Compressor map question

[marleyskater420]

Why is it that on compressor maps, at the same boost, it shows the turbo go from lets say:

60% - 65% - 70% - 75% - 78% -75% -70% - 65% - 60%

Why does it say different levels of efficiency at the same boost level?

Does this mean that as the turbo is begining to be spooled by exhaust gases, its still pushing 15psi of air lets say, but the turbo is just spooling enough to push that much air. And as the exhaust gases increase, and the wheel spins faster, still giving that same boost level, the wheel becomes more efficient because it is right where it needs to be operating wise. Not spinning to slow, not too fast... And as the exhaust gases get faster, it becomes more inefficient?

Is this how it works? So at every boost level, our turbos are only most efficient for a certain moment of time?

On the maps it shows the levels of efficiency, and flow increases as the efficiency rises and decreases, all for the same boost..why is this?

 

[TurboTR]

Well it basically says that, for a given compressor at a set pressure ratio across it, there is a corresponding amount of airflow that best matches it. If you keep the pressure ratio constant but change that airflow amount up or down, then it is less effective at moving it and the efficiency goes down.

TurboTR

 

[marleyskater420]

Originally posted by TurboTR
Well it basically says that, for a given compressor at a set pressure ratio across it, there is a corresponding amount of airflow that best matches it. If you keep the pressure ratio constant but change that airflow amount up or down, then it is less effective at moving it and the efficiency goes down.

TurboTR

thanks