2025/2026 Hybrid Powerunit speculation

[Tommy Cookers]

To me, sounds like blipping throttle inputs between downshifts, probably burning as much fuel possible (allowed) in this time to increase recovery.

Rev matching.
Maximum permitted time for a downshift is 300ms. Not sure how much recovery can be done in that period.

Yes, I understand that as rev matching, but still it sounds quite aggresive (much crackling and "grunt" sounds). I think this rev matching is done under MGUK load.

downshift rev-matching requires PU rpm to be raised
suggesting MGU-K motor action not generator action (the MG is coupled to the ICE and is trying to help in rpm-raising)
but now they are allowed a bidirectional passive coupler slipping at 520 Nm - rather decoupling the MG from the ICE
(is the magic 350 kW now based on torque sensor readings at MG nose ie not on DC line power ?)

on upshifts (I assume) the PU power is eased by MG generator action starting c. 10 msec before the (clutchless) shift
the MG can change its torque (when there's little or no rpm change required) far quicker than it can change its rpm

[diffuser]

you must brake 500m before turn? that is bullshit, that is not racing, it is efficiency competition

That was from before they changed the regs and allowed the MGU-K to charge the battery. So what Max described will no longer be so. The also limit how much electric power you can deploy at higher speeds.

[wuzak]

you must brake 500m before turn? that is bullshit, that is not racing, it is efficiency competition

They won't brake 500m before a turn.

They may run out of energy and start recovering energy well before the corner, which may require them to downshift.

But they won't be actively braking.

[wuzak]

To me, sounds like blipping throttle inputs between downshifts, probably burning as much fuel possible (allowed) in this time to increase recovery.

Rev matching.

Maximum permitted time for a downshift is 300ms. Not sure how much recovery can be done in that period.

Yes, I understand that as rev matching, but still it sounds quite aggresive (much crackling and "grunt" sounds). I think this rev matching is done under MGUK load.

Sounds like the rev matching used in the V10s, V8s and hybrid V6s before.

As noted previously, the gears are quite closely spaced, so the downshifts come rapidly.

[vorticism]

Might even be only an ICE working against the dyno pump or motor or whatever is used, not through a transmission. In which case gear ratios are being simulated and the engine speed climb/descend rate could be whatever is specified.

[hsg]

They won't brake 500m before a turn.

They may run out of energy and start recovering energy well before the corner, which may require them to downshift.

But they won't be actively braking.

this is bullshit not racing, maybe they can introduce reverse grid as well..it is tragedy what f1 become, return V10 NA engine and fuuk of turbo and electric craps

[mzso]

Well, that would depend on what the math says, but that’s my point, I don’t understand how that would mathematically be possible, surely burning petrol to generate electricity is wholly inefficient. That is What I want explaining

Your example would require 100% Efficiency, and that is not possible

Not as inefficient as you seem to expect. And in some circumstances it could be more efficient, when you use the best time to charge and deploy. Due to the ICE having a narrow efficiency range, near the peak, and the MG having a broader one, as well as being a lot more efficient overall.

Don't forget, this is not fuel that was pulled out of the ground. It's sustainable fuel...To a certain degree, they don't care how much of it they need to burn.

It doesn't matter what they actually burn. The efficiency of the technology is what matters.

Is that is case, late brake drivers will loose their performances?

Not sure you understand, in 2026 you will have less downforce, normal braking will just take more meters because if you brake harder, you'll just lock up the wheels. The late brakers have the ability to stop later that others and still not lock up the tires. That will not change. Just late braking in 2026 will not be as late as it was in 2025. You still need the "touch" to perform the late braking and if you have it, you'll still be able to make use of it.

In the context, it seemed to me that he meant that late brakers will have less power available, due to reduced regen.

[BorisTheBlade]

In the context, it seemed to me that he meant that late brakers will have less power available, due to reduced regen.

Think you are right with your interpretation and in earlier iterations of the regulations this might have indeed been true.
But for the most recent version I have a strong feeling, that recovering with up to 250 kW at the end of a long straight while still having 150 kW of power to the wheels and braking as late as possible will gain you more laptime than braking earlier and recovering 350 kW for a longer duration. But it is still just a feeling as I don't have enough insight to do the math accordingly.
One intermediary step would be to calculate the amount of time you need to recover during full throttle in addition to braking and part throttle recovery on a typical track like Barcelona in order to get the maximum possible energy per lap of 8-9.000 kWs. That at least could give us a better feeling of what the trade-offs might look like. Might try that during the Holidays.

[venkyhere]

Let me ask a basic question , kindly help me :

My understanding about 2014 to 2025
a) brake pedal pressure affects the hydraulic pressure and decides the 'force' pressing the brake pads to the disc, which decides lockup or no lockup and this is the 'feel/touch' that drivers need to have
b) steering button/switch selectable software/firmware settings control the 'fierceness' of engine braking / recharge by choosing different voltage for the stator windings in MGU-K

What about 2026 regs ?
a) of course, yes
b) will it remain simple like previous era where the only choice the driver has is 'different static rates' for braking/recharge OR whether pedal pressure / travel can also modulate the braking/recharging 'rate' of MGU-K via 'dynamic stator voltage control' ? OR whether the 'pedal modulation' is going to be limited to a basic 'step function' reaction to pedal pressure/travel ? (reason for Q : rotational inertia offered by ICE will be much lesser and physical brakes are also going to be smaller)

