"The BIG BOV thread" (Where all bov question threads get merged) - Page 33
Page 33 of 788 FirstFirst ... 23242526272829303132333435363738394041424383133533 ... LastLast
Results 481 to 495 of 11815

This is a discussion on "The BIG BOV thread" (Where all bov question threads get merged) within the Engine Modifications forums, part of the Tech & Modifying & General Repairs category; ok, i think i'm starting to get it. i guess i just have a hard time seeing how it works. ...

  1. #481
    Registered User gifty74's Avatar
    Join Date
    Mar 2002
    Location
    Lancaster, PA
    Posts
    213
    ok, i think i'm starting to get it. i guess i just have a hard time seeing how it works. so it's venting off pressure the turbo is still trying to ram in there when you shift? does it just vent anything over a given psi? are BOV's rated on their psi? i guess i'm just stuck on pressure relief valves, that open at a given pressure.

  2. Remove Advertisements
    ClubWRX.net
    Advertisements
     

  3. #482
    Registered User TB RACING's Avatar
    Join Date
    Jun 2002
    Posts
    258
    as far as I know they are an all or nothing thing, someone correct me if I'm wrong,

    the pressure ratings are how much pressure the bov can handle

  4. #483
    MisterX's Avatar
    Join Date
    May 2002
    Location
    Prague, Czech Republic
    Posts
    2,971
    The stock BOV is fine. Unless you want noise. The minor, if any, improvement in performance from replacing the BOV is so small as to be negligable.

    BOVs which vent 100% to atmosphere ase nonsense.

    Cocentrate on beneficial mods.

  5. #484
    Registered User TB RACING's Avatar
    Join Date
    Jun 2002
    Posts
    258
    Originally posted by russ
    The stock BOV is fine. Unless you want noise. The minor, if any, improvement in performance from replacing the BOV is so small as to be negligable.

    BOVs which vent 100% to atmosphere ase nonsense.

    Cocentrate on beneficial mods.

    thanks for tip, and you are 100% correct, in low boost conditions the stock BOV is fine

    however that isnt really what we are discussing here

  6. #485
    Registered User gifty74's Avatar
    Join Date
    Mar 2002
    Location
    Lancaster, PA
    Posts
    213
    no, i wasn't planning to get an aftermarket at all. i just wanted to understand the system better, and why i can get a boost signal from that line. i'm starting to grasp it, just a few things i can't quite understand. i know they are all for sound. i was just looking at mine tonight and tried to figure out how it works. i knew it vented excessive pressure, i just didn't know why we can get boost signal from that line even though its a "valve" that vents pressure.

  7. #486
    Moderator GV27's Avatar
    Join Date
    Jun 2002
    Location
    Green Mountain, Colorado
    Posts
    5,585
    I Support ClubWRX
    OK, here's how it works. The big tube is the pressure relief tube and is plumbed back to the intake. It's not a big deal that it vents back to the intake, just that the computer expects this behavior so it runs lousy when you change the venting to 100% atmosphere. The blow off valve is designed to hold more pressure than it needs to. Not sure what the max for the stocker is, but something well over 17 psi - plenty for stock boost and quite a bit more. The little tube is plumbed to the intake manifold on the engine side of the throttle butterfly. When you close the throttle, the manifold has vaccum. This vaccum pulls the BOV open, venting the pressure and eliminating the pressure wave that would otherwise stop the turbo cold or even cause it to backspin. This has two benefits, the first is to let the turbo keep spinning, reducing lag when you get back on the throttle. The second and more important function is to protect the turbo bearing from the tremendous shock that would be created when the turbo went from spinning at several 10s of thousands of RPM to a dead stop virtually instantaneously. SOme manufactureres claim that their valves are so superior that they largely eliminate lag, but this is not true. The stocker is quite good, and only needs to be replaced if you're running very high boost pressures.

    To answer yor question about guageing pressure, what you're really interested in is manifold pressure or vaccum. So the little tube is good, but the big tube is only seeing what is happening in the intake.
    Last edited by GV27; 07-10-2002 at 07:20 PM.
    "Inasmuch as ye have done it to one of the least of these my brethren, ye have done it to me." -Jesus

    1990 Alfa Romeo Spider Veloce
    1992 Toyota 4Runner SR5 3.Slow
    1993 Honda CBR600F2
    2002 WRX SportWagon *sold*

  8. #487
    Registered User Marcolus's Avatar
    Join Date
    Jun 2002
    Location
    NoVA
    Posts
    83
    Originally posted by russ
    The stock BOV is fine. Unless you want noise. The minor, if any, improvement in performance from replacing the BOV is so small as to be negligable.

    BOVs which vent 100% to atmosphere ase nonsense.

    Cocentrate on beneficial mods.
    yeah leave the atm BOV's for the rice boys and sTuNnAz,

    Ive found that affixing the bov discharge in the intake so as to point at the compressor blades helps to keep the speed from falling off too sharply between shifts.

