BOV questions

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blazer71

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• Mar 13, 2014

• #1

Who is running a BOV? I'm not versed in the box kit late model stuff like Silber and BD to even know what components are used. Listening to videos, that flutter noise sound is what I'm use to hearing without a BOV as boost chops it way through the impeller housing fighting the compressor wheel on the otherwise. My BOV makes one single wish noise.

For those running a BOV, where are you pulling your signal from? I've heard two different theory's. Signal must come from a vacuum source on engine side of throttle plate. Then I've seen that signal come straight from boost manifold right to the BOV.

Let's hear it?

 

friscospices.com

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• Mar 13, 2014

• #2

One side of the blow off is in the boost tube holding the boost pressure from escaping the othe ra small hose from the engine side of the throttle bodies pulls a vacuum on the BOV allowing the boost to escape when the throttle bodies close. Different BOV's sound different you can actually buy ones that are louder but they all do the same thing.

 

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blazer71

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• Mar 14, 2014

• #3

Thanks for your feedback. That's how I set mine up based on my boost knowledge from the automotive world.

 

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St0rm77

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• Mar 14, 2014

• #4

mine is mounted on my intercooler, just after the charge tube enters it, that side is referenced to boost, while the sensing line side is referenced to the engine side of the throttle bodies. when the throttle is chopped, vacuum is pulled on the sensing line side, causing my plunger to move and relieve boost pressure from the charge side of the turbo, mitigating/eliminating the 'flutter' which is compressor surge. Surging repeatedly can damage turbo bearings and compressor wheels.

 

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NEWDUCK

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• Mar 20, 2014

• #5

Is it normal to have a bov open at an idle? Mine sits and "flutters"

 

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St0rm77

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• Mar 20, 2014

• #6

i would think not; you shouldn't be building any significant level of boost at idle. i would check to make sure that the 'flutter' is indeed coming from the BOV, and not internal to the turbo or intake tube, seeing as the flutter i'm used to is compressor surge.
If it is coming from the BOV, i'd look for leaks in your BOV tubing from the throttle bodies, check the spring in the BOV for damage, and make sure the shuttle body moves freely.
anybody else more versed in turbos have any other ideas?

NEWDUCK said:

Is it normal to have a bov open at an idle? Mine sits and "flutters"

Click to expand...

 

Polarisrocks

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• Mar 21, 2014

• #7

It will help if you can tie into both cylinders you will have a more stable vacuum signal. Also don't share anything from this line either.. You will need to modify your bov spring so its open or half open at an idle with the sled warm. If you crack the throttle the valve should open all the way at 2500-3500. I had to get a light spring from a old set of Polaris round slide carbs. It went right in and I didn't have to trim any coils to get it be open at idle.

Jim

 

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blazer71

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• Mar 22, 2014

• #8

Polaris Rocks is right about the pulse signal. If you could pull it from both cylinders it would be more smooth. The spool valve in my BOV "flutters" at idle too. And by flutter I mean a rapid up/down cycling of about 1/16th to 1/8th inch. It's because there isn't a smooth application of vacuum coming from a signal vacuum pulse of a single cylinder. Like a car would have a more static vaccum signal due to multiple cylinders.

What I don't agree with is after you crack the throttle and eliminate manifold vacuum, the BOV should immediately close , not open.

In my opinion, if it seats as soon as you crack the throttle, teeing the pulse signal lines of both cylinders together has no advantage.

 

Last edited: Mar 22, 2014

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NEWDUCK

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• Mar 22, 2014

• #9

I started watching it and Im good to go. At idle it opens then shuts down when enough throttle is applied and vacuum is lost. Just seemed odd after 2 years I never noticed it opening at an idle.

 

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INDEEP

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Nov 26, 2007

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• Mar 7, 2017

• #10

Is the reason you want it to be open at idle more available air pre boost?

 

AKFULLTHROTTLE

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• Mar 7, 2017

• #11

Funny this is brought up because I have been thinking about it. All of our Silber sleds seam to be a little different.

We tie in with a hole in the PTO side TB boot.

I see MTNTK has it coming front the side of the Reed cage.

It does sound more like flutter than BOV and I have "T" into it for a boost gauge which IMO makes it louder.