2025/2026 Hybrid Powerunit speculation

[johnny comelately]

Ice water stat
(no pun intended)

[Martin Keene]

Hot V configurations are currently banned so they’d have to change the regs.

Yes

5.3.5 Engine exhaust gases may only exit the cylinder head through outlets outboard of the
cylinder bore centre line and not from within the “V” centre.

I really don't understand why they need to prescribe this, hot vee's are very common in the automotive world now.
These regulations are not at all visionary, and I have a very hard time understanding why they have to prescribe so much with the engine regulations, when there now is a budget cap so there won't be an spending war.

I read the regs to see what it said about turbocharger position and somehow missed that line!

Banning hot vee does seem over the top.

[wuzak]

Is there any possibility of using big turbos, possibly with some sort of flywheel or simply heavy turbine - compressor wheels?

While it will be slow to spin up to optimal speed at startup, it could keep spooled during the braking / cornering time, to minimize turbo lag when the driver applies the throttle another time.

Obviously, when the throttle is closed, you should vent the compressed air to the intake. Or not closing the throttle at all while at 0% throttle pedal. Only cutting fuel / spark and keeping the air flowing through the ICE.

5.5.5 Referring to Drawing 4 of Appendix 2, the turbocharger compressor and turbine must satisfy the following dimensional constraints:
a. The compressor exducer diameter (A) must lie between 100mm and 110mm
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 37.5mm and 42.5mm
c. The turbine inducer diameter (C) must lie between 95mm and 105mm
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 30mm and 35mm
e. The maximum distance between the rear of the compressor exducer and the front of the turbine inducer (E) will be 175mm

[BassVirolla]

Is there any possibility of using big turbos, possibly with some sort of flywheel or simply heavy turbine - compressor wheels?

While it will be slow to spin up to optimal speed at startup, it could keep spooled during the braking / cornering time, to minimize turbo lag when the driver applies the throttle another time.

Obviously, when the throttle is closed, you should vent the compressed air to the intake. Or not closing the throttle at all while at 0% throttle pedal. Only cutting fuel / spark and keeping the air flowing through the ICE.

5.5.5 Referring to Drawing 4 of Appendix 2, the turbocharger compressor and turbine must satisfy the following dimensional constraints:
a. The compressor exducer diameter (A) must lie between 100mm and 110mm
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 37.5mm and 42.5mm
c. The turbine inducer diameter (C) must lie between 95mm and 105mm
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 30mm and 35mm
e. The maximum distance between the rear of the compressor exducer and the front of the turbine inducer (E) will be 175mm

Well, not explicitly baned but dimensionally limited.

Tungsten for the turbo?

[Tommy Cookers]

Tungsten for the turbo? :lol:

my guess - insufficient strength to allow it the rpm necessary with those dimensions mandated

and the 'it' would be some tungsten heavy alloy THA, what we call tungsten (but its not exactly)

[johnny comelately]

Where is that ice water ! ?

[johnny comelately]

5.5 Turbocharger
5.5.1 Pressure charging may only be affected by the use of a sole single stage, single sided compressor with a single inlet linked to a sole single stage exhaust turbine by a shaft assembly. The compressor blades must be attached to a common hub surface and all air entering the combustion chamber must pass through the single exducer of these blades. The shaft must be designed so as to ensure that the shaft assembly, the compressor and the turbine always rotate about a common axis and at the same angular velocity. The energy of the rotating parts of the turbocharger may not be transferrable to any other component. Only parts approved by the FIA Technical Department may be used. Subject for provision of the Article 17.3.5, the approval of the FIA Technical Department is conditional upon the PU manufacturer, intending to use such parts during a Championship season undertaking not to conclude any exclusivity agreement (see definition article 5.1.30) for the supply of such parts with the supplier of these parts. The approval request form must be sent by the PU Manufacturer to the FIA before the 1st of November of the preceding year.

Cannot transfer energy to or from rotating components?

Also, parts have to be approved by FIA.

Your question is exactly the answer.
If a turbo cannot transfer energy it cannot be/function and hence becomes ballast seeing as how you "have" to have one....as circuitous as that transfer may be

[gruntguru]

The best solution for turbo lag would be to permit ICE>GUK>ES charging. This allows the large GUK to be used to load the ice even when the driver is off throttle - keeping the turbo spooled ready for corner exit. Even the ICE is developing power in the off-throttle condition meaning that throttle response will be as fast as the power electronics can unload the GUK and switch it to MUK mode. From EV experience we know that is very fast indeed. So you have a situation where power output can be increased almost instantly by 700kW (MGUK switches from -350 to +350 kW)

[NL_Fer]

I doubt lag is going to be a serious problem. The mgu-k will produce 350kw, should be enough to spin the tyres at low speed. So I believe the initial power needed to accelerate out of the corner could be delivered by the mgu-k.

