2025/2026 Hybrid Powerunit speculation

[saviour stivala]

Energy harvested above the 4mj energy store (ES) state of charge (SOC) limit is dissipated as heat because the system cannot store it. Managing energy deployment and recovery throughout the race is going to be critical.

[wuzak]

If they add a generator on the front axle for 2026, how will this affect the racing?

Also, what would happen if they’re allowed to harvest more energy per lap? With or without the front generator

Harevsting the energy allowed will be difficult and require burning extra fuel to achieve it.

Harvesting more would likely require a larger, and heavier, battery.

I've said it before, I don't think front harvesting will help much, unless the total recovery power is much greater.

And it doesn't help with the deployment if the front MGU also deploys.
You would still run out of energy quickly.

[saviour stivala]

Braking will be the only way to recover energy in 2026. The battery (ES) can only be charged by braking. But the brakes will not be the only way to slow down the car.

[DenBommer]

If they add a generator on the front axle for 2026, how will this affect the racing?

Also, what would happen if they’re allowed to harvest more energy per lap? With or without the front generator

Harevsting the energy allowed will be difficult and require burning extra fuel to achieve it.

Harvesting more would likely require a larger, and heavier, battery.

I've said it before, I don't think front harvesting will help much, unless the total recovery power is much greater.

And it doesn't help with the deployment if the front MGU also deploys.
You would still run out of energy quickly.

So, is a front generator just not a good idea? especially considering they want the cars to be smaller and lighter?

[wuzak]

If they add a generator on the front axle for 2026, how will this affect the racing?

Also, what would happen if they’re allowed to harvest more energy per lap? With or without the front generator

Harevsting the energy allowed will be difficult and require burning extra fuel to achieve it.

Harvesting more would likely require a larger, and heavier, battery.

I've said it before, I don't think front harvesting will help much, unless the total recovery power is much greater.

And it doesn't help with the deployment if the front MGU also deploys.
You would still run out of energy quickly.

So, is a front generator just not a good idea? especially considering they want the cars to be smaller and lighter?

A front generator certainly wouldn't help the quest for lightness.

[wuzak]

Braking will be the only way to recover energy in 2026. The battery (ES) can only be charged by braking. But the brakes will not be the only way to slow down the car.

The battery can be charged:

• During braking (driver uses brake pedal)
• Under Full Throttle - at the end of maximum power demand sections, ie straights, the MGUK output can be reduced up to 600kW, down to -250kW. That is, up to 250kW can begenerated when the driver is at full throttle. This will slow the car by a small amount.
• Under Part Throttle - when the power demand is less than the ICE can produce, the MGUK can be used to generate some power. Thsi could slow the car, or be at a steady speed, or under acceleration (in traction zones, for example).
• Lift and Coast - Driver lifts off the throttle early to allow the car to coast to the corner, using the aero to slow the car. The MGUK may also be used to generate some power and slow the car more.

Only in the first is the driver actively braking, the last is also used to slow the car, mainly for fuel saving and prtecting the brakes. The second will slow the car, but that is not the purpose of doing it.

[saviour stivala]

No, The MGU-K in 2026 F1 cars will not be harvesting energy under full throttle at the end of a straight. When driver is still at full throttle, the car is still accelerating, when the car is accelerating, at whatever the throttle position is/at whatever amount of throttle the driver is using, the MGU-K will not harvest energy.

[diffuser]

Braking will be the only way to recover energy in 2026. The battery (ES) can only be charged by braking. But the brakes will not be the only way to slow down the car.

The battery can be charged:

• During braking (driver uses brake pedal)
• Under Full Throttle - at the end of maximum power demand sections, ie straights, the MGUK output can be reduced up to 600kW, down to -250kW. That is, up to 250kW can begenerated when the driver is at full throttle. This will slow the car by a small amount.
• Under Part Throttle - when the power demand is less than the ICE can produce, the MGUK can be used to generate some power. Thsi could slow the car, or be at a steady speed, or under acceleration (in traction zones, for example).
• Lift and Coast - Driver lifts off the throttle early to allow the car to coast to the corner, using the aero to slow the car. The MGUK may also be used to generate some power and slow the car more.

Only in the first is the driver actively braking, the last is also used to slow the car, mainly for fuel saving and prtecting the brakes. The second will slow the car, but that is not the purpose of doing it.

Excellent post .... I would have written slightly different but excellent none the less.

The battery can be charged in the following scenarios:

During braking – When the driver uses the brake pedal, the MGUK (Motor Generator Unit - Kinetic) can harvest energy.

