F1 today | Wolff furious at Mercedes engine speculation, as Ferrari shock paddock with upgrade

Toto Wolff slammed the speculation surrounding the Mercedes engine 'loophole,' despite accepting the FIA's proposal of a mid-season change on how the F1 2026 cars' compression ratios will be measured.

If approved, the proposal will require teams to demonstrate that their compression ratio complies with the rules not only under ambient conditions but also when measured at a "representative operating temperature" of 130°C.

Wolff said he "philosophically" disagrees with the changes but said Mercedes had no choice but to accept the change. The Mercedes boss then reacted angrily to rumours around fuel supplier Petronas.

Wolff said: "This is another of these stories. We were told the compression ratio was illegal, which is total b*llsh*t, utter b*llsh*t. And now the next story comes up that our fuel is illegal. I don’t know where that comes from and it starts spinning again. Maybe tomorrow we’ll invent something else, I don’t know."

On track, it was a successful day for Mercedes, as Kimi Antonelli went quickest in Bahrain Test 2 with a 1:32.803, while they racked up 158 laps overall, just two laps behind leaders McLaren.

Read more to hear what else Wolff had to say on the 'loophole' saga.

It was a very mixed bag for Ferrari on Day 2 of the final Bahrain test. Lewis Hamilton's full day of running was affected by several issues, and the seven-time world champion could only achieve 78 laps overall for the Scuderia.

Nonetheless, Ferrari shocked the rest of the grid with a radical rear-wing design, which was particularly noticeable when the car activated straight mode. Normally, an F1's rear wing would go flat to reduce drag down the straights, but the SF-26's went almost 270°, thus going completely upside down.

The innovative idea was only on display for five laps in the morning, however, as Hamilton's first session saw issues that kept him in the garage for more than three hours. The Briton returned in the afternoon with an old spec rear wing, and finished P4 in the timing charts, sixth tenths off leader Antonelli as he struggled to put in clean quali laps towards the end of the session.