2025/2026 Hybrid Powerunit speculation

[Stu]

With turbo-compounding?

What compounding?

The maximum efficiency was when the MGUH fed power directly to the MGUK.

This is turbo-compounding.

@FW17 - turbo compounding is different to compound turbo-charging.

[wuzak]

What compounding?

The maximum efficiency was when the MGUH fed power directly to the MGUK.

This is turbo-compounding.

@FW17 - turbo compounding is different to compound turbo-charging.

I think this is the one you should be responding to:

In not sure you understand the definition of the word compounding, you can’t compound a turbo without a second turbine!

[Bill]

Some teams are experiencing fuel combustions problems with there engine and have ask for some concessions from fia to run fuel that has not been homologated during testing.so why are the media not reporting on these and follow up the story do some digging and identify who these are.do some real reporting not lazy click bait thing maybe they are afraid of what they may find maybe it will conflict with the prevailing narrative that a particular manufacturer is going to dominate.

[wuzak]

Some teams are experiencing fuel combustions problems with there engine and have ask for some concessions from fia to run fuel that has not been homologated during testing.so why are the media not reporting on these and follow up the story do some digging and identify who these are.do some real reporting not lazy click bait thing maybe they are afraid of what they may find maybe it will conflict with the prevailing narrative that a particular manufacturer is going to dominate.

Combustion or production issues?

[Bill]

Some teams are experiencing fuel combustions problems with there engine and have ask for some concessions from fia to run fuel that has not been homologated during testing.so why are the media not reporting on these and follow up the story do some digging and identify who these are.do some real reporting not lazy click bait thing maybe they are afraid of what they may find maybe it will conflict with the prevailing narrative that a particular manufacturer is going to dominate.

Combustion or production issues?

Both the engine are sensitive to very small variations in fuel quality

[gearboxtrouble]

Some teams are experiencing fuel combustions problems with there engine and have ask for some concessions from fia to run fuel that has not been homologated during testing.so why are the media not reporting on these and follow up the story do some digging and identify who these are.do some real reporting not lazy click bait thing maybe they are afraid of what they may find maybe it will conflict with the prevailing narrative that a particular manufacturer is going to dominate.

I read that this was because there was a manufacturing constraint for the Barcelona test. My guess is its Mercedes/Petronas because they have 4 teams to supply and Petronas just isn't in the same league as the other fuel suppliers who have decades of R&D and tens of billions invested in sustainable fuels.

[Bill]

The only news in town that the mercedes are going are going to blow the socks out of everyone. so if Petronas are having some trouble how did the media come to that conclusions

[Hoffman900]

The only news in town that the mercedes are going are going to blow the socks out of everyone. so if Petronas are having some trouble how did the media come to that conclusions

About the same way any of us, throwing at a dart board. The manufacturers aren’t running to to the media with anything.

[PlatinumZealot]

What compounding?

The maximum efficiency was when the MGUH fed power directly to the MGUK.

This is turbo-compounding.

With compounding of MGU H it was 59%

51% was only from ICE

No. The MUGH considered part of the ICE. This is everything part of the fuel to shaft energy loop in steady state. It was about 52% to 53% thermal efficiency.


There is no more waste heat recovery in 2026.

I have to check back the 2014 engine threads but I believed total ICE power was around 840hp or 620kW. We calculated the MGUH at something like 60kW to 100kW i do not remember right now. But expect these new engines to be less thermally efficient.

I hear the 470kW being bandied about by posters here... And they are saying 1100hp (820kW total?) and if 350kW is MGUK that 470kW (630hp) does make sense, maybe on the lower side of things. It's fair to say weaker by about 150hp to 200hp?

Thermal efficiency would drop to 40%. (max out maybe 43%)

[gruntguru]

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.

The turbine used in F1 utilises both pressure and blowdown pulses. Have you heard of a company call GARRETT? They know a thing or two about turbochargers. Here is an article posted on their website. https://www.garrettmotion.com/wp-conten ... vanced.pdf

(From page 5 and 6)
A design feature that can be common to both manifold types is a " DIVIDED MANIFOLD" , typically employed with " DIVIDED " or "twin-scroll" turbine housings. Divided exhaust manifolds can be incorporated into either a cast or welded tubular manifolds. The concept is to DIVIDE or separate the cylinders whose cycles interfere with one another to best utilize the engine’s exhaust pulse energy.
For example, on a four-cylinder engine with firing order 1-3-4-2, cylinder #1 is ending its expansion stroke and opening its exhaust valve while cylinder #2 still has its exhaust valve open (cylinder #2 is in its overlap period). In an undivided exhaust manifold, this pressure pulse from cylinder #1’s exhaust blowdown event is much more likely to contaminate cylinder #2 with high pressure exhaust gas. Not only does this hurt cylinder #2’s ability to breathe properly, but this pulse energy would have been better utilized in the turbine. The proper grouping for this engine is to keep complementary cylinders grouped together-- #1 and #4 are complementary; as are cylinders #2 and #3.
Because of the better utilization of the exhaust pulse energy, the turbine’s performance is improved and boost increases more quickly.

[saviour stivala]

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.

