McLaren Disappointed With Mercedes Over Power Unit Information Gap

• McLaren team principal Andrea Stella said the flow of information from Mercedes’ engine division has fallen short of expectations, leaving the reigning champions scrambling to extract the same potential from their power unit as the works team.
• Williams team principal James Vowles reported a similar disconnect after Australia, estimating his team is approximately three-tenths per lap off the pace from the power unit alone and pointing to an inherent knowledge gap with Mercedes.
• All three Mercedes engine customers, McLaren, Williams, and Alpine, started the 2026 season well behind the works Mercedes outfit, which locked out the front row and won the Australian Grand Prix by more than 50 seconds.

McLaren has confirmed that the information coming from its Mercedes engine supplier has not matched what the team anticipated, leaving the reigning world champions at a disadvantage in extracting the full potential of the new power unit as the 2026 Formula 1 season gets underway.

At the season-opening Australian Grand Prix, McLaren qualified 0.8 seconds off George Russell’s pole position time and finished the race more than 50 seconds behind the lead Mercedes. All three Mercedes customer teams, McLaren, Williams, and Alpine, ended the opening round well adrift of the works outfit, which dominated from qualifying through to the checkered flag.

F1 engine suppliers are required to offer equal hardware to their customer teams, but the 2026 regulations place a far greater share of performance in how the hybrid system is operated rather than in the hardware itself. McLaren believes a significant gap exists between its own grasp of how to run the power unit and the knowledge held at the Mercedes works operation.

“We have work to do to exploit the potential of the power unit, which, once I see the potential that HPP [Mercedes High Performance Powertrains] is extracting, looks like there’s more that is available,” McLaren team principal Andrea Stella said.

“Now, it’s not obvious how you do that — for us, we are in a journey of knowledge, but certainly a journey that is at an earlier stage than the works team.

“The works team and HPP will have worked together for a long time. So, they will have collaborated, talked about how to use the power unit, that’s fair enough. But, we’ll definitely intensify the collaboration with HPP because our understanding is that there is some low-hanging fruit that we should be able to cash in.”

The factory Mercedes team is not obliged to share its operational methods with customer teams, but Stella said the flow of information from Mercedes’ engine department had not met his expectations.

“What they are doing shows they understand a lot more, and maybe the flow of information hasn’t been as anticipated,” he added.

Stella said McLaren had already raised the issue with Mercedes’ engine division and described a situation in which the team had been reacting to what the car was doing rather than predicting and planning ahead.

“The discussion with HPP about having more information has been going on for weeks,” he said. “Because even in testing, we were pretty much going on track, running the car, looking at the data and, ‘oh, that’s what we have — good, now we have to react to what we have’.

“But that’s not how you work in Formula 1. In Formula 1, what happens on track, you simulate [before], you know what is happening, you know what you are programming, you know how the car is going to behave.

“So you also have your plans as to how you evolve it that you have figured out before because you know what you are expecting from the car. So, I have to say, since we are a customer team, this is the first time that we feel we are on the back foot even when it comes to the ability to predict how the car will behave and the ability to anticipate how we can improve the car.”

McLaren outperformed Mercedes at the end of the previous regulatory era while using the same engine, but the operating parameters of that power unit generation were well established and carried less weight in determining overall lap time. Under the 2026 rules, the emphasis on electrical energy management means that how a driver approaches a single corner can shift deployment across an entire lap.

Stella outlined why that sensitivity makes the current situation harder than anything McLaren has faced as a customer team.

“There’s one more factor, though, and this is perhaps for you useful to understand what kind of Formula 1 we are experiencing,” Stella added. “Everything is very sensitive.

“Why are the tools important? Because you may change the amount of lift and coast before Turn 1 and this affects the deployment through the entire lap, which is also what puts off the drivers when they have to optimise the driving, the battery, because this is now a fundamental way of driving a Formula 1 now, you are driving the battery.

“So, when everything is so sensitive, the reliance on the tools is even more important. Like with last year, where everything was calmer in terms of power unit behaviour and electrical energy deployment, we had the tools, but we weren’t so reliant on the tools.

“But now it’s pretty much all about the tools because changing a detail in one place affects something much bigger in a very faraway place of the circuit, which is just difficult to predict.”

Williams team principal James Vowles described a similar experience after his team also found itself caught off guard by the size of the gap to the Mercedes works operation in Australia.

“What Mercedes are doing on the power unit is something that caught us off guard,” Vowles said ahead of Sunday’s race. “It took a qualifying for us to really see just how off the pace we are. In that regard, that’s probably three tenths [missing from the engine] – something in that ballpark.”

Vowles, who left Mercedes to join Williams in 2022, said he had anticipated some degree of information restriction but acknowledged the scale of the gap was larger than expected.

“I had expected it to a certain extent, yes. That’s why I said I was caught out yesterday.

“It is not an open door, as you would imagine, because that’s where the performance is found. So it is down to us to try and work around it.

“We have to acknowledge that we, as Williams, do not have the sophistication that they have in other technologies, and definitely that’s on us. I would say the converse is that there’s some inherent knowledge they have which we don’t. And that’s down to us to figure out.”