2026 Hybrid Powerunits

[AR3-GP]

During the last test, I noticed drivers experimenting with different ways to open their hot laps. They would drive at 50-60% throttle out of the last corner, and only go full throttle near the finish line. This "method" is focused on setting up for a hot lap, not race runs. Let's think about why that is...

(1) If the driver drives flatout exiting the last corner, they won't have a topped-up battery at the finish line. That means they will have much less energy to use inside the lap. (let's say 0.5-1MJ) and the 8.5MJ recovery limit which is around 9-10MJ instead of the maximum of 4MJ + 8.5 which is 12.5 MJ.

(2) If they hold back and charge the battery to 4MJ just before the line, they will be able to deploy 4MJ and the 8.5MJ recovery limit inside the next lap.

So which one has the potential to be faster? The fact that we have to even consider this shows how broken the PU regs and qualifying are going to be, but that's for another thread

Back to the original point. If you don't go flat-out out of the last corner, lose some time in the run to T1, but then have 12.5MJ which can be deployed for the rest of the lap, can it actually be faster than starting the lap by going flat out of the last corner and only have 8.5-9.5MJ of electric power to use inside the hot lap?

Imo, this is basically a "loophole" on certain tracks to use more electric energy. It's especially powerful on circuits where there is a relatively shorter run to T1 after the finish line (Baku, Monaco, etc) so that the time you lose is relatively lower, in exchange for being able to use an extra 3-4MJ inside the hot lap.

Now there might be a counterargument by some that the energy you put in before the start finish line carries into the next lap so this is not really a loophole, but using that 4MJ getting up to speed before the start of the lap comes at a cost. It's less efficient (drag) to drive at top speed than it is to drive at low speed so that energy you put in before the lap starts is basically worth less when its being "re-used" at high speed.

[mzso]

But this road relevance/eco shroud can't last forever unless someone actually develops a process that's not super costly and environmentally destructive.

If you care about CO2 from the production of electrical power, you wanna use as little as possible. E-fuel is the opposite of that. The efficiency is very low. Takes a lot of energy to make the hydrogen, a lot of energy to capture the co2, then you burn it in a combustion engine at 25% efficiency. It's 5-10 times worse than running directly on electricity. Meaning we need a lot more wind farms, solar power etc. Or burn even more coal.

If you don't care about CO2, then why bother at all? Use regular fossil fuel then.

You cannot burn dinosaurs to make fuel afaik. What’s the point of supply chain checks if you could?

The whole supply chain has to be carbon neutral and validated. Even if it’s inefficient, it’s such a small chunk and good for research.

The discussion was more generic at that point. How long can they pretend that bio/synthetic fuel is eco/green or whatever, when it's an environmental and/or economic disaster?

[dialtone]

The discussion was more generic at that point. How long can they pretend that bio/synthetic fuel is eco/green or whatever, when it's an environmental and/or economic disaster?

I need you to win me a marathon tomorrow. You are under no circumstances allowed to train for it.

[Ferry]

You cannot burn dinosaurs to make fuel afaik. What’s the point of supply chain checks if you could?

Not within the rules of Formula 1, I guess no you can't. But in the context of criticism of BEVs having lot's of CO2 emission because of the electrical power generation being dirty. E-fuel would be much worse. We have to compare with the same source of electricity. If the grid contains 50% fossil power, and the emission from a BEV is X. Then the emission from a e-fuel driven ICE would be 5X. Or both of them are zero.

The whole supply chain has to be carbon neutral and validated. Even if it’s inefficient, it’s such a small chunk and good for research.

I'm all for the research and testing in real life. But when I see how sceptical many people are to emissions from electricity, how can spending 5 times as much be a good thing? That's even more of the wind turbines everybody "loves so much". More solar panels. More batteries with cobalt from the poor children in Congo. It's everything hated upon now, just more of it.

[mzso]

The discussion was more generic at that point. How long can they pretend that bio/synthetic fuel is eco/green or whatever, when it's an environmental and/or economic disaster?

