2025/2026 Hybrid Powerunit speculation

[MtthsMlw]

Does anybody understand the new "boost mode" and "overtake mode" terminology? What's the difference between those modes (apart from overtake activation limited to being within 1 sec).

I've read a few different articles and am struggling...

Boost Mode

What it is: A driver-operated energy deployment tool drawn from the Energy Recovery System (ERS).

How it works: At the push of a button, drivers can access maximum combined power from the engine and battery -- anywhere on track. It can be used offensively to attack or defensively to protect position.

Why it matters: Boost Mode puts control firmly in the driver's hands and adds a new layer of racecraft, particularly in wheel-to-wheel battles.

Overtake Mode

What it is: Overtake Mode replaces the Drag Reduction System (DRS), which had been used since 2011, as the primary passing aid. It was previously known in the regulations as Manual Override Mode.

How it works: When a driver is within one second of the car ahead, they can deploy extra power to help initiate an overtake. Unlike DRS, which was tied to specific zones, Overtake Mode can be used strategically -- either all at once or spread across a lap.

Why it matters: Passing becomes less automatic and more tactical. Drivers must decide when to attack, not simply wait for a detection line.

https://www.espn.co.uk/f1/story/_/id/47 ... ions-rules

Stumbled over this too. I found an explanation of the overtake mode on the FIA website:

When drivers are within a second of the car in front at activation points, they will be able to deploy additional power energy to try to pass, with an extra +0.5MJ of extra energy available. The chances of an overtake occurring will also be increased by the leading car’s energy deployment tapering off after 290km/h, while the car behind can use the override for a full 350kW up to 337km/h. The speed differential should help make passing moves possible.

So boost and overtake give the same power (in kW) but overtake holds this for a longer.
https://www.fia.com/news/f1s-new-era-ev ... itive-more

[karana]

Does anybody understand the new "boost mode" and "overtake mode" terminology? What's the difference between those modes (apart from overtake activation limited to being within 1 sec).

I've read a few different articles and am struggling...

Boost Mode

What it is: A driver-operated energy deployment tool drawn from the Energy Recovery System (ERS).

How it works: At the push of a button, drivers can access maximum combined power from the engine and battery -- anywhere on track. It can be used offensively to attack or defensively to protect position.

Why it matters: Boost Mode puts control firmly in the driver's hands and adds a new layer of racecraft, particularly in wheel-to-wheel battles.

Overtake Mode

What it is: Overtake Mode replaces the Drag Reduction System (DRS), which had been used since 2011, as the primary passing aid. It was previously known in the regulations as Manual Override Mode.

How it works: When a driver is within one second of the car ahead, they can deploy extra power to help initiate an overtake. Unlike DRS, which was tied to specific zones, Overtake Mode can be used strategically -- either all at once or spread across a lap.

Why it matters: Passing becomes less automatic and more tactical. Drivers must decide when to attack, not simply wait for a detection line.

https://www.espn.co.uk/f1/story/_/id/47 ... ions-rules

My guess is the boost mode will be what in past was known as "overtake button" with basically the same functionality as in that it provides full power even when the ECU would reduce the output as part of the deployment strategy.

There might be possibly a rule change allowing to increase driver maximum power demand when using this mode, currently this is only allowed in overtake mode.

But it will still only be full power depending on car speed, so still lower than overtake mode above 290kph.

[BorisTheBlade]

This should put the whole "recovery is only allowed under braking" shenanigans to rest. It also makes clear, that "super clipping" will be preferable over "lift and coast".

Recharge
Cars will harvest energy to charge the battery when braking, on part throttle, when lifting off (when a driver lifts off the throttle early – often referred to as lift and coast) or when ‘super clipping’ (when some harvesting happens at the end of the straight when a car is still at full throttle – although this depends on the particular engine map being used, the circuit profile, and the overall Recharge energy allowance for that circuit, which varies as per the regulations).

