Secret Honda engine upgrade emerges after latest FIA findings

Aston Martin engine partner Honda has revealed that it secretly introduced its ADUO2 upgrade at last month’s Spanish Grand Prix in Madrid.

Honda has struggled after linking up with Aston Martin ahead of the F1 2026 campaign, with the Japanese manufacturer beset by a severe engine vibration issue at the start of the season.

Honda introduced ADUO2 engine at Spanish Grand Prix in Madrid

The FIA set up its ADUO (Additional Development and Upgrade Opportunities) scheme ahead of this season in a bid to help struggling manufacturers catch up.

The ADUO system sees engine performance measured across specific windows during the F1 2026 season, with Honda’s internal combustion engine ranked last after the first two checkpoints.

Honda introduced its first ADUO upgrade at the Dutch Grand Prix in August, with Fernando Alonso claiming the team’s second points finish of 2026 at Zandvoort.

It was previously thought that Honda had not yet introduced its second upgrade under the ADUO system.

Fernando Alonso vs Lance Stroll: Aston Martin head-to-head stats for F1 2026 season

F1 2026: Head-to-head qualifying statistics between teammates

F1 2026: Head-to-head race statistics between teammates

However, Koji Watanabe, the president of the Honda Racing Corporation, revealed this week that a second upgrade was introduced at the Spanish Grand Prix in Madrid last month.

Honda has now confirmed that an improved turbocharger was fitted to Lance Stroll’s car at the Madring.

Alonso also ran the new turbo for the first time at last weekend’s Azerbaijan Grand Prix in Baku.

Speaking to PlanetF1.com and other media outlets ahead of this weekend’s Bahrain Grand Prix in Malaysia, Honda’s Shintaro Orihara revealed that the new turbo reduces lag on corner exit as well as aiding energy management.

Orihara went on to stress that the new turbo brings only a small performance advantage.

He said: “We used ADUO2 to introduce a new turbocharger to improve driveability and also boost lag at exit of the corner.

“We could also have engine turbo lag, then we need to use MGU-K to compensate for the lag.

“That sacrifices some energy. So the upgrade of the turbocharger will help drivability, but also give us some gain of energy management.

“Still, I’m not talking about a big number [in terms of gains], still a small number, but we keep pushing to find this type of small improvement.”

Discussing Honda’s progress since the summer break, Orihara confirmed that the step in Madrid was backed up by the new turbo’s performance in Baku last weekend.

He explained: “At Zandvoort, which is a fast event, we introduced the ADUO engine.

“There was a lesson to improve performance by changing calibration and we have been working on that area to improve performance by changing calibration.

“It’s not a big improvement from calibration, but we keep working to find some small performance gains.

“And then in Madrid and also Baku, we introduced an upgrade to the turbocharger using ADUO2.

“We found some room to improve on boost following the main effect on driveability.

“So we introduced and updated the turbocharger to improve boost following and we confirmed the effect in Baku, where boost following is quite important.”

Additional reporting by Thomas Maher

Want to be the first to know exclusive information from the F1 paddock? Join our broadcast channel on WhatsApp to get the scoop on the latest developments from our team of accredited journalists.

You can also subscribe to the PlanetF1 YouTube channel for exclusive features, hear from our paddock journalists with stories from the heart of Formula 1 and much more!

Read next: Bahrain GP predictions: Russell’s final nail, Verstappen lockdown, rain chaos