The first draft for the 2026 power unit regulations was approved and published last August. The ratification had been subject to several postponements due to the lack of agreements on some key points of the new generation of engines. As reported at the time from Auto Motor und Sport in fact, possible entrants Audi and Porsche were in favor of using aluminum alloy pistons, which are lighter than steel components. Mercedes, Ferrari and Alpine instead pushed for the exclusive use of steel pistons, having little experience with aluminum in this particular application. The winners were Audi and Porsche, so much so that the first version of the regulations explicitly specified aluminum alloys together with the other materials allowed for the pistons. However, the discussions did not stop and led to a U-turn with the exclusion of aluminium, as initially desired by the already present motorists.
Heavier pistons
The first version of the technical regulation envisaged the use of aluminum alloys for the production of pistons. In detail, the Al 2618, 2219, 2040 and 4032 alloys were permitted. However, the discussions of recent months have banned the same alloys, allowing the exclusive use of steels AMS 6487, 15cdv16, 42CrMo4 to which has recently been added the X38CrMoV5-3. What changes, however, is not only the material, but also the minimum weight of each piston, initially set at 300 g in line with what is prescribed by the regulations of the current power units. However, following the changes, the minimum weight for the 2026 pistons has risen by around 16%, going to 350 g each, always also including the bands and oil seals.
Longer connecting rods
Piston assembly news doesn’t stop there. Indeed, the FIA increased the length of the connecting rods by about 5%, passing from 113.5 to 120mm, always maintaining a tolerance of ±0.5 mm. The choice slightly attenuates the speed and acceleration peaks of the pistons, as well as strengthening the connecting rods to better withstand the greater stresses deriving from heavier pistons. Finally, the piston pin will have a smaller diameter, now between 18 and 19 mm, while in the first version of the regulations it ranged between 21 and 22 mm.
The 2026 power unit regulations thus begin to change shape, also in reaction to the political balance behind the scenes. Compared to the discussions held until last summer, Porsche is no longer present, while Honda and Red Bull-Ford Powertrain participate as two separate entities. Ferrari had been excluded from the technical meetings straddling the months of November-December following the refusal to register together with the other engineers for 2026. The bone of contention was the recognition to Red Bull-Ford of the benefits of a new engineer, then partially revised. Since January the Cavallino has been participating again in meetings together with FIA and to the other motorists, to whom we owe the latest changes to the 2026 regulations.
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