[How to] Install a blow-off valve

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Postby BriinumsBo » Sat Oct 18, 2008 5:42 am

anywhere where you see a vacuum line coming out of intake manifold. try to find a line that connects to some non-vital part. e.g. if you connect to the line that goes to fuel pump pressure sensor, you might get a slower fuel pump switch (from low to high mode, if st165 has it). its not that connecting something to the vacuum line makes a difference in other parts of the system, but it might if you give too much room in the vacuum hose :)
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recirculating the blowoff valve

Postby PatmanBBE » Fri Nov 21, 2008 8:38 pm

I am installing a GReddy BOV it has two lines coming out. I think one is supposed to tie into my wastegate actuator connecting it to the BOV and the other is vacuum. I just dont know which is the actuator connector and which is the vacuum.

Where should I connect the hose to recirculate the pressure? I have too many cops in my city to vent into the atmo. Also what can I use to recirculate it? I have some turbo tubing that fits onto the BOV but its not very flexible.

Also can I install my BOV after the FMIC or does it need to go on after the turbo and before the FMIC?
1988 Celica Alltrac Blue
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Re: recirculating the blowoff valve

Postby BriinumsBo » Sat Nov 22, 2008 7:53 am

PatmanBBE wrote:I am installing a GReddy BOV it has two lines coming out. I think one is supposed to tie into my wastegate actuator connecting it to the BOV and the other is vacuum. I just dont know which is the actuator connector and which is the vacuum.

Where should I connect the hose to recirculate the pressure? I have too many cops in my city to vent into the atmo. Also what can I use to recirculate it? I have some turbo tubing that fits onto the BOV but its not very flexible.

Also can I install my BOV after the FMIC or does it need to go on after the turbo and before the FMIC?


BOV hose for wastegate actuator? why would you do that? the only solution i have ever thought about is if some mechanism put vacuum on wastegate so that the turbine wheel isn`t stopped by vacuum between exhaust ports and turbo.. but i dont think a BOV could fulfill this.

recirculation must go back somewhere between air filter and turbo.

BOV can and SHOULD be after intercooler! in this way air is circulated throughout the intercooler and kept cool!

post your setup pic
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Postby 05christj » Sat Nov 22, 2008 5:23 pm

The top nipple is for vaccum (off your intake manifold) and the lower nipple is for pressure (off your IC pipe) however only the vacume line is needed. the pressure nipple is just there to help open up the BOV faster.




you can see how it would work here
http://images.google.com/imgres?imgurl= ... %26hl%3Den

the red part is the valve that releses the air you can see how vaccum from the top nipple would pull it up and how pressure building in the bottom (after the throttle plate closes) would help push the valve up to let air out
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Now I understand!

Postby PatmanBBE » Sun Nov 23, 2008 8:29 am

Ok kewl. I get it now. I am taking the car to get it smogged on monday. I hope it passes I set the timing back to almost stock settings, It makes the car drive like shit, but it should help me pass smog. Once I pass Im installing my BOV. Thanks guys for the help.
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Postby 05christj » Sun Nov 23, 2008 12:59 pm

let me know how it works out. I'll be following the build of this car and handing out any tips I might have. but it seems like you have a game plann good luck
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Postby kingcobb » Mon Nov 24, 2008 8:34 pm

does anyone know where to buy the samco silicon t-piece, speedfactor in winnipeg, which is a performance store don't sell them, and i'm really in need of one.
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Postby 05christj » Wed Nov 26, 2008 4:09 am

I'm sure 935 sells them
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Postby Sheng » Fri Jan 23, 2009 1:30 am

Just wondering what PSI should you set the BOV at, mine is adjustable so i was just wondering approximately what psi should i set the bov to open.

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Postby SuperWhite92 » Fri Jan 23, 2009 5:12 am

Sheng wrote:Just wondering what PSI should you set the BOV at, mine is adjustable so i was just wondering approximately what psi should i set the bov to open.

Sheng


You don't set a BOV to open at a PSI. You set it so it doesn't leak at whatever PSI you're already set at.
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Postby BriinumsBo » Fri Jan 23, 2009 9:21 am

the adjustment is for vacuum!!!
the BOV opens when a vacuum is reached in intake manifold (when the throttle valve is closed before the intake manifold). when there is a vacuum, the BOV opens, no mater how much boost or no boost is in the intercooler. the adjustment is for how much vacuum needs to be to open the valve. if your car doesnt run on high vacuum, it should be adjusted to softer setting so that it opens at all. but it if the adjustment is too soft, the boost pressure would push against and open the BOV, because of the soft resistance - in result the turbo would leak boost.
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Postby Sheng » Fri Jan 23, 2009 5:42 pm

So then another question :oops:, how would you know what setting on the bov would be ideal for the vaccum? is it when it stops leaking during idle?

Sheng
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Postby BriinumsBo » Sun Jan 25, 2009 4:59 pm

Sheng wrote:So then another question :oops:, how would you know what setting on the bov would be ideal for the vaccum? is it when it stops leaking during idle?

Sheng


no. during idle the car is in vacuum and it should be open (except if you vent to atmosphere and use AFM, then you will go LEAN). some BOVS open only when there is both vacuum in intake manifold AND boost in intercooler.
you dont want to leak it under boost conditions. at intake manifold vacuum it should open.
you have to make sure that when you accelerate (intake manifold gets positive pressure) the valve closes
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Postby Sheng » Sun Jan 25, 2009 7:36 pm

ahh k now i understand completely, since at idle it's at vaccum during acceleration it goes towards 0 and at boost it's + in pressure. k i was a complete noob when it came to this and trying to figure it out :oops:

thanks

Sheng
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JDM 2nd gen 3sgte, 3" turbo-back motoria exhaust, boost guage

after winter
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Postby Gary » Mon Jan 26, 2009 5:51 pm

Not really. BOV opens not just when there is vacuum in the intake manifold. There has to be pressure in the intercooler too. That mean it opens only when there is a difference in pressure between intercooler pipe and behind the throttle plate. It only occurs when you close the throttle plate abruptly (lift of your right gas pedal after boosting).
So, at idle, BOV should be completely close. If it is open at idle, you should adjust the spring tension so that it is close. While boosting, it should not leak (same pressure on both sides).
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