Mercedes has changed its approach to Formula 1’s ADUO development system and is now preparing new power-unit hardware for later in the 2026 season. The Brixworth engine division had initially intended to use its additional development allowance without introducing new performance components, but that plan has now reportedly changed, opening the door to an even stronger Mercedes power unit in the coming Grands Prix.
When the first details of the ADUO allocations emerged, Red Bull’s position at the top of the FIA’s ranking appeared surprising. The RB22’s on-track performance, particularly on the straights, has not been comparable with the Mercedes W17. However, the FIA assessment is based on the internal combustion engine rather than the performance of the complete hybrid power unit, and under those criteria Red Bull emerged as the benchmark.
Why Mercedes qualifies for an ADUO engine upgrade
Mercedes was assessed as being around 2% behind the benchmark in the relevant ADUO classification, giving the manufacturer the opportunity to introduce one additional homologation during 2026 and another in 2027. Ferrari, Audi and Honda, meanwhile, fall into the 4% category and therefore have access to twice the development resources and additional homologation opportunities.
The apparent contradiction comes from the way the system measures performance. Mercedes may not possess the highest-rated ICE under the FIA methodology, but the complete Mercedes power unit has demonstrated a clear competitive advantage on track, particularly through its combination of combustion performance, electrical deployment and energy management.
That advantage was especially visible at Monza, where Mercedes’ power-unit performance became one of the defining features of the Italian Grand Prix.
Mercedes changes its original ADUO development plan
There currently appears to be little competition with Mercedes when the complete power-unit package is considered. Kimi Antonelli provided the clearest example at Monza, where he won from 19th on the grid with a fresh but not upgraded power unit, combining the car’s performance with his own talent and a degree of good fortune.
The victory left Kimi Antonelli in an extremely strong position in the Drivers’ Championship, but Mercedes also wants to maximise its advantage in the Constructors’ Championship.
According to information reported by The Race, the powertrain division had previously not intended to introduce new hardware as part of its ADUO programme. That position has now changed. Brixworth is working towards a revised specification that could appear during the next phase of the championship, adding another performance step to a package that is already highly competitive.
The change of direction is also reflected in Mercedes’ plans for further W17 and ADUO development during the upcoming run of races.
George Russell could receive the new Mercedes engine first
There is not yet a confirmed debut race for the revised specification. Its introduction could come during the sequence involving Baku, Singapore and Malaysia, with George Russell potentially becoming the first Mercedes driver to receive it.
The British driver is approaching the point where fresh power-unit components will be required anyway, making his car the logical first candidate for the new specification.
Attention at Brixworth is expected to focus on areas including the turbocharger, MGU-K and exhaust system. One clue comes from the components Mercedes did not replace on Antonelli’s number 12 car at Monza. Although the Italian received fresh power-unit elements for his home Grand Prix, Mercedes held back other components that could potentially be introduced later in updated form.
Turbo and MGU-K development could add performance without changing the ICE
The technical logic is particularly significant because improvements to the turbocharger, MGU-K and related systems can increase the performance of the complete power unit without directly modifying the ICE, which is the component used as the basis for the FIA’s ADUO assessment.
That means Mercedes could potentially improve the areas that already make its overall power unit so competitive without necessarily changing its position relative to Red Bull in an ICE-based future ranking.
The turbocharger appears to be one of the most obvious areas for development. Formula 1 manufacturers can find significant gains not simply through peak combustion power, but through compressor efficiency, energy delivery and the interaction between the electrical and combustion elements of the power unit. Ferrari has followed a similar route with its own recent development, including reported changes to its ADUO-2 turbocharger specification.
Mercedes customer teams could make the upgrade even more damaging for Ferrari
The real strategic advantage for Mercedes extends beyond the factory team. Its customer teams will also be able to benefit from the revised power unit once the updated specification becomes available.
That could have important consequences in both championships. A team such as McLaren, for example, could potentially use the improved Mercedes power unit to place its cars between the works Mercedes drivers and Ferrari.
If that happens, Ferrari would not merely have to overcome Mercedes’ own performance advantage. Mercedes-powered customer cars could also take positions and points away from its closest challengers, increasing the championship impact of every additional power-unit gain.
Mercedes therefore finds itself in an unusual position. Formula 1’s catch-up mechanism has awarded it additional development freedom because its internal combustion engine does not sit at the top of the FIA’s specific performance index, yet on track the complete Mercedes package already appears to be the benchmark.
Now, after initially deciding against new ADUO hardware, Brixworth has changed course. If the revised turbo, MGU-K or other components deliver the expected gains, the strongest overall power-unit package in Formula 1 could become even more difficult for Mercedes’ rivals to contain during the closing stages of 2026.
Potential issue to verify
The “2%” figure for Mercedes should be treated as an ADUO performance band rather than a confirmed exact deficit. The FIA allocation establishes that Mercedes qualified in the threshold that grants one additional homologation, while Ferrari, Audi and Honda qualified for the higher level of development freedom; it does not publicly establish an exact 2.00% performance deficit.
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