Adjusting manual boost controller

So, after some looking around my engine bay, it seems Ihave found my 30 psi boost issue. I found a manual boost controller. It come from the Intake and goes to the n75 valve on the firewall. I'm not sure how to adjust it.

I suppose I should have searched a bit first, I was able to adjust it but at WOT it will still push 30 psi. I think having a vnt15 on the car when it was tuned for a vnt 17 has something to do with it now....

Which car are you going on about?
Pics would be cool either way!

I would like to post pics but I can't seem to be able to attach a pic and I don't have it on a website. My car 8 years ago was upgraded and tuned. It had a vnt17 (now a vnt15), larger Injectors, egr delete, 3 bar maf, muffler delete, clutch, and a tune by kerma

Are you sure that you are hitting 30 psi? Are you subtracting the atmospheric pressure from it? The MAP sensor reports the actual pressure in the intake track. For example when it reads 30 psi here in Albuquerque, the pressure is actually 30 - 12 = 18 psi. (12 psi is the normal at atmospheric pressure at 5000 ft)

One of the members here hooked up his computer and pulled the ECU file and someone else had messed with the file. He said the map was looking for 4600 mbar boost which would be about 56 psi. He's trying to remap it for me to limit to about 20