If u look at the onboards. They aren’t at full throttle under 200kph out of corners.

[vorticism]

From the vaults, regulations proposals from 2007:

https://www.autosport.com/f1/news/fia-p ... 6/4412016/

Engine efficiency

To limit engine power by imposing a maximum energy flow rate. However, there will be few restrictions on the engine cycle, which can include turbo-charging and energy recovery. It is believed that this will lead to a gain of at least 20% in thermal efficiency.

Drag

To allow moving aerodynamic devices, which will reduce drag by over 50% and allow a 40% reduction in the power required to maintain current speeds.

Energy recovery

Energy will be recovered during braking and returned to both front and rear axles when accelerating. The amount of energy returned on each straight will be limited in order to prevent top speeds exceeding the safety criteria for the circuits.

Fuel

The total amount of fuel energy to be consumed during a race will be regulated, encouraging further overall efficiency. The CO2 emitted will be further reduced by the introduction of gasoline which is partly derived from sustainable, non-food bio sources but complies fully with pump fuel legislation.

Overtaking

Formula One cars currently find it very difficult to overtake because of the influence of the car in front. New aerodynamic rules will halve the downforce, and de-sensitise the car to the influence of the wake of the car ahead. It is also proposed to eliminate automatically the downforce deficit of the following car.

Regulations

The best estimates of what these measures will mean in terms of regulations are currently as follows:
• 1.3-1.5 litre, 4-cylinder engine;
• no RPM or boost limit;
• energy flow rate to generate 300kW, including energy recovery from the exhaust;
• 200kW brake energy recovery, front and rear axle;
• 400-600kJ energy return per straight;
• pump-legal bio-fuel;
• FIA specified and supplied undertray and possibly other aerodynamic components;
• 50% 2007 downforce;
• adjustable, regulated wings and cooling;
• automatic downforce adjustment when following another car;
• lap times and top speeds maintained at 2009 levels;
• over 50% reduction in fuel consumed.

Costs

A number of measures to constrain costs are proposed, including:
• standardisation of components;
• homologation of components and assemblies;
• material restrictions;
• extended life of assemblies;
• restrictions on personnel and work at races;
• restrictions on the use of certain facilities (eg wind tunnels).

[wuzak]

The best solution for turbo lag would be to permit ICE>GUK>ES charging. This allows the large GUK to be used to load the ice even when the driver is off throttle - keeping the turbo spooled ready for corner exit. Even the ICE is developing power in the off-throttle condition meaning that throttle response will be as fast as the power electronics can unload the GUK and switch it to MUK mode. From EV experience we know that is very fast indeed. So you have a situation where power output can be increased almost instantly by 700kW (MGUK switches from -350 to +350 kW)

I believe the FIA want the turbo lag to make driving "harder".

And how much time could the MGUK be generating 350kW over a lap? A few seconds?

[mzso]

Startup times where the main issue I was referring to. I’ve found a few papers discussing fast start up SOFC units (5mins) but they are tiny 10W cells.

Most of the commercially available units list starting times of Cold 24 hrs and Hot 2 hrs.

https://power.mhi.com/products/sofc/pdf/sofc_en.pdf

Just doesn’t seem very practical to me right now. Especially considering a 210kW unit is 33t (prolly half that when you remove all the turbine heat systems etc).

Ps for reference I used to manage a data centre with 3x 1.1MW 32ltr Cat Diesel generators that only weighed 6t each!

I would expect that those are monster sized cell stacks. I'm more optimistic about it. If they were to increase power density to be more suitable to F1, it would also decrease the mass and bulk of the fuel cell. At worst they could allow to pre-heat it.

I’m going to remain pessimistic for now, imo the tech is just moving too slowly despite decades of development and billions invested.

I think only proton exchange membrane (hydrogen fuel cell) received significant amount of attention and funding, and it works, albeit doomed by batteries being a lot more efficient. The other's are rather obscure.

[sticktion]

I believe the FIA want the turbo lag to make driving "harder".

They've done a rotten job of it then.
Is there any realistic scenario where a driver would not have enough energy to compensate for throttle lag on corner exit? I can't think of any. They'd have to limit low-speed or low-RPM deployment somehow.

This just seems like another fib from FOM's 2026 puff pieces.

[NL_Fer]

Any idea how lean they will run? With the MGU-H recovery gone, how much sense does running lean make? Does it make sense at all?

I can imagen that low turbo pressure will reduce the lag.

[gruntguru]

AFR will be similar. They will still be seeking the highest possible thermal efficiency and that appears to be around lambda 1.4 - 1.8 with this engine configuration.

The reduction in turbine power and exhaust back pressure may change that number a bit. (The engines will have a significant positive pressure differential (MAP>EAP) under the new rules.)