3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.
Sponsored by:

Quick question about my BOV

Thread Tools
 
Search this Thread
 
Old 02-14-08, 10:18 AM
  #1  
Senior Member

Thread Starter
iTrader: (1)
 
katit's Avatar
 
Join Date: Jul 2006
Location: St. Louis
Posts: 505
Likes: 0
Received 2 Likes on 2 Posts
Quick question about my BOV

I have Greddy Type-S I beleive (attached).

Where do I connect hose from UIM? Nipple on upper pink half?
What is other niple for?

Thanks!
Attached Thumbnails Quick question about my BOV-bov1.jpg  
Old 02-14-08, 10:30 AM
  #2  
I'm the Juggernaut BITCH!

iTrader: (7)
 
RXtacy's Avatar
 
Join Date: Feb 2004
Location: Rockville MD
Posts: 1,342
Likes: 0
Received 5 Likes on 5 Posts
Yes you attatch the vacuum line to the nipple on the right hand side of the pink top. The top should just be an adjustment screw.
Old 02-14-08, 10:32 AM
  #3  
Time or Money, Pick one

iTrader: (37)
 
silverTRD's Avatar
 
Join Date: Oct 2005
Location: Torrance, ca.
Posts: 3,354
Received 154 Likes on 125 Posts
what he said. the top is just an adjustment screw to change the sound, well not the reason for it but thats what people use it for, hehe. just use the nipple on the side.
Old 02-14-08, 10:48 AM
  #4  
Senior Member

Thread Starter
iTrader: (1)
 
katit's Avatar
 
Join Date: Jul 2006
Location: St. Louis
Posts: 505
Likes: 0
Received 2 Likes on 2 Posts
I understand that it's screw. There is 2 nipples. 2nd one comes from aluminum bottom half (kind of seen on a picture)

I wonder whats it for?
Old 02-14-08, 01:23 PM
  #5  
Big Snail

 
93FD3S's Avatar
 
Join Date: Dec 2001
Location: San Antonio
Posts: 1,230
Likes: 0
Received 3 Likes on 3 Posts
Found this...

The diaphragm is pushed downward by a spring. The tension on this
spring is controlled by the adjustment nut at the top of the BOV.

The valve opens when the diaphragm moves upwards. This happens when
the vacuum at the upper nipple (normally connected to the intake
manifold) is enough to overcome both spring tension and whatever
pressure is present at the lower nipple (connected either to the
atmosphere or to the compressor outlet). So the valve's position is
determined by the differential pressure between the two nipples.

(Technically, the pressure at the inlet of the valve is also involved
since it pushes up against the spring too, but let's assume GReddy
designed it so that effect would be minimized by giving the diaphragm
a lot more surface area than whatever the seal is at the valve seat.
This seems reasonable since it would explain the hat-shaped top of the
BOV.)

So. If you leave the lower nipple disconnected, you end up in a
situation where manifold vacuum alone determines when the valve opens.
To keep the valve closed at idle, you have to set the spring so it
won't allow the valve to open until you get to around 10 psi of
vacuum. This is pretty extreme; it's easy to get compressor surge with
less vacuum than that. So you can either set the spring to shut the
valve at idle, or set it to prevent compressor surge. But probably not
both.

But if you connect the lower nipple to a pre-throttle boost pressure
source, then you can set it up so opening requires both high vacuum in
the manifold and high pressure at the compressor outlet. So say you
set the spring to, say, 11 psi. Manifold vacuum at idle will never be
that high. But, if the turbo's making even the slightest amount of
boost, it'll push over the limit and let the valve open. And if the
turbo's making more boost, the valve will open with even less vacuum.
So you have a good chance of setting things up to minimize or
eliminate compressor surge while also minimizing or eliminating leak
at idle. You still end up with a little more lag since you're not
equalizing pressures across the compressor wheel, but that effect is
pretty small anyway.

Last edited by 93FD3S; 02-14-08 at 01:28 PM.
Old 02-14-08, 01:40 PM
  #6  
Senior Member

Thread Starter
iTrader: (1)
 
katit's Avatar
 
Join Date: Jul 2006
Location: St. Louis
Posts: 505
Likes: 0
Received 2 Likes on 2 Posts
So, there is nothing to do with main inlet?(from Y-pipe)

I bought car like this and forgot which nipple hose was connected. Now I understand that it's top one. If I'm to route another one - what is the best way to test it?

Where is
pre-throttle boost pressure
source
?
Old 02-14-08, 02:36 PM
  #7  
Banned. I got OWNED!!!
 
1souped7's Avatar
 
Join Date: Jan 2008
Location: Trent
Posts: 170
Likes: 0
Received 0 Likes on 0 Posts
It's a vaccum line. You can get it from anywhere but make sure the one you lost lisn't lsot forever. it = boost leak
Old 02-14-08, 02:44 PM
  #8  
Senior Member

Thread Starter
iTrader: (1)
 
katit's Avatar
 
Join Date: Jul 2006
Location: St. Louis
Posts: 505
Likes: 0
Received 2 Likes on 2 Posts
I don't think I lost anything. I will connect vaccum line from UIM to top portion of BOV. There was nothing connected to bottom (OE style). Stock BOV has only 1 nipple
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
sctRota
Old School and Other Rotary
7
11-10-15 12:57 PM
SakeBomb Garage
Group Buy & Product Dev. FD RX-7
8
10-09-15 10:05 PM
ZacMan
Build Threads
4
09-19-15 09:20 PM



Quick Reply: Quick question about my BOV



All times are GMT -5. The time now is 02:53 PM.