This is a fallacy.
The amount of power you make is directly proportional to the amount of fuel you are burning.
You cannot burn more fuel without more air. This is where the entire concept of A/F ratios and wide bands comes from.
Your engine has a constant volume. Without boring or stroking the engine it is impossible to make more power without increasing the pressure. (assuming afr, Ev and timing are optimal)
Therefore you will not be “flowing more at lower boost” since this is physically impossible.
As for your concerns about the lifespan of a K03 under high pressure, they are probably warranted. There is only so much you can do with a turbo the size of a walnut.
I will however point point out that the axial load on a turbocharger is proportional to the ratio of pressure/flow * pressure, so stating that more pressure is damaging the turbocharger is sort of true but not really.
There are two primary sources of axial load in a turbocharger.
- The turbine wheel.
Any swept blade turbine wheel has both an axial and a tangential force component. The ratio of these components is proportional to the blade angle, which is a complex curve requiring gradient analysis. This is Calc 3 and a bit out of my comfort zone.
However logically it is easy to see. as the turbine wheel extracts power from the exhaust, it is providing torque to the compressor wheel. The more torque the compressor wheel requires, the more axial force is created. This force pulls the shaft tword the turbine end of the turbo.
- The compressor wheel.
Obviously there is pressure on top of the compressor wheel. The maximum pressure is proportional to the cube of the tip velocity. The velocity gradient is proportional to the maximum pressure, the velocity distribution, and the wheel area. None of these are linear terms. All of this pushes the shaft in the same direction is the turbine load. They are additive, they do NOT cancel each other.
Now if you have ever looked at a turbo you will notice there is an annular gap between the compressor wheel and the diffuser plate. You will also note that the wheel is lower than the diffuser plate. The is ring feeds a stagnant volume of air which is trapped behind the compressor wheel, which DOES act in the opposite direction of the two other loads, and this attempts to reduce the axial load to zero. The compressor blade geometry also has a load reducing screw effect but this is negligible.
This is why a Garrett GT turbine wheel has a significantly steeper blade angle, creating higher performance and greater axial loads. A fluid thrust bearing cannot handle these loads with standard oiling pressure. Therefore the ball bearing technology was employed to carry the additional loads created by the advanced turbine wheel geometry.
GT turbine wheels = rolling element bearings.
T turbine wheels = fluid bearings