wastegate spring limits?

[renxun]

actually this idea actually stuck my mind... how do we determine that a spring in a wastegate isnt holding the boost and leak during boost build up?

lets say i have a 0.8bar spring and a boost controller. although i have a boost control and can push way up to 25psi but how do i know if my wastegate spring had hit its limit? how do i know if there is any boost escaping during boost buildups? i had always wonder that i might having somesort of leak hence slow down my boost building up which is not a good thing...

since im using a trust 50mm.. there is a screw to tightened the spring preload.... if i were to tightened it a fair bit, would i be facing boost creeping?

[NME308]

Assuming your wastegate is a regular style with boost nipple input both on top and underneath the diaphram...
You will want a spring pressure in the gate of the minimum boost from which point you want your electronic controller to take over from. So lets say you wanted to program your electronic boost controller to control the boost against various parameters from 5psi, then the spring in your wastegate must be 5psi or lighter.
With boost pressure beneath the wastegate diaphram and boost pressure + spring pressure above the diaphram your wastegate will be firmly shut. As soon as the electronic boost controller wants to ditch some boost it will vent the top port of the wastegate to atmosphere instantly allowing the pressure under the diaphram to open the gate.
So assuming no leaks and correct boost control valve operation, your wastegate should not be leaking boost early!

Cheers