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They aerodynamic gain is great, with then turbo inside the V, whole engine will be lower and the turbine is closer to the engine. With an mgu-compressor-turbine setup, the turbine will be mounted more to the back and sticking out of the package.

Besides aero, maybe some lower center of grafity?

NL_Fer wrote:They aerodynamic gain is great, with then turbo inside the V, whole engine will be lower and the turbine is closer to the engine. With an mgu-compressor-turbine setup, the turbine will be mounted more to the back and sticking out of the package.

Besides aero, maybe some lower center of grafity?

What about power itself? I read somewhere that higher rpm TC is good for acceleration out of slow corners and esspecialy the starts!?

GoranF1 wrote:

NL_Fer wrote:They aerodynamic gain is great, with then turbo inside the V, whole engine will be lower and the turbine is closer to the engine. With an mgu-compressor-turbine setup, the turbine will be mounted more to the back and sticking out of the package.

Besides aero, maybe some lower center of grafity?

What about power itself? I read somewhere that higher rpm TC is good for acceleration out of slow corners and esspecialy the starts!?

What would the mechanism behind such a different set of properties be? A smaller inertia to overcome?

I don't think so. The mgu-h will keep the turbo spinning at the required rpm levels, so lag is no issue. A smaller turbo is also less efficient, in producing boost, from exhaust fumes.

Maybe there is more room to play around with the intercooler and intake manifold inside that V, but if the compressor was taken out, what would give even more space.

The transient behavior of the turbo/MGU-H complex is too small to sacrifice steady performance, IMO.

That little bit of energy you harvest at the braking point or this little bit of energy you save when spooling uo the turbo at corner exit is very small compared to steady state MGU-H harvesting at WOT.

I don't believe Honda made the turbo to spin faster JUST for transient turbo behavior.

As stated before, I think running a faster turbo would introduce greater aerodynamic and mechanical losses inside the turbo, not to mention vibration issues inside the PU.

I would go for the BIGGEST turbine and compressor possible if I were designing a PU. Merc's advantage with the split turbo was that they were able to package a bigger turbine and compressor into the PU by placing them separately. (There's also the fact that the compressor gets cooler and less turbulent air, but that's another subject)
The shaft which spins at ~100k RPM and carries up to 80 hp would carry 35 Nm torque, which is actually quite a feat considering the small diameter of it inside the cramped V.

The turbo, compressor, shaft and MGU-H (if not clutched, and I don't believe it is) actually adds up to quite a bit of inertia but this doesn't seem to hold Merc up much.

Like i said, the mgu keeps the lag down, so there is no need for a smaller turbo, from a performance kind of view.

I agree that the inertia effect should not offer a benefit, especially when you consider the angular velocity (and acceleration) increase required to spin up the turbo to and achieve the same dynamic pressure at the impeller tip.

Other losses (aero, mech) are higher and thermal management in the vee with a less efficient turbo-machine is presumably also harder.

I wonder if Honda estimated that they could achieve "competitive power with better package"; but then the onward march of Merc and Ferrari, plus their own "as-installed" issues revealed the true competitive gap?

Who knows, the Japanees only looked at a proper sized turbo for the engine and looked at the mgu-h' harvest function as a replacement of the wastegate, instead of a major source of ERS power.

NL_Fer wrote:The Japanese only looked at a proper sized turbo for the engine and looked at the mgu-h harvest function as a replacement of the wastegate, instead of a major source of ERS power.

What is the source of that stated Honda design assumption?

I don't believe Honda disregarded MGU-H recovery as much as that. They compromised MGU-H recovery for better packaging and thought they could compensate for that with superior ICE performance, but that didn't work as they expected. But still, IMO it's highly unlikely that they would disregard/overlook the "free" energy being dumped through the exhaust, excessive vibration or some other issue is preventing them from harvesting it to the fullest.

This engine formula actually simplifies things in a way, the only way to get more power is through better efficiency. Even with a class-leading ICE, if you're not utilizing exhaust and brake energy as good as (say) Merc, you're going backwards.

Honda F1 boss already stated that the 2016 PU will have about the same size compressor as MB.So that means a larger turbine too.

I think this is probably the worst engine in the last 20 year at least. they really are #MakingHistory

At the moment it's a total waste of money from McLaren and Honda, I really hope they'll be stronger next year. I'll be disappointend if they will not be at least at Williams' level.

livinglikethathuh wrote:I don't believe Honda disregarded MGU-H recovery as much as that. They compromised MGU-H recovery for better packaging and thought they could compensate for that with superior ICE performance, but that didn't work as they expected. But still, IMO it's highly unlikely that they would disregard/overlook the "free" energy being dumped through the exhaust, excessive vibration or some other issue is preventing them from harvesting it to the fullest.

This engine formula actually simplifies things in a way, the only way to get more power is through better efficiency. Even with a class-leading ICE, if you're not utilizing exhaust and brake energy as good as (say) Merc, you're going backwards.

We will never know, since they never got the turbo running at the design target rpm. But if the turbo would reach that target rpm, maybe it would just be the ICE delivering predicted power levels. I suspect harvesting would have been cripled anyway, for the sake of aero.

Harvesting more requires either a faster or larger turbine.
Faster --> vibrations and internal losses
Larger --> packaging, associated issues with updated part (tokens, homologation etc.)

By going down the route they did, Honda actually painted itself into a corner. They cannot put a larger turbine right away, as that would require a repack of all the engine bay and too many tokens, and they cannot run it faster because of vibration and/or MGU-K rotational speed limit.

With 32 tokens for next season, I'm thinking they could improve on this quite a bit and be somewhere between Ferrari and Renault in engine terms. This is probably why Arai-san and Alonso have stated they have found out what is wrong with the PU.

If McLaren does not build a killer chassis sculpted with the hands of Athena, this means no podium for McHonda for another year.

NL_Fer wrote:

livinglikethathuh wrote:I don't believe Honda disregarded MGU-H recovery as much as that. They compromised MGU-H recovery for better packaging and thought they could compensate for that with superior ICE performance, but that didn't work as they expected. But still, IMO it's highly unlikely that they would disregard/overlook the "free" energy being dumped through the exhaust, excessive vibration or some other issue is preventing them from harvesting it to the fullest.

This engine formula actually simplifies things in a way, the only way to get more power is through better efficiency. Even with a class-leading ICE, if you're not utilizing exhaust and brake energy as good as (say) Merc, you're going backwards.

We will never know, since they never got the turbo running at the design target rpm. But if the turbo would reach that target rpm, maybe it would just be the ICE delivering predicted power levels. I suspect harvesting would have been cripled anyway, for the sake of aero.

This thing about the turbocharger "not reaching its target rpm" is a load of hogwash. Go and look at a turbocharger compressor graph. Turbochargers do not operate at a fixed rpm. The rpm will fluctuate up and down to meet the pressure ratio/mass flow ratio required by the ICE and that which is provided by the turbine and/or MGU-H.

There has never been any actual evidence to say that the turbocharger does not meet the maximum rpm target.