Poor boost - only 9psi

Discussion in 'Modifications & DIY how-to' started by goixiz, Jun 12, 2006.

  1. goixiz

    goixiz Active Member

    Tonight is the first time i hooked up my AP to read boost
    I do not have a boost gauge.
    at idle -8.9 psi warmed up and car drives fine but finaly want to see my boost level and now i know im missing all this fun

    Im only reaching 9.0 +/- 0.2 PSI in both 3rd and 4th gear than road ended.

    What can be causing me to only have so low a boost.
    Any suggestions greatly appreciated

    I want to get my fun i feel cheated
     
  2. moose

    moose Infina Mooooooose!

    Have you changed/removed/replaced anything that could cause a leak?
     
  3. longfury

    longfury Active Member

    Boost will be tapered at redline. What RPM are you seeing 9psi? If its redline thats probably right. If its at 4K then something is wrong.

    Check for leaks and damaged vac lines.
     
  4. goixiz

    goixiz Active Member

    I have AP stg1
    Im seeing 9psi at about 6000rpm

    i dont think i did anything to cause boost leak. I can check tomorrow. only thing i can think of is WG ctrl arm i turned it 1.5 turns clockwise (shortening the arm).

    I can do a reset with the AP
    and check and then maybe go back to stock (but i dont think that is it)
     
  5. moose

    moose Infina Mooooooose!

    If anything shortening the WG arm would possibly increase your boost if you overdid it. Check the hoses going from the compressor side to the T to the wastegate actuator.
     
  6. goixiz

    goixiz Active Member

    Yes I did and will again tomorrow
    But if there is a leak on those hoses - doesnt that mean that the WG actuator arm is not opening and Boost keeps goin up ?. I have a feeling i may need to take the IC off and see if any hoses are loose or this may be my prob too
    [​IMG]
    but i dont know where that picture is even until i guess to pull the IC off.

    The link for the above pic is
    http://forums.nasioc.com/forums/showthread.php?postid=14106865#poststop
     
  7. 9psi at 6k doesn't seem that wrong...

    I'm not familiar with the AP stg 1 but what is the target boost?

    Edit:
    Target boost pressure is 14.7psi +/- 0.5psi depending on vehicle and conditions.

    Cobb also suggests using a HWY map if you are not hitting target boost.
     
  8. goixiz

    goixiz Active Member

    I just replace the lines before and after the T for the boost solenoid. Did not replace the line to the boost solenoid.
    Im goin out for a quick run and I will BRB

    NOPE still at 9 psi at 5600-5800 rpm
    reached 8.8 at about 5k rpm
    target boost should be about 14.7psi for AP stage 1

    Im quite sure i adjusted the WG correctly because i have to slightly tug the arm(hole) to meet the post.

    Could it be my boost solenoid is not triggered and the boost is opening the WG at 9 psi. is there a way to check the function of the boost solenoid or even if its getting signal.
     
    Last edited: Jun 13, 2006
  9. GTscoob

    GTscoob Black is Beautiful

    Have you tried putting the wastegate arm back to the stock position? I'm more of the if it aint broke dont fix it type so I wouldnt play around with any of that stuff . . .

    Have you cleaned the MAF/air filter recently?
     
  10. jt money

    jt money 350hp mmm mmm Good! Supporting Member

    did you remove the ristrictor beed when replacing those lines? you will see only 9 psi if there no restrictor in that one hose.
     
  11. goixiz

    goixiz Active Member

    I assume you mean the union plastic joint after the "T" connector on the way to the boost solenoid. Yes Its there (the stock one)

    Correct me if im wrong,
    the boost solenoid is venting back into the intake and will be triggered when boost is exceeding target (computer controlled). What if boost solenoid went "bad" and the wastegate is seeing boost all the time and i assume the spring is 9psi so at 9psi the wg is opening and the boost solenoid is not venting

    THIS AM I PLAN TO DO THIS

    1. remove the turbo heatshield while its cool
    2. check Wastegate and return it back to stock (1.5 turns counterclockwise on arm)
    3. Test drive - Check if the boost psi is back to normal 14+
    4. If not, drive to somewhere when i can reset the conputer with my AP and then do a Vishnu reset. and see how it goes.
    5. If yes, then do nothing and put the turbo Heatshield back and chalk a lesson learned.

    but my wastegate flutter is better now with the current setting but i ll take the WG flutter over the 9 psi

    bobby, i have not cleaned MAF
    i only replaced the filter a month ago
     
    Last edited: Jun 13, 2006
  12. suby113

    suby113 Member

    still make sure that the little brass beed with a hole in it is still inside the vaccum line conected to the turbo side not the waste gate side. If you replaced those lines this should be put back in the new lines. if you still have an issue i would take the car to subaru because something isn't right.
     
