The numbers that matter for 2027

Why can’t Mercedes simply give Russell the new engine?

This is where the customer-team situation becomes important.

Mercedes High Performance Powertrains supplies engines to its factory team as well as customer teams. McLaren and Williams are among the teams using Mercedes power units, meaning that a new engine specification has implications beyond the two cars in the Mercedes garage.

Under the 2026 FIA technical regulations, an updated homologated power unit must be made available to every team supplied by that manufacturer at the event where the specification is first introduced, with at least one power unit of the new specification available to each team. This is a regulatory requirement, not simply a matter of Mercedes choosing which driver gets the upgrade.

According to Sky Sport Italia’s report on 8 October, Mercedes had not completed production and homologation of ADUO 1 in time for Singapore while meeting the requirement to make the revised components available to its customer teams. The report specifically identifies the turbocharger as a key component in the supply arrangements.

This explains why the situation is more complicated than fitting a new engine to Russell’s car.

Mercedes must coordinate the upgrade’s introduction across its customer supply operation. It needs the appropriate components, a completed and approved specification, and sufficient hardware to meet the applicable requirements at the first event of introduction.

The important qualification: the reporting points to the time needed to complete and supply the new specification. It does not establish that Mercedes has run out of all engines or that every customer team is currently short of power units. Those are different claims.

The factory team cannot treat ADUO 1 as an exclusive upgrade for Russell or Antonelli and introduce it on one car while ignoring the supply obligations to its customers.

Why must Russell start from the back of the grid?

The frustrating part for Russell is that he is taking an engine change in Singapore without receiving the ADUO performance upgrade he had hoped to combine with it.

The Malaysian retirement changed Mercedes’ plans.

Russell was running third when his power unit failed with five laps remaining. He had already used his allocated four engines for the season, so replacing the failed unit pushed him beyond the permitted allocation. Under the regulations, using additional power-unit elements triggers grid penalties at the first event in which those elements are used. Mercedes has confirmed that Russell will start Sunday’s Singapore Grand Prix from the back of the grid.

The original plan was to coordinate his engine change with the ADUO upgrade. That would have meant taking the penalty when the new specification became available, rather than introducing a fresh engine now and potentially taking another penalty when the upgraded specification arrives.

The failure removed that flexibility.

Russell explained that Mercedes had been waiting to take the engine penalty alongside the ADUO update, but the retirement forced the team to act sooner. With seven races remaining, he also expects to take another engine-related penalty before the season ends because the remaining mileage exceeds what his available engines are expected to cover.

In other words, Russell is not starting at the back because he has been refused a performance upgrade. He is starting at the back because he needs a replacement power unit now, before the upgraded specification is ready.

The distinction matters. His immediate penalty is the consequence of reliability and component-allocation limits, while the delay to ADUO 1 is a separate development and supply-timing issue.

### When will we see the first ADUO 1 engine?

![2025 United States GP: Challenging Sunday in Austin – Mercedes-AMG PETRONAS F1

EXPECTED INTRODUCTION

United States GP

October 23–25, 2026

Reported target

The latest reporting points to the United States Grand Prix at Austin, Texas, on 23–25 October as the expected first appearance of Mercedes’ ADUO 1 power-unit upgrade.

Sky Sports reported on 8 October that the new specification would not be available in Singapore and was instead expected at a later round, with Austin the next race on the calendar. Earlier reporting had suggested Austin or Mexico City as possible introduction points.

Austin is therefore the next significant date to watch, but the reported target should not be confused with an officially confirmed delivery date. Mercedes must complete development, validate the specification and have the necessary hardware available for the teams it supplies.

The first appearance of ADUO 1 should also be understood as the introduction of a revised power-unit specification, not necessarily a completely redesigned engine. The upgrade is expected to involve performance-related changes, with the turbocharger identified in reporting as one of the key components under consideration. The precise final specification and its measured performance gain have not been publicly established.

If Austin remains the target, Mercedes will have an opportunity to introduce the new specification with five rounds still remaining after Singapore. That would leave limited time to exploit the upgrade, but potentially enough to influence the closing stages of the championship.

