In 2026, Formula 1 entered a new era not only for the cars, but also for the power units. A power unit is the heart of an F1 car, combining the internal combustion engine, electric motor systems, battery and energy recovery technology. One of the new mechanisms introduced under these rules is called ADUO.
│What is ADUO?
ADUO stands for Additional Development and Upgrade Opportunities.
In simple terms, it is a mechanism that gives extra development chances to power unit manufacturers whose performance falls significantly behind.
This does not mean the FIA simply gives more power to a weaker engine, and it is not a system designed to hand victory to a specific team. Instead, it is meant to prevent one manufacturer from falling so far behind that its customer teams suffer for a long time.
│How far behind does a manufacturer have to be?
ADUO is judged using the performance of the ICE, the internal combustion engine.
The FIA monitors ICE performance and creates an ICE Performance Index.
If a manufacturer is at least 2% but less than 4% behind the leading ICE, it becomes eligible for one extra homologation upgrade in the current season and one in the following season.
If it is 4% or more behind, it becomes eligible for two extra upgrades in the current season and two more in the following season.
So ADUO is not there for someone who is just slightly slower.
It only applies once a meaningful gap is confirmed.
│What can actually be changed under ADUO?
The judgment is based on ICE performance, but the possible upgrade areas are wider than the engine alone.
According to the FIA list, permitted developments can include parts of the ICE, the exhaust system, turbocharger and waste gate, electrical components and sensors mounted around the ICE or exhaust, the ERS and its cooling systems, the MGU-K, control electronics, and even hydraulic functions, fluids and ballast.
The important point is that ADUO is not a magic performance button.
The FIA does not directly increase fuel flow or alter ballast to help a weaker manufacturer.
What ADUO provides is an extra chance to develop within the rules.
Whether that chance turns into real performance depends on the manufacturer’s own engineering ability.
FIA Single Seater Director Nikolas Tombazis has described ADUO as a cost cap relief mechanism, not a balance-of-performance system.
│When is it judged?
For 2026, the FIA monitors ICE performance across three periods.
The first period covers the opening five races: Australia, China, Japan, Miami and Canada.
Results from that first period are due no later than two weeks after the Canadian Grand Prix.
After that, eligible manufacturers can introduce upgrades as early as the following race.
The second period runs from Monaco to Hungary, and the third from the Netherlands to Mexico City.
That means the competitive order seen at the start of 2026 does not necessarily have to stay fixed all year.
A manufacturer that struggles early on could gain ADUO eligibility, improve its package, and close the gap later in the season. This is an inference from the FIA timetable and eligibility structure.
│What about the cost cap?
ADUO is also connected to the power unit financial rules.
Manufacturers that fall behind receive a downward adjustment in relevant cost-cap calculations, which effectively creates extra budget room for development.
The relief starts at up to $3.0 million for a deficit of 2% to under 4%, rises through larger bands, and reaches up to $11 million for a deficit of 10% or more, with extra 2026-specific support also mentioned for the biggest shortfalls.
This is financial breathing room, not a direct performance handout.
│Summary
Whether a manufacturer can truly use ADUO well still depends on its technical strength.
In 2026 F1, the development race between power unit manufacturers is one of the biggest stories.
ADUO is not simple rescue.
It is a structured chance to catch up, designed to keep the competition closer for longer.