BOOST FLUTTER? Blowing my mind please help!!!!! - Page 2
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This is a discussion on BOOST FLUTTER? Blowing my mind please help!!!!! within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; i called cob. it was a dull convo and they didnt have anything to say. said it could be a ...

  1. #16
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    i called cob. it was a dull convo and they didnt have anything to say. said it could be a number of things and suggested it was a mechanical thing

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  3. #17
    Moderator Donkey's Avatar
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    Quote Originally Posted by my96sti View Post
    i took it to a mechanic i know well, what happens is if its your actuator the arm with let out prematurely under higher boost causing boost flutter, the tps and knock sensor have to do with the car being fed the wrong reading under acceleration causing flucuation in rpms/boost etc.... id seriously just take it to a local mechanic, the sensors are a pretty easy fix but if you dont fix them soon they can start causing other problems, if its the actuator you could just do it yourself, both parts are cheap under 200$
    On the USDM OBDII cars if it was a sensor you would have a CEL with a DTC code to go with it. This is one of the most common problems on a moddified USDM WRX. It needs to be custom tuned.
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  4. #18
    Moderator Donkey's Avatar
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    Quote Originally Posted by pittielove View Post
    i adjusted the wastegate arm 1 full turn (2 half turns) reset ECU and that didnt help.
    Did you make the arm shorter or longer?
    Quote Originally Posted by pittielove
    i say this because the arm was very rusty and brittle. which leads me to thin the whole thing is in bad shape.
    The outside is no indication of what shape the inside diaphragm is. The actuators themselves rarely ever fail and they are easy to test with an air compressor with an adjustable regulator.
    Quote Originally Posted by pittielove
    what gets me is why only in high gears?
    Thats because boost is load dependent. Its almost impossible to hit max boost in first gear and if you do it will be around 6500-7000rpm while in 4th or 5th you will hit max boost around 2800-3200rpm. The answer I gave you earlier is pretty much the issue. I have been tuning these cars in particular as a hobby for well over 4 years. Hence the screen shot from my tuning software.
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  5. #19
    Registered User cjm1991's Avatar
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    I had your same problem until I got a real tune, problem went away immediately. Donkey is right, your WGDC is probably off and needs adjusting. Easiest way to fix it would be a custom tune, either street or dyno. Theres nothing wrong mechanically, just the mapping of the ECU. Do you have a reputable tuner near you?
    Chris
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    Bolt ons and tuned - 349rwhp/362rwtq
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    Bolt ons/Cam/tune - 436rwhp/424rwtq

  6. #20
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    [QUOTE=Donkey;2720192]Did you make the arm shorter or longer?
    i made it shorter.


    SO what you are saying is because when i flashed the stage 2 it was summer and the temps where warm i didnt see the problem. but now that it is getting colder i am seeing the problem. meaning the MAP tells it (WGDC) to function properly when the temps are warm? So if i didnt do anything do you think the car would run fine in the summer? Further more if i do get it pro tuned now (in the cold) will i have the same problem in the summer?

    I am in MA so i can get it tuned at DSG just thought thats why i bought the Cobb.

    Just having a hard time understanding why cobb would sell something that has a big enuf "hole" in it that you, or anyone, would say it is a common problem with there product. and then have really nothing to say about it when i called. In fact they almost acted shocked about the problem and sounded more stumped then i am.

    Another point, it dosnt happen every pull. if it was a WGDC problem would it not be constant? SOme times i hit perfect boost all day. Other days, once every other time i hit the gas. In fact, it has never done it every time i gas it on one trip on the high way. does that rule anything out?

  7. #21
    Moderator Donkey's Avatar
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    [QUOTE=pittielove;2720440]
    Quote Originally Posted by Donkey View Post
    Just having a hard time understanding why cobb would sell something that has a big enuf "hole" in it that you, or anyone, would say it is a common problem with there product.
    Has nothing to do with just their product. Any generic map is going to have the same issue.
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  8. #22
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    so am i going to have the same problem in the warmer weather if i get it tuned now?

  9. #23
    Master Baiter EJ257's Avatar
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    Quote Originally Posted by pittielove
    so am i going to have the same problem in the warmer weather if i get it tuned now?
    The tuner will likely adjust the compensation tables. Obviously, they won't get them perfect, but they should have tuned enough cars to come close. If you do have an issue, they would likely touch it up free/cheap.
    2005 WRX STi (Mods | Virtual Dyno)

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