one quick question, on my 97 when im drivin down the road i can hear a hissin noise comin from the defrost vents in the dash.. it starts when my boost hits rite around 15psi and jus gets louder the higher it gets...does anyone have a clue what mite b causin this and how to fix it..any info would b great Thanks

 

My guess would be that its the turbo singin. Have you takin out your silencer ring

 

man i think i have the same issue? like passenger side glovebox area? almost sounds like running water? its got me stumped too

 

I'm thinkin the turbo? Unless yall have something hung on the brake rotor, but doubt that's it. AC maybe?

 

could be the heater core they can make a gergling or hissing sound

 

How do you have the line routed for your boost gauge. Maybe it has a hole in it?

 

WHEN MY 95 HAD A HOLE IN THE HOSE I COULN'T BUILD OVER 5LB BOOST AT WOT

 

I have this same noise did you ever figure out what it was