I have never had a turbo before and am trying to understand how the turbo works. I have read on the forums about Peak @ 21psi, holding 18psi. How does it work and when does it happen? Is peak boost when the turbo first spools up and you get that initial kick? When it drops from ‘peak’ to ‘hold’ should you be able to feel it? Why can it not peak and hold the same pressure?

Is there anything that can effect the holding pressure? Leaky dump valve? Weak actuator

Any info would be great.