Why McLaren has struggled to get the most of Mercedes’ F1 engine

After winning both the drivers’ and constructors’ championship in Formula 1 last year, McLaren has been experiencing a tougher 2026 campaign amid new technical regulations, as powertrain supplier Mercedes dominates.

The Woking-based team has clinched its first pole position and victory of the season right before the summer break in Hungary, courtesy of Lando Norris, after taking just four podium finishes in the previous 10 rounds.

F1 has switched to new engine specifications featuring a 53-47 power split between combustion and electric, and McLaren has felt like this area is holding the MCL40 back.

More specifically, given how complex the new power unit are, team principal Andrea Stella has suggested that being an engine customer was a disadvantage. In late June, the Italian explained that McLaren was still losing up to 0.15s a lap to Mercedes in straightline speed. However, there’s more to it than the mere customer status.

"From a PU perspective, it was quite clear that we still had a lot to learn about how to operate the PU and the complexities of the PU, that between us and HPP [Mercedes High Performance Powertrains] we hadn't put enough resource behind [this], and so went into the start of the season knowing that there was a big opportunity there," McLaren’s technical director for engineering Neil Houldey has explained.

"We knew that these regulations were going to be a challenge from an energy management perspective, and we put things in place that we thought were good to get us started. 

Lando Norris, McLaren

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"I think both us and HPP could have done more work on the software side leading up to the test and the first races that would have put us in a position where we'd have been more capable on an energy management perspective, and it's still the case to this day that we've still got work to do, and I don't think that on the software side there's still performance out there that we're not grabbing.

"Our car is different to the works team, and therefore we need specific calibrations for our car that we're not capable at the moment of signing off quickly. The summary from me would be that we made some really good steps in the first three to four races. Those have carried through, but actually, there's still steps that we need to be making over the next few races and going into 2027 to unlock that final tenth that might be available from the PU that we're not able to really grab at the moment."

One key difference with the Mercedes-spec powertrain is McLaren picking shorter gear ratios, which provides better acceleration and which Stella described as “overall positive” back in May, but Houldey’s stance differs.

Asked if McLaren would position those ratios ‘slightly differently’ with the knowledge it has accrued as of now, Houldey replied: "I think we would if we had our time again, we'd re-ratio to be closer to where Mercedes are.

"There are some performance opportunities that we can take because the ratios are shorter. We end up shifting less into lower gears around corners, potentially on restarts, things like that. When you've got the lower ratios, it's a performance opportunity, starts. But when you're looking at the high-speed side, you'd probably take what the other teams have got.

"So it's a couple of compromises in either direction, but again it's small lap time, but all these small little lap times add up to be some decent lap time performance.

Lando Norris, McLaren, George Russell, Mercedes

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"The PU changes into next year, car speed potentially changes. The aerodynamic regulations obviously have tried to drop the load a little bit, and we're working through now what the ideal ratios are, based on actually not too much data at the moment – but hopefully soon that data, that information will coalesce, and we'll be able to make a decision on ratios that probably will end up with us going a little bit longer.

"But we don't know what the works team will be doing. HPP won't know their final power curve until whatever date it might be, which is way beyond after we've chosen our ratios. I think we made a good decision with the information we had around us at the time. With the information that we have around us now, the decision might be slightly different. But we're talking milliseconds, not tenths."