More noob questions...boost issues
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This is a discussion on More noob questions...boost issues within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; Hey guys, I've recently been dealing with a host of issues on my car and am trying to get everything ...

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    More noob questions...boost issues

    Hey guys, I've recently been dealing with a host of issues on my car and am trying to get everything sorted out. The last (hopefully not still current) problem was the ECU limiting boost to wastegate pressure only (7-8 psi) for reasons unknown. Before that happened, power delivery would be rough with an occasional backfire around 4k rpm.

    I've changed spark plugs, cleaned the MAF, checked vacuum hoses, put in a new air filter, etc and it seems smoother so far.

    Problem is that I'm not sure what's up with my boost. I get around 14psi according to my gauge, but around 5-6k rpm, it sometimes drops down to about 10psi. I don't think this is normal...also - what boost levels should I be getting? Could/is this associated with the wastegate arm adjustment?

    2002 wrx - Cobb AP Stage 2 91 octane map, gutted up-pipe, MRT catted TBE.

    Any help is appreciated. Thanks guys

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    Moderator Donkey's Avatar
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    Read......Cobb's......map notes..........................................



    Boost Targets
    : ~15.8psi +/- 0.5psi peak boost pressure tapering down
    to ~13psi, depending on vehicle and conditions. If your vehicle is
    not achieving or exceeding the boost targets, you may need to
    mechanically adjust your boost control system, please refer to this
    document “
    How Subaru’s Factory Boost Control System Works v1.X” for

    instructions.


    http://www.accessecu.com/accessport/...03WRXMaps.html
    Resident Adviser @ WTF Tuning, LLC
    2002 FORESTER S
    1998 FORESTER S




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    Quote Originally Posted by Donkey View Post
    Read......Cobb's......map notes..........................................



    Boost Targets
    : ~15.8psi +/- 0.5psi peak boost pressure tapering down
    to ~13psi, depending on vehicle and conditions. If your vehicle is
    not achieving or exceeding the boost targets, you may need to
    mechanically adjust your boost control system, please refer to this
    document “
    How Subaru’s Factory Boost Control System Works v1.X” for

    instructions.


    http://www.accessecu.com/accessport/...03WRXMaps.html


    Thanks, I did read them earlier today, but I just need help making sense of it and figuring out what to adjust or if I should just let it be. Target boost for the map would be around 15.8 psi...and then it says tapering down to around 13 psi. I'm assuming that means that the car would hit around 16 for a bit and fall back down to 13ish near red-line. However, I'm getting about 10psi around redline...doesn't that seem a bit low? Is there something I need to adjust?

  5. #4
    Moderator Donkey's Avatar
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    What gear are you referencing boost in?
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    Generally this happens in 2nd and 3rd gear WOT

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    Moderator Donkey's Avatar
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    Try 4th gear. You will never see full boost in 1st,2nd or sometimes not even 3rd. Boost is load/gear dependent. Also read again,slowly,what I posted from Cobb's map notes. Something....something..overboosting/underboosting...something...something...
    Last edited by Donkey; 09-12-2010 at 08:57 AM.
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    Quote Originally Posted by Donkey View Post
    Try 4th gear. You will never see full boost in 1st,2nd or sometimes not even 3rd. Boost is load/gear dependent. Also read again,slowly,what I posted from Cobb's map notes. Something....something..overboosting/underboosting...something...something...
    Haha alright, thanks man. I'll take it out for a drive later today and try to see specifically what its doing and compare it to the map notes.

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