Formula 1’s governing body, the FIA, is reviewing its engine performance findings after Red Bull were identified as the manufacturer with the strongest power unit of the 2026 season. The verdict, delivered through the sport’s Additional Development and Upgrade Opportunities (ADUO) framework, has triggered a lively debate up and down the pit lane – not least from Red Bull themselves.
Here is a full breakdown of the ADUO engine rankings, who has been handed upgrade opportunities, why Red Bull are questioning the result, and what it all means heading into the Austrian Grand Prix.
What is the ADUO system in F1?
ADUO – Additional Development and Upgrade Opportunities – is the mechanism the FIA uses to rank the 2026 power unit manufacturers and decide who may develop their engines further during the season. The five manufacturers assessed are Red Bull, Mercedes, Ferrari, Audi and Honda.
Crucially, ADUO only measures the performance of the internal combustion engine (ICE). It does not account for the electrical side of the power unit, which contributes almost half of the total output under the 2026 regulations.
The F1 ADUO engine rankings explained
According to a document released to the teams earlier this month and seen by Sky Sports News, every manufacturer except Red Bull will be permitted to upgrade their engines this year. As the benchmark, Red Bull – building their own power unit for the first time in F1 – receive no upgrade at all.
The upgrade allocations break down as follows:
- Red Bull: benchmark engine – no upgrade permitted.
- Mercedes: judged more than 2% behind Red Bull – one upgrade this season (plus one for 2027).
- Ferrari: more than 4% adrift – two upgrades.
- Audi: more than 4% adrift – two upgrades.
- Honda: more than 4% adrift – two upgrades.
The FIA has not yet officially confirmed the results. The governing body is understood to be assessing its findings and holding talks with all teams and manufacturers ahead of the Austrian Grand Prix. Two further ADUO reviews are scheduled later in the year – after the Hungarian Grand Prix in late July and the Mexico City Grand Prix in early November – both of which will shape the 2027 season.
Why are Red Bull surprised to top the rankings?
The outcome has raised eyebrows at Red Bull, largely because Mercedes have won six of the seven races so far this season. Max Verstappen admitted at the Barcelona-Catalunya Grand Prix that he was taken aback to learn Red Bull had been judged to have the best engine.
Team principal Laurent Mekies stressed that Red Bull accept the principle of ranking only the ICE element and have no quarrel with the rule itself. Where they want a deeper conversation, he explained, is over the evidence – saying the team cannot find a single data sample suggesting they hold an advantage over Mercedes.
Mekies confirmed Red Bull have opened what he described as a constructive dialogue with the FIA to make sure the full picture is understood, adding that there is a common-sense aspect still to be worked through. He also pointed out that measuring engine power is genuinely difficult: the car carries a single sensor with several limitations, and teams rely on a range of other information to estimate output across the grid.
Mercedes back the FIA’s findings
Mercedes see things differently. Team principal Toto Wolff called the upgrade opportunity helpful and argued that measuring internal combustion engine output is relatively straightforward. In his view, the result simply reflects the FIA’s own torque-sensor data and analysis, with no political motive or favours involved.
Wolff framed ADUO as a safeguard against a repeat of 2014, when Mercedes built a dominant advantage at the start of a new engine era. He argued the sport needed to avoid leaving newcomers such as Audi – and to some extent Honda – stranded. At the same time, he was emphatic that this is not Balance of Performance, a concept he strongly dislikes, warning that BoP has created political problems and driven manufacturers out of other categories such as DTM, GTs and Le Mans.
Is ADUO good for Formula 1? The critics weigh in
Not everyone is convinced. Sky Sports F1 pundits Martin Brundle and Jacques Villeneuve have both voiced doubts about the system.
Brundle argued that F1 should be about excellence rather than levelling everyone to the lowest common denominator. While he accepted a struggling manufacturer such as Honda – and possibly Audi – might warrant a helping hand, he believes teams already have natural routes to improve their engines over time.
Villeneuve called the concept confusing, noting that the real effect is less about Mercedes receiving help and more about Red Bull being penalised. In his words, you should not have a rule that lets one team develop while forbidding another – if you do a good job within a fixed set of rules, you should be rewarded for it.
F1 2026 teams and their engines
| Team | Engine |
| McLaren | Mercedes |
| Mercedes | Mercedes |
| Red Bull | Red Bull-Ford |
| Ferrari | Ferrari |
| Williams | Mercedes |
| Haas | Ferrari |
| Aston Martin | Honda |
| Racing Bulls | Red Bull-Ford |
| Alpine | Mercedes |
| Audi | Audi |
| Cadillac | Ferrari |
What’s next: the Austrian Grand Prix
Formula 1’s European season rolls on with the Austrian Grand Prix on June 26–28, with the ADUO conversations set to rumble on in the background. Expect the FIA’s final confirmation – and Red Bull’s continued lobbying – to be a major talking point of the race weekend.
Frequently asked questions
What does ADUO stand for in F1?
ADUO stands for Additional Development and Upgrade Opportunities, the FIA framework used to rank 2026 power units and decide which manufacturers can upgrade their engines.
Which F1 team has the best engine in 2026?
Under the first ADUO review, Red Bull have been judged to have the best internal combustion engine and are treated as the benchmark, meaning they receive no upgrade.
Why don’t Red Bull get an engine upgrade?
Because they were ranked as the benchmark manufacturer. Every other supplier sits a defined percentage behind them, which earns those teams upgrade allocations.
Is ADUO the same as Balance of Performance?
The FIA says no. ADUO is described as a development mechanism rather than an artificial way to balance the grid, and figures such as Toto Wolff have been keen to distance it from Balance of Performance.
