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Was going to chime in but it looks like @XRJoe hit the nail on the head. Since the BOV is operated via an electronic solenoid it will vent very often, sometimes even when not in boost.

The only way to change this is by running an aftermarket tune where they adjust the BOV tables or by running a true vacuum source to the BOV such as a vacuum line from a Symposer Delete.
 

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"ADJUSTING YOUR BOV
The aim of the adjustment on the Dual port is to make sure that the piston is hard closed at idle and that the piston closes fast enough
to minimise backfiring and not stall the engine. In most cases, the cap is in the correct position from factory but with certain engine
modifications, springs changes are required to tune the performance of the valve to the turbo system.
Adjustment to the BOV is made by rotating the cap. To increase the spring force on the piston, rotate the cap clockwise in the direction
of hard as marked on the top of the cap. To decrease the spring force on the piston, rotate the cap anticlockwise in the direction of soft
as marked on the top of the cap - CAUTION - Do not rotate the cap beyond the O-Ring groove. Once it is confirmed that the piston is
fully closed at idle
, perform the following adjustment procedure.
 Start with the BOV cap at the maximum soft position (The O-Ring should be completely covered by the edge of the cap)
 With the engine at idle the exhaust port should be closed off by the piston – the piston should be hard against the seat and not
floating or moving
 Free rev the engine and back off quickly, the engine should return to normal idle speed – if the engine drops below idle or stalls
increase the spring tension by one turn
 Repeat this process until the engine free revs and returns to normal idle speed
 Test drive the car and ensure that when decelerating or changing gears that the engine has minimal backfiring and no stalling. If
backfiring is"

Here is also the instructions from turbosmart. Notice how they also state to have the piston fully closed at idle.
 

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"ADJUSTING YOUR BOV
The aim of the adjustment on the Dual port is to make sure that the piston is hard closed at idle and that the piston closes fast enough
to minimise backfiring and not stall the engine. In most cases, the cap is in the correct position from factory but with certain engine
modifications, springs changes are required to tune the performance of the valve to the turbo system.
Adjustment to the BOV is made by rotating the cap. To increase the spring force on the piston, rotate the cap clockwise in the direction
of hard as marked on the top of the cap. To decrease the spring force on the piston, rotate the cap anticlockwise in the direction of soft
as marked on the top of the cap - CAUTION - Do not rotate the cap beyond the O-Ring groove. Once it is confirmed that the piston is
fully closed at idle
, perform the following adjustment procedure.
 Start with the BOV cap at the maximum soft position (The O-Ring should be completely covered by the edge of the cap)
 With the engine at idle the exhaust port should be closed off by the piston — the piston should be hard against the seat and not
floating or moving
 Free rev the engine and back off quickly, the engine should return to normal idle speed — if the engine drops below idle or stalls
increase the spring tension by one turn

 Repeat this process until the engine free revs and returns to normal idle speed
 Test drive the car and ensure that when decelerating or changing gears that the engine has minimal backfiring and no stalling. If
backfiring is"


Here is also the instructions from turbosmart. Notice how they also state to have the piston fully closed at idle.
I bolded a few points above. Those directions would be for a MAF car (an application where you're venting metered air). Those wouldn't apply or be necessary on an ST or other MAP car. I still stand by that to have the best response, the valve should be open at idle. On a MAF car, that's not possible since the engine will stall or barely idle. Keeping the valve shut at idle means you'll lose responsiveness on the valve.

Regardless, an OEM BPV will be open at idle and on a MAF or MAP car, there's no drivability issues since if the air is metered, it isn't being lost.

I would trust @XRJoe advice here... The guy knows his turbos.
Thanks :)
 

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I bolded a few points above. Those directions would be for a MAF car (an application where you're venting metered air). Those wouldn't apply or be necessary on an ST or other MAP car. I still stand by that to have the best response, the valve should be open at idle. On a MAF car, that's not possible since the engine will stall or barely idle. Keeping the valve shut at idle means you'll lose responsiveness on the valve.

Regardless, an OEM BPV will be open at idle and on a MAF or MAP car, there's no drivability issues since if the air is metered, it isn't being lost.



Thanks :)
I'll stand by the companies that make the turbo parts for our cars. These instuctions where from them for the valve for our cars. They have alot more experience than you do.

Send from another galaxy.
 

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I'll stand by the companies that make the turbo parts for our cars. These instuctions where from them for the valve for our cars. They have alot more experience than you do.

Send from another galaxy.
Remember those instructions are universal for the following cars. Note that many of them are MAF-based and would need the valve closed to prevent stalling. Yes, Turbosmart does have more experience than I do working with turbos. Turbosmart also uses the same valve for the Focus on a wide range of applications, many of which require the valve being shut at idle to prevent stalling. The directions are universal.

