LWOS only recently reported on the likelihood of teams hiding their true performance during pre-season testing. In short, those who believe they have a significant advantage will try to maintain a low profile.
If any team is seen to have a major edge, rivals will inevitably look to protest any potentially dubious components.
With that said, despite testing being weeks away, this dynamic is already taking shape. Mercedes and Red Bull understood to be exploiting a grey area with their 2026 engine development.
The other engine manufacturers – Ferrari, Honda and Audi – are naturally unhappy with this news. All eyes are now on the FIA to see how they respond.
Red Bull and Mercedes work to achieve engine advantage
As mentioned previously on LWOS, Red Bull’s engine department should not be underestimated. The Milton Keynes outfit have assembled a group 600-strong for their powertrains unit, a very sizable workforce.
Perhaps most notably, Red Bull have signed dozens of engineers from Mercedes. Because of this, it makes sense that both teams are currently capitalising on the same idea for their 2026 power units.
The point of contention is the following section of the FIA Technical Regulations:
“No cylinder of the engine may have a geometric compression ratio higher than 16.0. The procedure which will be used to determine this value may be found in the document.”
Previously, the maximum compression ratio for engines was 18.0. In theory, a higher compression ratio can generate more performance and allow teams to deliver more horsepower.
However, the ratio lowered to 16.0 for the 2026 regulations – as part of F1’s efforts to attract more manufacturers.
Critically, the method used to measure compression ratio is done when the cars are static in the garage. When the cars are on track, however, temperature increases can cause thermal expansion.
This issue is at the heart of this regulatory controversy.
Mercedes and Red Bull are understood to have found a way to fulfil the 16.0 compression ratio during static tests – but also achieve a higher 18.0 ratio whilst out on track.
Thermal expansion is said to be the trick these powertrain departments are using. In effect, they are trying to hit two birds with one stone.
Should this solution be confirmed as permissible for 2026, it could provide a crucial edge.
Big question marks heading into Australia
According to The Race, the other manufacturers – Ferrari, Honda and Audi – have written a joint later to the FIA for clarification on this issue.
Broadly speaking, there are a few options the FIA could exercise. The first would be to alter the regulations to explicitly ban the trick Mercedes and Red Bull are using.
Of course, this would have a disastrous impact on these outfits – including Mercedes’ three customer teams.
With practically no time to make adjustments before pre-season, this would be a seismic decision, and is therefore deemed an extreme solution.
Another possibility is for the FIA to permit this use of thermal expansion for 2026, under the condition Red Bull and Mercedes would make changes for 2027.
For obvious reasons, this compromise would not be taken well by the other manufacturers. Although the exact benefit of this trick is unknown, gains of even a few tenths per lap will be seen as significant
This is not to say Honda, Ferrari and Audi could not catch up and improve their own engines in 2026 and beyond. Then again, none of these manufacturers want to give up lap-time for what they interpret as a violation of the regulations.
These manufacturers will point to C.1.5 of the 2026 Regulations:
“Formula 1 Cars must comply with these regulations in their entirety at all times during a competition.”
Ultimately, the FIA’s response to the letter written by rival manufacturers will be pivotal. Depending on whether they are satisfied by the action being taken, a protest could be lodged.
This would create a huge dilemma for the FIA even before the start of F1 2026.
In many ways, this saga is a reminder of the usual politics and extreme regulatory interpretations that define F1.
Similar stories, especially during such a radical regulation change, are likely to persist over the next twelve months.
Main photo: Sam Bloxham/LAT Images (Sauber Media Hub)
