The FIA has allowed four manufacturers to refine their engines.

      The FIA announced the results of the first two stages of engine assessment under the ADUO program, according to which the Red Bull-Ford internal combustion engine has been recognized as the benchmark, while Mercedes, Ferrari, Audi, and Honda have received additional opportunities to refine their power units.

      Following the first stage, which concluded after the Canadian Grand Prix, the FIA determined that the Mercedes internal combustion engine lags behind the benchmark Red Bull-Ford engine by a range of 2% to 4%. Therefore, the German manufacturer was allowed to conduct one additional homologation of the power unit in 2026 and 2027, as well as an increase in allowable spending within budget constraints and time for bench testing.

      The lag of the Ferrari, Audi, and Honda engines was more than 4% from the Red Bull-Ford engine, so each of these manufacturers received the right to two additional homologations in 2026 and another two in 2027, with a corresponding increase in allowable spending within budget constraints and time for bench testing.

      Following the second stage, which concluded after the Hungarian Grand Prix, no additional homologations were granted to any of the manufacturers. The FIA emphasized that it would not disclose details of the assessment results, as this information is confidential.

      The third stage of the ADUO assessment this season covers the events from the Dutch Grand Prix to the Mexican Grand Prix.

      Nicolas Tombazis, FIA Director of Single-Seater Racing: "As part of the analysis under the ADUO program, the FIA conducted a thorough and comprehensive review. After the completion of the second stage, we are confident in the assessment results, as the quality of the data and the work done allow us to speak with a high degree of certainty about the accuracy of the conclusions drawn.

      At the same time, we must maintain confidentiality and protect the intellectual property of the teams and power unit manufacturers, so we cannot disclose details of the results.

      This is the first year of the ADUO program, so it is natural that some of its elements may change over time. We will discuss possible changes with all power unit manufacturers."