I need you to win me a marathon tomorrow. You are under no circumstances allowed to train for it.

Not sure what's your purpose with this comment. If you meant it as an analogy, then training would be years of research and development for a an economical and environmentally friendly process to create bio or synth fuel. Then running it would be when you start to use it.
Since F1 in no way demands the fuel to be viable in the real world, using it in F1 can't be training.

[dialtone]

You cannot burn dinosaurs to make fuel afaik. What’s the point of supply chain checks if you could?

Not within the rules of Formula 1, I guess no you can't. But in the context of criticism of BEVs having lot's of CO2 emission because of the electrical power generation being dirty. E-fuel would be much worse. We have to compare with the same source of electricity. If the grid contains 50% fossil power, and the emission from a BEV is X. Then the emission from a e-fuel driven ICE would be 5X. Or both of them are zero.

"Electrical power generation being dirty" is wrong in multiple different ways of being wrong. To not make this political I can't go too much in the detail, but it's at minimum country dependent, and anyway it's technology dependent.

Most fundamentally this is wrong because the rules say that what you said would be illegal fuel.

C16.1.2
...
All AS components and fuels must be segregated from non-sustainable components
and fuels at all times. The final, blended fuel must achieve a greenhouse gas (GHG) emissions
savings, relative to fossil-derived gasoline, of at least that defined for the transport sector in the EU
Renewable Energy Directive RED(1), which was current on January 1st in the year prior to the relevant
Formula One Championship. The GHG savings calculation takes into account any net carbon
emissions from land-use change, the energy used in harvesting and transporting the biomass and
the production and processing of the advanced sustainable component. In any process where
sustainable energy is used, this must be surplus to the local domestic requirements. Where
available, GHG emission savings will be taken from the current EU Renewable Energy Directive
(RED) or other equivalent, internationally recognised sources.

I'm all for the research and testing in real life. But when I see how sceptical many people are to emissions from electricity, how can spending 5 times as much be a good thing? That's even more of the wind turbines everybody "loves so much". More solar panels. More batteries with cobalt from the poor children in Congo. It's everything hated upon now, just more of it.

You can certainly be skeptical of things you haven't checked with what is actually happening, yes.

[dialtone]

The discussion was more generic at that point. How long can they pretend that bio/synthetic fuel is eco/green or whatever, when it's an environmental and/or economic disaster?

I need you to win me a marathon tomorrow. You are under no circumstances allowed to train for it.

Not sure what's your purpose with this comment. If you meant it as an analogy, then training would be years of research and development for a an economical and environmentally friendly process to create bio or synth fuel. Then running it would be when you start to use it.
Since F1 in no way demands the fuel to be viable in the real world, using it in F1 can't be training.

This is like saying that animal drug research is useless because most drugs that work on animals don't work on humans. There's no way to know a priori what is viable in the real world and what isn't.

Before investing billions in scaling a process you want to figure out if it's even feasible, as in you endup with a good enough result at the end to understand if you want to invest the billions needed later.

Furthermore anyway, Shell has been using biofuels in Indycar since 2023.

[Cold Fussion]

Biofuels are not E-fuels and carry their own set of environmental questions.

[dialtone]

Biofuels are not E-fuels and carry their own set of environmental questions.

Same rules apply. C16.1 is titled "Basic principles" under C16 that is Fuel and Engine Oil.

Either fuel type has to reduce GHG emissions by 65% compared to traditional gasoline and has to do so for the entire supply chain, not just in the car.

[Rodak]

What I'm wondering, after watching the 'race starts' with the 10 second full throttle engine turbo spin-up stuff, is what will pit stops look like. Can the cars use electric power to leave the pits? Does the 50 kph rule apply? If it does then it will be very interesting. And if it doesn't it will be interesting.

[AR3-GP]

What I'm wondering, after watching the 'race starts' with the 10 second full throttle engine turbo spin-up stuff, is what will pit stops look like. Can the cars use electric power to leave the pits? Does the 50 kph rule apply? If it does then it will be very interesting. And if it doesn't it will be interesting.

