What is ADUO? F1’s new engine rule that could define 2026 explained

The 2026 Formula 1 regulations feature a new performance-balancing rule known as Additional Development Upgrade Opportunities or ADUO - here’s what it means and how it works.

ADUO is effectively a catch-up framework for power unit manufacturers who have fallen behind. The regulations set out three periods during the season with manufacturers judged to be between two and four per cent behind the class-leading engine awarded extra development opportunities for this year and next.

It can be viewed as a type of Balance of Performance (BoP), however the onus is on the trailing manufacturers to close the gap, rather than the leading one being pegged back, as is the case in the World Endurance Championship.

Who will ADUO benefit? 

Power unit manufacturers found to be between two and four per cent adrift will be permitted one immediate change, with those over the four per cent threshold granted further concessions. These will include increased dyno time and more cost cap flexibility.

While acting as a performance-balancer to prevent huge competitive gaps between the 11 teams being cemented for years to come, avoiding the kind of scenarios we saw back in 2014 amid the height of Mercedes dominance, ADUO does not provide opportunity for a quick fix.

“The lead times on engine development are very long,” Audi boss Mattia Binotto explained at the Japanese Grand Prix.

“We have assessed, I believe, that most of the gap we got to the top teams is from the power unit, which is not unexpected. We knew that would have been the biggest challenge.

“And we have got a plan to recover. But engine development, especially when it comes to some concepts, can take longer. It's not by chance that we have set 2030 as our objective [for competing for world championships].

“Because we know that it will take long. And I think what we need now is to be patient as well. We are very ambitious and we would like to see things solved in a couple of races. But sometimes that's not the case.

“So I think we need to understand exactly where we are as a team, what are the plans. And as well, stick to the plans. Because miracles are not possible.

“We are not here to create miracles. It's not us. We cannot do that. But we are here to have proper plans to address and to improve in the future. And I think that's also possible.”

Controversy as first ADUO verdict causes shock

F1 teams and power unit manufacturers learned over the Monaco Grand Prix weekend that Red Bull was judged to have the best engine in the 2026 season.

The rankings of the first ADUO verdict - which were let slip by Lewis Hamilton following the Monaco race - revealed under the ICE Performance Index that the Ford-branded Red Bull power unit was strongest, ahead of Mercedes, Ferrari Audi and Honda.

Given the general consensus in the paddock that Mercedes boasted the benchmark engine after dominating the start of the 2026 campaign, the news sent shockwaves through the F1 paddock.

The FIA is currently carrying out a review of the numbers as a result of one manufacturer, which Crash.net understands to be Red Bull Powertrains, questioning the findings.

Max Verstappen admitted the verdict took Red Bull by surprise. 

“We just feel surprised, because we don’t feel like we are the best,” Verstappen said at the Barcelona-Catalunya Grand Prix. 

“It is super impressive what they [Red Bull Powertrains] have done. If you look at it, we never thought we’d start there and it’s super impressive that in such a short timeframe what they have done.

“We still have some reliability things but overall it’s honestly nice to be a part of it and seeing the drive of it. They are never satisfied and they are equally disappointed when things don’t go right.

“Of course we are proud, just a bit confused as suddenly being portrayed as the best, because we don’t feel like that.”