Im no expert but I looked through my pectel datalogs and found one where I boot it in 4th gear at 2500rpm.

By 3200rpm it got full boost ie 1,6bar.
It then hold this and actually creeps a bit higher to around 1,7bar and it isnt until around 5500rpm that it starts to tail off very, very slowly. By 6400rpm it still holds 1,6 bar.