With ‘ADUO’ set to become one of the most frequently used acronyms in the Formula 1 paddock during the 2026 season, Sky Sports F1 explains why the sport’s new engine development rules are fast becoming a hot topic.
In what was widely considered to be the biggest regulation change in the sport’s history, the introduction of new power units, along with new chassis, saw electrical power increased to share a 50-50 split with internal combustion engines.
Any new set of engine regulations is likely to produce gaps in performance, which is why the rules included the potential for performance-balancing measures.
Additional Development and Upgrade Opportunities (ADUO) is a part of the F1 rules specifically relating to power units, giving the five manufacturers the potential to improve their models, should they be lagging behind the benchmark performer.
The merits of the provision are already evident, given that Aston Martin, a team that was expected to be competitive, are struggling at the back of the field due to extreme issues with their Honda power unit.
Without ADUO, they could have been confined to being backmarkers all season, but the opportunity to upgrade their engine provides hope that they can move forwards during the campaign.
However, while no one is questioning whether Honda should be allowed to improve their power unit, a dispute is developing over whether the other manufacturers – Ferrari, Red Bull and Audi – should be given the opportunity to bring their performance closer to that of the Mercedes power unit that has set the early benchmark.
Ferrari boss Fred Vasseur has spoken about ADUO being an opportunity to “close the gap” to Mercedes, but Silver Arrows chief Toto Wolff this week urged the FIA to ensure engine upgrades don’t interfere with the competitive pecking order.
Please use Chrome browser for a more accessible video player
George Russell weighs in on Max Verstappen’s future in Formula 1, admitting he’d ‘understand’ if the four-time world champion quit
How does ADUO work?
ADUO focuses on the performance of the non-electrical half of the power unit, the internal combustion engine (ICE).
The FIA are measuring the performance of the power units at every race using a performance index that is not available to the media.
ADUO will be granted to manufacturers who are down on performance to the leading ICE by two per cent or more.
Manufacturers trailing by between two and four per cent will be granted one opportunity to develop their power unit this season, while those trailing by four per cent or more will get two opportunities for improvement.
The results of the opening three rounds, each of which have been won by the Mercedes works team, suggest that the Silver Arrows’ self-made engine will be the benchmark.
There has been speculation that despite being well off the pace overall, Red Bull’s ICE performance is actually strong, and they are unlikely to be more than two per cent behind Mercedes, or not necessarily behind them at all.
Please use Chrome browser for a more accessible video player
Sky Sports F1’s Craig Slater shows off his keepy-uppy skills as he reports on Coventry City welcoming the Haas F1 team to the Sky Blue Lodge training ground
When is ADUO measured and implemented?
Ahead of the season, the FIA announced there would be three points during which ICE performance would be reviewed – after the sixth, 12th and 18th of the 24 scheduled rounds.
Those granted ADUO were to be given the opportunity to implement upgrades immediately for the seventh round, which was originally scheduled to be the Canadian Grand Prix.
However, the FIA are now reviewing this timeline as a result of what were scheduled to be rounds four and five in Bahrain and Saudi Arabia being cancelled because of conflict in the Middle East.
Please use Chrome browser for a more accessible video player
Look back at some of the most dramatic moments to have taken place around the Miami International Autodrome
The sport’s governing body are expected to announce before the Miami Grand Prix whether they are altering the timeline. The FIA also retains the right to alter the percentage thresholds they set before the season.
While manufacturers were set to be free to implement upgrades immediately after the first review, those supplying multiple teams would have to ensure that they could provide a sufficient number of engines.
For example, Ferrari, who supply engines for Haas and Cadillac, would need to offer their customers the same ICE specification they would have for themselves, to be allowed to introduce the upgraded model.
This creates a greater challenge than for say Audi, who are only building their own engines.
Please use Chrome browser for a more accessible video player
Ipswich’s Darnell Furlong displays his unlikely talent of guessing the F1 circuit by just listening to the sound of the car
Will manufacturers already be working on upgrades?
Yes! The three weeks between the Miami Grand Prix and Canadian Grand Prix would not be long enough for a manufacturer to design and produce upgrades.
They would have been working on improvements since submitting their first models for the start of the season.
Vasseur’s comments suggest that all four of Mercedes’ rival manufacturers are anticipating being granted ADUO and therefore will likely have been aiming to have new elements ready for the Canadian Grand Prix.
Even Mercedes will be working on developing their engine, given that all the manufacturers are able to introduce upgrades for the 2027 regardless of their standing in the pecking order.
It’s also worth remembering that any manufacturer will be able to make upgrades to all parts of their power units – including both the ICE and the electrical elements – should they be able to prove to the FIA that the changes are for the sole purposes of reliability, safety, cost-saving or supply issues.
Please use Chrome browser for a more accessible video player
The Miami Grand Prix is a unique experience, watch our favourite moments from the last few years!
Why could ADUO become a controversial topic?
While Vasseur – and the other teams using non-Mercedes engines – are eyeing an opportunity to make gains, Wolff appears unconvinced that any manufacturer other than Honda should be given scope to significantly upgrade their engine.
Speaking on April 20, Wolff said: “The principle of ADUO was to allow teams that were on the back foot in terms of the power unit to catch up, but not to leapfrog.
“And it needs to be very clear that whatever decisions are being made, whichever team is granted ADUO, that any such decision may have a big impact on the performance picture and on the championship, if not done with absolute precision and clarity and transparency.
“It needs to be clear that gamesmanship hasn’t got any place here, but it needs to be with the right spirit here that the FIA acts upon an ADUO.
Please use Chrome browser for a more accessible video player
Sky Sports F1 commentator David Croft shares his secret to identifying drivers on the track
“The teams will have their performance pictures and, as it seems for me, there’s one engine manufacturer that has a problem and we need to help. And then all the others are pretty much in the same ballpark.
“I would be very surprised, actually, and disappointed if ADUO decisions that were done would come up with any interferences into the competitive pecking order as it stands at the moment.”
While Wolff speaks of gamesmanship, he could potentially be referring to the possibility of teams attempting to display lower ICE performance to ensure a better outcome when it comes to ADUO.
As the season develops, ADUO appears likely to be a topic that keeps coming up.
Formula 1 returns on May 1-3 with the Miami Grand Prix, the season’s second Sprint weekend, live on Sky Sports F1. Stream Sky Sports with NOW – no contract, cancel anytime
