F1 braced for potential protest over alleged power unit trick - report

Formula 1 could be braced for a potential protest at the 2026 season-opening Australian Grand Prix over an alleged power unit trick, according to reports.

Motorsport Magazin has reported that Ferrari, Audi, and Honda have made representations to the FIA over a potential trick Mercedes High Performance Powertrains (HPP) and Red Bull Powertrains (RBPT) are alleged to have uncovered. 

For the radical rules shake-up coming in 2026, the geometric compression ratio of the power units is limited to 16:1 under the new technical regulations, with rival teams believing Mercedes and Red Bull could have discovered a method to bring this back up to the 18:1 level it is in 2025.

The geometric compression ratio refers to the volume of the engine cylinders when the pistons are at their lowest compared to their highest. A higher value means more power can be created. 

It is believed that the trick could be worth up to around 15bhp, which, around the Albert Park lap in Melbourne, could be worth up to three-tenths of a second per lap. 

Under current FIA procedures, the geometric compression ratio is measured statically at ambient temperatures. Whilst it is unclear how the trick works exactly, it is believed that higher internal temperatures could lead to components within the engine expanding, thus increasing cylinder volume, and bringing the ratio back up to 18:1. 

As per Motorsport Magazin, the FIA is aware of the situation and is "continuously reviewing such matters to ensure fairness and clarity" with further discussions planned between the FIA and power unit manufacturers.

If a protest is lodged and upheld, or indeed rejected in Melbourne, and the alleged trick is proved legal, potential changes are not the work of a moment. 

In terms of teams improving their engines to meet the 18:1 ratio, stronger engine connector rods and pistons would be required, whilst a downgrade of equipment would cause concern to modify the power units and still be able to supply customer teams with sufficient legal engines, as per the regulations.