Calibrating pop-off valve
 

I have a GReddy pop-off valve mounted on the hard pipe between the IC and the GReddy intake elbow as a fail safe to prevent boost creep and engine damage from over-boost. It was set at 15 psi some months ago, but I wanted to check if the setting had changed with time and vibration on the car. I used a somewhat crude method to check. I took the section of hard pipe with the pop-off valve off the car and using the neoprene sleeves blocked off both ends with two pieces of round PVC cut to tightly fit the hoses with the hose clamps. One PVC got a tire valve stem installed and on the other end I installed a threaded fitting and attached a spare boost gage. Then you can slowly pump up the pressure in the pipe and watch/listen for the pop-off valve to open. Note the pressure on the gage and adjust the valve as needed. One caution- tighten the hose clamps securely. During one test, I got up to about 14 psi and the entire PVC plug and boost valve blew off and shot across the garage.

so was the test ok ?

calibrating popoff valve
 

Kensin- Test was OK after I clamped down hard on the hose clamps. The valve was supposed to be set at 15 psi and that is when the gage showed the valve began to bleed off pressure.

I used to adjust my Greddy Type S (oldschool) with a pressure tester.

pop off valve
 

arghx said "I used to adjust my Greddy Type S (oldschool) with a pressure tester"

Well, that's sort of what I made, except it involved a tire pump and a bunch of clamps, hose, plastic and then the pressure gage. Not real pretty, but it worked. At my previous employer, I would have one of the metrology technicians, who calibrated gages and valves all day long, do the calibration for me.