2025/2026 Hybrid Powerunit speculation

[wuzak]

I've recently read an Italian report about Ferrari's material experiments for the new PU.
It stated that they tried a cylinder head made of steel, but couldn't make it work and reverted back to aluminum.
Why is it hard to make to it work and what are the benefits if a PU manufacturer succeed with steel?

current F1 engines have steel pistons as aluminium alloy has insufficient fatigue strength at the temperatures involved
(as they more than SI ever has before release the combustion heat in-cylinder before expansion)

and the engines have structural cut-outs in the head for the separate (CuBe) valve seat rings
steel heads would have no cut-outs - that might make more room for bigger valves/ports ...
or enable some other feature in eg the jet injector system

I guess the "can't make steel heads work" is that they can't get the weight down enough?

Or the CoG is too high?

IIRC, Ferrari used a cast steel block in the last of their F1 V12s.

I am not sure how much steel heads would weigh extra, but if t is more than 1-2kg then it suggests the ICE minimum weight could be reduced.

[Tommy Cookers]

... IIRC, Ferrari used a cast steel block in the last of their F1 V12s.

I remember a steel gearbox or transmission casing (for an F1 Ferrari c.20 years ago)

with boosted engines we might choose steel to allow cylinder liners integral with heads (losing gasket & deck & studs)
liner strength/stiffness might allow a thinner liner (if steel)

didn't BMW try this 'monobloc' with their V10 ? (in alloy not steel of course)

[diffuser]

current F1 engines have steel pistons as aluminium alloy has insufficient fatigue strength at the temperatures involved
(as they more than SI ever has before release the combustion heat in-cylinder before expansion)

and the engines have structural cut-outs in the head for the separate (CuBe) valve seat rings
steel heads would have no cut-outs - that might make more room for bigger valves/ports ...
or enable some other feature in eg the jet injector system

I guess the "can't make steel heads work" is that they can't get the weight down enough?

Or the CoG is too high?

IIRC, Ferrari used a cast steel block in the last of their F1 V12s.

I am not sure how much steel heads would weigh extra, but if t is more than 1-2kg then it suggests the ICE minimum weight could be reduced.

Think that steel heads are close to 100% heavier. Generally speaking, 8kg for aluminum vs 16kg for steel.

[BassVirolla]

current F1 engines have steel pistons as aluminium alloy has insufficient fatigue strength at the temperatures involved
(as they more than SI ever has before release the combustion heat in-cylinder before expansion)

and the engines have structural cut-outs in the head for the separate (CuBe) valve seat rings
steel heads would have no cut-outs - that might make more room for bigger valves/ports ...
or enable some other feature in eg the jet injector system

I guess the "can't make steel heads work" is that they can't get the weight down enough?

Or the CoG is too high?

IIRC, Ferrari used a cast steel block in the last of their F1 V12s.

I am not sure how much steel heads would weigh extra, but if t is more than 1-2kg then it suggests the ICE minimum weight could be reduced.

Or simply what mostly rode manufacturers away from them: Cooling concerns.

Yes, steel heads can withstand much strongee combustion and lead to lesser heat losses, but the lower heat transfer is the same for good combustion efficiency and for bad cooling.