I have owned my Turbo II for about a month now and I did my first oil change today and well I noticed this:


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.

 

try plugging it and see if anything changes.

 

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.

 

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?

 

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?

 

Anyone? Just need to know about a stock boost signal hole. or if i have to tap one.

 

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.

 

If it's not broke, don't fix it!