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Re: 2025/2026 Hybrid Powerunit speculation
Posted: 10 Oct 2025, 12:23
by Badger
wuzak wrote: ↑10 Oct 2025, 01:57
Badger wrote: ↑09 Oct 2025, 12:26
Now imagine every lap instead of braking at 80 meters down from 300kph, you’re now lifting at 300m, then coasting for 250m, and then braking the final 50m from a much lower speed. It will look like a joke compared to what we have now.
I don't think that will happen.
Instead, the drivers will be on full throttle when the system starts energy recovery, which slows the car down, before braking hard.
There will be a balancing act between recovering under full throttle and under braking, as the former reduces the time that the brakes will be deployed and the amount of energy recovery possible.
I think that if they were allowed more freedom with the active aero there would be some interesting solutions.
For maximum energy recovery they would want to be in low drag mode for braking.
But braking performance requires the downforce for grip, which increases drag and reduces the amount of energy recovery possible.
If they were allowed continuously variable wing adjustment, rather than the 2 positions for 2026, they could adjust the rear wing to maximise rear braking and reduce drag.
The 350 kW energy recovery more or less negates the full throttle, hence it will effectively be LiCo even if the engine is still revving (generator mode). The car will start slowing down due to drag and rolling resistance long before the normal braking zone.
My guess is they will be in low drag mode during this LiCo phase to minimise drag losses/maximise regen and time, and then go to high downforce mode for the final braking where you actually need grip.
But you can imagine how it’s going to work fairly easily, because for every second of LiCo you get one second of deployment (assuming full regen and deployment). So if you want 20 seconds of deployment per lap, say 8s at full power and 12s at on average half power, that’s 14 seconds of LiCo you need. That’s a lot of freaking LiCo. Now maybe some of that will be covered by regen mid corner.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 10 Oct 2025, 16:58
by dren
What's typical brake bias with the cars now? I'd assume they'll be shifting that further rear which will be interesting.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 10 Oct 2025, 18:26
by wuzak
Badger wrote: ↑10 Oct 2025, 12:23
The 350 kW energy recovery more or less negates the full throttle, hence it will effectively be LiCo even if the engine is still revving (generator mode). The car will start slowing down due to drag and rolling resistance long before the normal braking zone.
The maximum recovery when at full throttle (maximum power demand) is 250kW.
LiCo means there is minimal power from the ICE, so recovering 350kW would be effective braking.
Badger wrote: ↑10 Oct 2025, 12:23
My guess is they will be in low drag mode during this LiCo phase to minimise drag losses/maximise regen and time, and then go to high downforce mode for the final braking where you actually need grip.
I suspect that if they lift the low drag mode will be cancelled.
Badger wrote: ↑10 Oct 2025, 12:23
But you can imagine how it’s going to work fairly easily, because for every second of LiCo you get one second of deployment (assuming full regen and deployment). So if you want 20 seconds of deployment per lap, say 8s at full power and 12s at on average half power, that’s 14 seconds of LiCo you need. That’s a lot of freaking LiCo. Now maybe some of that will be covered by regen mid corner.
It will have to be a balance between LiCo, full throttle recovery and braking energy recovery.
Too much LiCo at the end of straights will slow the car and may lose time compared to some full throttle recovery and braking recovery.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 10 Oct 2025, 19:49
by saviour stivala
The 2026 formula 1 regulations are designed to prevent energy recovery while at full throttle, as the system will rely on drivers managing energy recovery during braking and cornering, not when accelerating. The removal of the MGU-H (which recovered energy from exhaust gases) means the cars can't harvest energy under full throttle.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 11 Oct 2025, 08:19
by Badger
wuzak wrote: ↑10 Oct 2025, 18:26
Badger wrote: ↑10 Oct 2025, 12:23
The 350 kW energy recovery more or less negates the full throttle, hence it will effectively be LiCo even if the engine is still revving (generator mode). The car will start slowing down due to drag and rolling resistance long before the normal braking zone.
The maximum recovery when at full throttle (maximum power demand) is 250kW.
LiCo means there is minimal power from the ICE, so recovering 350kW would be effective braking.
Badger wrote: ↑10 Oct 2025, 12:23
My guess is they will be in low drag mode during this LiCo phase to minimise drag losses/maximise regen and time, and then go to high downforce mode for the final braking where you actually need grip.
I suspect that if they lift the low drag mode will be cancelled.
Badger wrote: ↑10 Oct 2025, 12:23
But you can imagine how it’s going to work fairly easily, because for every second of LiCo you get one second of deployment (assuming full regen and deployment). So if you want 20 seconds of deployment per lap, say 8s at full power and 12s at on average half power, that’s 14 seconds of LiCo you need. That’s a lot of freaking LiCo. Now maybe some of that will be covered by regen mid corner.
It will have to be a balance between LiCo, full throttle recovery and braking energy recovery.
Too much LiCo at the end of straights will slow the car and may lose time compared to some full throttle recovery and braking recovery.
I think we are just misunderstanding what each other is talking about. When I say “LiCo”, I don’t mean it in the current way they do it. I mean essentially full throttle recovery where the engine keeps running but there is significantly less power going to the wheels, which practically leads to “coasting” or slowing down due to air and friction forces. There will need to be a lot of full throttle recovery at the end of the straight, then maybe a brief bit of real LiCo, and then a very short braking zone. Point is the car will start slowing down quite drastically when the full throttle recovery starts, and by the time it’s actually time to hit the brakes, the car will be much slower than current gen.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 11 Oct 2025, 13:10
by Tommy Cookers
Badger wrote: ↑11 Oct 2025, 08:19
... the car will start slowing down quite drastically when the full throttle recovery starts ...
and by the time it’s actually time to hit the brakes, the car will be much slower than current gen....
