ADUO explained as F1 waits for critical FIA announcement

What is ADUO in F1?

F1 is ablaze with ADUO conversations coming out of the Monaco Grand Prix as Lewis Hamilton let the cat out of the bag by confirming Ferrari and Mercedes would receive engine upgrades. 

Whilst there has been no official confirmation by the FIA as yet, it has become clear that Red Bull Powertrains has been deemed the strongest engine on the grid, with Mercedes HPP, Ferrari, Audi, and Honda all set to receive extra upgrades in a bid to close the gap. 

Below, RacingNews365 takes a look at what ADUO actually is, and how it works. 

ADUO in F1 explained

The Additional Development and Upgrade Opportunities (ADUO) system has been set up for F1's new 2026 power unit rules to cover and monitor power unit performance across the manufacturers. 

Essentially, the FIA gathers data and technical information from the five suppliers and evaluates the engines, with one declared the class-leader and the remaining four handed more development and upgrade opportunities to try to close the gap. 

F1's 2026 engines were homologated earlier in the year, meaning PUMs cannot add performance-improving upgrades, but ADUO offers this opportunity. 

For power units found to be between two per cent and four per cent behind, one ADUO opportunity will be granted for 2026 and one more for 2027. For those found to be four per cent or more down, two upgrades in both 2026 and 2027 will be allowed.

However, PUMs cannot 'stockpile' ADUO upgrade tokens, with further windows planned for after the Hungarian GP, and after Mexico City, which will affect 2027. 

The upgrade tokens awarded in ADUO are not cumulative, and only count on the first time they are awarded.

But why has Red Bull been deemed the best engine?

With Red Bull surprisingly being deemed the best engine despite the fact that Mercedes HPP has dominated the season thus far, it is important to know that ADUO only covers the Internal Combustion Engine (ICE). 

After analysing this, the FIA has decided that the RBPT ICE is the strongest in the field, and thus Mercedes HPP, Ferrari, Audi, and Honda all qualify for ADUO assistance. 

It has been judged that Mercedes HPP is two per cent behind, and receives one upgrade, whilst Ferrari, Audi, and Honda are all set to receive four per cent - with Honda also earning extra budget to develop given its woes.

It is important to note that the FIA has not publicly made its decision-making criteria available to the PUMs, or the media. This is because there were fears that some PUMs could 'game' the AUDO system by deliberately under-performing to earn upgrades. 

What can be upgraded under ADUO?

PUMs can apply their permitted ADUO tokens to a variety of power unit areas, including the ICE, the engine exhaust, the turbocharger, ERS, MGU-K, or the Control Electronics. 

It is entirely up to each PUM how it uses its allotted ADUO tokens. 

As every F1 PUM works under cost cap rules, changes to the cost cap have been factored in to reflect the awarding of ADUO, with Mercedes HPP set to receive a $3 million USD boost, whilst Audi, Ferrari, and Honda get up to $4.65 million.