For months, one of the most widely discussed topics surrounding Formula 1’s 2026 regulations has been the perceived hierarchy of the new power units. The common belief within the paddock has been that Mercedes developed the benchmark engine, while Ferrari was left chasing a significant performance deficit, reportedly worth as much as 30 horsepower according to some estimates.
However, recent rumors linked to the FIA’s new Allowance Development and Upgrade Opportunity system, better known as ADUO, are beginning to paint a very different picture.
If the latest information proves accurate, the strongest internal combustion engine may not belong to Mercedes at all. Instead, Red Bull Powertrains could be emerging as the reference point, while Mercedes itself may qualify for the very FIA concessions designed to help manufacturers close performance gaps.
ADUO could reshape the entire discussion
Ever since the first details about the 2026 power units began to emerge, speculation has focused heavily on the relative strengths of each manufacturer.
Mercedes was widely credited with finding an advantage through innovative solutions on the combustion engine side of the project. At the same time, Ferrari was often described as trailing behind, with some insiders suggesting a deficit of around 30 horsepower compared to the German manufacturer. That narrative became increasingly accepted as fact throughout the paddock.
The introduction of ADUO, however, may force many observers to reconsider those assumptions.
According to recent reports, the benchmark internal combustion engine is not currently Mercedes but Red Bull Powertrains. Even more surprisingly, Mercedes is said to fall within the performance threshold that would allow it to access development opportunities under the FIA concession system. If that is indeed the case, several long-standing assumptions about the 2026 engine battle may need to be revised.
Why Mercedes’ position is attracting attention
The most intriguing aspect of these reports is not Ferrari or Honda. It is Mercedes.
Information circulating within the paddock suggests that the German manufacturer may be operating with an internal combustion engine deficit of roughly 2% compared to the current benchmark.
That figure would be enough to qualify for certain ADUO development opportunities. The implication is significant. If Mercedes had genuinely built the strongest combustion engine in Formula 1’s next generation of power units, there would be little reason for the company to be included in a concession framework intended for manufacturers that are behind the leaders.
This apparent contradiction is exactly why engineers, analysts and fans are taking a closer look at the emerging reports.
Red Bull Powertrains could be the surprise leader
Perhaps the biggest surprise of all is the apparent competitiveness of Red Bull Powertrains.
When the project was first announced, many questioned whether a relatively new operation could realistically challenge established manufacturers such as Ferrari and Mercedes from day one.
Today, those doubts may be fading. Much of the project’s progress is believed to stem from an aggressive recruitment strategy that brought experienced specialists from Honda, Mercedes and Renault to Milton Keynes over the past few years.
Particularly important has been the integration of engineers who previously worked directly on Honda’s successful Formula 1 power unit programme. Their expertise appears to have provided valuable continuity and technical knowledge during the development process.
If the rumors are accurate, the result could be an internal combustion engine that currently sets the standard for the entire category.
Does Ferrari’s deficit tell the whole story?
This naturally leads to another important question: is Ferrari really as far behind as some reports have suggested?
Current ADUO-related speculation points to a possible deficit between 4% and 6% for Ferrari relative to the benchmark combustion engine. On the surface, that would confirm that the Maranello-based team is still trailing in terms of pure ICE performance.
However, there is a crucial detail that is often overlooked. The ADUO evaluations are focused exclusively on the internal combustion engine.
The 2026 Formula 1 power unit, by contrast, will rely heavily on electrification, with approximately half of its total output coming from the electrical component. This means that any ranking based solely on combustion engine performance provides only part of the picture. Ferrari may hold strengths in the electrical systems, energy deployment or recovery efficiency. Equally, Mercedes could compensate for a combustion engine deficit through superior hybrid performance.
Until the complete power units are tested under race conditions, drawing definitive conclusions remains difficult.
What about Mercedes’ compression ratio advantage?
One of the most popular theories in recent months revolved around Mercedes allegedly gaining a significant advantage through an innovative compression ratio strategy.
Many technical analyses pointed to this area as a key reason behind the expected superiority of the Mercedes power unit. The latest ADUO-related information appears to challenge that interpretation. If Mercedes is not currently the benchmark for combustion engine performance, then either the benefits of that solution have been overstated or its impact on overall performance is smaller than originally believed.
Without official FIA data, definitive conclusions remain impossible. Nevertheless, the possibility that Mercedes qualifies for concessions has reopened a debate that many thought had already been settled.
The transparency question remains
The situation also highlights another issue that continues to generate discussion.
How exactly are these performance assessments being conducted? Which parameters does the FIA use to determine the deficits assigned to each manufacturer? What testing procedures underpin the percentages being reported? At present, publicly available information remains limited.
The lack of transparency creates fertile ground for speculation, particularly in a technical area as complex and politically sensitive as Formula 1 power unit development.
The less information that becomes available, the more rumors, theories and competing interpretations are likely to emerge.
ADUO may have opened a new chapter in the 2026 engine battle
The latest reports surrounding ADUO have the potential to significantly alter perceptions of Formula 1’s upcoming power unit era.
For months, the dominant narrative suggested Mercedes was comfortably ahead while Ferrari struggled to close a substantial gap. The emerging rumors now point toward a different scenario, with Red Bull Powertrains potentially leading the way in combustion engine performance and Mercedes qualifying for development concessions.
This does not automatically mean Mercedes will be less competitive in 2026, nor does it imply Ferrari has suddenly solved every weakness in its programme. What it does suggest is that the certainty surrounding the current power unit hierarchy may have been overstated.
Perhaps the most important takeaway is that the battle for 2026 remains far more open than many previously believed. With the hybrid systems accounting for such a large proportion of overall performance, the final competitive order may not become clear until the cars finally hit the track.
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