2025/2026 Hybrid Powerunit speculation

[Holm86]

Without the mgu-h, will they go away from the split turbo? Is it even allowed to change this?

If i remember correctly the split turbo had been banned for 2026, FIA hates innovation

Wait.. what? It's banned?? Is that an effort to cut cost due to stabilising a very high RPM part across the distance of the V vs hot/cold being right next to one another?

This is the regulation that basically bans split turbochargers:

Referring to Drawing 4 of Appendix C3, the turbocharger compressor and turbine must satisfy the
following dimensional constraints. Only compressor and turbine wheels approved by the FIA
Technical Department will be allowed:

a. The compressor exducer blade outer diameter (A) must lie between 100mm and 110mm. For
the avoidance of doubt, no part of the compressor wheel (including blades, hub and any
blade/hub fillet radius) can have a diameter more than the upper limit and the maximum
diameter of the compressor wheel (including blades, hub and any blade/hub fillet radius)
cannot have a diameter smaller than the lower limit.
b. The compressor axial distance from the outside diameter of the inducer blade edge to rear
plane of exducer, at its outer diameter (B) must lie between 30mm and 35mm
c.
The turbine inducer blade outer diameter (C) must lie between 90mm and 100mm. For the
avoidance of doubt, no part of the turbine wheel (including blades, hub and any blade/hub fillet
radius) can have a diameter more than the upper limit and the maximum diameter of the
turbine wheel (including blades, hub and any blade/hub fillet radius) cannot have a diameter
smaller than the lower limit.
d. The turbine axial distance from the outside diameter of the exducer blade edge to forward
plane of inducer, at its outer diameter (D) must lie between 35mm and 40mm
e.
The maximum distance between the rear of the compressor exducer and the front of the
turbine inducer (E) will be 175mm

https://www.fia.com/sites/default/files ... -12-11.pdf

[michl420]

Aren`t that very small dimensions for the turbo?

[gruntguru]

Aren`t that very small dimensions for the turbo?

No. Those are dimensions of the rotating parts. This turbocharger https://www.garrettmotion.com/racing-an ... 0-80109mm/ is rated for 1,650 hp and has a compressor wheel diameter of 109 mm.

[basti313]

Without the mgu-h, will they go away from the split turbo? Is it even allowed to change this?

If i remember correctly the split turbo had been banned for 2026, FIA hates innovation

That was not an innovation, that was an expensive loop hole without any technical relevance outside of its hole. The error was not to ban it in 2015 or 2016.

Under the latest version of the regulations posted by the FIA there will be 8 forward gears.

I had expected them to reduce the number of gears, perhaps to 6.

Fewer gears would save some weight, but would also means that the engines would have to run to higher rpm in order to stay in the peak power range.

I do not think they can do this for gear span reasons. With fixed gear ratios it is simply impossible to cover all tracks with just one set.
Lowering the number of gears would need to lift the gear ratio fixing...I never understood why they are so eager to fix this to 1...would be enough to allow them ratios which need to be selected before the weekend.

[wuzak]

They could have had 6 forward gears and a set number of final drive ratios from which to choose.

[Martin Keene]

Aren`t that very small dimensions for the turbo?

No. Those are dimensions of the rotating parts. This turbocharger https://www.garrettmotion.com/racing-an ... 0-80109mm/ is rated for 1,650 hp and has a compressor wheel diameter of 109 mm.

Indeed. For a 1.6L engine that turbocharger is massive!