Mercedes rolls back ADUO engine debut

Mercedes’ upgraded Formula 1 engine won’t appear as initially expected at the United States Grand Prix.

Mercedes was deemed to be more than 2% adrift of the benchmark 2026 power unit (Red Bull) by F1’s Additional Development and Upgrade Opportunities (ADUO) system, meaning it can introduce a mid-season upgrade.

That upgrade was initially pencilled in for introduction at Austin this weekend, but that plan has been pushed back because the upgraded power unit isn’t ready. 

The Race understands it won’t be ready for next weekend’s Mexican Grand Prix either, meaning the Brazilian Grand Prix that concludes F1’s latest triple-header is the likely earliest date it will arrive.

George Russell’s engine failure at Sepang at the start of this month was a blow for him as it meant he had to take a grid penalty in Singapore.

He’ll have to take another grid penalty whenever he takes the ADUO Mercedes engine.

Mercedes only wants to introduce the ADUO engine when it’s convinced it’s a proper step forward.

The team’s all but certain to win both 2026 titles, but any car and engine upgrades introduced in late-2026 will have a significant impact on 2027.

So whatever progress Mercedes can make with its ADUO engine - even if it’s only used in two or three 2026 weekends - could be very useful for next year.

Mercedes is going to run the major chassis upgrade it debuted at Sepang on both cars at Austin, having taken the unusual route of splitting specification between its cars last time out in Singapore. 

That experiment taught Mercedes plenty during the Singapore weekend, and the debriefs the team has completed since that weekend have given it further clues as to how best to exploit the upgrade.

Both drivers will have the upgraded car right from FP1.