The FIA has completed its second review of Formula 1 engine performance under the new Additional Development and Upgrade Opportunities system, confirming that no additional engine upgrades have been granted to any power unit manufacturer for the latest period.

The second review concluded following the Hungarian Grand Prix and follows the opening assessment after the Canadian Grand Prix, when Mercedes, Audi, Ferrari and Honda were all granted additional development opportunities.

Known as ADUO, the system was introduced with Formula 1’s new power unit regulations to encourage close competition. It allows manufacturers whose internal combustion engines fall at least two per cent behind the best-performing engine during defined review periods additional opportunities to develop, along with increased spending and dyno testing allowances.

Nikolas Tombazis, FIA Director of Single Seater, said: “The FIA has undertaken thorough and exhaustive analysis as part of our ADUO review process. With the release of the findings of period 2, we are confident that, based on the quality of the data, its analysis is incredibly robust, giving us a high level of confidence in our findings. We also have to respect the confidentiality and intellectual property of the teams and their Power Unit Manufacturers in disseminating any details from the findings.

“This is the first year of ADUO so naturally there are areas which we may evolve over time, in discussion with all the PU Manufacturers”

What happened in the first review?

The first review concluded after the Canadian Grand Prix and found Mercedes to be within the two-to-four per cent performance window.

As a result, Mercedes was granted one additional opportunity to introduce an approved engine upgrade in 2026 and another in 2027, together with corresponding increases in its spending and dyno testing allowances.

Audi, Ferrari and Honda were each determined to be more than four per cent behind the leading internal combustion engine.

Each was therefore granted two additional engine upgrade opportunities in 2026 and two in 2027, together with corresponding increases in spending and dyno testing allowances.

Following the second review period, which covered races from Monaco through to the Hungarian Grand Prix, the FIA confirmed that no additional engine upgrades were granted to any of the power unit manufacturers.

Due to the confidential nature of the information, the governing body will not disclose further details of its power unit performance measurements.

Designed to encourage closer competition

ADUO was introduced as part of Formula 1’s 2026 Technical Regulations and is designed to give manufacturers that fall behind additional scope to develop their engines rather than remain locked into a performance deficit.

The FIA monitors the internal combustion engine supplied by each manufacturer and calculates an ICE Performance Index using several factors, including input shaft torque, engine speed and MGU-K power. A weighting is also used to account for the effect of power on lap time across the measured laps.

If a manufacturer’s engine is at least two per cent behind the best-performing engine, it can qualify for additional development opportunities.

However, the assessment should not be interpreted as a ranking of Formula 1’s complete power units.

The system focuses specifically on the internal combustion engine. The electrical energy recovery system also plays a crucial role in the overall power output, while factors including fluid temperatures and external aerodynamics can affect the on-car measurements.

ADUO is not Balance of Performance

While ADUO is intended to encourage closer competition, the FIA has stressed that it should not be confused with a Balance of Performance system.

“It’s important to make clear that ADUO is not a kind of balance of performance mechanism,” Tombazis said. “A team or manufacturer will not suddenly get greater fuel flow rate or more or less ballast. It is, in fact, a Cost Cap relief mechanism, where a PU manufacturer meeting ADUO criteria during a review period is given an opportunity to develop its engine through a downward adjustment.

“That’s not to underestimate it but a manufacturer will still need to make the best engine in order to win. It’s not a magic bullet, or like the FIA is handing out brownie points to somebody who’s behind, it simply provides them with leeway to develop their power unit within the framework laid out by the Technical Regulations.”

In simple terms, the FIA does not directly give a manufacturer more engine performance. Instead, those that meet the criteria are given additional scope and financial allowance to develop their power units.

How much additional development is available?

The financial allowance available through ADUO increases according to the size of the performance gap.

A manufacturer measured between two and four per cent behind can receive an allowance of up to $3 million.

That increases to $4.65 million for a deficit between four and six per cent, $6.35 million between six and eight per cent and $8 million between eight and 10 per cent.

A manufacturer with a deficit of 10 per cent or more can receive up to $11 million for an ADUO period.

For 2026 only, manufacturers in that final category also have the possibility of bringing forward up to $8 million of cost cap allowance from future periods to support development.

When is the next review?

The third ADUO review period of 2026 will begin with the Dutch Grand Prix and run through to the Mexico City Grand Prix, covering races 12 to 18.

During those seven rounds, the FIA will again monitor the performance of each manufacturer’s internal combustion engine against the leading benchmark.

Once the results have been communicated, manufacturers eligible for ADUO will receive separate notification detailing their allowance, with eligible upgrades able to be introduced as early as the following race.

The Mexico City Grand Prix will bring the third and final ADUO assessment period of the 2026 season to a close.

For more information on ADUO: https://api.fia.com/news/power-ups-how-f1s-additional-development-upgrade-opportunities-will-be-applied-and-whats