Vasseur’s warning echoes as Mercedes, Red Bull exploit engine loophole

Frederic Vasseur warned to ensure ideas are legal when building a car. His warning now echoes as a revised FIA rule creates a 2026 engine compression‑ratio loophole that Mercedes and Red Bull are exploiting, sparking debate.

Why it matters:

• Gives Mercedes and Red Bull a performance edge, exposing a loophole that could undermine the FIA’s effort to level the field.
• Raises questions about rule transparency and enforceability, likely prompting formal protests.

The details:

• The 2026 rule lowered the maximum compression ratio to 16:1, but the FIA now requires the measurement at ambient temperature.
• The rule lets a cold‑engine reading meet the limit even if the hot‑running ratio exceeds it, a nuance missing from the wording.
• Mercedes and Red Bull have designed V6s to meet the limit only when cold, gaining extra boost in race conditions.

What's next:

• The FIA says it will review the clause and could issue a clarification or amendment before the season opens.
• Closing the loophole would force costly redesigns, delaying performance gains.
• Rival teams are expected to lodge formal protests, and the issue may be taken up at the next World Motor Sport Council meeting.