Ford Falcon FG Ecoboost 2.0L 2012-current
Ford F150 3.5 EcoBoost 2011-2012
Ford Focus Mk3 ST 2.0 EcoBoost 2012-current
Ford Focus Mk1 RS 2002-2003
Ford Focus Mk2 XR5/RS/ST 2.5 5 cyl 2005-2010
Porsche 911 GT2 (997) 2008-2012
Porsche 911 Turbo (997) 2006-2013
Volvo C30 T5 2007-2013
Volvo C70 T5 2008-2013
Volvo S40 T5 2004-2012
Volvo S60 T5 2011-current
Volvo V50 T5 2004-2012
Volvo V70 T5 2010

Kompact Shortie - Dual Port
 

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I'll stand by the companies that make the turbo parts for our cars. These instuctions where from them for the valve for our cars. They have alot more experience than you do.

Send from another galaxy.
OP has a BOOMBA BOV...

BOOMBA said XRJoe was right.

why are opinions still being posted?
 

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Because every other source I can find says the opposite. That's why.

Send from another galaxy.
Remember. The other sources are universal valves that happen to fit our cars. They are also BOVs.

OEM BPVs are a different story, and so would be a valve designed specifically and only for MAP-based Focus ST.

I won't put words in Boomba's mouth, but they may have only been agreeing with me on the cycling comment and electronic control.
 

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I'll just believe Turbosport, TiAL and all the other manufactures that have been doing this for a log time. You believe what you want.

Send from another galaxy.
Sounds good! I like to learn from doing and experience, rather than universal directions. Fitting a BOV to a Mk1 FRS or Mk2 ST225/RS needs a completely different setup than the Mk3 ST. The instructions included are the safe, ones size fits all. Believe what you want to believe as well, not my car.
 

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Sounds good! I like to learn from doing and experience, rather than universal directions. Fitting a BOV to a Mk1 FRS or Mk2 ST225/RS needs a completely different setup than the Mk3 ST. The instructions included are the safe, ones size fits all. Believe what you want to believe as well, not my car.
Done plenty of testing on my own car. So don't speak about what I do and don't know.

Send from another galaxy.
 

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Done plenty of testing on my own car. So don't speak about what I do and don't know.

Send from another galaxy.
Care to share what you've learned? What happened with the valve was open at idle? What valves did you try? Was the OEM BPV open or closed at idle with manifold reference and the solenoid removed?

I've done a lot of work on other platforms checking the same things so I'm curious what you've come up with on the ST (serious, not being sarcastic).
 

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I have a stage 2 stratified tune, and currently have a Mountune BPV but I have a turbosmart dual port on the way. Will it cause issues since I am switching that would require me to have Stratified change anything in my tune? I'm very new to turbos so this makes me a bit nervous, though I'm super excited about my BOV.
 

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I have a stage 2 stratified tune, and currently have a Mountune BPV but I have a turbosmart dual port on the way. Will it cause issues since I am switching that would require me to have Stratified change anything in my tune? I'm very new to turbos so this makes me a bit nervous, though I'm super excited about my BOV.
I would reach out to Stratified and see. They'd hopefully know how the two valves behave and what, if anything, needs to be changed in the tune. If you want to use the manifold to directly control the valve then you would do all the fine tuning on your end with the hardware.
 

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The OEM valve should be closed at idle. There will be compressor outlet pressure on both sides, and the very light spring will hold it closed.

Its commonly the goal to keep the valve closed and thus the compressor capable of pressurizing the inlet to help response, with the exception of times where the valve is open to increase net turbocharger acceleration. From Ford's patent on this I linked in the other thread with a similar concern as this, they utilize this at high altitude on some vehicles, however the ST I'm pretty sure is not one of them. For a huge majority of the operating time of a turbocharger, the optimal bypass position is closed.

As such, you want the valve closed at idle. Anything else has the compressor rotating at a higher speed than intended by the ECU as its expecting the valve closed. In a lot of cases, because of the throttle plate delta pressure desired, it may even be commanding a throttle inlet pressure higher than ambient, and thus want the bypass valve certainly held closed.

While a speed density or blowthrough setup will meter air fine with the bypass open, the intent is to keep it closed. It'll operate with it open, but it will pretty much never be the "optimal" configuration.
 

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The OEM valve should be closed at idle. There will be compressor outlet pressure on both sides, and the very light spring will hold it closed.

Its commonly the goal to keep the valve closed and thus the compressor capable of pressurizing the inlet to help response, with the exception of times where the valve is open to increase net turbocharger acceleration. From Ford's patent on this I linked in the other thread with a similar concern as this, they utilize this at high altitude on some vehicles, however the ST I'm pretty sure is not one of them. For a huge majority of the operating time of a turbocharger, the optimal bypass position is closed.

As such, you want the valve closed at idle. Anything else has the compressor rotating at a higher speed than intended by the ECU as its expecting the valve closed. In a lot of cases, because of the throttle plate delta pressure desired, it may even be commanding a throttle inlet pressure higher than ambient, and thus want the bypass valve certainly held closed.

While a speed density or blowthrough setup will meter air fine with the bypass open, the intent is to keep it closed. It'll operate with it open, but it will pretty much never be the "optimal" configuration.
Thanks Bugasu. On other applications where you are running manifold reference directly to the valve, would those also be closed at idle in an OEM application? I see the benefit of keeping the valve closed, but also see the benefit of letting the compression "freewheel" to allow the car to be in boost sooner when the throttle is depressed and the valve closes.
 
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