Most of the time, the Recharge will be automated by use of selectable Recharge maps and targets so braking, part throttle and super clip will all be automated functions controlled by the ECU. The only Recharge mode the driver will have direct control of will be lift-off regen, whereby if the driver lifts off, then they can Recharge. However, doing this will disable the Active devices as well. In contrast, super clipping is still at full throttle and therefore the Active Aero will still be ‘open’.

https://www.formula1.com/en/latest/arti ... cIpGzoWkY0

[BorisTheBlade]

Some sepculation about how this all might influence racecraft:

At most circuits, they will not be able to recover the maximum allowed energy per lap by braking and partial throttle alone. In order to achieve that - and to maximize the usage of the "boost mode" - it will be required to make significant use of "super-clipping". Think of around 10s on a track such as Barcelona, to be spread over several "ends-of-straights".

This quite likely means, that in order to optimize lap-time, they will have to sacrifice top speed on certain straights when in clean air.
So when a driver comes under pressure from behind, he might be forced to reduce his "super-clipping" in order to stay in front. But that in turn will allow the following driver to build an ever increasing energy differential, allowing him to use more "boost mode" and/or the "overtake mode".

I think, this will allow for more overtakes, as the base-performance differential between two cars can be lower than today. Or the tire differential.
It is even possible, that situations arise, where the leading car might let itself get overtaken and stay behind for some laps, in order to gain an advantage later on.

Either way: This will add new strategical layers. In order to not confuse viewers, some visualizations will be needed. At least the current ES SOC and indicators for recovery as well as deployment for dog-fighting cars will be needed. And this can also spark additional excitement, seing how the following car builds up its ES SOC differential.

[peewon]

Some sepculation about how this all might influence racecraft:

At most circuits, they will not be able to recover the maximum allowed energy per lap by braking and partial throttle alone. In order to achieve that - and to maximize the usage of the "boost mode" - it will be required to make significant use of "super-clipping". Think of around 10s on a track such as Barcelona, to be spread over several "ends-of-straights".

This quite likely means, that in order to optimize lap-time, they will have to sacrifice top speed on certain straights when in clean air.
So when a driver comes under pressure from behind, he might be forced to reduce his "super-clipping" in order to stay in front. But that in turn will allow the following driver to build an ever increasing energy differential, allowing him to use more "boost mode" and/or the "overtake mode".

I think, this will allow for more overtakes, as the base-performance differential between two cars can be lower than today. Or the tire differential.
It is even possible, that situations arise, where the leading car might let itself get overtaken and stay behind for some laps, in order to gain an advantage later on.

Either way: This will add new strategical layers. In order to not confuse viewers, some visualizations will be needed. At least the current ES SOC and indicators for recovery as well as deployment for dog-fighting cars will be needed. And this can also spark additional excitement, seing how the following car builds up its ES SOC differential.

I'd like to know what the general opinion is on this type of racing is. Sounds to me that most overtakes will be 'artificial' and tactical rather than pure wheel to wheel racing skill.

[vas_04614]

Reading that samsung is coming out with silver solid state battery. Looks like lot happening in this area. May be we can expect some surprises by 2026 F1 PU's also in this area.

[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)

I very much doubt that it is this crude. I think it works as a proper brake, modulated by the brake pedal, and preferentially applied of course.

I don't see a reason for changing what they are currently doing. The harder you press the brake the quicker the car stops. Obviously it will brake as much as it can with the MGU-K first. Then when the pressure exceeds the amount the MGU-K can stop, the disks will start to apply. Over and above that you have some manual way to adjust the brake bias from front to back or vise versa.

Just so I understand you guys clearly, are you saying that 'pedal travel/pressure based' modulation of rate of energy recovery from MGU-K (instead of just 'steps' based on static selection) existed right from 2014 itself ?

[wuzak]

I don't get "boost" mode?

Surely the maximum MGUK will be given when the driver is at full throttle and energy levels allow it?

[karana]

I don't get "boost" mode?

Surely the maximum MGUK will be given when the driver is at full throttle and energy levels allow it?

