p.s.i. ?

i was thinking about turbos the other day and i have a question since the turbo piping is connected directly to the intake manifold is there a minimum amount of psi you need to run to get enough air to the engine?

no, before the turbo builds boost your engine runs as if it were naturally aspirated. Good quality setups with a intercooler typically drop less than 1 psi through the piping so even though your engine might be seeing 8 psi your turbo might be pushing around 9 psi, either way there isnt much difference.