The FIA explains ADUO, the mechanism by which manufacturers may upgrade their homologated power unit during a season, or the subsequent one, in ordr to encourage close competition.

Across defined periods in each full season from 2026-2030 the FIA will monitor the performance of the Internal Combustion Engine (ICE) part of the Power Units supplied by each PU Manufacturer to its customer F1 Teams and will calculate an ICE Performance Index. The calculation is based on a range of factors including input shaft torque, engine speed, MGUK power and a weighting to account for power sensitivity on lap time across measured laps. From the outset, it has been transparently discussed between the FIA and the PU manufacturers, that certain factors that may ultimately affect ICE performance, such as fluid temperatures, external aerodynamics, and similar variables, would be captured as part of the on-car measurements, and that no correction methodology would be applied. Similarly, as the ADUO assessment focuses solely on the ICE, it is not representative of full Power Unit performance, given the ERS system plays a crucial role in the overall power output. A PU manufacturer whose ICE lags behind the best performing ICE by at least 2% will be granted ADUO.

How does ADUO work regarding the Financial Regulations as they relate to Power Unit Manufacturers?

Financial savings are at the heart of ADUO opportunities, as FIA Single Seater Director Nikolas Tombazis explains.

"It's important to make clear that ADUO is not a kind of balance of performance mechanism," he says. "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."

The positive impact of ADUO on a manufacturer's expenditure is laid out in Article E4.1.1.t of the 2026 Formula 1 Regulations. The article defines the allowances granted for each ADUO period to manufacturers that falls 2% or more outside the performance of the best PU to support development activities outside its cost cap calculation. Specifically, every manufacturer from 2-4% behind will get allowances up to USD $3.0m. From 4-6% behind is up to USD $4.65m, from 6-8% is up to USD $6.35m, 8%-10% is up to USD $8m. For manufacturers having a deficit of 10% or more, in addition to an allowance for each ADUO period up to USD $11m, there's the additional possibility, for the season 2026 only, to anticipate up to USD $8m of Cost Cap of future periods to support development activities.

When are the monitoring periods and has the calendar update affected them?

Article 4.2 of Appendix C5 of the 2026 F1 Technical Regulations divided the 2026 season into three periods during which ICE performance will be analysed in order to determine whether a manufacturer might qualify for ADUO.

These 3 periods cover, respectively, races 1-6, 7-12, and 13-18. However, the first period, encompassing the Australian, Chinese, Japanese, Bahrain, Saudi Arabian and Miami grands prix was disrupted by the ongoing events in the middle east. The first period has therefore been adjusted and is now formed of the season's first five races (Australia, China, Japan, Miami and Canada). The results will be communicated no later than two weeks after the Canadian Grand Prix.

The 2nd period will cover races 6-11 (Monaco to Hungary) and the 3rd period from race 12 (Netherlands) to race 18 (Mexico City).

Once the results have been communicated, ADUO eligible PU manufacturers will receive a separate notification detailing their allowance. They will be able to implement upgrades as early as the following race.

How do manufacturers qualify for ADUO?

As set out in Article 4.3 of Appendix C5, a manufacturer whose ICE Performance Index is at least 2% but less than 4% below the best-performing ICE will be eligible for one additional homologation upgrade in the current season and an additional upgrade in the following season.

PU Manufacturers whose ICE Performance Index is at least 4% below the best-performing ICE will be eligible for two additional upgrades in the current season and two more during the following campaign.

However, PU manufacturers not granted ADUO after the first two periods of a season will not be eligible for ADUO after the final period of the same season.

Are upgrades cumulative within a season?

ADUO homologation upgrades are not cumulative within a season and will only be granted on the first occasion that the PU Manufacturer is assessed by the FIA as eligible.

However, upgrades granted for the following season (Season N+1) will still be usable in season N+1 if a team falls within the ADUO thresholds in the following season. E.g. Following the 2026 Canadian Grand Prix, PU manufacturers X measures below 4% of the best performing PU and is granted ADUO of two 2026 upgrades and two in 2027. However, if after Period 1 of 2027 it once again measures below 4% and is granted ADUO of two 2027 upgrades and two in 2028. It is therefore allowed to introduce four upgrades in 2027 (two from its 2026 ADUO award and two from its 2027 award).

Can upgrades be carried over from season to season?

No. Any upgrade unused by the final round of the season in which it is specified to be introduced will be forfeited. E.g. After the Canadian Grand Prix if PU manufacturer X is within 2% of the best performing power unit and is granted one upgrade in the 2026 season and one for the following season, it must introduce its 2026 upgrade before the end of the season or it will lose that opportunity. The upgrade for 2027 will still be valid.

What kind of upgrades can manufacturers make?

Although it is the ICE that serves as the measure by which an ADUO is granted, upgrades may be made to a wide variety of PU components. These are detailed in Table 1 of Appendix C4 of the 2026 Technical Regulations. Permitted upgrades include certain elements of the ICE, engine exhaust system, turbo and waste gate/pop-off, ICE or exhaust-mounted electrical components and sensors, ERS (and associated cooling systems), the MGU-K, and the car's Control Electronics, as well as certain hydraulic functions, fluids, and ballast.