Red Bull advisor Helmut Marko isn't sure where Mercedes have found their current straight-line speed advantage, noting that they were almost 15 kilometres faster at Istanbul Park.
Max Verstappen was unable to put any real pressure on Valtteri Bottas during the Turkish Grand Prix, with the Finn taking a relatively comfortable victory.
One factor that certainly helped Bottas is Mercedes' straight-line speed, with Marko stating it was as if the Silver Arrows drove with the DRS open for the entire race.
"We have to think of something, because Mercedes are so fast on the straights," Marko told Austrian broadcaster ORF. "They were almost 15 km/h faster here, like when you drive with DRS.
"It's been like this since Silverstone and the gap is only getting bigger...
"That engine superiority, I don't know what it is and what we can do about it. We need to optimise our chassis even more so that we can balance it out again somewhat."
Red Bull have reportedly asked the FIA for clarification regarding an intercooler trick that they theorise Mercedes are using to help generate more horsepower.