2025/2026 Hybrid Powerunit speculation

[Zynerji]

You'd need a supercharger or a completely different block architecture for a two stroke. A four stroke has a completely independent inlet stroke to draw in the inlet charge. A two stroke requires the use of the crankcase to force the charge from the bottom of the engine to the top for nat asp engines, or a mechanically driven supercharge to force the charge in against the exhaust plume.

'uniflow' (ie non crankcase-induction) 2 strokes have since the 1920s not (once started) needed a blower
(eg Petter 'Harmonic' and Crossley in the UK)
by having tuned-length exhaust systems .. and specially eg if they have eg an 8 speed transmission ....
yes a bit of induction air pressure (eg electrically-driven) is needed for starting
the hybrid F1 rules manage fueling and manage ICE load in a way helpful to the this ICE type

but the Zynergi-architecture engine won't have the sound he wants because the firing intervals will be so uneven

So, non-flat crank and no big-bang?

Not a 2stroke guy, but chain-sawing firewood recently seemed so simple and elegant with seemingly solvable drawbacks.

But just the current (modified) block with 2 stroke heads, probably hot V seemed like it could just be a simpler way to go. I haven't even gotten to the point of asking about using nitro-methane in them... Would 100L get a car to the end??

[Tommy Cookers]

....I haven't even gotten to the point of asking about using nitro-methane in them... Would 100L get a car to the end??

no
nitromethane is a very poor fuel compared to the conventional fuel

nitro has over twice the stoichiometric mass-specific energy ....
so makes over twice the power for a given air consumption ie from a given engine it gets over twice the power ....
but has about one eighth of the mass-specific energy so that power needs about eight times as much weight of nitro fuel

ie equal power might come from halving the engine size but would need 3 - 4 times as much weight of nitro fuel and ....

(nitromethane's own oxygen accessed by rich AFR) would allow an even smaller engine but need a disproportionate fuel load
such a semi-rocket piston engine might not last 5 races

[Zynerji]

....I haven't even gotten to the point of asking about using nitro-methane in them... Would 100L get a car to the end??

no
nitromethane is a very poor fuel compared to the conventional fuel

nitro has over twice the stoichiometric mass-specific energy ....
so makes over twice the power for a given air consumption ie from a given engine it gets over twice the power ....
but has about one eighth of the mass-specific energy so that power needs about eight times as much weight of nitro fuel

ie equal power might come from halving the engine size but would need 3 - 4 times as much weight of nitro fuel and ....

(nitromethane's own oxygen accessed by rich AFR) would allow an even smaller engine but need a disproportionate fuel load
such a semi-rocket piston engine might not last 5 races

As always, I love your responses!

Thank you!

[taperoo2k]

Is anyone actually happy with the expected 2026 engines?

I'm of the mind currently that it could seriously just be best to move to a 1.6l v6 N/A-DI 2 stroke (v12 sound, and high RPM feel) with the current (mostly) block architecture and delete the turbo. Keeping a 240kw KERS to torque fill would seem preferable for economy and drivability. Then 2008 sized cars, and I'm in.

In an ideal world with synthetic fuels you'd go back to the V10 or V12 screamers. But that is of no interest to the manufacturers. F1 is a testing ground for Hybrid technology amongst other elements of the PU alongside being a marketing exercise.

What I see and hear for 2026 currently simply does not feel very impressive, and that is hugely disappoint to this long-time fan.

It's either going to be a clown car show in terms of the racing or it might actually be exciting. It's hard to say at this point. Max wasn't very impressed with the simulator runs with the RB PU a couple of years ago now. Things have likely moved on since then.

When you look at the technical challenges the manufacturers face for 2026, it is quite interesting. You have to wonder how much of an impact the synthetic fuels are going to have on the respective PU's performance levels.