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need help with BOV

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Old Apr 20, 2014 | 02:18 AM
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Hey guys I fired up the truck for the first time tonight. Just wondering why the bov is open at idle. It is a 60mm Jgs unit. It came with two other springs. Do I need a stiffer spring or softer? Any help would be appreciated.
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Old Apr 20, 2014 | 07:48 AM
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thats normal
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Old Apr 20, 2014 | 08:01 AM
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Just means you're referencing your vacuum after the throttle body so its "pulling" on the Bov. not a big deal.

But if it bothers you reference it before the throttle body on the cold side. Zero vacuum but it will still see boost.

EDIT: Do NOT listen to my horrible advice ^^^^^^ was thinking about totally different ****.

Last edited by TrickrTreat; Apr 25, 2014 at 07:05 PM.
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Old Apr 20, 2014 | 08:12 AM
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Originally Posted by TrickrTreat
Just means you're referencing your vacuum after the throttle body so its "pulling" on the Bov. not a big deal.

But if it bothers you reference it before the throttle body on the cold side. Zero vacuum but it will still see boost.
lol, I would not listen to this guy. If you reference it to the charge pipe it will never see vacuum...
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Old Apr 20, 2014 | 08:26 AM
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I thought on a turbo car it should be closed on idle and supercharged open. If its open wont it suck in outside air and mess with the air fuel? Sorry for my ignorance I'm new to the turbo world. Would love for you guys to hear my hard work. How do I post a video?
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Old Apr 20, 2014 | 10:03 AM
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Originally Posted by 70c10
I thought on a turbo car it should be closed on idle and supercharged open. If its open wont it suck in outside air and mess with the air fuel? Sorry for my ignorance I'm new to the turbo world. Would love for you guys to hear my hard work. How do I post a video?
I'm new to the turbo world too but I think the Bov goes before all sensors so all the air is the same at that point.
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Old Apr 20, 2014 | 10:21 AM
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if your using a MAF you want the BOV in front of it.
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Old Apr 20, 2014 | 10:33 AM
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Originally Posted by samdogmx
if your using a MAF you want the BOV in front of it.
It is speed denisity.
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Old Apr 20, 2014 | 02:02 PM
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I put the next stiffer spring in mine. It stays closed at idle.
I measured the vacuum required to open it to be 16".
It is referenced to manifold vac.
Works perfect.
I assume it's open a bit at cruise, but I can't see under the hood while I'm driving. :-)

Ron
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Old Apr 20, 2014 | 02:40 PM
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Originally Posted by RonSSNova
I put the next stiffer spring in mine. It stays closed at idle.
I measured the vacuum required to open it to be 16".
It is referenced to manifold vac.
Works perfect.
I assume it's open a bit at cruise, but I can't see under the hood while I'm driving. :-)

Ron
Ok maybe I'll try that. At idle I'm seeing 16" inches of vacuum with it open and when I hit the gas the BOV closes and the gauge reads around 20-21". Also the my wide band shows the A/F around 14.6-14.9. Is that ok?
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Old Apr 20, 2014 | 08:18 PM
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Bov's should NOT be open on a turbo car at idle.

Look through the papers that came with the BOV. You'll have to use the correct spring rated for the amount of vaccum your engine makes at idle at operating temp. The correct spring will keep it closed at idle, but will crack a little with minor adjustments in the throttle (while driving) and off course when you let off at full boost.
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Old Apr 24, 2014 | 01:34 PM
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Originally Posted by Busa_rob
Bov's should NOT be open on a turbo car at idle.

Look through the papers that came with the BOV. You'll have to use the correct spring rated for the amount of vaccum your engine makes at idle at operating temp. The correct spring will keep it closed at idle, but will crack a little with minor adjustments in the throttle (while driving) and off course when you let off at full boost.
Ok I will try a different spring. At idle I'm seeing 16 " of vacuum with the BOV open. When I step on the gas the vacuum raises until it closes. Should I go off of the idle vacuum or what it takes it to close.
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Old Apr 24, 2014 | 05:21 PM
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Originally Posted by 70c10
Ok I will try a different spring. At idle I'm seeing 16 " of vacuum with the BOV open. When I step on the gas the vacuum raises until it closes. Should I go off of the idle vacuum or what it takes it to close.
Anyone?
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Old Apr 24, 2014 | 05:33 PM
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Just try the stronger spring.
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Old Apr 24, 2014 | 05:41 PM
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BOV should be closed at idle. At idle, the turbo likely isn't spinning fast enough to move more air than the engine is sucking in, so if the BOV is open at idle it will suck unfiltered air in through the BOV. You may need to shim the lighter spring or cut down the stiffer spring to get it to work correctly.
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Old Apr 24, 2014 | 06:32 PM
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Originally Posted by Ferocity02
BOV should be closed at idle. At idle, the turbo likely isn't spinning fast enough to move more air than the engine is sucking in, so if the BOV is open at idle it will suck unfiltered air in through the BOV. You may need to shim the lighter spring or cut down the stiffer spring to get it to work correctly.
Ok guys put in the stiffer spring and now it is closed on idle but it idles like crap. When I rev it up it opens a little then slams closed. Is this right?
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Old Apr 24, 2014 | 07:13 PM
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Here is a video clip with the stiffer spring. You can see a couple of times where it doesn't close all the way.
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Old Apr 24, 2014 | 08:24 PM
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It idles better now. I think it was too cold still. This video is with the large spring and small spring. It stays shut during idle. Should the valve open more then what it does when I let off the gas after a rev?
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Old Apr 25, 2014 | 02:54 AM
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Looks fine, when you've 20psi boost also pushing against the valve after you lift off momentarily, it will open as much as it needs.
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Old Apr 25, 2014 | 07:03 PM
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Originally Posted by samdogmx
lol, I would not listen to this guy. If you reference it to the charge pipe it will never see vacuum...

Lmao good catch brotha!!! I had my mind on FPR's for some reason. My bad
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