2025/2026 Hybrid Powerunit speculation

[diffuser]

... Likely more suitable for a generator type installation. It doesn't demand higher rpm/bhp facility to be effective....

we have a generator - it's called the MGU-K
it's slaved to the ICE crankshaft
to recover KE effectively it needs to be doing 10500 crankshaft rpm or more

That's a surprise to me. We're talking about the ICE crankshaft needing to be at 10.5k or more to recover KE effectively ? Why? There is a gear/MGU-K transmission between the MGU-K and the crankshaft.

[Tommy Cookers]

'Why ?'
because the KE available is proportionate to the square of the car's speed and to the square of the PU's speed
further, the aero DF is proportionate to the square of the car's speed
the 2026 rear axle KE potential recovery rate is about 1300 KW at 300 kph and about 250 KW at 150 kph but ....
to maintain MGU-K rpm as the car slows they downshift - this needs more wheel torque so eats into grip margin

if the MGU-K doesn't run at full RPM it can't make full voltage and so the battery will never be fully charged

[saviour stivala]

The higher the MGU-K RPM, the higher the energy recovery potential. MGU-K gearbox connection to crankshaft is of fixed ratio. 10500 crankshaft RPM is 0.7 of the maximum allowed. At 10500 crankshaft RPM, the MGU-K will be rotating at 35000 RPM, which is 0.7 of its maximum RPM allowed. But if the rules allows different manufacturers to use different MGU-K gearbox ratios , but still a of fixed ratio, the MGU-K can be made to rev at more than 35000 RPM when crankshaft is rotating at 10500 RPM.

[wuzak]

Do you mean with “weight savings may not be as much as people expect either” that if they go with a NA V8 ICE, they’re not going to save that much weight?

The 2013 V8 had a minimum weight of 95kg.
The 2026 V6 Turbo (without ERS) has a minimum weight of 130kg.

But the 2013 V8 didn't have to last 6+ events, nor did the minimum weight calculation include as many items, like the exhaust, for instance.

So, expect the V8's minimum weight to increase.

Say a saving of 30kg.

There will be some weight saving because the intercooler is not required, but some weight increase because larger coolant radiators and, potentially, engine oil heat exchangers.

If it remains the same size/capacity, there will be no weight savings in the ERS.

There is a minimum 55kg in the ERS, not including coolers for the battery and motor. Drastically reducing the power and energy storage of the ERS will save a lot of weight.

I think some people expect the weight to drop to 2013 weights of ~640kg. But the extra weight in items like the halo and larger wheels will make that impossible.

[DenBommer]

Do you mean with “weight savings may not be as much as people expect either” that if they go with a NA V8 ICE, they’re not going to save that much weight?

The 2013 V8 had a minimum weight of 95kg.
The 2026 V6 Turbo (without ERS) has a minimum weight of 130kg.

But the 2013 V8 didn't have to last 6+ events, nor did the minimum weight calculation include as many items, like the exhaust, for instance.

So, expect the V8's minimum weight to increase.

Say a saving of 30kg.

There will be some weight saving because the intercooler is not required, but some weight increase because larger coolant radiators and, potentially, engine oil heat exchangers.

If it remains the same size/capacity, there will be no weight savings in the ERS.

There is a minimum 55kg in the ERS, not including coolers for the battery and motor. Drastically reducing the power and energy storage of the ERS will save a lot of weight.

I think some people expect the weight to drop to 2013 weights of ~640kg. But the extra weight in items like the halo and larger wheels will make that impossible.

But with the V8 proposal, they want to bring the power from the ERS back to 120–140 kW instead of 350 kW next year. That will save some weight, right?

It also makes sense that if they want a NA V8 to last for 6–8 races, they’ll have to use stronger but probably heavier materials.

I think we just have to see how the next regulations work out. In 5–6 years, a lot can happen and change.

Also the extra fuel a NA V8 needs

[Badger]

Why go to a V8? Wouldn’t it just be simpler to keep the V6 Turbo and slightly increase the fuel flow? Keep the same architecture.

Does anyone have an insight into what the actual kW could be like from the ICE, we’ve heard 400 from F1 all this time but is that conservative or realistic? If we end up at say 390 kW or 425 kW could make a huge difference to the racing.

BTW, what happened to that proposal of limiting the MGU-K to 200 kW in races?

[wuzak]

Do you mean with “weight savings may not be as much as people expect either” that if they go with a NA V8 ICE, they’re not going to save that much weight?

The 2013 V8 had a minimum weight of 95kg.
The 2026 V6 Turbo (without ERS) has a minimum weight of 130kg.

