F1 US Grand Prix: No ADUO Engine Yet For the Mercedes Drivers

Mercedes drivers Kimi Antonelli and George Russell won't have upgraded engines in the 2026 Formula 1 United States Grand Prix.

Initially, it was expected that Mercedes would roll out their new Additional Development and Upgrade Opportunity (ADUO) engine in Austin, but that plan has now been scrapped. Apparently, the upgraded engine is not ready yet.

ADUO is the FIA's new cost-cap relief mechanism, which measures pure internal combustion engine (ICE) output against a benchmark. 

This season, Red Bull-Ford Powertrains, in their first season as a power unit manufacturer, became the benchmark.  Mercedes engines were 2-4% below Red Bull-Ford's benchmark, giving them one additional upgrade this year. Meanwhile, Ferrari, Audi, and Honda engines were more than 4% below the benchmark, so they get two additional upgrades.

During the Italian Grand Prix, Antonelli took a new power unit, but it wasn't the ADUO engine. It was reported back then that Mercedes' target date for the ADUO engine is in October, particularly at the start of the American triple-header. 

First of all, the ADUO itself does not trigger a penalty. Installing components beyond the drivers' permitted allocation does. 

For Antonelli, he already took a significant grid penalty at Monza for his fifth ICE. He also received a penalty for exceeding his limit for his energy store and control electronics. But he is still under his permitted allocation on the turbocharger, exhaust, and MGU-K. 

As for Russell, he already exceeded his allocation on all the components. The British driver has already acknowledged that he will receive a grid penalty whenever he takes the ADUO engine. That's why he wants to take it at a track where overtaking is easier.

Antonelli might also incur a penalty, but it might not be as hefty as Russell's.

Along with their new MANUFAKTUR-collaborated livery,  Mercedes is also bringing upgrades to Austin. Team principal Toto Wolff confirmed that they will have a new upgraded front wing this weekend.

Moreover, Russell's car will be fitted with new specifications, something that he didn't have during the Singapore Grand Prix. 

This is an important weekend for Mercedes, especially with Antonelli having the chance to clinch the Drivers' Championship. To do that, Antonelli must win, but he's also relying on other factors outside his control.

Also, Mercedes would want to bounce back as a team. Max Verstappen and Red Bull have won the last two races in Malaysia and Singapore. They seemingly lag behind Red Bull in pace, both in qualifying and in race trim.

Mercedes will be itching to change that narrative this weekend.