The landscape for Formula 1 power unit development changes significantly with the introduction of ADUO, an acronym for Additional Development and Upgrade Opportunities. Implemented for the 2026–2030 power unit cycle, the measure is intended to narrow gaps between suppliers without altering the core sporting parameters. The FIA will evaluate manufacturers on specific metrics focused on the internal combustion element of the power unit rather than a combined measure that includes recovery systems. That distinction matters because the ERS remains a major contributor to lap-time performance, so the ADUO assessment is deliberately ICE-centric.
The new process creates a formal performance benchmark known as the ICE Performance Index, which the FIA uses to determine who qualifies for extra upgrade opportunities. When a manufacturer’s ICE trails the leader by a threshold of at least 2%, that supplier becomes eligible for development allowances under the rules. These allowances translate into both the right to introduce specific homologation upgrades and into extra permitted expenditure that is carved out from the normal financial restrictions, intended as a targeted cost cap relief mechanism. The approach is not intended to be a balance-of-performance tool but rather a structured way to let trailing manufacturers close technical gaps while keeping the overall rule framework intact.
How the FIA measures performance
The ICE Performance Index is constructed from a set of engine parameters chosen to reflect raw combustion performance. Key inputs include engine speed, input shaft torque and the output of the MGU-K where applicable in measuring kinetic contributions to the ICE window. The index also applies a weighting to how sensitive lap time is to power changes across the laps sampled. Because the methodology isolates the ICE, the FIA acknowledges it does not represent a full power unit picture — the ERS and other hybrid elements remain outside that specific index — but the intent is to provide a repeatable, fair basis for defining ADUO eligibility.
The regulatory references and scope
The monitoring and eligibility mechanics are set out in the technical appendices: monitoring windows are defined in Article 4.2 of Appendix C5 and the upgrade entitlements appear in Article 4.3 of Appendix C5. ADUO applies across the 2026–2030 homologation cycle and triggers when a manufacturer is at least 2% behind the best-performing ICE. That threshold then determines the number of additional sanctioned homologation upgrades the manufacturer may introduce during the current season and the following season, so the system links short-term parity checks to near-term development opportunities.
When upgrades are allowed and how the season windows work
There are three review periods each season that determine ADUO status and timing. Because the original calendar changes affected some events, the first monitoring window in practice has been adapted: it now covers the opening five races — Australia, China, Japan, Miami and Canada — with results communicated no later than two weeks after the Canadian Grand Prix. The second window covers Rounds 6–11 (from Monaco to Hungary) and the third covers Rounds 12–18 (from the Netherlands to Mexico City). Once the FIA communicates results, eligible manufacturers receive a formal notification and may introduce the authorised upgrades as early as the next race.
Eligibility bands and upgrade counts
Qualification is tiered by the size of the deficit. If a manufacturer’s ICE Performance Index shows them 2%–4% behind the leader, they receive one additional upgrade in the current season and one in the following season. If they are 4% or more behind, they can introduce two upgrades in the current season plus two in the following season. Importantly, ADUO allowances are not cumulative inside a season: the entitlement is granted on the first occasion a manufacturer meets the criteria, and any unused upgrade slot for that season is forfeited. In other words, an upgrade awarded for 2026 must be used in 2026 or it is lost, even if the manufacturer has a separate entitlement for 2027.
Permitted changes and the cost-cap implications
The scope of permitted work under ADUO is relatively broad but clearly defined. Allowed developments include elements of the ICE itself, the engine exhaust system, turbocharger components and waste gate / pop-off, ICE- or exhaust-mounted electrical components and sensors, the ERS and related cooling systems, the MGU‑K, the car’s Control Electronics, and also hydraulic functions, fluids and ballast where relevant. The rulebook limits how the changes are combined and ensures manufacturers cannot exploit ADUO to alter unrelated performance parameters such as fuel flow or overall vehicle ballast.
The financial side is codified in Article E4.1.1.t: the FIA provides graduated allowances tied to the percentage deficit. Suppliers 2%–4% adrift get up to USD $3.0 million per period; 4%–6% up to USD $4.65 million; 6%–8% up to USD $6.35 million; 8%–10% up to USD $8.0 million; and those at 10% or more may receive up to USD $11.0 million per ADUO period, with the rules stating extra transitional support may be available in 2026 only. As Nikolas Tombazis of the FIA has stressed, ADUO is not a balance-of-performance fix but a targeted cost cap relief mechanism that gives trailing manufacturers structured space to evolve their engines without undermining the integrity of the regulations.
In summary, ADUO creates a measured pathway for engine makers to catch up: it is built on a repeatable ICE Performance Index, operates inside defined seasonal windows, limits what can be changed, and couples technical relief with controlled financial allowances. The system aims to keep competition closer while ensuring any developments remain transparent, regulated and aligned with the wider spirit of the 2026–2030 technical framework.