    It was easier on the mr2 :hammer:

    anyway, i guess any inlet pipe would need to be modified/made to do this.
    Edge of The Blade

  9. #488
    Registered User TB RACING's Avatar
    Join Date
    Jun 2002
    Posts
    258
    Originally posted by GV27
    OK, here's how it works. The big tube is the pressure relief tube and is plumbed back to the intake. It's not a big deal that it vents back to the intake, just that the computer expects this behavior so it runs lousy when you change the venting to 100% atmosphere. The blow off valve is designed to hold more pressure than it needs to. Not sure what the max for the stocker is, but something well over 17 psi - plenty for stock boost and quite a bit more. The little tube is plumbed to the intake manifold on the engine side of the throttle butterfly. When you close the throttle, the manifold has vaccum. This vaccum pulls the BOV open, venting the pressure and eliminating the pressure wave that would otherwise stop the turbo cold or even cause it to backspin. This has two benefits, the first is to let the turbo keep spinning, reducing lag when you get back on the throttle. The second and more important function is to protect the turbo bearing from the tremendous shock that would be created when the turbo went from spinning at several 10s of thousands of RPM to a dead stop virtually instantaneously. SOme manufactureres claim that their valves are so superior that they largely eliminate lag, but this is not true. The stocker is quite good, and only needs to be replaced if you're running very high boost pressures.

    To answer yor question about guageing pressure, what you're really interested in is manifold pressure or vaccum. So the little tube is good, but the big tube is only seeing what is happening in the intake.

    good explaination

    Originally posted by GV27

    yeah leave the atm BOV's for the rice boys and sTuNnAz,

    Ive found that affixing the bov discharge in the intake so as to point at the compressor blades helps to keep the speed from falling off too sharply between shifts.

    It was easier on the mr2 :hammer:

    anyway, i guess any inlet pipe would need to be modified/made to do this.
    ah, I'm so sick of hearing people say atmospheric BOV's are ricey, its so ignorant, I'm sorry. Yes in the current state of tune on stock WRX's its not the way to go since its tuned to expect the reciculation. However why dont you go upgrade your intercooler and turbo and use that same bov at high pressures and see how your car reacts.

    Either way, this is not what this post was discussing anyhow so lets just drop it.

    Please explain what you mean about "pointing" the discharge at the compressor blades

  10. #489
    Registered User gifty74's Avatar
    Join Date
    Mar 2002
    Location
    Lancaster, PA
    Posts
    213
    GV27, that is excellent, that is exactly what i was looking for. i was missing some "links" there that you really cleared up. i think i now actually grasp how it all works.

    so the smaller tube, on top of the BOV, just shows the actual pressure & vacuum in the intake in front of the throttle body (on the side towards the front of the car), and provides a vacuum source that opens the BOV to vent pressure on the opposite side (intercooler side of the throttle body) when the butterfly abruptly closes. this was the part that was confusing me. hopefully i got this right, i love learning more about the wrx...

  11. #490
    Registered User gifty74's Avatar
    Join Date
    Mar 2002
    Location
    Lancaster, PA
    Posts
    213
    oh, and another thing, why is the manifold in vacuum when at idle, or letting off the throttle? never really totally understood that either.

  12. #491
    Registered User TB RACING's Avatar
    Join Date
    Jun 2002
    Posts
    258
    Originally posted by gifty74
    oh, and another thing, why is the manifold in vacuum when at idle, or letting off the throttle? never really totally understood that either.
    easy, take a straw, put it into a glass of water.
    put one finger over the end and pick the straw up.

    you've created a vacuum

    now picture your finger as the throttle

  13. #492
    Registered User gifty74's Avatar
    Join Date
    Mar 2002
    Location
    Lancaster, PA
    Posts
    213
    but where is it sealed off? the butterfly is always cracked some, even at idle, to let some air in. is the piston motion creating the vacuum?

  14. #493
    Registered User kaizenfighter's Avatar
    Join Date
    May 2002
    Location
    Pigeon Forge, TN
    Posts
    333
    I'm installing mine tomorrow. Its the best bov for high boost applications. No leaks
    2005 STI
    Obsidian black with gold wheels







    Moderator of SE forum

    Quote:
    What is the handicapped parking situation at the special olympics?

  15. #494
    Registered User kaizenfighter's Avatar
    Join Date
    May 2002
    Location
    Pigeon Forge, TN
    Posts
    333

    Bov install help?

    Quick question. I cant seem to get the clamp off of the air bypass hose. I'm scared I'll break it. Any suggestions. Its the hks bov if it matters
    2005 STI
    Obsidian black with gold wheels







    Moderator of SE forum

    Quote:
    What is the handicapped parking situation at the special olympics?

  16. #495
    Registered User
    Join Date
    Apr 2002
    Location
    757
    Posts
    163
    i have a questions for those who have the HKS SSQ...

    are u just going to suck-up the sluggish feel...and the risk of running to rich? or are u buying the recirc. kit....

    If u are buying the recirc kit for the HKS SSQ, can u please tell me what it sounds like, and if it sounds loud enough for people to hear and turn heads. THANK YOU.
    My02 WRB WRX
    Go Hokies!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •