As I posted in the chat with you:
It has a perrin turbo inlet, an aftermarket blow off valve that I can't tell what it is (get a picture of that for me if you don't mind). I can't tell what brand that intake is... probably INJEN. They were popular for those years. It has an Agency Power alternator cover and Ebay strut tower bar.
Boost isn't related to throttle position. It's related to engine load. At partial throttle acceleration you'll have partial boost because it's not as much load on the engine as when you're at full throttle. You'll notice that if you have it in neutral and do half throttle you won't have 10psi of boost.