2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

quick vacuum question - picture

Thread Tools
 
Search this Thread
 
Old 08-08-10, 07:02 PM
  #1  
Make It Happen!

Thread Starter
iTrader: (11)
 
AmT_T's Avatar
 
Join Date: Jun 2010
Location: Ontario, Canada
Posts: 522
Likes: 0
Received 0 Likes on 0 Posts
ON quick vacuum question - picture

I have owned my Turbo II for about a month now and I did my first oil change today and well I noticed this:
quick vacuum question - picture-p_00512.jpg

There is an unplugged line at the lower base on my hks bov. My question is should that line be plugged? The car appears to drive normally and unaffected by this. Thanks in advance for any advice.
Old 08-08-10, 07:17 PM
  #2  
Senior Member
iTrader: (1)
 
The Wildchild's Avatar
 
Join Date: Aug 2009
Location: Healy AK
Posts: 277
Likes: 0
Received 0 Likes on 0 Posts
try plugging it and see if anything changes.
Old 08-08-10, 11:58 PM
  #3  
rotorhead

iTrader: (3)
 
arghx's Avatar
 
Join Date: Aug 2004
Location: cold
Posts: 16,182
Received 429 Likes on 263 Posts
That's an oldschool Greddy Type S, not an HKS. I had one. See this link: http://www.stealth316.com/2-greddy-bov-anatomy.htm







You can supply boost pressure to that bottom vacuum port (pressure from BEFORE the throttle plates, not a manifold vacuum source). That will affect its response, most likely making it open easier. It works just like an OEM blowoff valve on an STi and 02-08 WRX actually:



The JDM WRX has just an open hole, like you have on your type S. The USDM WRX has a little hole inside the flanged surface. The WRX BOV bolts directly to the intercooler so the hole on the USDM BOV receives boost pressure right from the intercooler (before the throttle plates). This is equivalent in design to you hooking up that bottom port on your Greddy Type S. And then on the USDM WRX there is still a manifold vacuum source hooked to the top.

Just about every diaphragm chamber on a car uses either one of these designs. You either have pressure/vacuum on one side and atmosphere on the other, or you have two different pressure/vacuum sources, one on each side of the diaphragm. An external wastegate works on the same principle. The dashpot and double throttle on the FC throttlebody work like this. It's basic mechanical engineering.
Attached Thumbnails quick vacuum question - picture-greddysopensm.jpg   quick vacuum question - picture-greddysvolumessm.jpg   quick vacuum question - picture-greddysclosedsm.jpg   quick vacuum question - picture-wrx_bov.jpg  
Old 08-09-10, 04:00 PM
  #4  
Make It Happen!

Thread Starter
iTrader: (11)
 
AmT_T's Avatar
 
Join Date: Jun 2010
Location: Ontario, Canada
Posts: 522
Likes: 0
Received 0 Likes on 0 Posts
My bad haha I know it's a greddy type s I was tired when I posted that. I feel dumb now :s Thanks for the advice. So I just need to run a line from the intake before the throttle plate and bob's my uncle? any adjustment needed to the screw on top?
Old 08-09-10, 04:16 PM
  #5  
Make It Happen!

Thread Starter
iTrader: (11)
 
AmT_T's Avatar
 
Join Date: Jun 2010
Location: Ontario, Canada
Posts: 522
Likes: 0
Received 0 Likes on 0 Posts
ON

Ok so I was just out trying to locate somewhere to run a line from and I can't seem to find one anywhere. I'm thinking maybe under the manifold there may be a line but im not sure. Can anyone tell me if there is or do I have to tap a hole somewhere and run a line from that?
Old 08-13-10, 01:22 PM
  #6  
Make It Happen!

Thread Starter
iTrader: (11)
 
AmT_T's Avatar
 
Join Date: Jun 2010
Location: Ontario, Canada
Posts: 522
Likes: 0
Received 0 Likes on 0 Posts
ON

Anyone? Just need to know about a stock boost signal hole. or if i have to tap one.
Old 08-14-10, 07:21 AM
  #7  
Boosted. I got BLOWN!!!

iTrader: (29)
 
beefhole's Avatar
 
Join Date: Sep 2003
Location: Queens, NY
Posts: 3,742
Likes: 0
Received 1 Like on 1 Post
If you are looking at the engine from the front of the car, there is a nipple on the left side of the UIM (near the BAC valve). You can tee into that line. Also, there are 3 nipples on the front of the UIM near the TB connection. You can use either the top one, or the bottom one. You should be able to tee into any of these easily.
Old 08-14-10, 07:38 AM
  #8  
Disco Biscuit

iTrader: (9)
 
LunchboxCritter's Avatar
 
Join Date: Dec 2006
Location: Florida
Posts: 755
Likes: 0
Received 1 Like on 1 Post
If it's not broke, don't fix it!
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
trickster
2nd Generation Specific (1986-1992)
25
07-01-23 04:40 PM
bb6guy
Old School and Other Rotary
10
10-01-18 08:07 AM



Quick Reply: quick vacuum question - picture



All times are GMT -5. The time now is 02:25 AM.