Jump to content
SAU Community

Stopping Your BOV From Leaking - A How To

Jay95R33

By Jay95R33,
in Engines & Forced Induction

 Share

Recommended Posts

Jay95R33 Grand Master

Jay95R33

Posted
Posted

I took my BOV off today cause I was sure it was leaking, and you wouldn't believe what I found out...

The factory BOV is designed to leak !!!!

Yepp, it's designed to leak....

Have a look at the attached pic. If you blow into the return pipe (big pipe on the bottom lefthand side) it will blow through the BOV and out that little hole on the front. That means there is always a path to recuiculate a small amount of air even when the BOV is totally shut !!!

I don't know why....

Anyway, here is a quick "how too".

I got this idea from a bloke on SDU. The link is here http://forums.skylinesdownunder.co.nz/show...=&postid=191358

J

Link to comment
Share on other sites
  • Replies 85
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Posted Images

Jay95R33 Grand Master

Jay95R33

Posted
  • Author
Posted

I found a wood screw that had a flat head that was about 1 1/2 inches long. It'll be hard to find one that fits good, but keep looking.

The important thing to do is to counter sink the hole a little in the BOV so when you screw the screw in it sits flat with the base of the BOV.

You can see it in this pic.

Link to comment
Share on other sites
Jay95R33 Grand Master

Jay95R33

Posted
  • Author
Posted

Put it back on the car and your all finished.

The car does feel more responsive when on boost. And there isn't that sound of recirculating air when your on boost as much.

The sound it makes has changed slightly. Before it was more of a ssssssshhhhhhhtttttt noise. But now is more of a pppppssssshhttt noise (if that makes sense !!).

It sound like it's holding the boost until you come off the throttle instead of passing air (LMAO :lol: ) when your foot is still down.

It can't be bad for it, have a look at any of the after market BOV and they don't have this little bleed hole, so what the hell

Have fun.

J

Link to comment
Share on other sites
MYGTST Collaborator

MYGTST

Posted
Posted

th hole is ther to recirculate a little air when off boost

its supposed to keep the turbo spinning faster so it spools up quicker

but if you want to block it all you need to do is put a thick peice of gasket paper over the hole and when you clamp the bov back down again it will be held in place and thats enought to block it properly

no screws required

Link to comment
Share on other sites
Jay95R33 Grand Master

Jay95R33

Posted
  • Author
Posted

Cool, good to see there's some sort of reason why it's there. It's a shame that sometime effects it pretty bad when running higher boost :wave:

Joe - that screw won't go anywhere, when you bolt the BOV back on it's hard up against the crossover pipe mounting point. No way it's coming out :)

Link to comment
Share on other sites
Jay95R33 Grand Master

Jay95R33

Posted
  • Author
Posted

I've been keeping an eye on the boost gauge today.

With lite throttle boost situations it seems to come on faster. Before if I was accelerating slowing and it gradually came on boost I found it would get to about 1-2psi, then drop back to 0 and then build up again. Not sure why, but that has now stopped.

I figure that hole would bleed at least 2-3psi of boost. I think the hole is a great idea if your running standard boost, but if you up the boost it'll bleed more.

I'll be leaving mine with it in. Can't hurt, plus the noise is fulsik now.... maaaateee... :lol: :lol:

Link to comment
Share on other sites
Jay95R33 Grand Master

Jay95R33

Posted
  • Author
Posted

Well it looks like someone else came up with the same idea a while ago!!

Have a look here;

http://www.thedodgegarage.com/turbo_bov_mod.html

But they did it slightly different so you could have it "fast open - like stock" or normal so it hold boost better.

Rev, I can't confirm any times or anything, and I'm not going to guess, but to me it feels more positive. Either way it's easy to reverse if need it be. OH, BTW - I did the thermo fan install yesterday. It does rev slightly faster now, nothing amazing, but there is a difference. It's so quiet now too, but when the fan turns on it sounds like a jet engine !!! I now like your idea about reducing rotational masses. :) :uh-huh:

J

Link to comment
Share on other sites
Guest /\/\/\/\/\/\/\/\/\/\/\/\/

Guest /\/\/\/\/\/\/\/\/\/\/\/\/

Posted
Posted

Hi, that was my original post on sdu

the boost doesn't actually leak thru that hole, when enough pressure goes throught that hole it opens the bov piston. and the boost escapes through there.

it is just a system nissan has put there to prevent overboosting

Link to comment
Share on other sites
Jay95R33 Grand Master

Jay95R33

Posted
  • Author
Posted
Originally posted by turbomad

I noticed that extra port doesn't actually go into the plumb back section of the BOV, it has it's own tunnel into the diaphram part, how does it circulate air?

