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Old 09-16-2008, 01:25 AM   #1
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Default BOV installation and andjustment questions

i purchased a bosch style BOV from ebay (i know purple is lame, but cheap is good). This one:

It seems people mount these two ways as shown below. Whats the right/better way to mount it when recirculating it back to the intake.



Also it came with 2 springs and its also adjustable from above. Sorry for the newb question but what am i trying to achive when adjusting it. i noticed that its very stiff to push up the piston by hand. How stiff should it be for a low boost application 6-7psi greddy
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Old 09-16-2008, 01:36 AM   #2
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Old 09-16-2008, 01:45 AM   #3
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thanks paul, when searching i found some of those posts.
i think i answered my own question reguarding adjusting the bov, but those threads didnt answer my question reguarding proper installation.

also my greddy is now intercooled, whats this i hear about having to change the vacum line for the WG from the turbo to the intake mani. would having a boost controler in between make any difference.
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Old 09-16-2008, 01:57 AM   #4
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vacuum line to wastegate actuator DOES NOT go to the intake manifold. you don't want the actuator to see vacuum. The diaphragm is not designed for it.

some people are saying they have better results moving the line to the cold side, post intercooler, but pre throttle body
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Old 09-16-2008, 01:58 AM   #5
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Not to the intake manifold itself, but to the pipe between the intercooler outlet and the throttle body.

Boost controller or not, it makes no difference. And this isn't even Greddy-specific, it's just an intercooler thing. The point is to compensate for the fact that pressure drop across the intercooler (and there is always some) increases with RPM, because airflow increases with RPM. If you take the sample from before the I/C, you'll find that your boost falls off as RPM increases. By placing the sample after the I/C, boost (at the IM) will remain constant- it will actually increase with RPM in the section before the IC. Yes, this does create some additional heat, which is kind of an interesting catch-22: Adding an intercooler causes you to produce more heat in the compressor.
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Old 09-16-2008, 02:10 AM   #6
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ok that makes sense, i'll have to give that a try.
Any answers on proper mounting the BOV
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Old 09-16-2008, 04:25 AM   #7
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Forget it,
I found the thread where this (wastegate signal) was discussed.
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Old 09-16-2008, 04:43 AM   #8
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just mount it anywhere youd like and run a hose from bov outlet back into intake before compressor.
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Old 09-16-2008, 11:16 AM   #9
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OK I can comment on the pictures above because that is my car. The BOV works either way, just the noise it makes changes depending on the inlet/outlet selection. The top setup is a bit quieter and is the way I run it now. There is a thread discussing this around here somewhere.

All of this depends on the details of the valve design for the BOV you use. Try it both ways, see which works better or sounds better. If you are going to recirculate the outlet, the sound difference may not matter.
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Old 09-16-2008, 11:40 AM   #10
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Quote:
Originally Posted by ZX-Tex View Post
OK I can comment on the pictures above because that is my car. The BOV works either way, just the noise it makes changes depending on the inlet/outlet selection. The top setup is a bit quieter and is the way I run it now. There is a thread discussing this around here somewhere.

All of this depends on the details of the valve design for the BOV you use. Try it both ways, see which works better or sounds better. If you are going to recirculate the outlet, the sound difference may not matter.

ok so it does work both ways, that what i was wondering about.

i'll take all the helpfull comments into consideration.
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Old 09-16-2008, 12:25 PM   #11
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I'm going to be a pain again, this is my personal experience that goes against the 'common wisdom' here.

My initial setup had the WG signal coming from the turbo discharge. The problem with this is that when the throttle blade closed, the WG would stay open for a while, greatly dropping the pressure between the turbo and the BOV. This caused massive lag between shifts.

When switching the WG signal to the manifold the between shift lag went away. When the throttle closes, so does the WG. which lets the turbo remain spinning, the excess is bled off by the BOV and velocity through the system is maintained. I thought that this is how things are supposed to work.

The only way I see the WG signal attached to the turbo discharge working properly is having a boost control solenoid in line. And that the 'logic' on it is backwards in a non failsafe mode, or that your boost controller blocks the signal when the throttle blade closes.

Has anyone actually had WG failure due to the diaphragm seeing vacuum? Actuator type or external?

Just my personal experience. YMMV.

Last edited by dvcn; 09-18-2008 at 06:00 PM.
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Old 09-18-2008, 05:33 PM   #12
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Quote:
Originally Posted by ZX-Tex View Post
OK I can comment on the pictures above because that is my car. The BOV works either way, just the noise it makes changes depending on the inlet/outlet selection. The top setup is a bit quieter and is the way I run it now. There is a thread discussing this around here somewhere.

All of this depends on the details of the valve design for the BOV you use. Try it both ways, see which works better or sounds better. If you are going to recirculate the outlet, the sound difference may not matter.
does anyone else have imput on the proper way to mount it. I dont want to base my decision on which way is quieter, i want to know which way performs better. it seems that mouting it the second way, boost would be able to simply push the piston and cause it to leak pressure.

i can push down the piston with my finger on the "inlet" side, seems the turbo will be able to do the same
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Old 09-18-2008, 07:38 PM   #13
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Mine works equally well in either orientation. The spring tension makes more of a difference than the inlet/outlet arrangement. YMMV.
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