"The BIG BOV thread" (Where all bov question threads get merged) - Page 162
+ Reply to Thread

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; The stock blow off valve doesnt hold over 20psi very well so if you are boosting over that, that could ...

  1. #2416
    Registered User silverscooby's Avatar
    Join Date
    Oct 2002
    Location
    Cary, NC
    Posts
    976
    The stock blow off valve doesnt hold over 20psi very well so if you are boosting over that, that could be your problem.

    I'm running a GFB on my setup and it works fine. I say buy a used blow off valve and swap it on. If it runs better with it keep it. If it doesnt, you know that isnt your problem.

    Better yet, if you have someone local with an aftermarket blow off valve borrow his for some tests.

    Hope that helps
    2002 WRX 352whp & 341ft-lbs *SOLD*
    12.5@109
    2004 SRT4 449whp & 457ft-lbs
    11.6@125

  2. Remove Advertisements
    ClubWRX.net
    Advertisements
     

  3. #2417
    Registered User Bask Oner's Avatar
    Join Date
    Jun 2002
    Location
    Chicago, IL
    Posts
    2,587
    Definitely get a BOV - preferrably a GFB Hybrid (or the lastest equivalent model).
    Matt
    WRX-less, now RSX-y!!!

  4. #2418
    Registered User
    Join Date
    Mar 2003
    Location
    No VA
    Posts
    146
    I run A VF24 and a 50/50 GFB BOV. It relaeses air at 5000rpm. I would shy away from the stock BOV at 17 or higher boost.

  5. #2419
    Registered User WRC_Obsessed's Avatar
    Join Date
    Jan 2002
    Location
    Boston/NNJ
    Posts
    9,026
    The first time that I installed my Forge 100% BOV with the softest spring I was only running an MBC. I did not have any problems with this set up.

    I then went to a TXS uppipe and TBE. I continued to run the Forge with the softest spring without and problems.

    About a month and a half after I installed the exhaust I went to a stage 4. Initially, I was still running the Forge with the softest spring and it was not holding boost because the spring was too soft. I went with the hardest spring and it only blows off about 5000rpm. I am not having any problems running this setup.

    How much boost are you running?

    If you are running above 18psi (which I guess you are) I would definitely upgrade to an aftermarket BOV.

    If you are having problems runing the stock BOV with the stage 4 try turning down the boost to 14psi and see if you are still having problems. I don't think you should not have and problems running low boost.
    -Brian

    Twisty Monster - 335 ft/lb of torque @ 3600 rpm on a stock turbo. Is that possible? Yes it is.

  6. #2420
    Registered User
    Join Date
    Apr 2003
    Location
    Mesa, AZ
    Posts
    282

    stock BOV 100% atmosphere?

    so, from what i understand, aftermarket BOV's are not beneficial to the performance of our cars, and some would even say that they hurt our (and probably most) engines. so i had a theory. would it be possible to just disconnect the outlet tube for the stock BOV, and plug up the tube that goes back to the turbo, and thus creating a 100% atmospheric BOV? is there any unforseen issues with this that im not seeing? i figure if people buy them for the sound, then a 5 minute quick change under the hood for someone whos in the mood to show off for the evening, but doesnt want to deal with the sound and effects everyday, would be a great idea. lemmie know if im missing something on this, and what would be the best way to temporarily plug up the tube going back to the turbo. also, i had a question about BOV's in general. lots of people say that they extend the life of a stock turbo. is this because the recirculated air slows down the turbo, causing further stress on it, or is it because the recirculated air keeps the turbine spinning, never giving it a chance to freely spin?
    03, wrx, aspen white, K&N drop in filter, for now waitin for warranty to go bye bye.

  7. #2421
    Registered User GTIWRX's Avatar
    Join Date
    Mar 2002
    Location
    Conshohocken,PA
    Posts
    3,273
    a few people,myself included, have tried to do this...it dosent work. The car runs like crap, and it dosent even sound so great. The maf "sees" the air coming into the intake, and plans on all that air being used. When you get a 100 percent bov in the mix, that metered air goes out of the system, and the ecu thinks it still is there, and injects the proper amt of fuel for that amount of air. If that air is gone the engine runs too rich.

  8. #2422
    Registered User virpacalis's Avatar
    Join Date
    Dec 2002
    Location
    in the slow lane
    Posts
    317
    Not much help here but I have no complaints about my APS dual vent bov. I'm running 18+ psi and a fmic too.
    '07 STI UGM: Protuned Cobb DP, Walbro, Prodrive BCS; Cobb heat shield; extra stock rims with Hankook iPike W409's; Subaru hitch mount; a Limited roof and wing
    '02 WRX PS: quick & trouble free but sold with 110K miles
    mods

  9. #2423
    Moderating U! KurleeDaddeeWRX's Avatar
    Join Date
    Mar 2002
    Location
    San Jose, CA
    Posts
    6,317
    I Support ClubWRX
    Thanks guys for replying to this thread. I am not sure if I have a problem with my stock BOV or not. I have not heard it let off pressure in a long time. I am running 18psi everyday. And at the drag races, after every gear change, it seemed that the VF22 had to work extra hard to re-spool itself. I attribute that to a bad bypass valve. I may follow your suggestion, and see if someone is willing to let me borrow an aftermarket BOV to remedy my problem.