But the 2013 V8 didn't have to last 6+ events, nor did the minimum weight calculation include as many items, like the exhaust, for instance.

So, expect the V8's minimum weight to increase.

Say a saving of 30kg.

There will be some weight saving because the intercooler is not required, but some weight increase because larger coolant radiators and, potentially, engine oil heat exchangers.

If it remains the same size/capacity, there will be no weight savings in the ERS.

There is a minimum 55kg in the ERS, not including coolers for the battery and motor. Drastically reducing the power and energy storage of the ERS will save a lot of weight.

I think some people expect the weight to drop to 2013 weights of ~640kg. But the extra weight in items like the halo and larger wheels will make that impossible.

But with the V8 proposal, they want to bring the power from the ERS back to 120–140 kW instead of 350 kW next year. That will save some weight, right?

It also makes sense that if they want a NA V8 to last for 6–8 races, they’ll have to use stronger but probably heavier materials.

I think we just have to see how the next regulations work out. In 5–6 years, a lot can happen and change.

Also the extra fuel a NA V8 needs

You can reduce the ERS for the turbo V6 and save some weight too.

The difference between the 2026 ICE and a 2013 like V8 is going to be ~30kg.

Lose the ERS altogether and you can save 55kg (ERS components) plus the weight of coolers for the ERS.

[wuzak]

Why go to a V8? Wouldn’t it just be simpler to keep the V6 Turbo and slightly increase the fuel flow? Keep the same architecture.

Does anyone have an insight into what the actual kW could be like from the ICE, we’ve heard 400 from F1 all this time but is that conservative or realistic? If we end up at say 390 kW or 425 kW could make a huge difference to the racing.

BTW, what happened to that proposal of limiting the MGU-K to 200 kW in races?

The proposal of limiting the MGUK to 200kW was Horner's, and never really got any traction.

The assumption was that the RBPT PU was in trouble.

IIRC, when the rules first came out, they talked of reducing from 600kW (804hp) to 400kW (536hp) be reducing fuel energy flow by about 1/3.

Lately it talk has been of 560kW (750hp) for the current PU. But that doesn't line up with the claims of 1,000hp, as it would only give a total of ~910hp.

Tombazis said, a year or so ago, that the 2026 PUs would have a peak of 100hp more than the current PU.

I assumed it to be 1,100hp, or 820kW, which would give the ICE 470kW (631hp).

If it is 100hp more than 910hp, then the power is 1,010hp (753kW), which gives the ICE 403kW (540hp), more or less in line with what they have been saying.

A couple of years ago, Mark Hughes of Motorsport Magazine suggested they were already exceeding 450kW from the ICE.

[Martin Keene]

That "could" still allow the arrangement by placing the exhaust valves in V side of bore centre and routing out vertically across centre line to exit head and above inlet cam location to fulfill that rules demand. The head exit point then being entirely in accord with directive.

Potentially yes. But packaging the ports in the cylinder head would be a nightmare and have appalling flow.

FWIW, I have no idea why they banned hot V, it would be a much better packaging solution for a single turbo engine and is widely used in road cars.

Are you sure of this?

Anyone have knowledge of this one https://www.mcnews.com.au/highly-succes ... l-aynsley/ to demonstrate the principal ..... here on intake side, but vertical port between cam and central spark plug location none the less.
They could exit the head in conformance with rules in being outside centre line of bore by then having a manifold bring it over the top of exhaust cam direct to turbo hot side.

Yes, you have compared 4 inlet port going straight up to atmosphere, with 6 exhaust ports that all need to meet in a central location to drive a turbocharger. The they some how also need to get the air from the airbox in the roll hoop through that lot as well.

[Badger]

Why go to a V8? Wouldn’t it just be simpler to keep the V6 Turbo and slightly increase the fuel flow? Keep the same architecture.

Does anyone have an insight into what the actual kW could be like from the ICE, we’ve heard 400 from F1 all this time but is that conservative or realistic? If we end up at say 390 kW or 425 kW could make a huge difference to the racing.

BTW, what happened to that proposal of limiting the MGU-K to 200 kW in races?

The proposal of limiting the MGUK to 200kW was Horner's, and never really got any traction.

The assumption was that the RBPT PU was in trouble.

IIRC, when the rules first came out, they talked of reducing from 600kW (804hp) to 400kW (536hp) be reducing fuel energy flow by about 1/3.

Lately it talk has been of 560kW (750hp) for the current PU. But that doesn't line up with the claims of 1,000hp, as it would only give a total of ~910hp.

