Why Ferrari urgently needs the 4% ADUO concession in the F1 engine battle. F1 ADUO rules: Why Ferrari is fighting for the 4% performance deficit bracket.

The FIA has finally clarified how the ADUO system will work and what concessions will be available to Formula 1 power unit manufacturers. For Ferrari, one objective now stands out above all others: securing the 4% threshold, a target that has become increasingly important given the team’s current engine performance deficit.

The Scuderia is fully aware that it currently trails Mercedes in power unit performance by an estimated 30 horsepower. That is why Ferrari now has a strong need to secure a 4% ADUO concession from the FIA. Here is a full breakdown of how the system works and why the threshold matters so much.

We already know that Ferrari’s updated engine could arrive as early as the Belgian Grand Prix at Spa. Frederic Vasseur remains confident that Ferrari will qualify for ADUO support, although the scale of that support remains uncertain. Many within the paddock believe Ferrari could fall into the 4% category rather than the 2% bracket — and the difference would be highly significant for several reasons.

Maranello will obviously not be able to erase a 25–30 horsepower gap in a single development window. That kind of recovery will require time and multiple upgrade phases. After the Canadian Grand Prix, the FIA will publish the first performance evaluations that will determine which manufacturers qualify for support under the Additional Development and Upgrade Opportunities framework.

One component at a time: why 4% would be vital for Ferrari

“It is important to clarify: ADUO is not some form of Balance of Performance mechanism. A team or manufacturer will not suddenly receive greater fuel flow or more or less ballast. It is effectively a Cost Cap relief mechanism, where a power unit manufacturer that meets the criteria receives the opportunity to develop its engine through reduced cost restrictions. It is not a magic solution, nor is it the FIA handing out bonus points to those who are behind. It simply gives them room to develop their power unit within the limits established by the Technical Regulations.”

Those were the words of FIA Single-Seater Director Nikolas Tombazis.

The FIA has now fully explained through multiple pages of technical documentation how ADUO eligibility will be assessed. The key factor is the Performance Index, which will determine how far each manufacturer is from the benchmark engine package.

There will be three monitoring opportunities during the season: after the Canadian Grand Prix, after the Hungarian Grand Prix and after the Mexico City Grand Prix. Two weeks after each evaluation deadline, the FIA will announce which manufacturers qualify for ADUO support and how many development tokens they will receive.

These tokens can only be used within the relevant period and are not cumulative within the same season, although allocations for the following year can also be granted depending on performance deficit levels.

Here is how the ADUO thresholds are structured:

Deficit between 2% and 4%: up to $3 million in additional development budget.
Deficit between 4% and 6%: up to $4.65 million.
Deficit between 6% and 8%: up to $6.35 million.
Deficit between 8% and 10%: up to $8 million.
Deficit greater than 10%: up to $11 million in extra development margin during 2026.

But what does that actually mean in practical terms?

First, it is important to define which power unit components can be updated under ADUO. Eligible development areas include the internal combustion engine (ICE), turbocharger, exhaust system, ERS, cooling systems, electronic sensors, the MGU-K, as well as selected electronic and hydraulic systems associated with the car.

Each token allows the team to update only one individual component chosen from those approved areas. That means a manufacturer cannot simply redesign the entire power unit in one move.

If a team qualifies in the 2% to 4% bracket, it receives one development token for 2026 and one for 2027.

If the deficit exceeds 4%, the package becomes significantly more powerful: two tokens for 2026 and two for 2027.

That is precisely why falling into the higher bracket would be absolutely critical for Ferrari. With a power deficit estimated at around 30 horsepower, the extra flexibility, budget relief and additional upgrade opportunities could make a major difference in the Scuderia’s attempt to close the gap to Mercedes over time.