I mean the exhaust side of a -5 can out flow what ever the compressor side can send it
I mean exhaust housing and turbine wheel, the more variation in pressure from pre and post turbine the better the turbo can work, just to spell it out the lower the pressure in the exhaust post turbine compaired to the pressure in the manifold/exhaust housing the better the turbo will work
Boost v backpressure in this instance is obvious but I will spell it out also for the knowledge lacking few, the backpressure pre turbine v how much boost the compressor is making
We measured it in the BSM GTR time attack/ sports sedan when it was running -10s and ended up controlling boost according to exhaust manifold pressure
if everyone had to explain everything that is posted this thread would be a fark load longer, certain things just need to be expected to be common knowledge, if there is something someone doesn't know they should ask a specific question