Hi I am trying to get to the real answer to this question. From what I have heard the HKS popoff valve allows you Bleed the
excess boost pressure at the certain psi limit that you set? (eg if you set it at 17psi it will it stay at 17, like a boost controller.
From what the people at RP say the greddy relieve valve does something different by simply popping off and relieving
all the pressure into the atmosphere, not maintaining any intake boost pressure that you previouslly set.

I have asked this question at many places and have gotten different answers. I want the truth!

THanks

P.S. Don't tell me I can't handle the truth

 

I have the GReddy popoff valve. It is really like any other pressure relief valve you might find on air or steam fittings, only a higher quality construction. If you set it to, for example, 15 psi, when the pressure reaches 15 psi, it opens and vents until the pressure goes below 15 psi, then it closes. You may momentarily go slightly below 15 psi, but you do not lose *all* of the pressure. For the GReddy, you will have to calibrate it with a gauge, since there is only a set-screw-like adjustment to inrease or decrease the tension on the release spring. Instructions included are plainly given in Japanese. The mechanism is really simple and pretty foolproof and is good insurance for protection against boost spikes or creep, if your system is running higher boost or if you have removed your main cat and are using a midpipe. Only disadvantage is that it is a PIA to fabricate a place to attach it to your intake. There is an adapter plate available, but you still have some welding and grinding to do to make it fit.

 

If your interested I have a HKS pop off valve w/ a 18lb spring already set at 17lbs for sale. $50 and its yours. Email me if your interested. Its only 4months old. I took it off when I installed my single turbo. ErnieRX7@aol.com

 

Holy Across the Ocean, Batman! I didn't notice where your from.....:p You pick up the shipping costs...