Under full throttle – At the end of maximum power demand sections (e.g. straights), the MGUK output can be reduced from up to +600 kW to as low as -250 kW. In this mode, up to 250 kW can be generated even when the driver is at full throttle. This process slightly slows the car.

Under part throttle – When power demand is less than what the internal combustion engine (ICE) can provide, the MGUK can be used to generate energy. This may slow the car, keep it at a steady speed, or even allow for light acceleration (e.g. in traction zones).

Lift and coast – The driver lifts off the throttle early, allowing the car to coast into a corner while using aerodynamic drag to decelerate. The MGUK may also be used to generate energy and provide additional slowing.

Notes:

Only in the first scenario is the driver actively braking.

The "lift and coast" technique is mainly used for fuel saving, reducing tire wear, and protecting the brakes, though it also slows the car.

In the second scenario (full throttle charging), the car is slowed as a side effect, but that is not the primary intention.

[saviour stivala]

At end of a straight, an F1 car throttle position will be at or near 100% until the driver begins to brake. While the car is at full throttle, it will be accelerating or trying to maintain top speed. The MGU-K harvests energy during deceleration not while driver is at full throttled. When a driver is at full throttle, the MGU-K is in 'motor' mode, not in harvesting mode.

[wuzak]

Braking will be the only way to recover energy in 2026. The battery (ES) can only be charged by braking. But the brakes will not be the only way to slow down the car.

The battery can be charged:

• During braking (driver uses brake pedal)
• Under Full Throttle - at the end of maximum power demand sections, ie straights, the MGUK output can be reduced up to 600kW, down to -250kW. That is, up to 250kW can begenerated when the driver is at full throttle. This will slow the car by a small amount.
• Under Part Throttle - when the power demand is less than the ICE can produce, the MGUK can be used to generate some power. Thsi could slow the car, or be at a steady speed, or under acceleration (in traction zones, for example).
• Lift and Coast - Driver lifts off the throttle early to allow the car to coast to the corner, using the aero to slow the car. The MGUK may also be used to generate some power and slow the car more.

Only in the first is the driver actively braking, the last is also used to slow the car, mainly for fuel saving and prtecting the brakes. The second will slow the car, but that is not the purpose of doing it.

Excellent post .... I would have written slightly different but excellent none the less.

The battery can be charged in the following scenarios:

During braking – When the driver uses the brake pedal, the MGUK (Motor Generator Unit - Kinetic) can harvest energy.

Under full throttle – At the end of maximum power demand sections (e.g. straights), the MGUK output can be reduced from up to +600 kW to as low as -250 kW. In this mode, up to 250 kW can be generated even when the driver is at full throttle. This process slightly slows the car.

Under part throttle – When power demand is less than what the internal combustion engine (ICE) can provide, the MGUK can be used to generate energy. This may slow the car, keep it at a steady speed, or even allow for light acceleration (e.g. in traction zones).

Lift and coast – The driver lifts off the throttle early, allowing the car to coast into a corner while using aerodynamic drag to decelerate. The MGUK may also be used to generate energy and provide additional slowing.

Notes:

Only in the first scenario is the driver actively braking.

The "lift and coast" technique is mainly used for fuel saving, reducing tire wear, and protecting the brakes, though it also slows the car.

In the second scenario (full throttle charging), the car is slowed as a side effect, but that is not the primary intention.

Thanks, that is clearer.

[Tommy Cookers]

Under full throttle – At the end of maximum power demand sections (e.g. straights), the MGUK output can be reduced from up to +600 kW to as low as -250 kW.

well no it can't ....
the MGU-K output can't ever be 600 kW
the MGU-K output cannot exceed 350 kW

the MGU-K output swings by 600 kW in going from 350 kW motor action (+350 kW) to 250 kW generating action (-250 kW)

[Mattchu]

Braking will be the only way to recover energy in 2026. The battery (ES) can only be charged by braking. But the brakes will not be the only way to slow down the car.

Why do keep repeating this when its been shown by many to be complete horseshit!

The car can harvest electrical energy without the brake pedal being touched. The teams do it now, this from Honda:

Looking at MGU-K and MGU-H usage by driving situation, the MGU-K is fully used during deceleration to recover kinetic energy, while the MGU-H is used to recover energy at the same time. What this specifically means is that exhaust temperature is intentionally allowed to increase when off-throttle to allow recovery of the heat energy from the exhaust gas and storage in the ES. The team developing this control technology have termed it Additional Harvest Power, or AHP.

