Mercedes' Engine Loophole Officially Closed as Monaco GP Drops Mandatory Two-Stop Rule

The 2026 Formula 1 season is only a few months old, but the FIA has already moved to close a significant loophole exploited by Mercedes. The technical directive, effective from the Monaco Grand Prix this weekend, officially outlaws the team's ability to run a compression ratio above the regulated 16:1 limit. During pre-season testing, Mercedes HPP was reported to have found a way to push its power unit to 18:1, a clear advantage now neutralized.

Why it matters:

The ban strikes at the heart of Mercedes' potential performance edge in the new power unit era. With the grid tightly packed and engine development frozen for much of the season, eliminating such a loophole levels the playing field—especially for rivals like Ferrari and Red Bull who were reportedly caught off guard.

The details:

• Compression ratio crackdown: The FIA's technical directive explicitly prohibits any engine configuration that exceeds the 16:1 limit, closing the interpretation that allowed Mercedes' 18:1 trick.
• Monaco GP rule reversal: Meanwhile, the mandatory two-pit stop rule introduced for the 2025 Monaco Grand Prix has been quietly dropped from the 2026 sporting regulations. The FIA implemented that rule last year to force more strategic variety, but after a single season, it has been removed without fanfare.
• Race implications: Monaco remains a unique challenge—overtaking almost impossible, qualifying king. Without the two-stop requirement, teams will revert to traditional one-stop strategies, likely reducing on-track action.

What's next:

The first race under the updated technical regulations will be a true test of the FIA's enforcement and the teams' adaptability. While Mercedes must now find performance elsewhere, rivals like Ferrari—tipped by Kimi Antonelli as the 'team to beat' in Monaco due to their low-speed cornering strength—will look to capitalize. The weekend also marks McLaren's 1000th grand prix, with a special livery celebrating the milestone.