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Boost Problem, need some advice.

1848 Views 2 Replies 2 Participants Last post by  SicLanEvo
Ok i'm not new to the 4g63, but i am kinda lost right now. Looking around i read that the evo when it's stock runs about 19psi and tapers to 17psi. I installed a Stewart Warner vac/boost gauge today, which is no big deal I have done numerous ones in the past. I run the car and in 4th and 5th gear, I hit 18psi but then it drops very fast to 15psi and then comes up and goes down. Does this sound normal? Also at idle the it is at 15-18 on the vac side, my DSM used to be around 25-22. If not then any sugesstions? I have a extreme motorsports DIS filter kit and a Greddy type-s with the single spring mod. Could it be that the BOV is opening early because of the single spring? Please someone shed some light on this for me. Thanks in advance

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I have an 04 Evo with Autometer boost gauge. Car is all stock. I peak at 20psi at around 4000-4500 rpm and then drop to around 17-18psi. Bov could be the problem.
I think i got it stablized, it was peaking at 19psi and then dropping to fast, So I played with the BOV and now it is holding 19psi for longer then tapering off slower which is normal from what i hear. I was just being paranoid i guess, problem is all fixed now, just haven't had a chance to post it yet.
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