Why nobody outside F1 can see the engine ranking
Formula 1 has completed the second assessment period of its new engine catch up system without publishing the ranking that decides which manufacturers receive development help.
The FIA can use ADUO, its Additional Development and Upgrade Opportunities mechanism, to give a power unit manufacturer extra homologation upgrades, cost cap relief and additional testing freedom when its combustion engine falls far enough behind the benchmark. Honda has already used the mechanism, its new Spec 2 engine running at Zandvoort this weekend as the first Honda upgrade produced through the ADUO allowance it earned earlier in the season. Fernando Alonso finished ninth and Honda said both new engines completed the weekend without major reliability problems.
What ADUO controls
The FIA assesses manufacturers on the internal combustion engine rather than the full power unit. Under the published method, the ICE Performance Index uses data including input shaft torque, engine speed and MGU-K power, weighted to account for how sensitive lap time is to power at each circuit. Manufacturers at least 2% behind the strongest ICE become eligible for help. A manufacturer between 2% and 4% behind earns one additional homologation upgrade for the current season and another for the following season. Manufacturers 4% or more behind earn two in each season. Power unit manufacturers can also receive cost cap relief from the same assessment. The FIA starts the adjustment at up to $3 million for a manufacturer between 2% and 4% behind and raises it to as much as $11 million at 10% or more. Manufacturers also receive additional testing allowances according to the ADUO result.
Nikolas Tombazis, the FIA's single-seater director, said in May: "ADUO is not a kind of balance of performance mechanism." Manufacturers do not receive more fuel flow on Sunday because an engine was slow on Saturday. They still have to design, manufacture and introduce something better. The FIA allocates development permission from its performance assessment. An eligible manufacturer can eventually put the result on track, as Honda has now done, but the public cannot consult the underlying ranking in an official table.
Red Bull's challenge after the first assessment showed why the distinction matters.
Motorsport.com reported in June that Red Bull Ford Powertrains had been assessed as the combustion engine benchmark. Mercedes, the next manufacturer in the reported order, was more than 2% behind. The Race reported Ferrari, Audi and Honda beyond the 4% threshold, leaving Red Bull as the only manufacturer without ADUO help. Lewis Hamilton had already spoken publicly about the allowances after the Monaco Grand Prix. Sky Sports F1 reported that the Ferrari driver named Red Bull as the strongest engine, Mercedes second and Ferrari behind, while PlanetF1 reported the same order from multiple informed sources. The governing body still had not published the assessment. PlanetF1 said on 7 June that the findings had yet to be publicly announced. On 5 July, the outlet again reported that the benchmarking had not been formally communicated to the public. Autosport was still reporting on 12 August that the first period's results had not been publicly announced.
Red Bull also disputed the result. Max Verstappen said in Barcelona: "We were all a little bit surprised with that news." Laurent Mekies said at the Austrian Grand Prix that Red Bull was still engaging with the FIA over the assessment. The team principal said the cost of a wrong answer could have "heavy consequences both in '26 and in '27." Autosport, Motorsport.com and The Race have already addressed whether ADUO measures the right thing, whether manufacturers can game it and whether the system needs redesigning. The public still cannot see the official ranking behind a regulatory decision with competitive consequences.
The missing ranking
The FIA divides the 2026 season into three ADUO assessment periods. Manufacturers were assessed from Monaco through Hungary in Period 2, which ended before the summer break. They entered Period 3 at Zandvoort. The FIA said in its May explainer that first-period results would be communicated no later than two weeks after the Canadian Grand Prix. The governing body gives no equivalent publication date for Period 2 in the public explainer.
Eligible manufacturers receive a separate notification detailing their allowance once results have been communicated. The FIA does not appear to require the full ranking to be released publicly in either the regulations or its public material. As of Monday evening, the governing body had not published an official Period 2 ranking through its public Formula 1 material. As of Monday evening, searches of the FIA's public Formula 1 material, Autosport, Motorsport.com, The Race and Formula1.com did not surface an official Period 2 ranking. The published material does not show that Formula 1's governing body has broken its own rules or that a completed result is being deliberately concealed. Manufacturers nevertheless receive public competitive advantages from an assessment the public cannot inspect. Red Bull faces higher stakes in Period 2 because of how eligibility works. A manufacturer which receives no ADUO after either of the first two periods cannot become eligible after the third. Red Bull received no allowance from the reported first assessment, so another zero would close its final route into the mechanism later this season.
Honda sits on the other side of the system. Honda has already converted its first ADUO permission into an engine that exists, raced and scored points. Chief engineer Shintaro Orihara said before Zandvoort that combustion engine performance remained the manufacturer's main weakness. The FIA designed the mechanism to help manufacturers that have fallen behind. The governing body can also reasonably argue that publishing sensitive performance measurements creates problems for the manufacturers whose data sits underneath the calculation. The FIA uses ADUO for more than an internal engineering comparison. Manufacturers are separated into regulatory categories which determine additional development opportunities, spending allowances, testing freedom and, in some cases, whether another opportunity will exist later in the season. Formula 1 already publishes documents on track limits, technical infringements and cost cap breaches. Viewers can see the consequences of ADUO mainly through what manufacturers are subsequently allowed to do. Reporters and Hamilton brought the first ADUO order into public view while no official FIA ranking appeared on the governing body's public channels. Hamilton told Sky Sports F1 after Monaco: "Red Bull have the most powerful engine, Mercedes second, and then we are behind."
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