Red Bull Reportedly Leads 2026 F1 Engine Race as Mercedes Becomes Eligible for Upgrades

Formula 1’s 2026 power-unit regulations are set to spark fresh controversy, with reports suggesting the first ADUO assessment has identified Red Bull as having the strongest engine, while Mercedes is eligible for upgrades.

ADUO (Additional Development and Upgrade Opportunities) was introduced for 2026 as a mechanism for the FIA to monitor performance across the five power-unit manufacturers (PUMs) and address significant performance gaps.

Under the regulations, 2026 power units are homologated, meaning manufacturers cannot introduce performance upgrades unless ADUO provisions are triggered. The system operates on a sliding scale: a manufacturer deemed to be 2% behind the benchmark can receive one upgrade opportunity in 2026 and another in 2027, while those 4% behind are eligible for two upgrades in each season.

There are two further ADUO assessment windows in 2026, running up to the Hungarian Grand Prix and then the Mexico City Grand Prix, with the latter feeding into 2027 development plans.

Manufacturers are not permitted to save upgrade tokens. They are neither cumulative nor transferable and must be used during the period in which they are granted.

While the FIA has yet to officially confirm the findings, the Monaco paddock was abuzz with reports of a document outlining the first ADUO assessment, which allegedly identified RBPT-Ford as the benchmark for internal combustion engine performance.

The controversy stems from the fact that ADUO only measures internal combustion engine output. Although RBPT-Ford is reportedly the class leader in that area, the regulations allow manufacturers granted development opportunities to make performance improvements across the entire power unit, including the energy recovery systems — an area in which Red Bull has reportedly lagged behind its rivals.

Championship leaders Mercedes, who are expected to receive one ADUO upgrade allocation for 2026, have built much of their advantage on a class-leading hybrid system. The prospect of Mercedes being allowed to further improve an already highly competitive package has left some in the paddock perplexed.

Ferrari, Audi and Honda are reportedly set to receive two upgrade opportunities after being classified within the 4% deficit group.

Speaking to Sky Sports F1 in Monaco, Lewis Hamilton suggested that teams had already been informed of the ADUO findings despite the FIA not yet making them public.

“Red Bull have the most powerful engine, Mercedes second, and then we [Ferrari] are behind,” the seven-time world champion said.

“We’ve got now these tokens to try to develop and close the gap. But that’s like an eight-to-10-month project, so it’s not something we can just do next week. We’ll be pushing as hard as we can to see how we can close it up.”

FIA Single-Seater Director Nikolas Tombazis has previously stressed that ADUO should not be viewed as a balance-of-performance mechanism.

“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.”

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Written by

Jawad Yaqub

An eCommerce Specialist by day and reporting on F1 by night. Jawad is passionate about motorsport, having provided accredited F1 coverage for more than a decade. Live blogging (almost) every grand prix too since 2014, as well as articles on the Supercars Championship. Also keen on sustainability, photography, collecting vinyl, (trying to) expertly barbeque and learning to Dad.

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