    I have owned 2 different BOV's in the past. The GFB 50/50 and a Forge 100%. I had idle problems with the GFB BOV. When I would rev the car, the idle would go down past 750 rpms, and then come back up. It would almost sound like it was going to stall. My Forge 100% BOV, no matter what spring I chose, would flutter occasionally. The futter was annoying, and sometimes made the car jerk a bit until the plunger made a good seal, and then it would hold pressure. When both of these BOV's were working properly, the car still ran rough, right after the BOV released pressure. I attributed that to the turbo being too small and was not able to keep up with the rest of the system, since it pumped too little air to supply the air circuit. Do you think this would be any better with a larger turbo, or is it the same mechanics? Since the BOV releases all the air built up in the circuit, it shouldn't matter how large the turbo is? I don't know.

  10. #2424
    Registered User
    Join Date
    Apr 2003
    Location
    Mesa, AZ
    Posts
    282
    why doesnt it work? im just not understanding why it would be any different then any other aftermarket 100% atmospheric BOV that make the engine run rich. you said it was running like crap, how bad, just a lil bit, or a lot?
    03, wrx, aspen white, K&N drop in filter, for now waitin for warranty to go bye bye.

  11. #2425
    Registered User
    Join Date
    Jan 2003
    Location
    Malaysia
    Posts
    173
    General consensus is that the stock bypass valve is good up to 18psi, beyond which it leaks.

    I say get a SSQV/ Forge.

  12. #2426
    God
    God is offline
    Registered User God's Avatar
    Join Date
    Aug 2001
    Location
    Detroit, MI
    Posts
    4,769
    Make sure you adjust the BOV to keep it shut at idle and part throttle or that could be causing problems. Any BOV will leak if not adjusted properly. SOmetimes with the FMIC's we have t use a stiffer spring or in the case of Turbo XS shim it out quite a bit to keep it shut.
    Daniel Ponze, Lead Tuner Tuning Factory, Inc.
    PH: (248) 477-0700___FX: (248) 477-0701

  13. #2427
    Registered User WRC_Obsessed's Avatar
    Join Date
    Jan 2002
    Location
    Boston/NNJ
    Posts
    9,026
    I would see if you could borrow an aftermarket BOV and see if you are running into problems.

    To God's point, are you have idle problems with the stock BOV? I would think that you shouldn't, even with a larger turbo. Someone please correct if I am wrong. If it is not suppose to be leaking, then there may be some other problems. Have you checked to see that all you hoses are fully connected?
    -Brian

    Twisty Monster - 335 ft/lb of torque @ 3600 rpm on a stock turbo. Is that possible? Yes it is.

  14. #2428
    Registered User jroman836's Avatar
    Join Date
    Apr 2003
    Location
    NJ
    Posts
    133
    The stock BOV is actually a "Bypass Valve", so making it act like a 100% vent to atmoshere BOV WILL NOT WORK.

    Read this http://www.spdusa.com/blow-off_valves.htm

    Hope it helps

    BTW, I've tried 2 diff. BOV's and Im now stock w/16psi

  15. #2429
    Registered User GTIWRX's Avatar
    Join Date
    Mar 2002
    Location
    Conshohocken,PA
    Posts
    3,273
    i dont know the technical reasons for it not working but i tried it and it ran real weird...like i would let off the gas and the car felt like it hit a wall e very time i shifted ...i mean i think the sound of a bov is cool...but i wouldnt buy one unless i had a huge turbo and needed a new one...and in that case i would make a port to the outside of my car for the thing to vent out to haha..pppshhhhhhhh

  16. #2430
    Registered User
    Join Date
    May 2002
    Posts
    899
    I have never had any issues running my Type-H w/my VF22 and FMIC. No stumbling, rough idle, etc. It does sound like your stock BPV could be defective in this case. Try this to check. With the car running, pop the hood. Put your ear near the turbo, and rev the engine pretty high using the throttle cable. When you let off, you'll be able to hear if there is compressor surge. It sounds like a "wub wub wub." If this is the case, ditch your stock BOV immediately to avoid damaging the turbo. I think any aftermarket valve would be ok....

+ Reply to Thread

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself. We strongly suggest that you stay away from using aol, yahoo, msn, and hotmail accounts. Sometimes the mail server blocks the emails from our server. As a result you will not receive any notifications including the confirmation email.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Posting Permissions

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