Greddy BOV...Vac from 2nd nip

[SleepingTsi94]

I have a greddy bov on my car. I got the top line hooked to the intake and have always left the 2nd one unhooked. Well now its pulling vac? Whats going on. My boost gauge does not show im losing vac or anything. So???

 

[winterftbl]

Its not your bov because the second hole should be left unplugged.

 

[marq95gst]

"My boost gauge does not show im losing vac or anything. So???"

So your car is idling fine? Then you shouldn't have a problem. You do have it hooked up to the intake manifold and not the intake right?

 

[SleepingTsi94]

Yes...run fine and hooked up right....Just it never pulled vac from the 2nd one.

 

[daren_p]

Where that lower port is fed off of is supposed to be a sealed chamber, so if your now seeing vacuum there you have a leak. More then likely you have a hole in the diaphragm.

 

[SleepingTsi94]

Sooo Time for new bov?

 

[UofACATS]

Air is not supposed to enter at the lower nipple. Something is wrong with the valve. You don't necessarily need a new one however, try capping it off first.

 

[EclipseTrbo420A]

Where that lower port is fed off of is supposed to be a sealed chamber, so if your now seeing vacuum there you have a leak. More then likely you have a hole in the diaphragm.

This is correct...you need a new BOV or a new diaphram.

 

[Slow 95 TSI]

If it's a real Greddy just rebuild it. If it's a greddy knock off toss it, they cost more to rebuild than to just buy another one.

 

[boostnhard]

Sorry for the dumb question, whats the lower nipple for?????

 

[EclipseTrbo420A]

a boost source... it alows the bov to hold more pressure and blow of more quickly

 

[daren_p]

a boost source... it alows the bov to hold more pressure and blow of more quickly

Blow off quicker, yes. Hold more pressure, no. If you hook up the lower nipple to a pressure only source (like off the comp, jpipe etc), you get a faster blow off, like how the factory 1g valve works but the trade off is it won't hold as much boost. You can tighten up the adjuster bolt to hold more boost but you still won't be able to hold as much pressure as a valve without the lower nipple connected thats adjusted to the same tension.

If it is the diaphragm leaking you can purchase just the diaphragm from Greddy but there not cheep, think around $75 or something.

 

[EclipseTrbo420A]

Blow off quicker, yes. Hold more pressure, no. If you hook up the lower nipple to a pressure only source (like off the comp, jpipe etc), you get a faster blow off, like how the factory 1g valve works but the trade off is it won't hold as much boost. You can tighten up the adjuster bolt to hold more boost but you still won't be able to hold as much pressure as a valve without the lower nipple connected thats adjusted to the same tension.

If it is the diaphragm leaking you can purchase just the diaphragm from Greddy but there not cheep, think around $75 or something.

See I think your wrong. I believe the adjustment screw all the way in, with bothsprings and with out the bottom nipple hooked will cause major surge IF it even opens ( DUH ), but adding the bottom nipple to the boost source will blow it open just fine.

We can agree that because the bottom nipple is hooked to a boost source, what ever PSI is built under the diaphragm at WOT will not help the BOV to hold more, but I think that the mechanics of the BOV are stronger than that of the pressure under the BOV.

Meaning tightening it all the way will OVER power the all the pressure wanting to push it open and allow for us to hold more, BUT ONLY when we let of the throttle and there is MORE pressure built on the underside of the piston and under the diaphragm AND theres VAC in the top chamber then those three working against the spring will beable to effectivly open the bov faster so heres an easy way to put it

With the bottom nipple hooked up:

Under WOT there 2 forces working to keep it closed and 2 working to keep it open.( The spring tension is adjustable, allowing us to hold more boost )

When Blowing off theres 3 forces working to open it and ONLY 1 working to keep it closed. ( Even though the added holding power from the spring at WOT was able to keep is closed because it was working along side the manifold pressure, the manifold pressure turns to VAC and teams up with the pressure UNDER the diaphragm and under the piston...so you see it does help hold more AND will make it blow off ALOT quicker.

At WOT the 2 forces to keep it closed are stronger

At Blow off the 3 forces are stronger to open it, than the 1 to keep it closed


I added a second nipple to my SSQ wont ever leak. but it IS different than the type S