HH Frenzen may have been the king of momentary 6g braking
2025 cars may be doing momentary 5g braking
2026 cars may do momentary 4g braking
but at WOT and 250 kW generation the 'slowing quite drastically' before braking will be maybe 0.1g
high aero DF yields momentary high deceleration (as one poster highlighted) ... but that promptly plummets
most of the braking time is (and always was) at lower speeds
just as people didn't register the momentary the 2026 braking won't be seen as (and won't be) 'much slower'
it's the qualities of the 2026 racing that they will register
btw & imo
re F1 'engine braking' - the induction air-related losses are maybe 3% but friction etc losses are maybe 12%
however they still downshift to keep revs high
re EB - it isn't recovery unless the heat caused by EB is turned into electrical or mechanical energy and so used
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 11 Oct 2025, 16:46
by diffuser
Tommy Cookers wrote: ↑11 Oct 2025, 13:10
Badger wrote: ↑11 Oct 2025, 08:19
... the car will start slowing down quite drastically when the full throttle recovery starts ...
and by the time it’s actually time to hit the brakes, the car will be much slower than current gen....
HH Frenzen may have been the king of momentary 6g braking
2025 cars may be doing momentary 5g braking
2026 cars may do momentary 4g braking
but at WOT and 250 kW generation the 'slowing quite drastically' before braking will be maybe 0.1g
high aero DF yields momentary high deceleration (as one poster highlighted) ... but that promptly plummets
most of the braking time is (and always was) at lower speeds
just as people didn't register the momentary the 2026 braking won't be seen as (and won't be) 'much slower'
it's the qualities of the 2026 racing that they will register
btw & imo
re F1 'engine braking' - the induction air-related losses are maybe 3% but friction etc losses are maybe 12%
however they still downshift to keep revs high
re EB - it isn't recovery unless the heat caused by EB is turned into electrical or mechanical energy and so used
3%? You ever try to suck air through a straw with and without you finger on the other end?
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 11 Oct 2025, 17:38
by Tommy Cookers
diffuser wrote: ↑11 Oct 2025, 16:46
Tommy Cookers wrote: ↑11 Oct 2025, 13:10
re F1 'engine braking' - the induction air-related losses are maybe 3% but friction etc losses are maybe 12%
however they still downshift to keep revs high
3%? You ever try to suck air through a straw with and without you finger on the other end?
the engine is a poor vacuum pump
it sucks for no more than half a rev then there's flow reversal due to valve overlap etc
the pressure difference isn't even 1 bar (ICE max bmep is 15 bar NA or more boosted)
hence the 3% of max power
the throttle is never fully closed
except eg if you put a gloved hand over the bellmouth of your motorcycle carburetor eg to unblock a jet
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 11 Oct 2025, 22:27
by saviour stivala
The throttle/s of a direct injected engine is/are fully closed at idle (throttle pedal not being pressed), and the engine relies on a bypass passage to allow the amount of air through to keep the engine running. This bypass insures the engine doesn't stall when the accelerator pedal is not pressed, an idle air control (iac) valve controls the engine at idle air needs for correct idle speed.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 11 Oct 2025, 23:57
by diffuser
Tommy Cookers wrote: ↑11 Oct 2025, 17:38
diffuser wrote: ↑11 Oct 2025, 16:46
Tommy Cookers wrote: ↑11 Oct 2025, 13:10
re F1 'engine braking' - the induction air-related losses are maybe 3% but friction etc losses are maybe 12%
however they still downshift to keep revs high
3%? You ever try to suck air through a straw with and without you finger on the other end?
the engine is a poor vacuum pump
it sucks for no more than half a rev then there's flow reversal due to valve overlap etc
the pressure difference isn't even 1 bar (ICE max bmep is 15 bar NA or more boosted)
hence the 3% of max power
the throttle is never fully closed
except eg if you put a gloved hand over the bellmouth of your motorcycle carburetor eg to unblock a jet
Ok....
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 14 Oct 2025, 04:37
by chipengineer
Quoted in the current Autosport, Brembo's Algeri says: "A light duty track in terms of torque, like Monaco or Singapore, will become quite strong for the brakes because you have a lot of time to recover energy and at a certain point the battery will be full, and then you have to use the brakes.
Is there any reason regen brake energy cannot be dumped to a resistive load cooled by the radiator when the battery is full?
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 14 Oct 2025, 14:21
by saviour stivala
Energy cannot be recovered beyond a certain threshold. The FIA has set limits on amount of energy that can be harvested as well as deployed per lap.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 14 Oct 2025, 15:02
by Ferry
The energy could be dumped in the electric motor instead of an external resistive load. Running the motor inefficiently should be easy, that's just a less than perfect drive modus. It's what Tesla is doing on passenger cars for heating the cabin or the battery. Circulating fluid to move the heat. Depends on the details of cooling capacity of the motor, I guess. No free lunch.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 14 Oct 2025, 15:58
by dren
chipengineer wrote: ↑14 Oct 2025, 04:37
Quoted in the current Autosport, Brembo's Algeri says: "A light duty track in terms of torque, like Monaco or Singapore, will become quite strong for the brakes because you have a lot of time to recover energy and at a certain point the battery will be full, and then you have to use the brakes.
Is there any reason regen brake energy cannot be dumped to a resistive load cooled by the radiator when the battery is full?
Not sure why you would ever get into a position where you have a full battery and need to continue to regen for braking/slowing the car. In order to regen, you have first had to accelerate meaning you'd be using the battery.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 14 Oct 2025, 16:14
by r85
How much could the new regs favor late or early brakers? As far as I know from our Formula Student car, longer and lighter braking is better for energy recovery while later and shorter braking is more reliant on the mechanical braking system but worse for recovery.