ADUO: how F1's engine catch-up mechanism turned its own logic upside down

When Formula 1 wrote the Additional Development and Upgrade Opportunities (ADUO) mechanism into its 2026 technical regulations, the logic seemed straightforward enough.

Engine development was frozen for five years to control costs, but to stop the field from being locked into a hierarchy of permanent winners and losers, any manufacturer whose internal combustion engine fell meaningfully short of the best on the grid would be allowed to break the freeze and catch up.

Before the FIA’s first evaluation finished, everyone assumed they knew roughly how that would play out after having witnessed what the competitive order looked like in the first six races of the season.

Mercedes had won every race until Barcelona. Red Bull, Honda and Audi, the most obviously underpowered entries, were the ones expected to need rescuing.

Then the FIA actually ran the numbers.

On race day at the Monaco Grand Prix, the governing body told the five power unit manufacturers where they stood after the season’s first ADUO assessment period, and the result inverted the story completely.

Red Bull, not Mercedes, was ranked as having Formula 1‘s benchmark internal combustion engine.

Mercedes, the team that had won every grand prix so far, was found to be more than 2% behind it.

Ferrari, Audi and Honda were all more than 4% adrift.

The consequence: the only manufacturer not entitled to any ADUO upgrade is one without any wins and a distant fourth in the constructors’ championship at the time the decision was announced.

Mercedes, meanwhile, gets one upgrade this year and one more in 2027. Ferrari, Audi and Honda get two each.

Two of those three had already used theirs by the time of the Austrian GP, the eighth race of the season.

Here’s how the mechanism actually worked.

The verdict nobody saw coming

The reaction inside Red Bull ranged from bafflement to humour. Verstappen called the team “a little bit surprised” by the news. His team-mate Isack Hadjar was more direct: “I was checking if we won the first six races of the year, you know, and we didn’t, so…”

Team principal Laurent Mekies put it plainly to the media in Barcelona: “We do not see one single data sample that indicates that we would have an advantage over our friends at Mercedes.”

Red Bull sought clarification from the FIA, and the FIA is believed to be ready to walk Red Bull through its methodology in detail, but the underlying finding — that Red Bull’s ICE has at least a 2% advantage over Mercedes’ — is expected to stand.

The explanation for the apparent contradiction lies in what ADUO actually measures.

The Performance Index looks only at the internal combustion engine: input shaft torque, engine speed, MGU-K power and a weighting for power sensitivity on lap time.

It says nothing about the battery, the energy recovery system or how that stored energy is deployed, and under the 2026 rules, those electrical components make up close to half of total power output.

Mercedes’ advantage, on the evidence of seven wins in eight races, lives in that other half.

As Honda’s Shintaro Watanabe put, “Mercedes did a great job on the electric side, as we have more deployment than the rest.”

That split has produced an odd kind of role reversal in the paddock all season, where manufacturers have had every incentive to look weaker than they are rather than stronger.

The sandbagging problem

Before the verdict was announced, both Mercedes and Ferrari had reason to suspect the other of not running its power unit at full potential: Mercedes to protect its advantage from the ADUO threshold, Ferrari to make sure it fell the right side of the 2% line and qualified for help it might not otherwise need.

The FIA’s own technical regulations anticipate exactly this, reserving the right to revoke a manufacturer’s ADUO privileges if it concludes the case for assistance was manufactured rather than genuine, though proving that, as opposed to simply suspecting it, is another matter.

For Red Bull specifically, the stakes in this game are higher than for anyone else, because Red Bull is the one party that structurally can’t win it.

Every other manufacturer can choose to look weak. Red Bull, ranked as the benchmark, has no equivalent lever. There’s no version of the index where appearing slower helps a team that’s already been told it’s the fastest.

Mekies has been explicit about the resulting trap: if Mercedes elects not to use its own ADUO token at all, or spends it purely on the electrical side of the power unit rather than the ICE, the FIA’s benchmark could remain unchanged through every future assessment window.

Red Bull would stay pinned at the top of a ranking it doesn’t believe reflects reality, locked out of development opportunities indefinitely while insisting, with no means of unilaterally proving it, that the ranking is wrong.

“There is a large risk there for Red Bull,” Mekies said. “It is one of the reasons why it is vital for Red Bull, and more generally for the sport, that we get that picture right.”

