ppj13 wrote:It is not clear that teams can benefit of powering the MGUH and venting exhaust gases to get very expensive extra hp for overtakings.
What do you mean by that? The MGUH is clutched, so you can simply disengage it and drive the MGUK 100% from the ES. But you'll be wasting exhaust gasses to control the turbine from overspeeding. As stated in earlier posts by TC the compounding from the MGUH (up to almost 20%) is "free" power. So you will be losing the 100-120hp from the MGUH->MGUK and pulling that from the ES to make up for it.
The overtaking maps are probably a switch to full fuel flow and full MGUK output and maybe an increase in rev limit to just pass 12k rpms. Mercedes is probably running like this most of the time due to superior energy management around a lap. I am guessing other teams are not able to use the full 160hp MGUK output as often.
I also think a poor brake by wire will still allow for high speed if the ES has the energy to give. You'll lose time in the braking zone, but after that you are on the throttle. The problems with the brake by wire seem to be driver feel and confidence. They may still be harvesting the needed energy, just forcing the driver to brake earlier/different. Lotus stated it is having brake by wire issues but is still having competitive cornering speeds. They just don't have the max power down the straights which I'm guessing is MGUH->MGUK issues stemming from their reported turbo cooling issues.