... even faster in 2nd despite the turbo noticeably runs out of puff somewhere around 60 on top of that same limiter....
I'm going to try to explain what you are feeling:
-as i've said before the ecu limits boost in the lower gears, by using the boost controller solenoid
-in 1st,2nd and a bit in 3rd the max boost is limited:
-1st ...0,1bar
-2nd...0,2bar
-3rd...0,5bar
-4th,5th,6th...0,8bar
The values are MAX values, approximately accurate(i had graphs of the boost in each gear...can't find them)
In each gear the boost graph raises to max, holds a bit, and then falls back down to the top of the rev range... you might think it's the turbo.. but it's actually the ECU => boost solenoid =>wastegate =>lower turbine pressure=>lower boost.
You can actually see this by using graphs on
MES.
There are numerous reasons why it's programmed that way, but in short it comes down to reliability (gearbox and engine) and efficiency.
So the idea is that the tuner can still raise the pressure twords the end of the rev range.... but it requires careful motorization, while tuning, on a dyno.. checking temps, knock, oil pressure, AFR...etc
Again.. for reliability they set it up so you wouldn't want to rev it over 5.5k (where the boost/torque really falls down)... if it doesn't feel good, people will not rev it that high=> longer life =>less chances of repairs under warranty and generally people considering the engines more reliable.
The behavior in the higher revs can be drastically changed by only upgrading to the VL36 turbo... it feel so much better now. Basically the cam shafts don't matter that much on a turbo car....where they might feel better is in the lower revs, just before the turbo kicks in; and of course in the higher revs it could make more power with lower boost... so more efficient.