adjusting turbo boost on a sd33t 85 nissan

[themacka1948]

hi my first time in this, I have put a turbo boost onto my MQ nissan patrol 1985 lwb and it was reading 6psi I have closed of the dump tube and the popper valve pops at 11psi, it is only a small turbo can i increase the psi and will new injectors help and at 9 psi will i do any damage to the head, love my old Mq Mk Square headlight it goes fantastic and we are going around Australia in her