Your still not getting it. unless you are referring to 7-8psi on that specific turbo (whatever it may be, your likely looking at some ebay piece of crap) then 7-8 means jack crap. Here, ill do the work for you before you waste money and blow your damn block to hell.

Turbo D16 • View topic - FAQ: Here's how much boost (psi) to run
And also read this
Turbo D16 • View topic - FREE TURBO'S HERE!!! ALL NOOBIES READ FIRST, TURBO HOW TOO**