Honda secretly introduced ADUO 2 F1 upgrade

Honda secretly introduced an upgrade to its Formula 1 power unit’s turbocharger at the Spanish Grand Prix last month, using the second of its Additional Development and Upgrade Opportunities (ADUO) tokens.

Honda debuted what it called a 'spec 2' power unit at the Dutch Grand Prix at Zandvoort in late August, but it initially framed that as the only ADUO upgrade it would deploy in 2026.

That’s despite Honda having been granted the opportunity to introduce two upgrades, having been judged - along with Ferrari - to be more than 4% off the benchmark power unit, Red Bull, in the ADUO engine catch-up system rules introduced for this year.

But it has now transpired at Sepang that Honda did take advantage of its ADUO allowance by introducing an updated turbocharger in Madrid on Lance Stroll’s Aston Martin.

His team-mate Fernando Alonso then received the update in Baku at the Azerbaijan GP.

Stroll and Alonso taking new turbochargers are listed in public FIA documents, but there’s no way to know if they’re upgraded unless the teams or engine manufacturers declare so.

“So Zandvoort is the first event we introduced the spec 2 engine, then we believe there was still room to improve performance by changing calibration and we have been working on the area to improve performance,” Honda’s chief engineer and trackside manager Shintaro Orihara explained.

“It's not a big improvement from calibration but we keep working to find some small performance gain.

“In Madrid and also Baku, we introduced [an] updated turbocharger using ADUO 2. We found some room to improve on boost following [likely refers to turbo lag], the main effect on driveability.

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

Honda has been working hard to improve the driveability of its power unit, the ADUO 2 turbocharger is part of that, but it should also be an energy management gain.

“Also if we have boost lag at the exit of corner, we could also have engine torque lag, then we need to use MGU-K to compensate that torque lag, that sacrificed some energy which we wanted to use,” Orihara said.

“So the updated turbocharger will help driveability but also give us some gain on energy management.

“Still I'm talking not a big number, still a small number, but we will keep pushing to find that type of small improvement.”

Honda 'question mark' for 2027

Now it’s used both its ADUO tokens, Honda will only be able to optimise the package that it has, with attention having already mostly turned to making a big step for 2027.

“We’re missing two seconds on engine, it’s difficult in places like Baku and Monza, when you’re missing two seconds of engine, not much you can do,” Stroll said at Sepang.

“On the car side, we know we started late compared to everyone else. We made a big step in Budapest, we have a clear direction on what we have to do on car development.

“But we’re lacking between a second and two seconds depending on the track every weekend on engine, there’s not much we can do with that.

“Right now that’s really our weakness.”

Stroll added: “I heard a lot of things, Honda is pushing flat-out to deliver more power [but] time will tell if we do.

“It’s just a question mark, we’ll see the first race next year.”