Under partial throttle when starting to exit a corner, a different control technology called partial recovery is employed. It is used to generate electricity by diverting excess output to the MGU-K after the engine generates enough output to meet the driver’s needs. Both AHP and partial recovery consume extra fuel, but this control technology was planned and implemented because increasing energy recovery and storing it in the ES to increase the amount of energy used for MGU-K assist achieves a greater performance gain than what could be achieved through fuel consumption alone.

https://global.honda/en/tech/motorsport ... train_ESS/

Great posts by wuzak and diffuser explain it very well...

[diffuser]

Under full throttle – At the end of maximum power demand sections (e.g. straights), the MGUK output can be reduced from up to +600 kW to as low as -250 kW.

well no it can't ....
the MGU-K output can't ever be 600 kW
the MGU-K output cannot exceed 350 kW

the MGU-K output swings by 600 kW in going from 350 kW motor action (+350 kW) to 250 kW generating action (-250 kW)

Thanks for that correction Tommy.

The battery can be charged in the following scenarios:

During braking – When the driver uses the brake pedal, the MGUK (Motor Generator Unit - Kinetic) can harvest energy.

Under full throttle – At the end of maximum power demand sections (e.g. straights), the MGU-K output can be reduced by up to 600 kW From 350 to as low as -250 kW. In this mode, up to 250 kW can be generated even when the driver is at full throttle. This process slightly slows the car.

Under part throttle – When power demand is less than what the internal combustion engine (ICE) can provide, the MGUK can be used to generate energy. This may slow the car, keep it at a steady speed, or even allow for light acceleration (e.g. in traction zones).

Lift and coast – The driver lifts off the throttle early, allowing the car to coast into a corner while using aerodynamic drag to decelerate. The MGUK may also be used to generate energy and provide additional slowing.

Notes:
-Only in the first scenario(During braking) is the driver actively braking.
-The "lift and coast" technique is mainly used for fuel saving, reducing tire wear, and protecting the brakes, though it also slows the car.
- In the second scenario (full throttle charging), the car is slowed as a side effect, but that is not the primary intention.

[saviour stivala]

Braking will be the only way to recover energy in 2026. The battery (ES) can only be charged by braking. But the brakes will not be the only way to slow down the car.

Why do keep repeating this when its been shown by many to be complete horseshit!

The car can harvest electrical energy without the brake pedal being touched. The teams do it now, this from Honda:

Looking at MGU-K and MGU-H usage by driving situation, the MGU-K is fully used during deceleration to recover kinetic energy, while the MGU-H is used to recover energy at the same time. What this specifically means is that exhaust temperature is intentionally allowed to increase when off-throttle to allow recovery of the heat energy from the exhaust gas and storage in the ES. The team developing this control technology have termed it Additional Harvest Power, or AHP.

Under partial throttle when starting to exit a corner, a different control technology called partial recovery is employed. It is used to generate electricity by diverting excess output to the MGU-K after the engine generates enough output to meet the driver’s needs. Both AHP and partial recovery consume extra fuel, but this control technology was planned and implemented because increasing energy recovery and storing it in the ES to increase the amount of energy used for MGU-K assist achieves a greater performance gain than what could be achieved through fuel consumption alone.

https://global.honda/en/tech/motorsport ... train_ESS/

Great posts by wuzak and diffuser explain it very well...

Regardless your choice of term (horseshit), I stand with what I wrote. As to the rest of your post, it does not concern the 2026 system. The posts by wuzak and diffuser, contrary to what you claim does not convince me otherwise, because I believe solidly that the 2026 MGU-K would only be able to deploy energy when car is accelerating, and it would only be able to harvest energy when the car is decelerating.

[DenBommer]

Harevsting the energy allowed will be difficult and require burning extra fuel to achieve it.

Harvesting more would likely require a larger, and heavier, battery.

I've said it before, I don't think front harvesting will help much, unless the total recovery power is much greater.

And it doesn't help with the deployment if the front MGU also deploys.
You would still run out of energy quickly.

So, is a front generator just not a good idea? especially considering they want the cars to be smaller and lighter?

A front generator certainly wouldn't help the quest for lightness.

But could a front generator make the front brakes smaller and lighter?

I know they’re already lightweight, but maybe you could make other parts in the wheel lighter too?

Look at what YASA just achieved. though that’s still in lab conditions. And for a few seconds

https://www.carscoops.com/2025/10/merce ... r-1000-hp/