That dynamic helps explain why Red Bull has pushed so hard for a methodology review rather than simply accepting the Monaco result and moving on. It isn’t only about contesting one data point, it’s about avoiding a structural position with no obvious exit ramp.

How the thresholds work

The mechanics themselves are unchanged from how they were written into the regulations.

A manufacturer whose ICE Performance Index sits 2% to 4% below the benchmark earns one additional homologation upgrade this season and one more in 2027. Fall 4% or more behind, and that doubles to two upgrades in each year.

Crucially, the allocation is fixed at the moment a manufacturer first qualifies; it isn’t cumulative, and a team that misses out in both of the first two assessment windows of a season cannot receive ADUO in the third at all.

There’s a financial layer too.

Manufacturers get cost cap relief, along with upgrade allowances, enabling them to spend more, beyond the cost cap:

• 2-4% behind, up to $3m more
• 4-6% behind, up to $4.65m
• 6-8% behind, up to $6.35m
• 8-10% behind, up to $8m
• 10% or worse, up to $11m — with a 2026-only provision allowing those in the deepest hole to use up to $8m of future cost-cap allowance early.

ADUO allowances also grant extended access to restricted test bench time.

The season is split into three assessment windows: the first ran to the Canadian Grand Prix, with results delivered in Monaco; the second runs from there to the Hungarian Grand Prix at the end of July; the third covers the Netherlands through to Mexico City in the autumn.

Any upgrade granted must be introduced before the season’s final race or it’s forfeited outright, there’s no carrying allowances over.

What can actually be changed is limited to a specific table of components inside the technical regulations’ Appendix C4, each one marked as either permissible or frozen even under ADUO status.

Audi first, quietly

What nobody perhaps anticipated was how fast the upgrades would actually appear. Audi got there first, and almost nobody noticed at the time.

An FIA technical document released during practice at the Barcelona-Catalunya Grand Prix, just a week after the Monaco ruling, showed both Audi cars had been fitted with new internal combustion engines and turbochargers.

At the time it barely registered. It has since emerged that the new specification included several refinements, focused chiefly on improving driveability – among them, addressing throttle response linked to the engine’s relatively large turbo – rather than a step change in outright power.

Audi’s technical leadership had evidently finished the development work well before the FIA’s verdict was even confirmed, and simply waited for the green light before shipping the parts to Barcelona.

“For Audi it will be a significant benefit,” team principal Mattia Binotto said. “Since the very start of the season, we knew that most of our gap to the top teams was on the power unit side. Not a surprise to us…

“We are looking for a big development, but more on the medium and long term. We will not see immediate benefits from the ADUO, but then it will be certainly beneficial for us.”

Ferrari’s turn in Austria

Ferrari’s first ADUO step arrived at the Red Bull Ring, timed for a circuit named after the manufacturer that the mechanism left out in the cold.

Power unit technical director Enrico Gualtieri had been careful to manage expectations ahead of the Austrian GP weekend: “The update we are bringing to Spielberg is a relatively minor one and it’s the result of the work completed in recent weeks to transfer improvements from our development programme to the track.

“It epitomises key principles of our sport: continuous improvement, reacting quickly, and deploying gains at the earliest opportunity.”

Worth noting: Ferrari’s ADUO allowance is for two upgrades this season, the same maximum tier as Audi and Honda, but being grouped together doesn’t mean the three are judged to be at an identical distance from Red Bull, only that all three fall somewhere beyond the 4% threshold where the allowance stops increasing.

Mercedes brought a parallel update to Austria, though not as a result of ADUO: a battery upgrade aimed at reliability (allowable under the regulations) after a string of issues cost the team points, not an ICE change gated by the FIA’s ruling.

Honda, the manufacturer the original ADUO conversation was largely framed around early in the year, is yet to bring its first step. The expectation in the paddock is for that to land just ahead of the August summer break, potentially as early as Spa in mid-July.

What it means heading into the second period

The irony embedded in the first ADUO ruling is one that the regulations didn’t anticipate: rather than closing the gap to Mercedes, the mechanism risked protecting it.

Mercedes is not a frozen target — it has its own upgrade allowance in hand — so Ferrari, Audi and Honda closing the gap to Red Bull’s benchmark ICE does nothing to guarantee they’d close the gap to Mercedes’ actual on-track pace, given how much of that pace lives in the electrical side that the index doesn’t measure at all.