F1 ADUO Explained: The New 2026 Rule That Could Rescue Struggling Engine Manufacturers

Formula 1's all-new 2026 regulations have introduced one of the most significant power unit development mechanisms in the sport's history. Known as ADUO - Additional Development and Upgrade Opportunities - the system has been designed to help manufacturers close performance gaps without resorting to a traditional Balance of Performance model.

With the FIA set to publish its first engine performance assessment following the Canadian Grand Prix, ADUO is about to become a major talking point in the new power unit era.

What is ADUO?

ADUO stands for Additional Development and Upgrade Opportunities. It is a concession system that allows underperforming power unit manufacturers to make additional upgrades to homologated engines during the season.

Under the previous regulations, manufacturers had very limited opportunities to modify their power units once homologation was completed. The new framework offers struggling suppliers a chance to catch up if they fall significantly behind the benchmark engine.

The FIA will assess engine performance through an ICE (Internal Combustion Engine) Performance Index, which measures factors such as:

• Engine speed
• Input shaft torque
• MGU-K power contribution
• Power sensitivity to lap time

Importantly, the assessment focuses only on the combustion engine component and does not represent the complete performance of the power unit package, which also includes hybrid systems and vehicle-related factors.

When does a manufacturer qualify for F1 ADUO?

A manufacturer becomes eligible when its ICE performance index falls at least 2% behind the best-performing engine on the grid.

The level of support depends on the size of the deficit.

Manufacturers between 2% and 4% behind

Eligible manufacturers receive:

• One homologation upgrade during the current season
• One homologation upgrade during the following season

Manufacturers more than 4% behind

Eligible manufacturers receive:

• Two homologation upgrades during the current season
• Two homologation upgrades during the following season

The upgrades can be introduced as early as the next race after the FIA confirms eligibility.

How will the FIA monitor engine performance?

The 2026 season has been divided into three assessment periods.

First review period

• Australian Grand Prix to Canadian Grand Prix
• Results published within two weeks of Canada

Second review period

• Monaco Grand Prix to Hungarian Grand Prix

Third review period

• Dutch Grand Prix to Mexico City Grand Prix

After each monitoring window, the FIA will calculate the performance index and notify eligible manufacturers about any development opportunities they have earned.

What parts can be upgraded under F1 ADUO?

Manufacturers granted ADUO concessions can modify a broad range of power unit components.

These include:

• Internal combustion engine components
• Exhaust systems
• Turbocharger assemblies
• Wastegate and pop-off valves
• MGU-K systems
• Energy Recovery System (ERS) components
• Cooling systems
• Control electronics
• Electrical sensors and hardware
• Hydraulic systems
• Fluids and ballast

The intention is to provide meaningful scope for performance gains while maintaining the overall homologation framework.

Are unused upgrades carried forward?

No.

One of the most important elements of ADUO is that upgrade allowances are not cumulative within a season.

For example:

• A manufacturer awarded one upgrade in 2026 must use it before the end of that season.
• If it is not used, the allowance expires.
• The separate allocation granted for 2027 remains available.

This prevents teams from stockpiling upgrades and deploying them all at once in future seasons.

Why ADUO is not Formula 1's version of Balance of Performance

The introduction of ADUO has led to comparisons with the Balance of Performance systems commonly used in endurance racing categories such as WEC.

However, the FIA insists the two concepts are fundamentally different.

Under a traditional BoP framework, organisers directly adjust performance through measures such as:

• Additional ballast
• Reduced power output
• Restricted fuel flow
• Aerodynamic limitations

ADUO does none of these things.

Instead, manufacturers are simply given extra development opportunities and additional spending allowances to improve their own engines. The leading manufacturers are not penalised or slowed down.

FIA Single-Seater Director Nikolas Tombazis described ADUO as a **"cost cap relief mechanism"** rather than a performance-balancing tool.

Manufacturers must still design and build a superior engine to become the benchmark.

How does F1 ADUO affect the power unit cost cap?

The system is closely linked to Formula 1's financial regulations.

Manufacturers qualifying for ADUO receive additional budget allowances depending on the size of their performance deficit.

Additional support may also be available in specific circumstances during the first year of the regulations.

Why ADUO could be crucial in 2026

The 2026 regulations represent one of the biggest technical resets in Formula 1 history, with all manufacturers introducing entirely new power units.

Historically, major regulation changes have often created significant performance gaps between suppliers. ADUO has been introduced to prevent manufacturers from becoming permanently trapped at the back of the field if they begin the cycle with an engine deficit.

While the mechanism will not guarantee convergence, it gives struggling manufacturers more flexibility, more resources and more opportunities to improve their products throughout the regulation cycle.

In simple terms, ADUO is Formula 1's attempt to keep the engine competition healthy without artificially slowing the frontrunners, helping ensure that manufacturers can fight their way back through engineering development rather than regulatory intervention.