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Re: 2025/2026 Hybrid Powerunit speculation
Posted: 23 Nov 2025, 04:21
by wuzak
diffuser wrote: ↑23 Nov 2025, 03:07
mzso wrote: ↑23 Nov 2025, 02:22
diffuser wrote: ↑23 Nov 2025, 02:19
The positioning is VERY restrictive. What I remember reading... it just about sounded like "you got to put it here". The tank itself is a bladder so it grows and shrinks with the amount of fuel in it. It's tall and slender. Has multiple compartments with fuel being able to go down a compartment but not back up. It's probably been behind the driver for the last 30 years, if not more.
I meant package stuff around it when you need a larger size and different aero cover.
I think the space is made there as part of the frame, the ICE is part of the frame. It could only be changed at great cost.
https://miro.medium.com/v2/resize:fit:1 ... fiJXQ.jpeg
https://miro.medium.com/v2/resize:fit:1 ... KFUU3g.png
The fuel cell must be within the Survival Cell.
The ICE connects to the rear of the Survival Cell.
For 2026, the MGUK can be mounted on the ICE or the Survival Cell.
The ES must be within the Survival Cell.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 23 Nov 2025, 05:24
by saviour stivala
''For 2026, the MGU-K can be mounted on the ICE or the survival cell''. This quote is incorrect, The MGU-K is to be mounted 'within' the survival cell for 2026, not on the ICE or the survival cell. This change is a safety measure to insure all high voltage equipment is contained within the chassis. Also, In 2026 the MGU-K will be mounted on the crankshaft, which is part of the 'ICE', and is not an option to be mounted on the 'ICE'. The 2026 PU regulations place the MGU-K on the 'crankshaft' of the ICE, for safety reasons the MGU-K will therefore be 'inside' the survival cel, it is not an alternative to the crankshaft mounting, is not about mounting it separately in the survival cell, as an alternative to the crankshaft.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 23 Nov 2025, 08:35
by michl420
mzso wrote: ↑23 Nov 2025, 01:51
diffuser wrote: ↑13 Nov 2025, 21:30
Multiple tanks is not allowed. There isn't a limit in tank size in the new regs. Just a flow rate restriction. I think my math says 93L/hr ish. You can do the math for a 1.5hr race.
I wonder if it's viable to have different fuel tank sizes and variable packaging.
The fuel tank can be 90cm wide next year. It was 80 cm since forever (maybe 30 years).
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 23 Nov 2025, 15:01
by mzso
diffuser wrote: ↑23 Nov 2025, 03:07
I think the space is made there as part of the frame, the ICE is part of the frame. It could only be changed at great cost.
Sure, but I was thinking it could be smaller when not on a fuel demanding circuit. And parts can be moved there to make the car leaner or better balanced.
michl420 wrote: ↑23 Nov 2025, 08:35
The fuel tank can be 90cm wide next year. It was 80 cm since forever (maybe 30 years).
What does that correspond to? ~20 liter?
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 23 Nov 2025, 15:19
by mzso
wuzak wrote: ↑23 Nov 2025, 04:21
For 2026, the MGUK can be mounted on the ICE or the Survival Cell.
I wonder why they made this addition. What difference does it make?
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 23 Nov 2025, 16:03
by wuzak
mzso wrote: ↑23 Nov 2025, 15:19
wuzak wrote: ↑23 Nov 2025, 04:21
For 2026, the MGUK can be mounted on the ICE or the Survival Cell.
I wonder why they made this addition. What difference does it make?
It allows the MGUK to be moved further forwards for better weight balance.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 23 Nov 2025, 16:33
by michl420
mzso wrote: ↑23 Nov 2025, 15:01
diffuser wrote: ↑23 Nov 2025, 03:07
I think the space is made there as part of the frame, the ICE is part of the frame. It could only be changed at great cost.
Sure, but I was thinking it could be smaller when not on a fuel demanding circuit. And parts can be moved there to make the car leaner or better balanced.
michl420 wrote: ↑23 Nov 2025, 08:35
The fuel tank can be 90cm wide next year. It was 80 cm since forever (maybe 30 years).
What does that correspond to? ~20 liter?
I think they made this primary for the shorter cars. Nothing to do with fuel capacity.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 23 Nov 2025, 17:58
by saviour stivala
wuzak wrote: ↑23 Nov 2025, 04:13
saviour stivala wrote: ↑22 Nov 2025, 11:40
michl420 wrote: ↑22 Nov 2025, 08:46
As I understand this, this is a possible race start procedure?!:
1 red light: ice up to rpm (10500?)
2 red light: MGUK start regeneration with allowed power (200kw?, 350kw?), batterie must be not full
lights out: MGUK reduces regeneration like driver demand.
This would give full power very early, and a (mostly) electric controlled start (if it is desired).
