Honda has finally said out loud which parts of its 2026 power unit it has been rebuilding. The Spec 2 engine runs for the first time at Zandvoort in the back of an Aston Martin, and the description of it is more specific than anything the manufacturer has offered all year.
Shintaro Orihara, Honda's trackside general manager and chief engineer, went through the list in a video released ahead of the Dutch Grand Prix.
"We focused on improving engine performance to make combustion faster," he said. "So, it's kind of a secret, but I can disclose a little bit. We changed pre-chamber to make combustion faster, and also we changed the piston shape to get good combustion. Also, we modified some lubrication systems to reduce friction."
The horsepower figure stayed behind the curtain. "I can't disclose the detailed number, but we have achieved our internal target, and I'm confident in what the HRC Sakura factory guys achieved for the Spec 2 engine," Orihara said. Paddock estimates have ranged between 30bhp and 50bhp, with Honda having publicly rejected the top of that range.
Why the update ignores energy management entirely comes down to an admission Orihara made to Autosport. Until the combustion side is fixed, he argues, there is nothing worth tuning around it.
"Our engine performance is definitely poor compared to other manufacturers. So probably the most important point to improve now is our engine performance because, as I mentioned, the gap is quite huge," he said. "Let's say, if we improve energy management, that doesn't help if the engine performance is poor."
This is Honda's first upgrade under the ADUO concession framework, which gives a trailing manufacturer extra development scope.
The chassis side has already moved. Aston Martin's 16-component B-spec package in Hungary reduced a race-pace deficit that stood at more than five seconds per lap at Silverstone and Spa to around two seconds, per Paceteq data - with the caveat that the Hungaroring is shorter and less power-hungry than either.
Lance Stroll, who finished ahead of Fernando Alonso in Budapest, was emphatic about it.
"It was the most encouraging upgrade we've had, I think, in a really, really long time, maybe in the history of this team," he told media including RacingNews365.
His forecast for the engine step was far more guarded, and named the circuits where he expects to suffer.
"We're going to find out at Zandvoort, the step you make with the engine," Stroll said. "And then it's still going to be a bit circuit dependent. I think even with the step of the engine, will we be as quick as Mercedes? I hope, but probably not so likely. So Baku, Monza, those power circuits will be more difficult."
Adrian Newey answered a question about the partnership by talking about people rather than parts.
"Out of what can only be called a disastrous start, the positive of that, because you're always looking for positives, is that it's brought Honda and ourselves, AMR, into a very close working relationship," the Aston Martin team principal said. "Normally, if relationships improve, then performance also improves."
He declined to convert that into a performance claim. "We're clearly playing a big catch-up game. Is it going to make us the quickest car? Unfortunately, not. But does it represent a good step forward from where we were? Yes, I believe it does."
Three people, three different measures of progress: an internal target Honda will not quantify, a chassis upgrade Stroll rates as the team's best ever, and a working relationship Newey is betting on. Aston Martin has one point from 11 rounds, with more upgrades due at Monza and Baku.