godlameroso wrote:You're the one that keeps saying you can't think of these engines as just turbocharged engines, you are not even considering why the turbo needs to be sized in this specific way. I'll let you explain why moving to larger more efficient turbos would help heat recovery then. I promise I won't say another word on the subject, just please answer me this, why does a larger more efficient turbo aid heat recovery?
Sorry to dig up this rather old post but I didn't have the chance to reply sooner. You really need to treat the compressor and turbine as two separate components when you discuss their sizing. The only thing they have in common is their RPM.
Compressor sizing is driven by what the ICE needs. It depends mainly on fuel flow, air-fuel ratio and desired in-cylinder pressure. All of this defines the required compressor work.
The turbine is different. Its massflow also comes from the ICE, but whereas in a conventional turbocharged engine the turbine work only needs to equal compressor work once the desired turbo RPM is reached, in the current F1 engines the turbine work simply needs to be as large as possible because any excess work can be harvested by the MGU-H.
Therefore the link between turbine size and compressor size in F1 is not as strong as in other turbocharger applications. When discussing Honda's redesign of the turbo to increase MGU-H harvesting, the compressor isn't even necessarily part of the story. If you get the compressor right once [to provide the necessary air conditions to the ICE], you can change the turbine capacity without changing the compressor [as long as you don't change the turbo RPM].
This is also why Mark Hughes is right when he says that the desired turbine capacity is related to the efficiency of energy transfer on the path MGU-H - controller - MGU-K. Taking more work out of the turbine inevitably means higher back pressure and lower ICE output. It's only worth it if this lower ICE output is compensated by higher MGU-K output - it is always a trade-off.
So like Mark Hughes says, if you can get the power electronics to work more efficiently, you will also want to increase turbine work. Whether or not this means actually having to make the turbine larger or smaller has already been commented on by other people in this topic who are more knowledgeable than I.