The turbine used in F1 utilises both pressure and blowdown pulses. Have you heard of a company call GARRETT? They know a thing or two about turbochargers. Here is an article posted on their website. https://www.garrettmotion.com/wp-conten ... vanced.pdf

(From page 5 and 6)
A design feature that can be common to both manifold types is a " DIVIDED MANIFOLD" , typically employed with " DIVIDED " or "twin-scroll" turbine housings. Divided exhaust manifolds can be incorporated into either a cast or welded tubular manifolds. The concept is to DIVIDE or separate the cylinders whose cycles interfere with one another to best utilize the engine’s exhaust pulse energy.
For example, on a four-cylinder engine with firing order 1-3-4-2, cylinder #1 is ending its expansion stroke and opening its exhaust valve while cylinder #2 still has its exhaust valve open (cylinder #2 is in its overlap period). In an undivided exhaust manifold, this pressure pulse from cylinder #1’s exhaust blowdown event is much more likely to contaminate cylinder #2 with high pressure exhaust gas. Not only does this hurt cylinder #2’s ability to breathe properly, but this pulse energy would have been better utilized in the turbine. The proper grouping for this engine is to keep complementary cylinders grouped together-- #1 and #4 are complementary; as are cylinders #2 and #3.
Because of the better utilization of the exhaust pulse energy, the turbine’s performance is improved and boost increases more quickly.

Yes. Agree that the 'twin-scroll' exhaust turbine housing design minimizes the effect of mixing all exhaust pulses into one collector, by dividing said pulses into two collectors. As the formula 1 ICE is a V-6 cylinder, using a twin-scroll exhaust turbine housing means that two sets of three selected cylinders will each blow their respective exhaust gas through a primary, with all three primary in the set pumping into a collector, with each of the two collectors pumping into the nozzle aimed at the turbine. The system of multi primaries (more than one) pumping into a collector with the collector pumping into the turbine nozzle aimed at the turbine, will still render the exhaust turbine a 'pressure turbine'. The fact that a variable opening waste-gate is used, provides the exhaust gases from cylinders to turbine with two paths, when the waste-gate is opened exhaust gas pressure is at atmospheric pressure, and no turbine recovery is possible, When it is closed, exhaust gas is above atmospheric pressure and turbine recovery is possible.

[FW17]

470kw from ICE would be over 56%

[PlatinumZealot]

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.

The turbine used in F1 utilises both pressure and blowdown pulses. Have you heard of a company call GARRETT? They know a thing or two about turbochargers. Here is an article posted on their website. https://www.garrettmotion.com/wp-conten ... vanced.pdf

(From page 5 and 6)
A design feature that can be common to both manifold types is a " DIVIDED MANIFOLD" , typically employed with " DIVIDED " or "twin-scroll" turbine housings. Divided exhaust manifolds can be incorporated into either a cast or welded tubular manifolds. The concept is to DIVIDE or separate the cylinders whose cycles interfere with one another to best utilize the engine’s exhaust pulse energy.
For example, on a four-cylinder engine with firing order 1-3-4-2, cylinder #1 is ending its expansion stroke and opening its exhaust valve while cylinder #2 still has its exhaust valve open (cylinder #2 is in its overlap period). In an undivided exhaust manifold, this pressure pulse from cylinder #1’s exhaust blowdown event is much more likely to contaminate cylinder #2 with high pressure exhaust gas. Not only does this hurt cylinder #2’s ability to breathe properly, but this pulse energy would have been better utilized in the turbine. The proper grouping for this engine is to keep complementary cylinders grouped together-- #1 and #4 are complementary; as are cylinders #2 and #3.
Because of the better utilization of the exhaust pulse energy, the turbine’s performance is improved and boost increases more quickly.

Yes. Agree that the 'twin-scroll' exhaust turbine housing design minimizes the effect of mixing all exhaust pulses into one collector, by dividing said pulses into two collectors. As the formula 1 ICE is a V-6 cylinder, using a twin-scroll exhaust turbine housing means that two sets of three selected cylinders will each blow their respective exhaust gas through a primary, with all three primary in the set pumping into a collector, with each of the two collectors pumping into the nozzle aimed at the turbine. The system of multi primaries (more than one) pumping into a collector with the collector pumping into the turbine nozzle aimed at the turbine, will still render the exhaust turbine a 'pressure turbine'. The fact that a variable opening waste-gate is used, provides the exhaust gases from cylinders to turbine with two paths, when the waste-gate is opened exhaust gas pressure is at atmospheric pressure, and no turbine recovery is possible, When it is closed, exhaust gas is above atmospheric pressure and turbine recovery is possible.

It uses some form of pulse effect because they would all stay with log manifolds if it were only a pressure turbine.
The exhaust lengths do indeed seem to be tuned, and notice each runner meets at nearly zero degrees to minimize pulse blow-back.

[PlatinumZealot]

470kw from ICE would be over 56%

Show your calculations please.

[johnnycesup]

470kw from ICE would be over 56%

Show your calculations please.

I'm not the person you're replying to, but there's a 3000MJ/h limit to the fuel energy flow in the regulations. Now MJ/h (unit of mechanical work per unit of time) is obviously a unit of power, so 3000 MJ/h = 833 kW.

So considering the internal combustion engine can burn the fuel perfectly and nothing else is burned (so no oil burning shenanigans), a 470kW output is equivalent to 56,4% thermal efficiency. A bit optimistic IMO


EDIT:
Just to add to the previous discussion, using a common LHV for gasoline (44.3MJ/kg), the previous ruleset had a total fuel energy flow of 1230kW. If the 1000hp rumours are true, that would be a total thermal efficiency of 60,6%, which is pretty incredible.