
The second period, covering the Monaco Grand Prix through to the Hungarian Grand Prix, has now concluded with the same hierarchy intact, leaving Red Bull as the benchmark for a second consecutive review period.
Mercedes, whose power unit serves McLaren, Williams, Mercedes and Alpine, remain within the two to four per cent bracket and will therefore receive one additional upgrade this season and one in 2027.
Ferrari, Honda and Audi all remain more than four per cent behind the Red Bull benchmark, meaning each of those manufacturers will be permitted two additional upgrades in 2026 and two more in 2027.
FIA single seat director Nikolas Tombazis addressed the findings directly, emphasising the thoroughness of the process behind the decision.
Tombazis said: “The FIA has undertaken thorough and exhaustive analysis as part of our ADUO review process.”
He added: “With the release of the findings of period 2, we are confident that, based on the quality of the data, its analysis is incredibly robust, giving us a high level of confidence in our findings.”
Tombazis also acknowledged the sensitivity around sharing the detailed results, stating: “We also have to respect the confidentiality and intellectual property of the teams and their Power Unit Manufacturers in disseminating any details from the findings.”
The FIA’s single seat director noted that the system remains in its infancy and may develop further over the course of its implementation.
Tombazis said: “This is the first year of ADUO so naturally there are areas which we may evolve over time, in discussion with all the PU Manufacturers.”
The third ADUO review period for 2026 will cover races 12 through 18 of the season, spanning from the Dutch Grand Prix to the Mexico City Grand Prix.