Carlos Sainz Backs the FIA Over Red Bull in ADUO Engine Row

Red Bull‘s fight with the FIA over the ADUO engine rankings has attracted a notable dissenting voice from the paddock – and it belongs to a driver running a rival power unit.

ADUO functions as an engine catch-up scheme, giving manufacturers running below the benchmark additional development opportunities to close the gap.

Red Bull Ford Powertrains emerged as the benchmark after the first assessment, with Mercedes trailing by 2–4% on the internal combustion engine – enough to earn one upgrade – while Ferrari, Audi, and Honda each fell more than 4% back, qualifying them for two.

Being named the benchmark means Red Bull gets nothing while its rivals develop. You can see why Milton Keynes is unhappy.

Team boss Laurent Mekies recently insisted Red Bull sees “not one single data sample” indicating an engine advantage over competitors.

The team had actually been expecting to qualify for ADUO upgrades before the rankings were communicated.

The ruling immediately sparked controversy because Mercedes-powered cars have won every race so far in 2026.

Sainz Saw It Coming from Bahrain

Carlos Sainz doesn’t share Red Bull’s surprise. The Williams driver, who runs a Mercedes power unit and has a well-established reputation for deep technical engagement with performance data, came out in support of the FIA’s conclusion.

“I know it surprised a lot of people, but not me,” said Sainz. “You know I like to delve into the data and examine everything very carefully,” he explained. “From the first test in Bahrain, honestly, Red Bull surprised me a lot. Red Bull and Racing Bulls.”

He said the races that followed only deepened that impression, pointing to specific events where the top-speed numbers told a clear story. “There have been races where the Red Bull engine was clearly the best,” he said. “In Canada, when it’s cold, or even in Monaco, top speeds were the highest.”

The detail Sainz keeps coming back to is that the performance pattern holds across both Red Bull-engined outfits. “This is no longer a coincidence,” he added. When the same trait shows up in two separate teams with the same power unit, the sample size is hard to dismiss.

Despite Red Bull’s ICE being ranked first, broad consensus in the paddock remains that Mercedes still possesses the best overall power unit.

ADUO only assesses the internal combustion engine, not the electrical element of the power unit, which makes up nearly 50% of the output.

That’s the crux of Red Bull’s frustration – winning on ICE horsepower while losing races because the electrical side isn’t keeping up is cold comfort, especially when the prize for winning the ICE contest is a development freeze.

The FIA assesses manufacturers three times during the season to determine who qualifies for ADUO, with the first evaluation having taken place after the Canadian Grand Prix.

The FIA has delayed finalising the rankings after fierce objections from Red Bull-Ford.

A resolution is expected before or at the Austrian Grand Prix this weekend. Whether the numbers change or stay fixed, Sainz’s opinion on the situation may linger.