View Poll Results: BOV location
Voters: 45. You may not vote on this poll
New BOV location
Former Vendor
Joined: Dec 2007
Posts: 271
Total Cats: 11
From: Texas Hill Country
I don't think there is a clear advantage either way, but the valve ought to be at one end or the other.
If a recirc, after the IC lightens the heat load very slightly. But, the work to push thru the IC is also very slightly greater thus the turbo would lose rpm quicker. Damn little.
My preference is at the TB end and it is, as stated earlier, to keep air heading one direction, and the IC a tick less drained.
Note that modern OEM's are now building it into the compressor housing. I hope Porsche doesn't succum to that approach.
Corky
If a recirc, after the IC lightens the heat load very slightly. But, the work to push thru the IC is also very slightly greater thus the turbo would lose rpm quicker. Damn little.
My preference is at the TB end and it is, as stated earlier, to keep air heading one direction, and the IC a tick less drained.
Note that modern OEM's are now building it into the compressor housing. I hope Porsche doesn't succum to that approach.
Corky
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as long as the compressor wheel is spinning it is moving air.
as long as the engine is on, the compressor wheel is spinning.
The only time I could POSSIBLY see the bov actually sucking in air is for that SPLIT SECOND when you stab the throttle and the car gulps in more air than is already moving through the system and the bov hasn't shut yet. We're talking less than a second worth of "sucking" time.
as long as the engine is on, the compressor wheel is spinning.
The only time I could POSSIBLY see the bov actually sucking in air is for that SPLIT SECOND when you stab the throttle and the car gulps in more air than is already moving through the system and the bov hasn't shut yet. We're talking less than a second worth of "sucking" time.
But anyway, even if it is a rare occurrence, which I agree that it probably is, it still could happen, and if your BOV is 2 inches from the ground you could possibly suck something up.
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Elite Member
Joined: Dec 2008
Posts: 1,642
Total Cats: 36
From: Colorado
OP, that location looks great to me, I would put it anywhere in that reigon where its out of the way.
Edit: Hey how vague can I be
I am refering to the coldside piping that you hit with the marker. One thing thats nice about that point is that you can do a piece of straight pipe there and thus have some real variability in the direction of the BOV, You can rotate the pipe to keep it out of the way and all.
Edit: Hey how vague can I be
I am refering to the coldside piping that you hit with the marker. One thing thats nice about that point is that you can do a piece of straight pipe there and thus have some real variability in the direction of the BOV, You can rotate the pipe to keep it out of the way and all.
Last edited by Sparetire; Mar 21, 2010 at 08:53 PM.
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The compressor wheel is spinning, but youre totally neglecting that the engine is still drawing in air. What makes you think that the compressor is ALWAYS pushing more air than the engine is taking in?
But anyway, even if it is a rare occurrence, which I agree that it probably is, it still could happen, and if your BOV is 2 inches from the ground you could possibly suck something up.
But anyway, even if it is a rare occurrence, which I agree that it probably is, it still could happen, and if your BOV is 2 inches from the ground you could possibly suck something up.
That's just my experience though. Maybe some cars actually do suck in air through the bov. I don't know
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I don't think there is a clear advantage either way, but the valve ought to be at one end or the other.
If a recirc, after the IC lightens the heat load very slightly. But, the work to push thru the IC is also very slightly greater thus the turbo would lose rpm quicker. Damn little.
My preference is at the TB end and it is, as stated earlier, to keep air heading one direction, and the IC a tick less drained.
Note that modern OEM's are now building it into the compressor housing. I hope Porsche doesn't succum to that approach.
Corky
If a recirc, after the IC lightens the heat load very slightly. But, the work to push thru the IC is also very slightly greater thus the turbo would lose rpm quicker. Damn little.
My preference is at the TB end and it is, as stated earlier, to keep air heading one direction, and the IC a tick less drained.
Note that modern OEM's are now building it into the compressor housing. I hope Porsche doesn't succum to that approach.
Corky
(G)
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Elite Member
Joined: Feb 2008
Posts: 2,321
Total Cats: 14
From: Victoria, BC
Under idle/light cruise conditions there is probably a bit of vacuum in the ic plumbing. Small, but a bit. How could the BOV then have air going out? That would be a major PITA for tuning with any MAF based EMS, as it would basically cause the car to run rich all the time.