  13. goixiz

    goixiz Active Member

    Can someone take a picture of the "little brass bead"
    I dont think i have seen the brass bead even on the original line.

    Will Subaru work on my SAABaru
    And Even if it has AP or do i revert back to stock first

    Still 9 psi turning WG back to stock
    and reset ECU
    and Vishnu reset

    I will check IC this PM after it cools down

    OHHHHHH MMMMMMYYYYY GOOOODDDDDD
    Im sorry to take so much of everyones time
    I found the pill and im soooooooo happy but in turn feeling so dumb. I replaced that line becasue i had some silicone hose and try to make give some blink to my engine and i did not see this "PILL"

    I am really sorry to take up space and time
    I will place the pill back in the system but in turn i also found a few articles thats interesting that may help others



    But that pill is such a poor design
    its almost round and if it turns in the tube you can get crazy boost. it should be longer and not able to turn
    I will measure and check what it is and if i have time ill make a brass tube that has the same dimensions (ID and OD)
     
    Last edited: Jun 13, 2006
  14. suby113

    suby113 Member

    Subaru will work on your car since it is a Subaru motor, just make sure that brass pill is put back in the line on the turbo side this should fix it if it doesn't Subaru can figure it out. Also are you sure you reflashed the correct map from the AP that is for your application?
     
  15. miloman

    miloman Retired Admin

    this thread is definitely not a waste of space or time... it is quite informative and will help someone who has a similar problem in the future to resolve the issue quickly... thanks for adding to WRXatlanta's information database :bigthumb:
     
  16. suby113

    suby113 Member

    I agree with Milo we are all on this forum for just this type of thing to help each other Suby owners out, thats why we are all fellow suby brothers! :p
     
  17. goixiz

    goixiz Active Member

    I call it the poison pill
     
  18. siegelracing

    siegelracing Registered Vendor<br><b><font color="#666666">bion

    HAHA!!! No worries here buddy. I can't even tell you how many times I have seen this.

    The worst part is that I've seen shops "sponsor" a car, replace all the lines with blingy colored vacuum lines, and then the car is SLOW :D

    That "restrictor pill" boost control is VERY popular on OEM cars, and many WELL respected tuners stay with it. By "tuning" your restrictor size, desired boost and wastegate tables, this can result in VERY good wastegate control / boost response.

    Welcome to Suby ownership. I would have to agree with GTScoob, "If it ain't broke, don't fix it." Or really a "hippocratic oath" of "First, do no harm." ALL the time people try to make a 1 hp improvement, and end up making a 50hp (or $5,000) mistake... we're all glad you didn't do THAT!

    SS
     
  19. goixiz

    goixiz Active Member

    I also have the poison pill from a VF39 setup and its even more bitter The STi's pill opening is only 0.9mm instead of 1.2mm

    Poison pill
    ID/OD/Turbo/notes/Material
    1.2mm/4.4mm/TD04/1 groove around the pill/Brass
    0.9mm/4.4mm/VF39/NO groove around the pill/Brass

    Scott, you should have posted last night so i have a few more hours of sleep

    Sorry Im some of your best customer - Engineers try to squeeze every drop out with min amt of $. a
     
    Last edited: Jun 13, 2006
  20. miloman

    miloman Retired Admin

    small restrictor :keke:
     
  21. moose

    moose Infina Mooooooose!

    See, you just learned a valuable lesson about ricing out your ride. :p

    I think some people posted on NASIOC about using welding nozzles to replace the restrictor pill. If you find a suitable one it would probably be less prone to rotating around like you're worried.
     
  22. jt money

    jt money 350hp mmm mmm Good! Supporting Member

    nope i meant the same thing as scott and the rest of them mentioned. im glad you got your problem narrowed down now. dont feel bad ive done this in the past also, thats how i knew.
     
  23. GTscoob

    GTscoob Black is Beautiful

    Go out and have some fun now!
     
  24. goixiz

    goixiz Active Member


    Ouch !!! go ahead take the shot while im weak and did not have enough sleep:naughty:
    :bowdown:
     
  25. Alex

    Alex Community Founder Staff Member

    Sweet, congratulations on the problemo solving!
     
  26. goixiz

    goixiz Active Member

    15.2 psi @ 3rd 5200rpm w/ 1 full turn of WG adj arm
    cool temps outside

    Napping and then ill go for my bike ride later
    thanks all you guys
    I ll bake a cake the next time we have a meet
     
  27. suby113

    suby113 Member

    Glad to see it's fixed Have fun!
     

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