Well, the ECU will reduce MGU-K output at the end of straights even if it isn't strictly necessary to have more battery left for the rest of the lap. The boost button likely allows the driver to override that (as long there is still enough battery left), which is to my understanding exactly what the overtake button in the last few years was doing.

[diffuser]

I very much doubt that it is this crude. I think it works as a proper brake, modulated by the brake pedal, and preferentially applied of course.

I don't see a reason for changing what they are currently doing. The harder you press the brake the quicker the car stops. Obviously it will brake as much as it can with the MGU-K first. Then when the pressure exceeds the amount the MGU-K can stop, the disks will start to apply. Over and above that you have some manual way to adjust the brake bias from front to back or vise versa.

Just so I understand you guys clearly, are you saying that 'pedal travel/pressure based' modulation of rate of energy recovery from MGU-K (instead of just 'steps' based on static selection) existed right from 2014 itself ?

It's probably improved alot since 2014 but the MGU-K has been there since 2014, it will just be more powerful in 2026. I presume that means just software tweaking for the current PU manufactures (Honda, Merc, Ferrari). The others RBR AUDI and Cadillac(when it introduce their PU) will have to write all that software from scratch.

[diffuser]

I don't get "boost" mode?

Surely the maximum MGUK will be given when the driver is at full throttle and energy levels allow it?

Well, the ECU will reduce MGU-K output at the end of straights even if it isn't strictly necessary to have more battery left for the rest of the lap. The boost button likely allows the driver to override that (as long there is still enough battery left), which is to my understanding exactly what the overtake button in the last few years was doing.

One of the criterial for "allowed" MGU-K boost is speed of the car. Remember the 2026 cars don't have a beam wing, have the ability to flatten/DRS both the front and rear wings. If the didn't curtail the MGU-K boost, they'd probably go well over 400KPH! Every race is gonna be with less than Mexico like drag when the wings are flattened. They'd also probably run out of battery more often.

[vorticism]

Regarding battery tech posted here and elsewhere: The pack weight and capacities are regulated so the ES performance differentiation should presumably arrive via durability & cost (budget cap) unless the minimum pack weight and maximum charge/discharge rates are hard to achieve.

Minimum ES weight
2025: 20kg
2026: 35kg

ES usable capacity/lap
2025: 1.1kWh
2026: 1.1kWh

ES total recharge/lap via MGUK
2025: 0.6kWh + unregulated MGUH recharge
2026: 2.5kWh

ES total discharge/lap
2025: 1.1kWh
2026: unregulated

ES mass increase: 75%
ES max recharge/lap increase: 125%
ES max deployment increase: infinite (1.1kWh to the now unlimited amount)

It’s a larger pack put through greater charge-discharge cycles per lap, although the increases are not numerically identical. Solving for the lattermost figures above may be where any development race occurs. Max total discharge/lap is not regulated but the total recharge/lap is, so that is the primary confine. It will allow a difference between max recharge and what the driver chooses to deploy, as some here have alluded to. As it relates to this post, that extra discharge relative to the peak recharge rate may be another development differentiator.

[dren]

I don't see a reason for changing what they are currently doing. The harder you press the brake the quicker the car stops. Obviously it will brake as much as it can with the MGU-K first. Then when the pressure exceeds the amount the MGU-K can stop, the disks will start to apply. Over and above that you have some manual way to adjust the brake bias from front to back or vise versa.

Just so I understand you guys clearly, are you saying that 'pedal travel/pressure based' modulation of rate of energy recovery from MGU-K (instead of just 'steps' based on static selection) existed right from 2014 itself ?

It's probably improved alot since 2014 but the MGU-K has been there since 2014, it will just be more powerful in 2026. I presume that means just software tweaking for the current PU manufactures (Honda, Merc, Ferrari). The others RBR AUDI and Cadillac(when it introduce their PU) will have to write all that software from scratch.

I was under the assumption some were doing it even back in the KERS days.