This preload had also nothing to do with the driveshaft cluch, because ICE and MGUK are both located "before" it.
MGU-K regeneration is the process of recovering energy during braking. This process is not compatible with race start, which is about using energy not recovering it.
saviour stivala wrote: ↑22 Nov 2025, 18:07
The regulations will not allow the engine to be run as a generator in stationary mode. Running the engine as a generator is a form of energy recovery, but it can only happen while the car is in motion, not when the car is stationary.
Please explain the meaning of the following regulation:
C5.2.19 When the car is
stationary on the grid prior to a standing start the
MGU-K torque may only be negative (i.e. charging the ES) except for torque requested by an MGU-K active damping strategy whose sole purpose is to protect the MGU-K Mechanical Transmission.
C5.2.19 When car is .........MGU-K Torque may only be negative (i.e. charging the ES). Your interpretation, (i.e. charging the ES) Is incorrect. The regulations will not allow the engine to be run as a generator in stationary mode. And will also not allow MGU-K to start contributing to crankshaft until the car reaches a speed of 50km/h from stationary.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 23 Nov 2025, 22:18
by diffuser
mzso wrote: ↑23 Nov 2025, 15:01
diffuser wrote: ↑23 Nov 2025, 03:07
I think the space is made there as part of the frame, the ICE is part of the frame. It could only be changed at great cost.
Sure, but I was thinking it could be smaller when not on a fuel demanding circuit. And parts can be moved there to make the car leaner or better balanced.
michl420 wrote: ↑23 Nov 2025, 08:35
The fuel tank can be 90cm wide next year. It was 80 cm since forever (maybe 30 years).
What does that correspond to? ~20 liter?
There are several security requirements for the fuel tank in the regulations making it's placement fall in a hard to modify aera. Anyways they stick the tank right in the middle to avoid it causing balance issue as the fuel level changes.
There isn't a liters limit for the fuel tank. The limit is max flow. If the max flow over 2 hrs is 130 liters, it doesn't make much sense to making the tank 200 liters does it ? The max flow is measured in energy so depending on the amount of energy in the fuel, you'd can flow more or less fuel. If I remember correctly the RON had a min max of 95 -102. I think it was 92 liters in 1 hr at 102 Ron. You're not gonna be at full throttle for the full lap.....just to show you that the calculation gets quit involved.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 23 Nov 2025, 22:39
by quincalla
diffuser wrote: ↑23 Nov 2025, 22:18
mzso wrote: ↑23 Nov 2025, 15:01
diffuser wrote: ↑23 Nov 2025, 03:07
I think the space is made there as part of the frame, the ICE is part of the frame. It could only be changed at great cost.
Sure, but I was thinking it could be smaller when not on a fuel demanding circuit. And parts can be moved there to make the car leaner or better balanced.
michl420 wrote: ↑23 Nov 2025, 08:35
The fuel tank can be 90cm wide next year. It was 80 cm since forever (maybe 30 years).
What does that correspond to? ~20 liter?
There are several security requirements for the fuel tank in the regulations making it's placement fall in a hard to modify aera. Anyways they stick the tank right in the middle to avoid it causing balance issue as the fuel level changes.
There isn't a liters limit for the fuel tank. The limit is max flow. If the max flow over 2 hrs is 130 liters, it doesn't make much sense to making the tank 200 liters does it ? The max flow is measured in energy so depending on the amount of energy in the fuel, you'd can flow more or less fuel. If I remember correctly the RON had a min max of 95 -102. I think it was 92 liters in 1 hr at 102 Ron. You're not gonna be at full throttle for the full lap.....just to show you that the calculation gets quit involved.
Could that also be a performance differentiator? A more energy dense fuel allowing the car to be lighter on race day? Or is there some other fuel-related regulation that limits this?
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 23 Nov 2025, 23:36
by mzso
diffuser wrote: ↑23 Nov 2025, 22:18
mzso wrote: ↑23 Nov 2025, 15:01
diffuser wrote: ↑23 Nov 2025, 03:07
I think the space is made there as part of the frame, the ICE is part of the frame. It could only be changed at great cost.
Sure, but I was thinking it could be smaller when not on a fuel demanding circuit. And parts can be moved there to make the car leaner or better balanced.
michl420 wrote: ↑23 Nov 2025, 08:35
The fuel tank can be 90cm wide next year. It was 80 cm since forever (maybe 30 years).
What does that correspond to? ~20 liter?
There are several security requirements for the fuel tank in the regulations making it's placement fall in a hard to modify aera. Anyways they stick the tank right in the middle to avoid it causing balance issue as the fuel level changes.
There isn't a liters limit for the fuel tank. The limit is max flow. If the max flow over 2 hrs is 130 liters, it doesn't make much sense to making the tank 200 liters does it ? The max flow is measured in energy so depending on the amount of energy in the fuel, you'd can flow more or less fuel. If I remember correctly the RON had a min max of 95 -102. I think it was 92 liters in 1 hr at 102 Ron. You're not gonna be at full throttle for the full lap.....just to show you that the calculation gets quit involved.
