McLaren makes fuel system fixes to end Norris' straight-line speed losses ahead of Singapore

McLaren has modified auxiliary components on Lando Norris’ Mercedes power unit ahead of Friday’s opening practice session at the Singapore Grand Prix, targeting a persistent fuel injection problem the team believes has cost the championship leader significant performance over the past two race weekends.

Norris was notably down on top speed during qualifying in Baku, with McLaren identifying a fuel injection fault as the primary culprit. The issue resurfaced intermittently during the race, also affecting Oscar Piastri’s car to a lesser degree, before returning to hamper both drivers at last weekend’s Malaysian Grand Prix in Sepang. The changes made are on the team’s side of the power unit rather than Mercedes’, meaning they fall within McLaren’s own engineering remit.

“It’s been a frustrating two weekends trying to figure out what the issue has been and why there’s just been a constant lack of straight-line speed and performance,” Norris said on Thursday. “And especially in this kind of battle we’ve been in, the last two qualifying [sessions] it’s been two or three positions. So, it’s cost me quite a lot.”

The reigning world champion said he remains cautiously optimistic but wants to see the results on track before drawing conclusions. “I’m hopeful that it’ll be better this weekend. But honestly, I have to get out on track and see first,” he added.

Singapore’s Marina Bay Street Circuit is one of the least power-sensitive venues on the calendar, with its tight, twisting layout limiting the impact of straight-line speed deficits. That context offers McLaren some breathing room, but with a close four-way fight at the top of the standings, the team cannot afford to surrender any performance.

“It’s obviously also a circuit where straights are not the highest priority and not as detrimental as the last few weekends,” Norris acknowledged. “But nevertheless, you always want to go down the straights as quick as you should be able to.”

Beyond the fuel system fix, Singapore also represents a broader checkpoint for McLaren after a puzzling weekend in Malaysia. The Sepang circuit was widely expected to suit the MCL40’s aerodynamic strengths, yet McLaren ended up as only the fourth-fastest team, a result the team believes may be linked to how the car’s aerodynamics interacted with Sepang’s unusually rough track surface. A strong showing in Singapore would help confirm whether that performance dip was a circuit-specific anomaly rather than a deeper underlying problem.