What does this mean for Russell and Antonelli?

The immediate difference between Mercedes’ two drivers is their engine situation and the role each will play in the Singapore technical evaluation.

| Factor | George Russell | Kimi Antonelli |

| ———————- | ———————————- | ——————————————————- |

| Singapore power unit | Replacement unit following failure | Existing allocated components and planned configuration |

| ADUO 1 in Singapore | Not available | Not available |

| Singapore car package | Older aerodynamic specification | Latest aerodynamic package |

| Main immediate concern | Recovery from the back of the grid | Extracting performance from the updated car |

| Next upgrade milestone | Expected ADUO 1 introduction later | Expected ADUO 1 introduction later |

Mercedes is also splitting the aerodynamic specifications between the drivers in Singapore. Russell will run the older package that helped him win in Baku, while Antonelli continues with the latest package introduced in Malaysia. Russell said he had supported the comparison before his engine failure, and the penalty made the decision easier because the team could use his weekend to gather more data.

That decision does not mean Russell is being sidelined. It gives Mercedes an opportunity to understand why the latest package failed to produce the expected results in Malaysia while preserving a proven configuration on Russell’s car.

The bigger concern is the championship.

Antonelli’s second place in Malaysia extended his lead over Russell to 84 points, with seven rounds remaining. Russell now has to recover ground while managing a power-unit allocation that has already forced one penalty and may force another.

Even if ADUO 1 delivers the expected improvement, the timing could be decisive. Antonelli may be better positioned to convert the remaining races into points if Russell continues to lose track position through penalties or suffers another reliability problem.

However, the upgrade’s actual effect on the championship will depend on its measured performance, reliability and the competitiveness of Mercedes’ rivals. There is not yet enough public information to quantify a lap-time gain.

The bigger picture: Mercedes has permission to improve, but must get the timing right

ADUO 1 represents an important development opportunity for Mercedes, but it also highlights the complexity of introducing new technology under the 2026 regulations.

Mercedes has one additional homologation upgrade available for 2026 because its internal combustion engine fell within the FIA’s 2–4% performance-gap category during the first assessment period. The opportunity is intended to help manufacturers improve, but it comes with regulatory requirements governing the introduction and availability of the revised power unit.

For Russell, the timing could hardly be worse. His Malaysia failure forced an early engine change, costing him a favourable starting position in Singapore without giving him access to the new ADUO specification. The expected Austin introduction could mean another engine change and another penalty if the team needs to replace additional components to accommodate the update.

For Mercedes’ customer teams, the same rollout requires coordination across the supply operation. The regulations mean that the manufacturer must prepare the updated specification for its supplied teams when it is first introduced, rather than treating the upgrade as a private development for its factory drivers.

The key question is whether Mercedes can deliver ADUO 1 in Austin as expected and whether the upgrade produces enough additional performance to justify the disruption.

For Russell, the clock is ticking. The upgrade could strengthen Mercedes for the final part of the season, but it cannot undo the points lost in Malaysia or guarantee that he avoids another penalty. His immediate priority is to recover in Singapore, preserve reliability and give himself the best possible position when the new engine specification finally arrives.

### Sources

* [FIA — ADUO assessment results for 2026](https://www.fia.com/news/fia-announces-aduo-results-following-first-and-second-review-periods-2026)

* [FIA — How ADUO works under the 2026 regulations](https://www.fia.com/news/power-ups-how-f1s-additional-development-upgrade-opportunities-will-be-applied-and-whats)

* [Sky Sport Italia — Mercedes without the new ADUO 1 engine in Singapore](https://sport.sky.it/formula-1/2026/10/08/f1-antonelli-russell-mercedes-motore-singapore-2026)

* [Formula 1 — Russell’s Singapore grid penalty confirmed](https://www.formula1.com/en/latest/article/mercedes-confirm-russell-is-set-for-grid-penalty-at-singapore-grand-prix.4Wp0nfUrqdG5TvhD76T8mw)

* [RACER — Russell to run older-spec Mercedes in Singapore](https://racer.com/2026/10/08/facing-double-pu-penalty-russell-will-run-old-spec-mercedes-in-singapore)