Alongside the compression ratio and potential rule changes for 2027, one topic has dominated discussions in the paddock during the opening months of this season: ADUO – the Additional Development and Upgrade Opportunities for manufacturers that are trailing behind.
The FIA introduced the system with the best of intentions, primarily to avoid a repeat of the situation Honda faced under the previous regulations, but it quickly turned into a political battleground.
During the April break, Toto Wolff stated firmly that only one manufacturer truly needed assistance (Honda), and that the system should not become a mechanism to “leapfrog” manufacturers that are relatively close together. Yet because of the way the system is structured, with the first threshold set at just 2%, that is logically exactly what can happen.
Everyone involved was fully aware of this, which has led to a political game being played out in public. Lewis Hamilton explained in Montreal how he could keep up with the Mercedes-powered cars through the corners, only to watch them visibly pull away on every straight. Naturally, it was a politically charged remark.
Mattia Binotto, speaking on behalf of Audi, stated that his team has the fourth-best chassis on the grid, underlining that the shortcomings are clearly on the power unit side. And so everyone contributed their piece to the narrative.
Wolff’s earlier comments were also political to a certain extent, since everyone assumed that Mercedes would be ranked at the top of the engine standings. Understandably, Wolff was not particularly enthusiastic about direct rivals receiving upgrade opportunities, hence his remarks that the system should be aimed solely at Honda and not function as a leapfrog mechanism.
Mercedes has dominated at the start of 2026, but according to the FIA's measurements it doesn't have the best engine
Photo by: Erik Junius
Discrepancy between measurement method and permitted upgrades
The surprise in the media centre on Sunday evening was all the greater when it emerged that the FIA had ranked Red Bull-Ford, rather than Mercedes, at the top of the internal combustion engine standings. If the results remain unchanged after Red Bull’s request for an additional review, that would mean no upgrade opportunities for the newcomer from Milton Keynes, while Mercedes would instead receive development opportunities.
Because Mercedes’ ICE deficit falls between 2% and 4%, the manufacturer would receive one upgrade opportunity this season and one next year. All other manufacturers – Ferrari, Audi and Honda – so far fall into the category of being more than 4% behind, meaning they would receive two upgrades this season and another two next year.
The outcome raises three crucial questions about whether the system is actually achieving what it was designed to do. First and foremost, there appears to be a massive discrepancy between the measurement method and the upgrade opportunities that are linked to it. And this particular outcome has exposed the issue extremely clearly.
Only the ICE is measured, but once a manufacturer qualifies for ADUO, it is also allowed to modify electrical components
The ADUO measurement is based solely on the power output of the internal combustion engine. It relies on sensors and real-world data, although the FIA has chosen not to disclose the exact methodology, since manufacturers could potentially manipulate the results if they knew precisely how the calculations were made.
However, it has been clear from the beginning that the measurement is based exclusively on the ICE, not on the electrical components of the power unit. Yet the upgrade opportunities attached to ADUO extend far beyond that, as the FIA itself explained in its own documentation:
“Although it is the ICE that serves as the measure by which an ADUO is granted, upgrades may be made to a wide variety of PU components. These are detailed in Table 1 of Appendix C4 of the 2026 Technical Regulations.
“Permitted upgrades include certain elements of the ICE, engine exhaust system, turbo and waste gate/pop-off, ICE or exhaust-mounted electrical components and sensors, ERS (and associated cooling systems), the MGU-K, and the car’s Control Electronics, as well as certain hydraulic functions, fluids, and ballast.”
Effectively the entire F1 paddock has agreed Honda needs upgrade assistance, but the rest is hotly debated
Photo by: Alastair Staley / LAT Images via Getty Images
As the FIA acknowledges, only the ICE is measured, but once a manufacturer qualifies for ADUO, it is also allowed to modify electrical components. And it is precisely this discrepancy between the measurement method and the permitted upgrades that leaves a lot of room for debate.
Despite Red Bull’s ICE being ranked first, broad consensus in the paddock remains that Mercedes still possesses the best overall power unit. The way ADUO is currently structured means that the manufacturer with the strongest power unit can improve its product even further, and that has never been the intention of this catch-up mechanism.
Red Bull may have the most powerful combustion engine, but it appears to be lacking on the electrical side of the PU. One could therefore argue that Red Bull is one of the manufacturers that needs an upgrade for its electrical components the most, yet under the current ADUO rules, getting such an upgrade is not possible.
Ferrari’s smaller turbo: Should that have been taken into account?
A second factor is that certain power unit design choices influence the measurement results, yet those aspects are not all taken into account either.
The most obvious example is Ferrari’s smaller turbo. The Scuderia benefits from that choice off the line, but it has an impact on the total power output. It raises the question of whether it is appropriate to receive additional upgrade opportunities when part of the deficit stems from a deliberate design choice. Or should it simply be a case of accepting the disadvantages alongside the advantages?
FIA single-seater director Nikolas Tombazis has indicated that, in his view, the measurement method could have been more sophisticated in order to account for such factors. Following discussions with the teams and manufacturers, however, it was decided to keep the system as simple as possible.
Ferrari's small turbo was made by design, so should that be cause for allowing upgrades?
Photo by: Alastair Staley / LAT Images via Getty Images
“In the spring of 2025 we had quite long discussions with them. We offered whether we wanted to consider certain things like the turbo pressures, or the turbo diameters, or the plenum operating temperature and such. And the universal position by the PU manufacturers back then was that we should keep it simple,” Tombazis said.
“So the fact that it is the current horsepower measurement of the internal combustion engine has been appreciated right from the start. I would personally be quite open to the idea of complicating the parameters a bit, but that discussion was had more than a year ago and it was quite clear what it concluded.”
While there is certainly an argument for keeping the procedure as straightforward and simple as possible, excluding such parameters inevitably means that the final picture does not provide a complete – or at least fully nuanced – representation of reality.
Taken together, all of these factors raise a fundamental question: is ADUO actually working?
Is ADUO still working as originally intended?
Finally, there are also questions surrounding the timing of the upgrades. ADUO upgrades are not cumulative within a season, nor can they be carried over, so manufacturers cannot simply stockpile tokens across multiple years.
There is, however, an unavoidable lead time associated with introducing upgrades, and that creates opportunities for strategic behaviour.
If Mercedes decides, based on the on-track picture, that it does not immediately need its upgrade opportunities for the combustion engine, it could effectively put Red Bull in a difficult position.
Mercedes could use the ADUO token structure against its rivals
Photo by: Anni Graf - Formula 1 via Getty Images
If Mercedes and Ferrari choose not to introduce (all) their upgrades before the next measurement point – or if they only introduce them on the electrical side – Red Bull would logically remain at the top of the standings at the next ICE assessment. As a result, Red Bull would once again be ineligible for development opportunities.
Taken together, all of these factors raise a fundamental question: is ADUO actually working in the way it was originally intended?
The measurement method does not align with the upgrades that are granted on the basis of those measurements, and beyond that, the system seems to have become exactly what Wolff warned against: not merely a safety net for Honda, but a leapfrog mechanism – one that is proving to be politically sensitive.
The review into ADUO will be completed after the Barcelona GP
Photo by: Alastair Staley / LAT Images via Getty Images
