blow off valve question
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From: its as intense as the time i forgot how to sit down
blow off valve question ok here it is,i have a single turbo and i have an hks blow off valve,on this said valve it has two vac. ports one on top and on on the side,now in the instructions it says to hook the one on the side to the turbo housing and the one on the top to an intake sorurce,it blows off to the atmosphere,now the question is is it supposed to be open at idle even after adjusting the screw all the way in and all the way out or is it supposed to close at idle and only open when it sees sudden vac and then close up again, i think i may have a deff. valve and befoe i send it back to hks i wanted to make sure it is supposed to do this
Well not from a HKS BOV but it might help. This is from an instruction sheet for a BOV that I have,
Adjustment of the BOV
1) With the vehicle idling, visually check that the exhaust ports of the BOV are FULLY CLOSED.
2) If the exhaust ports are not fully closed or if the engine is not idling smoothly, then the valve's spring needs to be tension needs to be increased. If the exhaust ports are closed and the vehicle is running smoothly, then no adjustment is required
J
Adjustment of the BOV
1) With the vehicle idling, visually check that the exhaust ports of the BOV are FULLY CLOSED.
2) If the exhaust ports are not fully closed or if the engine is not idling smoothly, then the valve's spring needs to be tension needs to be increased. If the exhaust ports are closed and the vehicle is running smoothly, then no adjustment is required
J
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The blowoff valve relieves pressure from the intake tract when the pressure is higher in the turbo discharge tubing than the pressure in the intake (indicating that the throttle blade has been closed). Sorry if that's obvious, but it gets everyone on the same page.
That said, the blowoff valve must remain closed under boost while accelerating or at idle. When the throttle is released, a differential between the intake and the turbo discharge tubing occurs, making the manifold see vacuum while the turbo discharge tubing is still seeing pressure. It's this differential that activates the BOV, so the port coinciding with the down stroke of the valve in the BOV should be ported to the positive pressure side of the equation, meaning the turbo discharge tubing. The vacuum side (intake) should be ported to the upstroke side of the BOV, which holds the BOV closed until the throttle begins to close.
Hope this helps.
SC-
OBTW - My friend here says to port a 15 lb bottle of nitrous to the BOV for best results.
ie- "MORE IS BETTER!"
That said, the blowoff valve must remain closed under boost while accelerating or at idle. When the throttle is released, a differential between the intake and the turbo discharge tubing occurs, making the manifold see vacuum while the turbo discharge tubing is still seeing pressure. It's this differential that activates the BOV, so the port coinciding with the down stroke of the valve in the BOV should be ported to the positive pressure side of the equation, meaning the turbo discharge tubing. The vacuum side (intake) should be ported to the upstroke side of the BOV, which holds the BOV closed until the throttle begins to close.
Hope this helps.
SC-
OBTW - My friend here says to port a 15 lb bottle of nitrous to the BOV for best results.
ie- "MORE IS BETTER!" Thread Starter
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From: its as intense as the time i forgot how to sit down
ok thats what i did,and even swtched them around to see if i was just stupid and the valve didnt relese at all,i put them back and let it idle turned the screw both ways and the valve still stays open during idle,so to you does that sound like a bad bov,rob is nice enough to put it on his car and see if is not working properly,and if it isnt he is going to give me his but i feel bad is there a way that i can contact hks and get it replaced through them rather than burdon rob,because when i got it in the kit the box was opened and the valve had marks on it where it looks like it was previously installed,thanks guys
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For HKS Product Technical Questions
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By phone
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M thru F 8am-5pm PST
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By mail
HKS USA
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www.hksusa.com
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