[diffuser]

Regarding battery tech posted here and elsewhere: The pack weight and capacities are regulated so the ES performance differentiation should presumably arrive via durability & cost (budget cap) unless the minimum pack weight and maximum charge/discharge rates are hard to achieve.

Minimum ES weight
2025: 20kg
2026: 35kg

ES usable capacity/lap
2025: 1.1kWh
2026: 1.1kWh

ES total recharge/lap via MGUK
2025: 0.6kWh + unregulated MGUH recharge
2026: 2.5kWh

ES total discharge/lap
2025: 1.1kWh
2026: unregulated

ES mass increase: 75%
ES max recharge/lap increase: 125%
ES max deployment increase: infinite (1.1kWh to the now unlimited amount)

It’s a larger pack put through greater charge-discharge cycles per lap, although the increases are not numerically identical. Solving for the lattermost figures above may be where any development race occurs. Max total discharge/lap is not regulated but the total recharge/lap is, so that is the primary confine. It will allow a difference between max recharge and what the driver chooses to deploy, as some here have alluded to. As it relates to this post, that extra discharge relative to the peak recharge rate may be another development differentiator.

Kind of sad ....

Energy density Wh/kg.

Given Energy capacity: 4 MJ
Battery mass: 35 kg

Convert MJ → Wh

4MJ = 4,000,000J
1Wh = 3,600J
4,000,000÷3,600=1,111Wh

Energy density
1,111Wh ÷ 35kg = 31.7Wh/kg

If we look at the batteries for the Audi e-tron S6, the energy density of those batteries are 130 or 135Wh/kg. FIA aren't asking for cutting edge of battery technology.


If my calculations are right, they could have made the min battery weight easily 10KG.



hmmm but the F1 Batteries can be discharged over two times per lap (9MJ charge limit per lap) so maybe that's playing into it. Don't think you could do that with the AUDI e-tron batteries.

[karana]

Regarding battery tech posted here and elsewhere: The pack weight and capacities are regulated so the ES performance differentiation should presumably arrive via durability & cost (budget cap) unless the minimum pack weight and maximum charge/discharge rates are hard to achieve.

Minimum ES weight
2025: 20kg
2026: 35kg

ES usable capacity/lap
2025: 1.1kWh
2026: 1.1kWh

ES total recharge/lap via MGUK
2025: 0.6kWh + unregulated MGUH recharge
2026: 2.5kWh

ES total discharge/lap
2025: 1.1kWh
2026: unregulated

ES mass increase: 75%
ES max recharge/lap increase: 125%
ES max deployment increase: infinite (1.1kWh to the now unlimited amount)

It’s a larger pack put through greater charge-discharge cycles per lap, although the increases are not numerically identical. Solving for the lattermost figures above may be where any development race occurs. Max total discharge/lap is not regulated but the total recharge/lap is, so that is the primary confine. It will allow a difference between max recharge and what the driver chooses to deploy, as some here have alluded to. As it relates to this post, that extra discharge relative to the peak recharge rate may be another development differentiator.

Kind of sad ....

Energy density Wh/kg.

Given Energy capacity: 4 MJ
Battery mass: 35 kg

Convert MJ → Wh

4MJ = 4,000,000J
1Wh = 3,600J
4,000,000÷3,600=1,111Wh

Energy density
1,111Wh ÷ 35kg = 31.7Wh/kg

If we look at the batteries for the Audi e-tron S6, the energy density of those batteries are 130 or 135Wh/kg. FIA aren't asking for cutting edge of battery technology.


If my calculations are right, they could have made the min battery weight easily 10KG.



hmmm but the F1 Batteries can be discharged over two times per lap (9MJ charge limit per lap) so maybe that's playing into it. Don't think you could do that with the AUDI e-tron batteries.

One thing to keep in mind is that the battery capacity is likely higher than 4MJ, only the difference in SOC must be at most 4MJ. I think I remember there being discussions about this somewhere on this forum.

Also, the 35kg applies to the entire ES main enclosure, not just the ES itself. The ES main enclosure in the old regulations had a minimum weight of 31kg.