2025/2026 Hybrid Powerunit speculation

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
wuzak
wuzak
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Joined: 30 Aug 2011, 03:26

Re: 2025/2026 Hybrid Powerunit speculation

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Depending on track, and the availability of braking energy recovery, the amount of fuel required for fuel burning is around 10kg - 12kg.

Say that the energy density is 41MJ/kg, the ICE efficiency is 48%, and the extra energy required by fuel burning is 4MJ (ie 4.5MJ from braking/lift-and-coast).

Fuel energy required is 4MJ/48% = 8.3MJ.
8.3MJ/(41MJ/kg) = 0.2033kg/lap.

Most races fall in the 50-60 lap range.

Extra fuel:
50 * 0.2033 = 10.2kg
60 * 0.2033 = 12.2kg

There may be a balance point where recovering extra energy per lap (up to the maximum) costs more in lap time than the extra energy deployment gains.

With the slightly lower minimum weight, I expect that the lap times will be more sensative to extra weight than in the last rule set.

The 2025 rules did not have a race fuel maximum usage. And the 2026 rules also don't have this limit.

I'd suggest that 85-90kg is more likely than 100kg.

This is based on 3000MJ for the race (2014-2016 rules had 100kg/h and 100kg race fuel), fuel energy density near the maximum (41MJ/kg) and the above calculation for extra fuel required.

3000MJ/(41MJ/kg) = 73.2kg.

73.2kg + 10.2kg = 83.4kg
73.2kg + 12.2kg = 85.4kg

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FW17
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Joined: 06 Jan 2010, 10:56

Re: 2025/2026 Hybrid Powerunit speculation

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wuzak wrote:
25 Jan 2026, 04:35


Fuel energy required is 4MJ/48% = 8.3MJ.
8.3MJ/(41MJ/kg) = 0.2033kg/lap.

Most races fall in the 50-60 lap range.

Extra fuel:
50 * 0.2033 = 10.2kg
60 * 0.2033 = 12.2kg

That is 14 sec for a 100 sec lap (50 lap race), 73 kg fuel, 1.4 kg per lap
and 13 sec for a 80 sec lap (60 lap race) 73 kg fuel, 1.2 kg per lap

Even a third of it seems excessive lift and coast for each lap

wuzak
wuzak
522
Joined: 30 Aug 2011, 03:26

Re: 2025/2026 Hybrid Powerunit speculation

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FW17 wrote:
25 Jan 2026, 05:41
wuzak wrote:
25 Jan 2026, 04:35


Fuel energy required is 4MJ/48% = 8.3MJ.
8.3MJ/(41MJ/kg) = 0.2033kg/lap.

Most races fall in the 50-60 lap range.

Extra fuel:
50 * 0.2033 = 10.2kg
60 * 0.2033 = 12.2kg

That is 14 sec for a 100 sec lap (50 lap race), 73 kg fuel, 1.4 kg per lap
and 13 sec for a 80 sec lap (60 lap race) 73 kg fuel, 1.2 kg per lap

Even a third of it seems excessive lift and coast for each lap
It does.

But it also includes part throttle and full throttle recovery.

Also, lift-and-coast isn't burning fuel to generate power.

4MJ is, likely, at the higher end of energy required for fuel burning.