Formula 1 ADUO for Dummies

It is called ADUO, short for Additional Development and Upgrade Opportunities, and it gives manufacturers who fall behind a chance to catch up without abandoning Formula 1's strict cost cap philosophy.

Rather than freezing struggling engine suppliers into years of uncompetitive performance, the FIA has created a structured mechanism allowing additional development if an engine falls sufficiently behind the benchmark. The system will remain in place until the end of the current power unit cycle in 2030.

Throughout each Formula 1 season, the FIA measures the performance of every manufacturer's internal combustion engine and calculates what it calls an ICE Performance Index.

The assessment considers several technical factors, including engine speed, input shaft torque, MGU K power output and the influence each has on lap time across measured sessions.

Importantly, the assessment focuses only on the internal combustion engine rather than the complete power unit. While hybrid systems remain a crucial part of overall performance, the FIA uses the ICE as the common reference point when deciding whether additional development should be allowed.

The trigger is based on how far behind a manufacturer's engine is compared to the strongest performer. If an engine is between 2% and 4% behind the leading ICE, that manufacturer receives one additional homologation upgrade during the current season and another in the following season.

If the performance deficit reaches 4% or more, the manufacturer receives two additional upgrades during the current season and another two the following year.

These opportunities are granted only once during a season. They do not continue accumulating after each review period. Likewise, unused upgrades cannot be carried over. If a manufacturer fails to introduce an approved upgrade before the end of the season, that opportunity is lost.

The FIA reviews engine performance three times during every championship. Following revisions to the original calendar, the first review now covers the opening five races of the season, from Australia through Canada. The second review covers Monaco through Hungary. The final assessment runs from the Dutch Grand Prix to Mexico City.

Manufacturers are informed of the results shortly after each monitoring period concludes. If they qualify for ADUO, they can introduce upgrades from the very next race weekend.

The system allows development across most major power unit components. Manufacturers may update parts of the internal combustion engine, exhaust system, turbocharger, wastegate, electrical components, sensors, ERS hardware, cooling systems, MGU K, control electronics, hydraulic functions, fluids and ballast.

The regulations therefore provide considerable technical freedom while still operating within the homologation framework. Because ADUO helps manufacturers who fall behind, comparisons have inevitably been made with Balance of Performance systems used elsewhere in motorsport.

The FIA insists that comparison is incorrect. FIA Single Seater Director Nikolas Tombazis explained: "It's important to make clear that ADUO is not a kind of balance of performance mechanism. 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," added Tombazis.

ADUO also comes with additional financial headroom under Formula 1's power unit cost cap. Manufacturers trailing by between 2% and 4% receive up to $3m of additional spending allowance.

That rises to $4.65m for deficits between 4% and 6%, $6.35m for deficits between 6% and 8%, and $8m for manufacturers between 8% and 10% behind the benchmark.

Should an engine supplier fall more than 10% behind, the FIA allows spending of up to $11m during each ADUO review period. During the inaugural 2026 season, additional support may also be provided if required.

The objective is simple. Rather than allowing one manufacturer to remain permanently disadvantaged throughout an engine cycle, Formula 1 hopes ADUO will maintain closer competition while preserving technical innovation and the financial discipline introduced under the sport's cost cap regulations.