What secret ADUO upgrade suggests about Honda's F1 hopes

On Thursday at Sepang, it was revealed that Honda used a second engine development opportunity at the Spanish Grand Prix. As far as anyone could tell, nothing happened. There was no announcement and no visible step in the results.

Only now has it emerged that Honda introduced its second engine upgrade in Madrid, and when Lance Stroll was asked in Sepang whether it felt like an improvement, his answer was short: “Not much. We’re really struggling on the engine side.”

It was yet another blunt and honest verdict that even Honda itself is not trying to contradict.

The Japanese manufacturer’s own description of the upgrade is just as modest, which is what makes the question of what comes next so interesting.

Shintaro Orihara, Honda‘s chief engineer and trackside manager, said Zandvoort was the first event with the spec 2 engine and Honda believed there was still room to improve by changing the calibration. The result, in his words, was “not a big improvement.”

Honda‘s internal combustion engine (ICE) performance was assessed as more than 4% behind the Red Bull‘s class-leading engine, so the Japanese marque received maximum help under the ADUO process, designed to avoid domination by one power unit manufacturer: Honda was given two upgrade opportunities for the 2026 season, plus two additional opportunities for 2027.

In June, Honda said it did not intend to use both but the plan clearly changed without notice.

“We are planning to introduce a new engine around summer,” Orihara said back then. “Then I don’t think we have another step in this year.”

In Madrid, and again in Baku, Honda introduced an updated turbocharger as part of the ADUO2 update.

The target was what Orihara calls boost following, the way the turbo builds and delivers its pressure when the driver gets back on the throttle.

A turbo that responds late produces a lag in torque at the exit of a corner, and the car then has to cover that gap with its electric motor.

That costs energy Honda would rather have used elsewhere. Orihara said the effect was confirmed in Baku, “where boost following is quite important.”

This is a drivability fix first and an energy-management gain second. It is not a peak power upgrade, and Orihara was careful not to oversell it, saying it was “still a small number”, but one Honda will keep pushing.

Set that against Stroll’s comments on the same day: “We’re missing two seconds in engines,” he said during Thursday’s press conference at Sepang, adding that at places like Baku and Monza “there’s not much you can do.”

“I think, you know, on the car side, we know we started late compared to everyone else, development for the new regulations,” Stroll added.

“We’re lacking between a second and two seconds, depending on the tracks, every weekend in engine.

“So, you know, right now that’s really our weakness.”

The pattern across the calendar, and Aston Martin‘s results, support Stroll’s version: Budapest, with plenty of corners and few straights, was Aston Martin‘s best race of the year.

The long-straight tracks are where it is worst, and the last few races have been exactly that kind of circuit, leaving Aston once again at the bottom of the grid both at Monza, Madrid and Baku.

Stroll named Monza and Baku as the kind of places where the engine deficit left the team with nothing to work with; the Canadian qualified last at Monza, and penultimate in Madrid and Baku, where he was nearly four seconds off the pace.

Stroll himself separated two distinct problems: drivability, “a big limitation for us,” and then “just power down the straights.”

The ADUO2 turbo addressed, or tried to address, the first of those. By the evidence of Baku, the second remains largely untouched, which suggests the remainder of the 2026 season is unlikely to change much for Aston Martin.

The ADUO mechanism exists so that a manufacturer behind the benchmark can catch up through additional development opportunities.

As noted above, Honda was judged to be the weakest engine and so was given the biggest opportunities to recover this year and to try to get back on track when 2027 begins.

That is the context for the most important question both Aston and Honda are facing here: If each opportunity delivers a gain Honda itself describes as small, how many does it take to close a gap Stroll puts at a second on some tracks and up to two on others? And how realistic is it to expect Honda to produce a competitive power unit next year?

Asked directly by Sky Sports’ David Croft whether Aston Martin would consider moving away from Honda, Stroll was diplomatic: “Right now we’re working together to get it right,” he said.

“We have some ideas for next year, so hopefully we’re in a much better spot.”

Not surprisingly given how this season has gone, the language around 2027 was conditional almost every time Stroll used it.

Honda is “pushing flat out, doing everything they can to bring more power,” he said, “so time will tell if we do.” The engine is “a question mark.” And then: “We’ll see the first race next year.”