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Discussion Starter · #1 ·
Hey there, i have a GFB mach 1 bov, and was what exactly happens if i screw the nut type thing that the rubber hose is attached to on the top of the bov in or out....

My under standing is the lower or tighter the screw is the more pressure is needed to release the valve to make it move.

where is the optimal place to have it???

And buy screwing it in or out , does this affect the performance and or noise??

Hope this makes sense thanx
 

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im not sure about the GFB BOV's...but if its a type 1 equivalent, u cant adjust it(correct me if im wrong).
that bolt thingy on the top that the vacuum hose goes to doesnt matter how tight or loose it is(i tried running my BOV with it all the way in, then all the way up...and it made no difference). it just holds the vacuum hose in place. or so ive been told to believe. im sure someone will correct me if im wrong.

so to answer your question. leave it all the way down(tightest so no air escapes around the edge of the vacuum hose and the bolt)

cheers mate :)
 

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I think the adjustment is more of not opening while under load and passing off load .. IE if you are boosting (spooling up) it should be sealed, and if you have it to loose/open it may pass..
And the other side of the equation is you do want it to open under minimal boost-relece .. You will have to trial and error it to your own liking/setup .. .
 

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I don't have a BOV, but I would assume that you'd want to make sure it wasn't venting at idle vacuum. Use that as a starting point and work from there. I wonder what vacuum actuates the BPV???
 

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ok i went and screwed mine all the way to the bottom. it was finger tightened about half way until now.
ill get back to you on how it goes.

cheers :)
 

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to set your BOV the best way due to intercooler restriction

is to idle your car warm take it for a few hits

Then adjust it till it leaks at idle car= make it looser make is leak then turn it untill it stops leaking give it a few revs between.

THEN turn it 1 and 1/2 turns tighter. Done it shouldn't leak and when the pressure is right it will work correctly.
 

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does it hurt to leave it all the way down?
 

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No your one I think you can only change with shims inside.
 

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Just talked to my mate he has a maximus GFB's one

if it is leaking loosen the holding nut or ring thing
and screw the top bit with hose in to tighten up the BOV if it's too tight go the other way.

I would go untill it leaks and again a at least 1 and 1/2 turns. reason for this is so that incase you get a surge of vacum in the manifold and if pressures become unequal - not uncomon it won't leak just after you lift off.
 

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No your one I think you can only change with shims inside.
so it doesnt matter how high(how toghtly screwed in) it is?
 

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if it is tightened too much, then you will get a substantial amount of compressor surge before it blows off. i set my ts type2 to where the top section of the bov (where u adjust it from) just covers the lip of the top section of the actual bov. it was the best point for maximum/instant blow off. basically, it was going off at 5vacuum. so aim for about that when you are adjusting it.
 

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Idle vaccum is 19~21 in-Hg so that would mean you're venting at idle. You've fuel economy must be sh!t. Without owning one and never adjusting one, my gut feeling would be to adjust it to vent at 25~30. But I really wouldn't know.XO
 

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your right crusty but on type 2 it has a stronger spring but it would leak if adjusted like that.
Bov's can go off with out being under bosot but as you still have some pressure. weak springs I've seen go off real quickly.
 

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ok i played around with my one today. with it all the way down, u could hardly hear it even under the hardest boost. i played with it until i got it to vent only under medium/high boosting.

so in the end, the screw is about 70% tightened. i.e. only 30% of the thread is visible.

hope this helps maz22t :)
 

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Discussion Starter · #15 ·
Thanx guys, had a bit of a play with mine today, and got it to vent around light to medium, boost which is almost where, it was b4, but it seems to vent alittle earlyer....... thanx for the feedback
 

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try running the BOV with the screw the tightest it can go for a week. then try it all the way open for a week.

then see if ur fuel economy dramatically changes between those 2 weeks.
im personally curious to see if a leaking BOV can cause richness to such an extent as to cause economy to be around 13L/100km which mine is now.

if economy does not change...u would be able to set it on the highest level that it opens all the time(keeps turbine spinning no matter what) but this is unlikely i think.
 
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