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Elite Member
Joined: Feb 2008
Posts: 2,321
Total Cats: 14
From: Victoria, BC
not really. I've put my hand up to the bov on my car as well as many others while idling, and while revving, and while stabbing the throttle suddenly, each time it was exactly the same: at idle it was pushing out air, at slow revs it was pushing out air, at stabbing it would close super fast but before that it would be pushing out air. There was not one single time where I could get it to suck in air. And I TRIED to get it to do that.
That's just my experience though. Maybe some cars actually do suck in air through the bov. I don't know
That's just my experience though. Maybe some cars actually do suck in air through the bov. I don't know
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Just make sure your not going to have clearance problems with your diverter and cooling fans/radiator. My old setup had the diverter pressed against the cooling fan, it was a major pita to install and uninstall.
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Joined: Jun 2006
Posts: 29,085
Total Cats: 375
From: Republic of Dallas
This.
Pressure is pressure. The time difference in reducing it at the TB or the compressor housing from a 'cold-side' to 'hot-side' placement is miniscule and insignificant unlkess you have such a large volume at such high density that the BOV is not large enough to really effectively release it. I doubt anybody here is anywhere near that point.
So put it out of the way. If it were me, with most of the setups I have seen, near the IC outlet would be a great bet.
Pressure is pressure. The time difference in reducing it at the TB or the compressor housing from a 'cold-side' to 'hot-side' placement is miniscule and insignificant unlkess you have such a large volume at such high density that the BOV is not large enough to really effectively release it. I doubt anybody here is anywhere near that point.
So put it out of the way. If it were me, with most of the setups I have seen, near the IC outlet would be a great bet.
Anyone that tells you "compressor surge" off the throttle is a problem is a certified moron and you should not believe anything else they say.
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Junior Member
Joined: Dec 2009
Posts: 332
Total Cats: 1
From: Shelbina, MO (North East)
Pressure is pressure, but mass and velocity can co-exist in separate conditions under the same pressure. If boost is vented to atm near the TB then the turbo stays spooled and probably increases RPM. All air post compressor to BOV keeps it's velocity. Then when TB is opened the only air that has to start moving (still under pressure) is from the BOV to the TB, not compressor, IC, piping and TB. If this was not important why to we even bother with "tuned" intake manifolds?
My
My
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Pressure is pressure, but mass and velocity can co-exist in separate conditions under the same pressure. If boost is vented to atm near the TB then the turbo stays spooled and probably increases RPM. All air post compressor to BOV keeps it's velocity. Then when TB is opened the only air that has to start moving (still under pressure) is from the BOV to the TB, not compressor, IC, piping and TB. If this was not important why to we even bother with "tuned" intake manifolds?
My
My
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Seriously you guys are overthinking this one, and this is coming from an R&D Engineer who tends to overthink everything. Just place it where it is easiest.
I had my BOV on the hot side of the IC. Then when I switched to a Tial Q (big, like my *****) it would not fit on the hot side. So, I moved it to the cold side. All else was the same, and I did not notice a difference. Really, no big deal.
And welding it to the IC tank is not a bad idea if it is convenient. Why not? I considered it because it is a naturally good location clearance-wise for a v-mount setup when placed on the 'inside' of the V.
I had my BOV on the hot side of the IC. Then when I switched to a Tial Q (big, like my *****) it would not fit on the hot side. So, I moved it to the cold side. All else was the same, and I did not notice a difference. Really, no big deal.
And welding it to the IC tank is not a bad idea if it is convenient. Why not? I considered it because it is a naturally good location clearance-wise for a v-mount setup when placed on the 'inside' of the V.
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Newb
Joined: Jan 2010
Posts: 28
Total Cats: 0
From: Jackson Ga.
seems to me like thats not true b/c you have a person asking where he should place his bov. If yall didnt do **** to be "different" he would be putting the ******* valve where every other person places their valve. Come to think of it the thread wouldnt even be here.
The bov on the intercooler has a purpose. The only difference is there are not any miatas running 40-50psi.
The bov on the intercooler has a purpose. The only difference is there are not any miatas running 40-50psi.
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