Stock 2.0l with forged pistons
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This is a discussion on Stock 2.0l with forged pistons within the Tuning: Electronic Engine Management forums, part of the Tech & Modifying & General Repairs category; Hey guys I have an odd sort of question. I am rebuilding my 2002 wrx motor at the moment because ...

  1. #1
    Registered User Cripple'sWRX's Avatar
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    Apr 2012

    Stock 2.0l with forged pistons

    Hey guys I have an odd sort of question. I am rebuilding my 2002 wrx motor at the moment because at 130k miles the bolt holding my timing tensioner pulley snapped. Unfortunately my valves made enough contact with the pistons to require replacement. My car was previously tuned at p&l motorsports for a catless uppipe and downpipe. I called them and asked for their opinion and was told cp forged pistons would be best. My goals are to have it e85 capable in the coming year, a new header, possibly a vf39 and better tmic. I bought the cp pistons after being told I wouldn't need a retune by P&L. According to them my compression is only changing from 8.0:1 to 8.2:1. I trust their opinion but I always like to get more than one.

    In your opinion do I need a retune? I'm also wondering is it absolutely necessary to let the car warm up at idle with forged pistons?
    Im only asking because I honestly need some guidance and this is my first rebuild!

    Bugeye wrx

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  3. #2
    Registered User Obeisance's Avatar
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    Apr 2012
    Ann Arbor
    I don't know anything about a rebuild, but I have certainly dreamed about adding nicer pistons when my engine finally gives out. I do have an unrelated comment..

    The tensioner bolt which snapped... should that bolt have a lot of stress on it under normal operation? My intuition is that it should not... is it possible that something else seized (double check your oil pump), leading to stress being transferred ultimately to the timing belt, and as the tensioner tried to move (but can't do so easily due to it's hydraulic pusher) it acted as a lever on the bolt, giving a bending stress that lead to failure?
    David - '05 WRX

  4. #3
    Moderator Donkey's Avatar
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    Apr 2005
    Da boonies
    I Support ClubWRX
    I would just datalog the car after the rebuild but the 2.0L is normaly a 8.2:1 from the factory.
    Resident Adviser @ WTF Tuning, LLC
    2002 FORESTER S
    1998 FORESTER S

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