There are dimension limits, right? So that corresponds to a max volume.
Anyway that's tangential. I was thinking most races might be ideal with let's say 95 liters or less, but for some it would be more advantageous to burn a lot of fuel rather than keep saving fuel, so you'd want 120 liters.
So in the first case they would have other parts above the fuel tank, and in the latter case they'd use a taller tank and move those parts elsewhere.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 24 Nov 2025, 01:13
by wuzak
quincalla wrote: ↑23 Nov 2025, 22:39
diffuser wrote: ↑23 Nov 2025, 22:18
mzso wrote: ↑23 Nov 2025, 15:01
Sure, but I was thinking it could be smaller when not on a fuel demanding circuit. And parts can be moved there to make the car leaner or better balanced.
What does that correspond to? ~20 liter?
There are several security requirements for the fuel tank in the regulations making it's placement fall in a hard to modify aera. Anyways they stick the tank right in the middle to avoid it causing balance issue as the fuel level changes.
There isn't a liters limit for the fuel tank. The limit is max flow. If the max flow over 2 hrs is 130 liters, it doesn't make much sense to making the tank 200 liters does it ? The max flow is measured in energy so depending on the amount of energy in the fuel, you'd can flow more or less fuel. If I remember correctly the RON had a min max of 95 -102. I think it was 92 liters in 1 hr at 102 Ron. You're not gonna be at full throttle for the full lap.....just to show you that the calculation gets quit involved.
Could that also be a performance differentiator? A more energy dense fuel allowing the car to be lighter on race day? Or is there some other fuel-related regulation that limits this?
Fuel energy density must be between 38.0 MJ/kg and 41.0 MJ/kg. That's about 8% difference, so teh weight difference will be significant.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 24 Nov 2025, 02:53
by diffuser
mzso wrote: ↑23 Nov 2025, 23:36
diffuser wrote: ↑23 Nov 2025, 22:18
mzso wrote: ↑23 Nov 2025, 15:01
Sure, but I was thinking it could be smaller when not on a fuel demanding circuit. And parts can be moved there to make the car leaner or better balanced.
What does that correspond to? ~20 liter?
There are several security requirements for the fuel tank in the regulations making it's placement fall in a hard to modify aera. Anyways they stick the tank right in the middle to avoid it causing balance issue as the fuel level changes.
There isn't a liters limit for the fuel tank. The limit is max flow. If the max flow over 2 hrs is 130 liters, it doesn't make much sense to making the tank 200 liters does it ? The max flow is measured in energy so depending on the amount of energy in the fuel, you'd can flow more or less fuel. If I remember correctly the RON had a min max of 95 -102. I think it was 92 liters in 1 hr at 102 Ron. You're not gonna be at full throttle for the full lap.....just to show you that the calculation gets quit involved.
There are dimension limits, right? So that corresponds to a max volume.
Anyway that's tangential. I was thinking most races might be ideal with let's say 95 liters or less, but for some it would be more advantageous to burn a lot of fuel rather than keep saving fuel, so you'd want 120 liters.
So in the first case they would have other parts above the fuel tank, and in the latter case they'd use a taller tank and move those parts elsewhere.
Don't forget when power demand falls bellow the need for electrical power + enough to start charging the battery, the ICE will start charging the battery. It will use more fuel to do that. So there will be plenty of scenarios in 2026 when the ICE will have demand unrelated to the drivers power requests, where a 2025 ICE would be using less fuel. That how the 2026 PU will make up for the removal of the MGU-H.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 24 Nov 2025, 03:50
by gruntguru
saviour stivala wrote: ↑22 Nov 2025, 18:07
IN MY HUMBLE OPINION the regulations will not allow the engine to be run as a generator in stationary mode. Running the engine as a generator is a form of energy recovery, but it can only happen while the car is in motion, not when the car is stationary.
Re: 2025/2026 Hybrid Powerunit speculation
Posted: 24 Nov 2025, 03:57
by diffuser
gruntguru wrote: ↑24 Nov 2025, 03:50
saviour stivala wrote: ↑22 Nov 2025, 18:07
IN MY HUMBLE OPINION the regulations will not allow the engine to be run as a generator in stationary mode. Running the engine as a generator is a form of energy recovery, but it can only happen while the car is in motion, not when the car is stationary.
Is this statement in reference to my post? I don't think anyone is really concerned with that ...The only time a F1 car is stationary is at the start of the race and in the pit box. Going in and out of the pits it will be charging the battery, if it isn't full. Well, unless there is some rule I haven't heard of that prevents it. It will charge the battery under Saftey car and VSC conditions. etc etc etc .