McLaren team principal Andrea Stella said on July 6, 2026, that his team is not fully utilizing the Mercedes power unit after observing rival drivers use unexplained throttle-lift techniques during sprint qualifying at the British Grand Prix on July 5.

Telemetry from the sprint qualifying showed Kimi Antonelli and George Russell briefly lifting off the throttle just before crossing the finish line. "Once we saw it yesterday in the sprint qualifying applied by Antonelli, kind of surprised us a little bit, because it's not something that we discussed and nor I'm sure at all that is available to us because it requires probably some further elements, let's say, to use the power unit," Stella said.

Stella stated that McLaren appears to have a deficit in extracting performance from the Mercedes High Performance Powertrains (HPP) unit. "I have to say, and I said that other times, that we still seem to have a little bit of a deficit in extracting the most from the HPP power unit," he said. "Plus, the exploitation of the power unit on which we seem to be having a bit of a deficit."

Stella noted that the British Grand Prix circuit places heavy demands on energy and power unit performance. "It's a circuit where there's an important starvation from an energy point of view and power unit exploitation and power unit performance is particularly important," Stella said. He added that difficult conditions during the sprint qualifying appeared to widen McLaren's gaps in the corners. "We need to add the fact that the conditions were difficult and if anything, in these conditions, we seem to be having even more of a gap in the corners," he said.

Stella indicated that technical discussions with HPP are ongoing. "So, like I've said before, there's definitely conversations ongoing with HPP at technical level to make sure that we use what is available in this power unit, which is brilliant," Stella said. "If you look at the GPS overlays, it becomes apparent that somehow we need to keep our conversation open with HPP, because there's some performance we seem to be leaving behind." He described the power unit as "a really great piece of technology."

McLaren is waiting to receive the latest Mercedes power unit specification. "We are now waiting to see if we can upgrade our specification and if this helps exploitation somehow," Stella said. When asked if the upgrade would address the exploitation issue, he replied, "It should be just a reliability upgrade, so I'm not sure that's the case." Stella emphasized that other factors remain under discussion. "But definitely there's some other factors that we need to keep discussing with HPP because when we look at the performance in the straights, even taking into account the fact that they may have less drag, there's still some question mark," he said.

Formula 1 regulations require engine manufacturers to supply customer teams with the same engine specification used by the works outfit. Responsibility for optimizing the power unit remains with the customer team rather than the supplier. The 2026 technical regulations increased the role of the MGU-K and rely on more sophisticated energy management software systems than the previous season.