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Old 05-01-2013, 01:39 PM   #1
carfan771
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Member#: 315743
Join Date: Apr 2012
Vehicle:
2008 WRX HATCH-VF52
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Default Can a Faulty BPV cause Overboost?

Since installing my stage 2 map I've been hearing a "fluttering" noise (like air escaping) and power hesitation at full throttle that lasts a few seconds and stops. Recently started to happen at half throttle and today, at just half throttle, some lights on the dash were illuminated (like when "boost creep" happens: traction control etc...) but did not stayed on. Could it be overboost being caused by a faulty stock BPV?

My 2008 WRX have the following power mods:
Perrin catted downpipe
Grimmspeed 3 port EBCS
Turbo XS intake
Walbro 255
VF-52 turbo
Cobb AP with Torqued Performance stage 2.52 map at 19 psi on 91 octane (fine tuned by Eric)
Stock Cat back
Stock BPV
Stock intercooler

Thanks.
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Old 05-01-2013, 02:17 PM   #2
dpenn
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2008 WRX
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A faulty stock bpv will not cause an overboost condition...a faulty wastegate could...

are you going wot before 3000rpm in 4th or 5th gear?
that is a known condition that can cause wastegate flutter / overboosting
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Old 05-01-2013, 05:38 PM   #3
jpatt006
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Join Date: Jul 2011
Chapter/Region: MAIC
Location: West Chester, PA
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2011 WRX stage 2+
DGM

Default

Quote:
Originally Posted by dpenn View Post
A faulty stock bpv will not cause an overboost condition...a faulty wastegate could...

are you going wot before 3000rpm in 4th or 5th gear?
that is a known condition that can cause wastegate flutter / overboosting
^This...what gear are you going WOT in?
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Old 05-01-2013, 06:28 PM   #4
freshsti
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Chapter/Region: Tri-State
Location: new jerz
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2005 ewg gt52 sti
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My stock bpv started to stick and caused massive surge causing the car to buck and shake.Got so bad it was doing it even on light acceleration.
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Old 05-01-2013, 08:31 PM   #5
carfan771
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Default

Thank you all for taking the time to answer. Most of the time I have seen over boost in 5th gear (WOT)after 6000 rpm. After my first post I took the car for a 2 hour round trip and used the COBB AP to record the highest boost achieved. It was 20.5 psi in 5th at WOT (19 psi target). I've read that this is a common issue associated with the turbine's mechanical waste gate. Some people solved it with just the EBCS and others (like me it seems) have to resort to installing an external waste gate. I just though that a faulty BPV could cause pressure fluctuations and false readings so that it could aggravate the overboost issue. In any case I ordered a Forge BPV that should at least get rid of the boost leak.
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Old 05-02-2013, 07:29 AM   #6
jpatt006
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Quote:
Originally Posted by carfan771 View Post
Thank you all for taking the time to answer. Most of the time I have seen over boost in 5th gear (WOT)after 6000 rpm.
And there is your problem. There is no need to be going WOT in 5th gear. Just downshift if you want to punch it. WOT in 5th gear and overboosting at 6000rpm would easily have you going over 120mph. If you are doing this often enough that you consider overboosting a problem...then well, you have a different problem to worry about. I hope that frequent 5th gear WOT pulls up to 6000rpms is occurring on a track.

Second, how are you defining overboost? Does your dash turn into a Christmas tree and your engine feel like it explodes and immediately shuts down? 1.5psi over target doesnt seem to me like it would be enough to throw an overboost code. Unless of course your tuner did not reset the parameters.
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