Tombazis said, a year or so ago, that the 2026 PUs would have a peak of 100hp more than the current PU.

I assumed it to be 1,100hp, or 820kW, which would give the ICE 470kW (631hp).

If it is 100hp more than 910hp, then the power is 1,010hp (753kW), which gives the ICE 403kW (540hp), more or less in line with what they have been saying.

A couple of years ago, Mark Hughes of Motorsport Magazine suggested they were already exceeding 450kW from the ICE.

400 kW is like a GT3 car. The idea that you can run a 350 kW MGU-K in conjunction with that small ICE, and only rear brake harvest to boot, it’s very optimistic.

My suspicion is that they will not be running much if any of the full 350 kW deployment in the races, regardless if there’s a regulatory cap at 200 kW or not. It will be a quick burst onto the big straights, a second or two, then back to tapering the deployment, before harvesting in the second half of every straight. I think some people are gonna be shocked when they see the final product, and probably not in a good way.

Overtaking is probably just gonna be that one guy pressed the override on the harvest mode for 2 seconds and flew past well before braking.

[diffuser]

'Why ?'
because the KE available is proportionate to the square of the car's speed and to the square of the PU's speed
further, the aero DF is proportionate to the square of the car's speed
the 2026 rear axle KE potential recovery rate is about 1300 KW at 300 kph and about 250 KW at 150 kph but ....
to maintain MGU-K rpm as the car slows they downshift - this needs more wheel torque so eats into grip margin

if the MGU-K doesn't run at full RPM it can't make full voltage and so the battery will never be fully charged

If the Max rpm of the MGU-K is 60K how do you decide on a ratio of ICE crankshaft to MGU-K? Do you design it to hit 60K rpm on the MGU-K at 10.5K or do you set it higher/lower? What happens when the RPM on the ICE is pushing the MGU-K beyond 60K? Does it disengage/re-engage?

[saviour stivala]

If the rules allow it, which I think they do, best will be for the MGU-K gearbox ratio to run the MGU-K as near to maximum RPM allowed (50k) as possible at ICE crankshaft RPM of 10500.

[saviour stivala]

The MGU-K to crankshaft drive connection is not allowed to be disengaged.

[DenBommer]

The 2013 V8 had a minimum weight of 95kg.
The 2026 V6 Turbo (without ERS) has a minimum weight of 130kg.

But the 2013 V8 didn't have to last 6+ events, nor did the minimum weight calculation include as many items, like the exhaust, for instance.

So, expect the V8's minimum weight to increase.

Say a saving of 30kg.

There will be some weight saving because the intercooler is not required, but some weight increase because larger coolant radiators and, potentially, engine oil heat exchangers.

If it remains the same size/capacity, there will be no weight savings in the ERS.

There is a minimum 55kg in the ERS, not including coolers for the battery and motor. Drastically reducing the power and energy storage of the ERS will save a lot of weight.

I think some people expect the weight to drop to 2013 weights of ~640kg. But the extra weight in items like the halo and larger wheels will make that impossible.

But with the V8 proposal, they want to bring the power from the ERS back to 120–140 kW instead of 350 kW next year. That will save some weight, right?

It also makes sense that if they want a NA V8 to last for 6–8 races, they’ll have to use stronger but probably heavier materials.

I think we just have to see how the next regulations work out. In 5–6 years, a lot can happen and change.

Also the extra fuel a NA V8 needs

You can reduce the ERS for the turbo V6 and save some weight too.

The difference between the 2026 ICE and a 2013 like V8 is going to be ~30kg.

Lose the ERS altogether and you can save 55kg (ERS components) plus the weight of coolers for the ERS.

Or you could remove the turbo and keep the ERS, making it a 2.5 L naturally aspirated V6?

[diffuser]

You can reduce the ERS for the turbo V6 and save some weight too.

The difference between the 2026 ICE and a 2013 like V8 is going to be ~30kg.

Lose the ERS altogether and you can save 55kg (ERS components) plus the weight of coolers for the ERS.

The V8 is heavier right ?
The 2025 ICE (V6 1.6L turbo, not including the MGUs) 100KG + 15KG for Turbocharger & ancillaries, total 115KG. If you divide the 100KG by 3 then multiply by 4 to get you V8 weight, it comes out to 133KG but that assume everything else is the same and only gets to 2.13 Liters. So I think the V8 will be more like 140KG - 150KG.

Plus 40KG more fuel at the beginning of the race if we go back to 110KG limit.