One thing we learned at todays FP's was that they shortshift these new engines massively. At least they did during todays free practice's.
If we watch the video's I link to below, we will see that they keep the revs around 8-11k most of the time. On the odd occation we see 12k, but never higher. Not strange that the sound is a bit low frequency compared to last year, as the drop in max rpm isn't from 18k to 15k, it's down to 10-11k!!!
Of course the nengines have loads of torque in the mid range, but for maximum power the higher you can rev, the better (more combustions per minute). So, there must be a reason why they shortshift the way they do.
My view is that they probably need to keep the revs at around 10k to maximize their fuel efficiency and perhaps also because of the max fuel flow limits. Going above 11-12k makes no sense as they both consume to much fuel at that part of the rev range and also perhaps because they can't flow enough fuel to make any more power above those rpm's.
I guess qualifying tomorrow will answer whether it's just fuel conservation that is the reason behind this or whether the fuel flow limit also is a factor. Because there is no need to save fuel during qualy they should be able to rev to 15k to extract maximum Power. If they don't rev to 15k, then there seems to not be enough fuel flow to support an increase in power above 11-12k...