BOV, how many inches HG does the valve open?

[sly dvl]

Re: BOV, how many inches HG does the valve open?

Ok,
lets try this again.
With the truck idleing the engine produces 18-19 inches of vacuum.

Now,,,, with the engine idleing,,,the BOV is partially open,,,,,,,is this normal??????

As soon as I give it some throttle the BOV closes shut & when I floor it,,, the engine will produce 5-7 psi of boost pressure @ approx 5000 RPM (car parked)

Before ,,,with my 20G turbo & 12 CM housing I got approx 2-3 PSI @ 5000RPM in park.
Guys,am I saying something wrong here?

My turbo now is a TD06H-20G 12 CM turbine housing w/a new 60-1 compressor wheel.

Your BOV is open at idle? You have a problem. Put the spring back in that you removed.
You need MAX vacuum & MAX boost to open that BOV which you are never going to be able to achieve standing still.

 

[It's just a six]

Re: BOV, how many inches HG does the valve open?

Your BOV is open at idle? You have a problem. Put the spring back in that you removed.
You need MAX vacuum & MAX boost to open that BOV which you are never going to be able to achieve standing still.

I allready tried that way (both springs installed) & the BOV never opens.

I ran 22 psi let off the throttle & the BOV never opens period.

It seems to be sealing since I allready see 5-7 psi in park when floored.

I am just concerned that the engine could be injesting unfiltered air since the BOV is partially open?

When I have the engine idleing (18 or so inches of vacuum) & the BOV is partially open I put my hand over the exit of the BOV ,,,but I cannot feel any vacuum there. Weird? yes,no?


Any bit of throttle & if the vacuum drops to about 13-15 inches the BOV is closed.
So if I the engine was under load w/vacuum say 5 inches,the BOV would be closed & sealed. Make sense?

 

[It's just a six]

Re: BOV, how many inches HG does the valve open?

Hey look @ these BOV's they are open under vacuum/idleing also.
http://youtube.com/watch?v=2vTU83Z96-Q
One is a Tial the other a Synasp (SP)

They are pricey & they are both open when the engine is @ idle.

 

[SY2932]

Re: BOV, how many inches HG does the valve open?

x2

and a $19 BOV from egay? you might be working with something that may not be working. :2cents:

X3 No doubt. Now I know why I paid $250+ for my HKS back in the day and I'm about to spend that again on a Tial...

 

[sy2675]

Re: BOV, how many inches HG does the valve open?

again.....how can these bov's work if they open under vaccum? what tells them to close? boost? how can you build boost if that bov is open?

My HKS will open if i rev my truck in "N" and then i let off the throttle, but it is never open when at idol, only opens when the pressure on the turbo side of the throttle body is greater than that of the engine side.


edit....my truck makes 0 boost in P or N,

 

[It's just a six]

Re: BOV, how many inches HG does the valve open?

X3 No doubt. Now I know why I paid $250+ for my HKS back in the day and I'm about to spend that again on a Tial...

Well it works,
No real reason to spend 250 + for a BOV when my $20 one works fine?
Especially when you are on a tight income.

You are looking @ a Tial BOV in the video,,,if you looked @ it & yes, the Tial BOV is open when the engine is ideling.

 

[It's just a six]

Re: BOV, how many inches HG does the valve open?

again.....how can these bov's work if they open under vaccum? what tells them to close? boost? how can you build boost if that bov is open?

My HKS will open if i rev my truck in "N" and then i let off the throttle, but it is never open when at idol, only opens when the pressure on the turbo side of the throttle body is greater than that of the engine side.


edit....my truck makes 0 boost in P or N,

The BOV is to relieve excess boost pressure when your throttle is closed.
What closes them?,,,,,,,,,,,,,, The spring that is in the BOV closes it ,,,,when your engines vacuum is reduced or has zero vacuum.
how can you build boost if that bov is open? the valve closes as soon as you have little to no vacuum from your engine,,,,,so when your BOV is close,you can build boost pressure.
This how the tial BOV is working in the video I posted from youtube ,,and also the Synasp BOV
BTW,what turbo do you have on there that it cannot make boost in park or neutral?

Watch the video & get back to me http://youtube.com/watch?v=2vTU83Z96-Q

The BOV is open when they start up the engine & when they let it idle.

 

[skwayb]

Re: BOV, how many inches HG does the valve open?

Well it works,
No real reason to spend 250 + for a BOV when my $20 one works fine?
Especially when you are on a tight income.

You are looking @ a Tial BOV in the video,,,if you looked @ it & yes, the Tial BOV is open when the engine is ideling.

Well you get what you pay for. Just ask Syclone0565 the difference. His nice $20 ebay special caused him to have all kinds of boost problems.

I'll go start my Ty and see what my TIAL BOV does and report back.

 

[It's just a six]

Re: BOV, how many inches HG does the valve open?

Well you get what you pay for. Just ask Syclone0565 the difference. His nice $20 ebay special caused him to have all kinds of boost problems.

I'll go start my Ty and see what my TIAL BOV does and report back.

I looked under Syclone0565 name here & did not see any topics about him haveing boost problems.

Do you have the link?
Besides,,, If I have boost problems now, I might know where to look? I can allways install a block off plate or install another BOV.

It seems I allready have boost problems now since I can get 5-7 PSi of boost pressure in park & reving the engine to 5K,or @ least that is what some people here seem to think. :rotf:

Did Syclone0565 have the same BOV I have?

Thank you.

 

[Syclone Rob]

Re: BOV, how many inches HG does the valve open?

I have the vortech BOV that I bought from RPM, I checked and at idle, it is slightly open. I screwed down the adjustment screw and its still open at idle a little bit. I put my hand in front of it and I can feel air coming out. As soon as I press the gas a bit, it closes and stays closed till I let off the gas. Maybe I should look into something if this is a problem:dunno:

 

[skwayb]

Re: BOV, how many inches HG does the valve open?

