2025/2026 Hybrid Powerunit speculation

[saviour stivala]

As said, ES capacity is the same so what goes to 'K' is the same, as regards ES capacity, no matter if its at start of race, overtake or diffend. In any which case, no more than ES capacity can move from ES TO 'k'.

"ES capacity" does not define the per-lap deployment. The ES can be charged and discharged many times during a lap.

Yes, The ''ES capacity'' capacity does not define the per-lap deployment, And yes, the ES can be charged many times during a lap. Still, the above does not change the fact that unlike the system up to last year, no 'extra' charge over and above what the ES holds can be send to the 'K'. I don't blame you for the above (your post), as if not for the site system, ''delayed moderation'' you would have read my explanation and understood what I was saying.

[Tommy Cookers]

... back-pressure... is an inherent part of the turbocharging process, not something that is avoided. The difference in pressure between the exhaust manifold (pre-turbine) and the exhaust pipe (post-turbine) is what causes the turbine to spin. This pressure to flow creates back pressure in the exhaust manifold...

none of the above is necessarily true eg in a modern SI engine

here we had this dispute 12 years ago (see the 2014-2020 thread)
one poster described his Porsche as showing (unless driven hard) less exhaust pressure than induction pressure
and another site showed the early boost-restricted turbo Indycars to be that way throughout

the Wright TurboCompound was able always to match supercharger power with turbine-recovered power
so turbocharging would have worked (without mean exhaust pressure exceeding ambient pressure)
(these were 15000 engines wherein the 3 exhaust turbines recovery power was monitored in flight)
Wright explained it in a brochure c.1958 ? (accessible on the AEHS website or by a link in 2014-2020 thread)
and in a 1956? SAE paper their preservation of exhaust pulses (to get recovery power matching supercharger power)

at high boost the TC recovered a 'free' 600 bhp (without mean exhaust pressure exceeding ambient pressure)
exhaust energy is recovered at the brief energy-peaks (ie within the 'pulses') - not from the lower-energy flow time

yes this 'free energy' recovery is also present in designs where the exhaust mean pressure is raised above ambient
(and the pulses have been preserved by the design of engine operation and exhaust system)

yes ... other design approaches are available

[saviour stivala]

... back-pressure... is an inherent part of the turbocharging process, not something that is avoided. The difference in pressure between the exhaust manifold (pre-turbine) and the exhaust pipe (post-turbine) is what causes the turbine to spin. This pressure to flow creates back pressure in the exhaust manifold...

none of the above is true (at least in a modern SI engine)
we had here this argument 12 years ago (feel free to look at the 2014-2020 thread)
one poster described his Porsche as showing (unless driven hard) less exhaust pressure than induction pressure
(and the early boost-restricted turbo Indycars were said to be that way throughout)

I have here a chart of a Wright TurboCompound showing parity of turbine power and supercharger power
these were 15000 engines wherein the 3 exhaust turbines recovery recovery power was measured
Wright explained it in a brochure c.1958 ? (it can be accessed on the AEHS website or there's a link in 2014-2020 thread)
and in a 1956? SAE paper how they preserved the exhaust pulses (to get recovery power matching supercharger power)

at high boost the TC recovered a 'free' 600 bhp (ie without the energy cost of driving the supercharger mechanically)
with the mean exhaust pressure not exceeding ambient pressure
because the exhaust energy recovered is at the brief peak-times (ie within the 'pulses') - not from other flow time

yes this 'free energy' recovery is also present where the exhaust mean pressure is by design raised above ambient
(where the pulses have been preserved by the engine operation and exhaust system design)

yes other design approaches are available

Re your persistence colossal mix-up of the Wright turbo compounding by the use of a ''BLOW-DOWN TURBINE'' with that of the Formula 1 turbocharger ''PRESSURE TURBINE''. While the ''blow-down type of turbine is powered by engine exhaust gasses that are at atmospheric pressure, the the pressure type of turbine is powered by engine exhaust gasses that are above atmospheric pressure. In a pressure type of turbine all cylinders exhausts into a common collector with two exit paths, one through a variable opening waste-gate, and the other through a nozzle aimed at the turbine wheel. With the waste-gate fully open, there is no ristrition, and collector pressure is at atmospheric pressure. however, as the waste-gate is closed, pressure builds-up in the collector, with the gas forced through the nozzle turning the turbine which in turn drives the compressor wheel. No power recovery by the turbine is possible in such a system as the pressure turbine, unless the collector gas is above atmospheric pressure.

[gearboxtrouble]

Longtime lurker here - I had to create an account to ask a question about the new engine regs thats been in my head for a while.

With harvesting on throttle likely becoming a huge part of the new formula I can't help but think you might be able to functionally replicate some form of traction control in these new PUs using variable harvesting from the sized up MGUK in the acceleration phase.

TC itself has been banned in F1 for many years now but there's nothing that I can find that would block variable harvesting off the MGUK linked to steering angle and engine rpm. Heck you could even run wheel speed sensors in FP and use those to pre program a harvesting map to function as TC in the competitive sessions where those would be removed.

Does anyone think this would be technically feasible and within the letter of the new regulations?

[Tommy Cookers]

there is no collector (aka 'log') manifold

there is an exhaust system that preserves the 'pulses'
F1 learned its value on turbocharged engines 50 years ago

the 100 year old dogma of 'Blowdown' vs 'Pressure' doesn't apply
unless the F1 turbine reacts to only one or the other of the human's analogies

[vorticism]

Re your persistence colossal mix-up of the Wright turbo compounding by the use of a ''BLOW-DOWN TURBINE'' with that of the Formula 1 turbocharger ''PRESSURE TURBINE''.

