The FIA has officially confirmed Red Bull-Ford Powertrains possesses the most powerful internal combustion engine (ICE) in Formula 1, following the first two Additional Development and Upgrade Opportunities (ADUO) review periods of the 2026 season. This ruling means Red Bull-Ford is ineligible for engine upgrades under the ADUO system.
The ADUO mechanism, outlined in Article C4 of the 2026 F1 Technical Regulations, aims to promote competitive balance by allowing power unit manufacturers with a performance deficit to introduce additional homologated upgrades.
Eligibility for ADUO is determined by an ICE performance index, with manufacturers needing to be at least two per cent below the leading engine. A deficit exceeding four per cent grants further development opportunities.
The FIA’s analysis focuses exclusively on the internal combustion engine, a point of ongoing discussion within the paddock, as it does not account for the full power unit’s electrical components.
Mercedes was found to be in the 2-4 per cent performance window behind Red Bull-Ford’s ICE. As a result, Mercedes will receive one additional homologation for upgrades in 2026 and another in 2027.
This allowance for Mercedes also includes an extra $3 million in cost cap allowance and an additional 70 hours of dyno testing.
Audi, Ferrari, and Honda were determined to be more than four per cent adrift of Red Bull-Ford’s benchmark ICE performance. These manufacturers are permitted two additional homologations in both 2026 and 2027.
The first ADUO review period covered the initial five races of the season, from the Australian Grand Prix to the Canadian Grand Prix. The second period spanned rounds six to eleven, concluding after the Hungarian Grand Prix.
Results from both periods were communicated privately to teams after the Canadian Grand Prix and publicly released on Wednesday, August 26, 2026.
Despite Red Bull’s internal review request following the initial findings, the FIA confirmed no additional homologations were granted to any power unit manufacturers for the second period, indicating consistent performance gaps.
Nikolas Tombazis, FIA Director of Single Seater, expressed confidence in the evaluation process.
‘The FIA has undertaken thorough and exhaustive analysis as part of our ADUO review process,’ Tombazis stated. ‘With the release of the findings of period two, 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 that as this is the inaugural year for ADUO, the system may evolve through discussions with power unit manufacturers.
Since the initial ADUO reporting, Audi has utilised one token for power unit developments in Barcelona. Ferrari introduced an engine upgrade at the Austrian Grand Prix, with their updated unit potentially debuting at Monza next weekend. Honda also brought a significant upgrade to the Dutch Grand Prix.
The third ADUO review period for the current season is underway, covering races from the Dutch Grand Prix to the Mexican Grand Prix. The FIA will conduct a further evaluation and allocate additional tokens as necessary after this period.