I looked under Syclone0565 name here & did not see any topics about him haveing boost problems.

Do you have the link?
Besides,,, If I have boost problems now, I might know where to look? I can allways install a block off plate or install another BOV.

It seems I allready have boost problems now since I can get 5-7 PSi of boost pressure in park & reving the engine to 5K,or @ least that is what some people here seem to think. :rotf:

Did Syclone0565 have the same BOV I have?

Thank you.

He didn't post about it. I saw it happen at NATS and when I road in his truck. Once he removed the eBay BOV, his problem went away. Then he decided to do a Turbo'd LS in his Sy.

I just checked my TIAL BOV and it doesn't open at all at idle. So not sure why that one in the video did.

 

[ashman]

Re: BOV, how many inches HG does the valve open?

so, based on what everyone is saying, the BOV operates when it see a difference between manifold vacuum and turbo output. and, in this case, the BOV starts opening at 14in difference.

if your BOV is opening, then the difference in manifold vacuum and turbo output is greater than 14in which is probably normal. if you have a tight engine and the vacuum is very good and the turbo is pressurizing the intake tube at idle (with throttle blade closed), then the BOV should be opening slightly because the difference is even greater. but, it's not sucking in air, it's blowing out excess turbo air and will close as soon as the throttle is opened.

if it's not opening at idle, then the BOV is set to operate at a greater difference or the difference generated by the engine/turbo is not as high.

 

[It's just a six]

Re: BOV, how many inches HG does the valve open?

He didn't post about it. I saw it happen at NATS and when I road in his truck. Once he removed the eBay BOV, his problem went away. Then he decided to do a Turbo'd LS in his Sy.

I just checked my TIAL BOV and it doesn't open at all at idle. So not sure why that one in the video did.

Here is what Syclone0565 just PM'd me Quote"
"I never purchased a BOV from ebay. I do not run one. Sorry"

Quote:
Originally Posted by It's just a six
Hi,
I was wondering what BOV you purchased on Ebay for $20 that gave you all kinds of boost problems?

There is a topic I started about my cheap BOV I purchased from Ebay.
Thanks

__________________

 

[sly dvl]

Re: BOV, how many inches HG does the valve open?

so, if you have a tight engine and the vacuum is very good and the turbo is pressurizing the intake tube at idle (

How can a turbo create any pressure at idle? C'mon now.
The only pressure applied to that BOV at idle is atmospheric.

 

[It's just a six]

Re: BOV, how many inches HG does the valve open?

I have the vortech BOV that I bought from RPM, I checked and at idle, it is slightly open. I screwed down the adjustment screw and its still open at idle a little bit. I put my hand in front of it and I can feel air coming out. As soon as I press the gas a bit, it closes and stays closed till I let off the gas. Maybe I should look into something if this is a problem:dunno:

Well,as far as my Sy goes ,it seems to be working OK.
But I have a feeling that some guys just install a BOV & do not check it (look at it to see it opperate.

Now,before I posted this topic,,you had allready installed it correct & did not look @ it opperate ,correct? ,,,,,,,,,,,,,,,,,,,,,,,,,,Just my point.

Most people jumped on the band wagon & said there is something wrong w/my BOV,get what you pay for & so on.,,,without even looking @ the video I posted & without looking @ there own vehicles. Maybe?yes,maybe no?

I just wanted some feedback to see if this is normal operation & people started posting without actually looking @ the video or @ there own vehicle.

No harm,no foul.

 

[sy2675]

Re: BOV, how many inches HG does the valve open?

BTW,what turbo do you have on there that it cannot make boost in park or neutral?.

Help me out here fellas, by a show of hands, how many of you can build boost in park or neutral?

And i do understand what a BOV does, but how much difference can there be from one side of the throttle body can there be at idle to warrant it to be open?

edit: I have a PTE52 turbo

 

[ashman]

Re: BOV, how many inches HG does the valve open?

How can a turbo create any pressure at idle? C'mon now.
The only pressure applied to that BOV at idle is atmospheric.

effectively, it's a fan blowing into a sealed tube...i'm sure there a small amount of pressure there. just because you're idling doesn't mean the turbo is not spinning. i may be wrong :lol:

 

[THEMADTYPH00N]

Re: BOV, how many inches HG does the valve open?

The BOV is open when they start up the engine & when they let it idle.

They have it adjusted incorrectly. This is how it should be

http://youtube.com/watch?v=8-JTfgpFKrM&feature=related

Notice it closes when the car returns to idle.

 

[sy2675]

Re: BOV, how many inches HG does the valve open?

They have it adjusted incorrectly. This is how it should be

http://youtube.com/watch?v=8-JTfgpFKrM&feature=related

Notice it closes when the car returns to idle.

That is how it should work in my mind, and how my hks works.

effectively, it's a fan blowing into a sealed tube...i'm sure there a small amount of pressure there. just because you're idling doesn't mean the turbo is not spinning. i may be wrong :lol:

x2, when reving my BOV will vent when you let off, even in N or Park. but not much, at idle its completely sealed.

at least im back to feeling confident that i know how its supposed to work.

 

[Syclone Rob]

Re: BOV, how many inches HG does the valve open?

How can a turbo create any pressure at idle? C'mon now.
The only pressure applied to that BOV at idle is atmospheric.

But the reference vacuum is taken after the Tb pblades and at idle would be in a vacuum state.. Before the tb blades it would be close to atmospheric pressure, after should be in vacuum. Which is why I thought it was normal for my BOV to be slightly open @ idle but if that it should be closed (which truthfully I do prefer it to be) would be nice to know how to fix.