50km/h only applies to standing starts on the grid.

[astracrazy]

What I'm wondering, after watching the 'race starts' with the 10 second full throttle engine turbo spin-up stuff, is what will pit stops look like. Can the cars use electric power to leave the pits? Does the 50 kph rule apply? If it does then it will be very interesting. And if it doesn't it will be interesting.

Like the GTP's?

[mzso]

So Croft said a few minutes ago that PU manufacturers and the FIA developed a to quantify how the CR changes to ambient to operating conditions. And that from Aug 1. they need to demonstrate compliance with 1:16 at "representative" temperature 130°C.

Is representative and 130 degrees seem a tad contradictory to anyone else? Still seems ripe for machinations.
And if it's august 1 then it's most of the season anyway. Knowing F1 teams they will push it to the end to the year.

Edit:
Here's the actual FIA statement:

Over recent weeks and months, the FIA and the Power Unit Manufacturers have collaboratively developed a methodology to quantify how the compression ratio changes from ambient to operating conditions. Following validation of this approach, a proposal has been submitted whereby, from 1 August 2026, compliance with the compression ratio limit must be demonstrated not only at ambient conditions, but also at a representative operating temperature of 130°C.

The vote has been submitted to the Power Unit Manufacturers, and its outcome is expected within the next 10 days and will be communicated in due course. As with all Formula 1 regulatory changes, any amendment remains subject to final approval by the FIA World Motor Sport Council.

[vorticism]

- what conditions are the 1.6L capacity measured?
- Must this 1.6L limit be maintained at all times during normal operating conditions?
- How is this policed?

...

How can the 1.6L be so well controlled...

The FIA define cubic capacity as the swept volume of the pistons i.e. the volume encapsulated by the bore and the two most distant positions of the piston face. We don't, afaik, know how the FIA measures this, or when they inspect it. It is potentially easy to measure, as all you need to do is measure any fixed point upon the piston crown through its full travel. The size of the combustion chamber volume is not regulated directly but the spec GCR limits its minimum volume to around 18cc. Which means the total closed capacities of the engines are around 1.7l minimum.

To say it in a more confusing way: the "cubic capacity" is dictated by the spec bore diameter & cylinder count, while the cubic capacity is defined by the geometric compression ratio.

I would consider swept volume as displacement in the true sense of that term, not necessarily as capacity--regular terms in the ICE world often have multiple connotations and can be considered colloquialisms. There may even be translation artifacts between languages.

The question of how the ~1.7 liter and 108cc closed capacities i.e. the large and small parts of the GC ratio are potentially measured is the more prescient question in regards to the recent rumors.

[chipengineer]

- what conditions are the 1.6L capacity measured?
- Must this 1.6L limit be maintained at all times during normal operating conditions?
- How is this policed?

...

How can the 1.6L be so well controlled...

The FIA define cubic capacity as the swept volume of the pistons i.e. the volume encapsulated by the bore and the two most distant positions of the piston face. We don't, afaik, know how the FIA measures this, or when they inspect it. It is potentially easy to measure, as all you need to do is measure any fixed point upon the piston crown through its full travel. The size of the combustion chamber volume is not regulated directly but the spec GCR limits its minimum volume to around 18cc. Which means the total closed capacities of the engines are around 1.7l minimum.

To say it in a more confusing way: the "cubic capacity" is dictated by the spec bore diameter & cylinder count, while the cubic capacity is defined by the geometric compression ratio.

I would consider swept volume as displacement in the true sense of that term, not necessarily as capacity--regular terms in the ICE world often have multiple connotations and can be considered colloquialisms. There may even be translation artifacts between languages.

The question of how the ~1.7 liter and 108cc closed capacities i.e. the large and small parts of the GC ratio are potentially measured is the more prescient question in regards to the recent rumors.

If teams were allowed to use any values for bore, stroke, and displacement that they wanted (given the current allowed energy/hour), what might they choose?