Originally Posted by turbotoaster

Boost threshold is the point of rpm when the turbo pushes enough air to reach a certain pressure(say 15psi)

People commonly assume that the later in the rpm it hits this pressure the laggier it is.

Thats a mistake, its called boost threshold.


Lag in its easiest context is the time when your rpm is above the boost threshold and you come off the throttle, you then reapply throttle and lag is the time it takes for the turbo to come back to full pressure.

Some people quote this as 'response'