The MGUH-era turbo was both as evidenced by the existence of both tuned headers and wastegates on those engines. You made a blanket statement about "the turbocharging process" requiring backpressure, which is what Tommy countered.

[saviour stivala]

Re your persistence colossal mix-up of the Wright turbo compounding by the use of a ''BLOW-DOWN TURBINE'' with that of the Formula 1 turbocharger ''PRESSURE TURBINE''.

The MGUH-era turbo was both as evidenced by the existence of both tuned headers and wastegates on those engines. You made a blanket statement about "the turbocharging process" requiring backpressure, which is what Tommy countered.

The MGU-H- ERA turbocharger turbine used in formula 1 is a pressure turbine type and not a blow-down type of turbine, no matter what you and T C says. If it wasn't a pressure type of turbine, a wate-gate would not be used.

[saviour stivala]

there is no collector (aka 'log') manifold

there is an exhaust system that preserves the 'pulses'
F1 learned its value on turbocharged engines 50 years ago

the 100 year old dogma of 'Blowdown' vs 'Pressure' doesn't apply
unless the F1 turbine reacts to only one or the other of the human's analogies

What makes the formula 1 turbocharger turbine a pressure type of turbine is the fact that all three exhaust primeres of each bank leads into a collector and collector leads into a nozzle pumping into the turbine.

[Hoffman900]

Longtime lurker here - I had to create an account to ask a question about the new engine regs thats been in my head for a while.

With harvesting on throttle likely becoming a huge part of the new formula I can't help but think you might be able to functionally replicate some form of traction control in these new PUs using variable harvesting from the sized up MGUK in the acceleration phase.

TC itself has been banned in F1 for many years now but there's nothing that I can find that would block variable harvesting off the MGUK linked to steering angle and engine rpm. Heck you could even run wheel speed sensors in FP and use those to pre program a harvesting map to function as TC in the competitive sessions where those would be removed.

Does anyone think this would be technically feasible and within the letter of the new regulations?

Despite what they say, with the cylinder deactivation strategies and other harvesting strategies, there are psuedo traction control strategies at play and have been since 2014.

[lio007]

Does anyone know if vibrations like on a race track can be simulated on test benches to a certain extent?

[gearboxtrouble]

Despite what they say, with the cylinder deactivation strategies and other harvesting strategies, there are psuedo traction control strategies at play and have been since 2014.

Indeed. That's what I think makes this even more feasible now because you have a 350KW MGUK providing negative torque that can be varied on demand when it's "harvesting". Instead of the brute force approach of deactivation you now have a fine grained approach of harvesting during the acceleration phase in certain conditions in a way that's a lot closer to real traction control. Given the torque of these new PUs, this could be very important for everything from tire wear to performance.

[saviour stivala]

Does anyone know if vibrations like on a race track can be simulated on test benches to a certain extent?

A long time ago I was reading an article where Ross Brawn at the time at FERRARI, said that they are making use of an electric motor to test the gearbox in running conditions that can simulate the 3-litre V10 engine RPM as well as vibrations. It was explained that this gearbox test rig consisted of three electric motors, the driver motor could be programed to simulate the three-litre v-10 engine output, RPM as well as the V-10 vibrations, and two driven electric motors, with one mounted to each half-shaft simulating the loads and speed on track.

[wuzak]

Despite what they say, with the cylinder deactivation strategies and other harvesting strategies, there are psuedo traction control strategies at play and have been since 2014.

Indeed. That's what I think makes this even more feasible now because you have a 350KW MGUK providing negative torque that can be varied on demand when it's "harvesting". Instead of the brute force approach of deactivation you now have a fine grained approach of harvesting during the acceleration phase in certain conditions in a way that's a lot closer to real traction control. Given the torque of these new PUs, this could be very important for everything from tire wear to performance.

There is a rule (or rules) governing the ouput of the PU based on the driver input.

For example, the power output cannot be reduced (ie MGUK harvesting increased) unless the driver reduces demand (there are exceptions based on ERS parameters - but that involves deployment, not recovery).

[gearboxtrouble]

Despite what they say, with the cylinder deactivation strategies and other harvesting strategies, there are psuedo traction control strategies at play and have been since 2014.

Indeed. That's what I think makes this even more feasible now because you have a 350KW MGUK providing negative torque that can be varied on demand when it's "harvesting". Instead of the brute force approach of deactivation you now have a fine grained approach of harvesting during the acceleration phase in certain conditions in a way that's a lot closer to real traction control. Given the torque of these new PUs, this could be very important for everything from tire wear to performance.

There is a rule (or rules) governing the ouput of the PU based on the driver input.

For example, the power output cannot be reduced (ie MGUK harvesting increased) unless the driver reduces demand (there are exceptions based on ERS parameters - but that involves deployment, not recovery).

Wouldn’t that depend on where that power is measured? I could see engine output rising with throttle but MGUK harvesting lowering wheel torque based on parameters programmed into the throttle maps and harvesting algo. Would seem that the rules offer enough space for creative interpretation in this area.

[FW17]

How likely are we to see 450KW~600hp from the engine 54% eff at the start of 2026 season


I think it will be somewhere between 570 and 600 hp from ICE