i have this off brand boost gauge only because it was the only one i could find that was reverse indiglo

problem is that whatever vacuum line i hook it up to it reads -50, when i give it gas it reads 0 then as it starts to boost it goes up to about 1 bar. strange thing is that this is my setup

d16y8
greddy kit 5.5 psi nonintercooled
b&m command flo with relief hole
255lb pump
vafc hack
dsm 450cc injectors

i checked the vacuum lines and none appear to have any leaks, my fuel pressure at idle with open vacuum is around 50

so do i have an unknown vacuum leak or is the gauge fubar? another prob is that its boosting good until about 5~6k then it kinda feels like it dies off

 

Try a different vacuum source although it should read fine anyways. Idle vacuum for me is around 18, in gear 20-22.