If you've got the BOV sitting in your hand and you blow into the plumbback pipe, air will come out that small port, regardless if the valve is open or closed.

Link to comment
Share on other sites
Blackness Enthusiast

Blackness

Posted
Posted

Jay95R33

thanks for the great post ... I found a spare factory BOV in the depths of my boot :P ... have also just found the HKS turbo timer measures boostD :D :D , just need to connect it ...

over the weekend I will try both BOV's (unmod &mod)and if I have any interesting figures I'll post it

Link to comment
Share on other sites
Jay95R33 Grand Master

Jay95R33

Posted
  • Author
Posted
Originally posted by Blackness

Jay95R33  

 

thanks for the great post ... I found a spare factory BOV in the depths of my boot :P ... have also just found the HKS turbo timer measures boostD :D :D , just need to connect it ...

over the weekend I will try both BOV's (unmod &mod)and if I have any interesting figures I'll post it

Balckness - dude that would be great if you post up how it goes. And good find in your boot, all I found in my boot when I got the car was a dirty old ash tray from some brothel in japan :(

Link to comment
Share on other sites
Blackness Enthusiast

Blackness

Posted
Posted

also found one thrashed jack with no handle, an ultra light spare tyre and tyre brace (read none) and a dirty Nike hat...:P

the spare BOV has a couple of scratches on the face plate, but I might get keen with some fine sand paper .....

Does the BOV have rubber grommet as a seal or is it a flush metal disk (the spring loaded part)....

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      Fake ARP bolts?

      By GTSBoy · Posted

      Meh. I "see" a typo above, that should have been "sell".
    • joshuaho96
      Nismo copper mix twin “pull” pedal height engagement

      By joshuaho96 · Posted

      The clutch pedal has a procedure for adjustment. This can only be done after you are 100% sure the system is absolutely free of air bubbles. You must bleed the clutch master cylinder first, then the "separation pipe" which is the clutch damper line, then the operating cylinder as detailed in the service manual. Also, you must fully depress the clutch pedal between shifts. Just because you can't feel it grabbing does not mean the input shaft is truly decoupled from the crank. At high RPM clutch plates are vibrating and moving around, you need to give it the best possible chance of success. On the BCNR33 Nissan revises these adjustment procedures slightly but not by much: I would be careful with trying to play games with these adjustments. As for the Nismo operating cylinder they say a lot of things. In practice the twin plate clutch needs less movement on the clutch fork to disengage because the whole stackup of the flywheel + friction plates + pressure plate is much taller. Personally if you find that the clutch still disengages too high at the top of the travel I would try the Nismo operating cylinder. Make sure to follow the air bleed procedures. 
    • 25RBGT
      Got this r31 silhouette flood car to rebuild.

      By 25RBGT · Posted

      Thank you for the links. I’m going to go with the 6pin plug you used. next step is rust treating re painting dash support bar and steering column then the 6pin cradle plug when it arrives in the mail.
    • soviet_merlin
      Nismo copper mix twin “pull” pedal height engagement

      By soviet_merlin · Posted

      I don't how much the car makes a difference or whether it is just a question of gearbox and clutch. On mine it's fine. Pull type Nismo coppermix twin (standard, not competition) on the 5 speed in my Stagea. OEM slave cylinder. Bite point is a few cm off the very bottom of the pedal. Clutch pedal all the way down to put in gear, and when heading off at the lights, there's a tiny bit of nothing and then it starts biting. And fully engaged before the pedal is all the way released. There's a bit of play at the top where the pedal does nothing anymore. Are you in Australia @ck_chino? If you are set on using a Nismo slave cylinder I have one new-in-box at home. Ordered it together with the clutch but didn't get it fitted. We can work something out if you want it
    • Butters
      Nismo copper mix twin “pull” pedal height engagement

      By Butters · Posted

      I am using a pull nismo coppermix twin in an r34 getrag box, had both the standard slave and  then the nismo one. Adjusted pedal to get bite point how I wanted , it is on the higher side, but would fully disengage past half way down.  I also read that the nismo slave won't work but I had no issues with the stroke, might become one later as clutch wears but 2+ years of happy motoring so far.  Take the above as one input only, specially as my setup is a bit unique in that I am using an S15 clutch master , cefiro clutch pedal, custom braided clutch line. Lots of variables at play. 
×
×
  • Create New...