Hey, twin turbo guys!

[Aussie-up-north]

Hey all, when idling your twin turbo set ups are the BOVs closed or open?

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[Jackson1320]

Hey all, when idling your twin turbo set ups are the BOVs closed or open?

Closed. When you idle you are not making any boost so you have no need for the bov to be open.

 

[80FoxCoupe]

At idle, a vacuum condition is present in the intake manifold. The BOV vacuum source is from the intake manifold. Therefore the BOV is open at idle.

 

[Jackson1320]

At idle, a vacuum condition is present in the intake manifold. The BOV vacuum source is from the intake manifold. Therefore the BOV is open at idle.

Are you 100% I have never seen a bov open at idle. It will pull in unfiltered air through the bov if it is open. Only open on centrifugals

 

[Zrussian13]

I think 80fox is correct. I only noticed this when I had my bumper off running the car looking for false knock a couple weeks ago. Open at idle and snap shut right when you hit the gas.

 

[Jackson1320]

I think 80fox is correct. I only noticed this when I had my bumper off running the car looking for false knock a couple weeks ago. Open at idle and snap shut right when you hit the gas.

Is there a filter on the bov?

 

[Zrussian13]

Not unless it's integrated in the bov.

 

[80FoxCoupe]

Are you 100% I have never seen a bov open at idle. It will pull in unfiltered air through the bov if it is open. Only open on centrifugals

I always had my BOV cracked open just a touch at idle. I suppose you could adjust it to be closed at idle if unfiltered air or unmetered air was an issue. I always had no filters on turbo and MAF downstream of BOV , so open at idle was the setup.

 

[WD Pro]

BOV on my old school Cosworth was defo open at idle.

The BOV I have for my latest engine has an inbuilt K&N to allow for what would have been unfiltered air

Twin piston BOV’s were also available to stop the unfiltered air, but I have had trouble with those ‘sticking’.

WD

 

[Jackson1320]

Ok you are talking about a diverter valve does it have springs inside that you can swap and a adjustment?

 

[WD Pro]

Valve connected either side of the throttle body.

Intercooler side is sealed with a silicon Kevlar diaphragm.

Spring sits on the back of the diaphragm and keeps it closed when both sides see the same pressure.

Engine side connects to inlet manifold.

Dunno what you guys call them, but over here this is an old school dump valve (but rare with a K&N) - here’s an exploded view of the type that I have :

Heres mine, but with the filter and filter securing plate stripped off and bagged whilst it’s in storage :

WD

 

[beefcake]

if you have a -2 spring, which most do, and your idling at -10, you will be open....

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