ok i have a ZPI pulley, which supposed to generate 9lbs of boost on the TRD supercharger that i ha ve right, but somehow it only generates 7lbs i think...does anything know what could possibly be the causes or symptom? please let me know thanks ahead.

 

You have the stock BPV? It can't hold past 7 psi. Get a better one (forge 007).

 

Do you have a boost guage? Just wondering about the " I think" part. And yeah what he said ^, you need to upgrade the BPV. I got the forge 007 also, it is a really nice bpv that you can get for 130$ A cheaper product is the Bosch 110 for around 60.

 

i do have the FOrge 007 and yes i have boost gauge that's why i know i'm loosing boost lol....which spring do u use..they gie u like 3 of them right...