2025/2026 Hybrid Powerunit speculation

[dren]

What's typical brake bias with the cars now? I'd assume they'll be shifting that further rear which will be interesting.

[wuzak]

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.

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.

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.

[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.

[Badger]

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.

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.

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.

[Tommy Cookers]

... 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

[diffuser]

... 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?

[Tommy Cookers]

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

[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.

[diffuser]

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....