cant lower boost on racegate under 20-24psi

[crazygn]

i have my racegate hooked on my down pipe and i only have the turbo port hooked to the bottom port on the gate none on top.

I have the screw turned all the way out and cant get the boost under 20-24 psi, i tried cleaning the gate good and all, is there some thing that could be doing this.

thanks