im running a IHI RHB5, the wastegate is set to 8psi, but im only getting 6 psi at low rpms like 3000, but as they go higher to 5000rpms boost goes down to 3 or 4 psi... and i feel like if i have something limiting my revs because i canot go higher than 6500rpms...
i have a minime D15/D16z6 Head... WTF is happening

 

thats a pretty small turbo, its probably dyin out via higher rpms, or its dead as in needing a rebuild, or you have a boost leak somewhere, i like the first couple ideas better though better though, usually you dont have a boost spike and then loose boost if you have a leak

 

boost leak or exhaust restriction. try running open downpipe with it and see if it makes a difference.

 

 

I forgot to mention that at first i was running no BOV, and didnt had this problem... so could it be the BOV its brand new... $24.99 ebay...

 

theres your answer....boost leaking from the bov are probably....tighten it down and see if it helps