[diffuser]

Let me ask a basic question , kindly help me :

My understanding about 2014 to 2025
a) brake pedal pressure affects the hydraulic pressure and decides the 'force' pressing the brake pads to the disc, which decides lockup or no lockup and this is the 'feel/touch' that drivers need to have
b) steering button/switch selectable software/firmware settings control the 'fierceness' of engine braking / recharge by choosing different voltage for the stator windings in MGU-K

What about 2026 regs ?
a) of course, yes
b) will it remain simple like previous era where the only choice the driver has is 'different static rates' for braking/recharge OR whether pedal pressure / travel can also modulate the braking/recharging 'rate' of MGU-K via 'dynamic stator voltage control' ? OR whether the 'pedal modulation' is going to be limited to a basic 'step function' reaction to pedal pressure/travel ? (reason for Q : rotational inertia offered by ICE will be much lesser and physical brakes are also going to be smaller)

I don't think it gonna change. You'll just have brake bias front to rear. The more rear bias the more bite the rear brakes will have.

Think most drivers will have the brake bias more to the rear next year than they normally did this year.

[diffuser]

Not as inefficient as you seem to expect. And in some circumstances it could be more efficient, when you use the best time to charge and deploy. Due to the ICE having a narrow efficiency range, near the peak, and the MG having a broader one, as well as being a lot more efficient overall.

Don't forget, this is not fuel that was pulled out of the ground. It's sustainable fuel...To a certain degree, they don't care how much of it they need to burn.

It doesn't matter what they actually burn. The efficiency of the technology is what matters.

Is that is case, late brake drivers will loose their performances?

Not sure you understand, in 2026 you will have less downforce, normal braking will just take more meters because if you brake harder, you'll just lock up the wheels. The late brakers have the ability to stop later that others and still not lock up the tires. That will not change. Just late braking in 2026 will not be as late as it was in 2025. You still need the "touch" to perform the late braking and if you have it, you'll still be able to make use of it.

In the context, it seemed to me that he meant that late brakers will have less power available, due to reduced regen.

What does less power have to do with braking late?

With regards to efficiency...I meant the FIA don't care how much fuel you burn over a race(fuel efficiency). There is no fuel tank size limit, just a flow limit. The fuel itself isn't considered creating CO2 emissions. I'm not talking about from a racing perspective. Obviously, from a racing perspective, the more fuel you have to carry, the slower you'll be. The fuel flow limit is measured in energy. We did the calculations a couple of weeks ago in these pages. Full throttle for 1.5 hours, you can easily burn through 150 liters. The ICE will work harder next year off full throttle to make up for a lack of MGU-H. Let's say the PU power comes 50% from the MGU-K and 50% ICE. Anything 50% and less will come the ICE only. If the demand for power is 30%, the ICE will be working at Max power with 30% going to drive and the other 20% to spin the MGU-K to charge the battery. All this to say, next year it's gonna be interesting to see on a track that normally was 65% full throttle, how much more of the time the ICE will be at 100%!. A track like Monza that was like 75% full throttle in 2025 will the ICE be at 100% for 95% of the race?

[wuzak]

Monza is likely one of the tracks where the allowed energy recovery is lowered to 5MJ.

Say 10s of braking at 350kW recovery = 3.5MJ.

Part throttle and full throttle recovery required is 1.5MJ.

2s full throttle recovery at the end of the three flat out sections = 6s @ 125kW (average recovery under full throttle) = 750kJ.

Leaves 750kJ for part throttle recovery. Can be done exiting the first two chicanes, the Lesmos and Parabolica.

If we say they can recover 100kW, on average, in these periods, it would be 7.5s, of ~2s on 4 occasions.

1.5MJ recovered by fuel burning = ~3MJ of fuel energy, ~0.0732kg/lap (assuming maximum fuel energy density).

Monza has 53 laps, so total fuel burned to generate electricity is approximately 4kg.

The equation would be more difficult if the full 8.5MJ recovery allowance is used.

The extra energy required from burning fuel would be 5MJ = ~10MJ of fuel energy, 0.244kg/lap = ~13kg total.

But where could they recover that amount?

[wuzak]

My numbers are slightly incorrect.

The MGUK must not reduce by more than 100kW/s at most tracks, or 50kW/s on tracks with long flat out sections.

For Monza, it would likely require 5s to go from 0kW to -250kW, meaning energy recovery in this period would be 625kJ.

A couple of times per lap would almost give the required recovery.

[wuzak]

Maybe the 100kW/s or 50kW/s maximum rate of reduction doesn't apply in recovery?

C5.12.6 Unless the electrical DC power of the ERS-K is negative, the driver maximum power demand must not be reduced at any greater than the rates defined below:
a. 50kW in any 1s period at Competitions where the FIA determines that the power limited distance exceeds 3500m. These Competitions and the vehicle fundamentals used for the calculation of the power limited distance may be found in the document FIA-F1-DOC-Cxxx.
b. 100kW in any 1s period at all other Competitions.
Furthermore, the total power reduction is limited to a maximum of 600kW and the resulting electrical DC power of the ERS-K must remain above −250kW.

[gruntguru]

Not sure what you are getting at there Wuzak. Is it the following?

My understanding is the power reduction rate limits only apply to "un-commanded" power reduction. So driver demand can reduce instantaneously if required and switching that surplus power to MGU-K recovery (genset mode) can also be instantaneous.