Former Honda chief makes claim on why Aston Martin F1 power unit is the worst

Former Honda engineer Yasuaki Asaki has claimed he knows why the Japanese manufacturer's power unit is currently the worst on the F1 grid, and it's all to do with a key detail in the 2026 regulations.

Aston Martin are currently the only team to use Honda power units, having made the switch from Mercedes to Honda for the 2026 season, but so far it has been a move that has led to an immense struggle.

The team currently sit 10th in the constructors' standings with just seven points on the board heading to the United States Grand Prix this weekend, and while there were issues with their chassis and the aerodynamics of their car earlier in the season, the Honda power unit has been their main downfall.

Upgrades in recent months have not remedied the situation, and there is even set to be a change at the top of Honda, with the President and CEO of Honda Racing Corporation, Koji Watanabe, set to retire, effective on January 1, 2027.

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Former Honda engineer pinpoints power unit problem

Now, writing in Japanese outlet Sportiva, Asaki, who previously led Honda's power unit development in F1, has issued his verdict on the manufacturer's problems in 2026.

"The fundamental reason why Honda's power unit is currently losing to its rivals is simply 'lack of power'. Nothing more, nothing less," Asaki said.

So, what is behind that lack of power? The ex-Honda man continued: "I believe the main reason for this is that this year's regulation changes lowered the upper limit of the compression ratio for internal combustion engines from 18:1 to 16:1, making high-speed combustion less likely.

"The Spec 2 engine introduced at the Dutch GP also achieved high-speed combustion, resulting in a slight power increase. However, in my opinion, it still hasn't reached a sufficient level compared to its rivals."

Asaki: Honda engine this year has failed in key area

Asaki says that Honda's power unit rivals, such as Mercedes and Ferrari, have achieved this high-speed combustion, and says that Aston Martin's power unit has failed when it comes to how quickly it can burn fuel.

"Given the current regulations on fuel energy flow rates, the only way to improve thermal efficiency is to burn fuel as quickly as possible," Asaki added.

"That's the only thing we can pursue, but Honda's internal combustion engine this year has failed in that regard. Failure is relative, but in my opinion, its combustion speed is slower than that of newcomer Audi."

The fix to all of this, Asaki believes, is to remedy the above, and for Honda to exploit loopholes that he believes other manufacturers are using.

"To win in F1, it's necessary to exploit loopholes in the rules," he concluded.

"First, I believe that unless the combustion problem is resolved, we won't even be able to get to the starting line of competing for the championship."

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