I am working on a hatch with a b16a and a T28 turbo at 8psi. Turbo doesnt boosting till about 4500rmps and its killing its 1st gear. Why is spool so late, I would think with the small T28 spool would be fast.

 

maybe you have some sort of boost leak. eg. mine had a few pin sized holes in a couple of welds making my get full boost at 6500 and after fixin those it made full boost at 4900. Try tighting all your couplers and check all of your manifold to turbo bolts and manifold to head bolts to see that you dont have a pre turbo boost leak.