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Old 04-10-2013, 03:06 AM   #1
subaru505
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Subaru Stars boost spike and drops when in full boost

Well I have an 02 wrx with Perrin short ram and Perrin single cat down pipe and whenever I get boost it will go to about 7 pounds then drop to about four then go right back up repeating untili get out of boost
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Old 04-10-2013, 07:35 AM   #2
wrxlaunch
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Vac leak or bad bcs... install a 3 port, all new vac lines and get a protune
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Old 04-10-2013, 08:03 AM   #3
HinshawWRX
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7 PSI is not full boost, that is wastegate pressure. You have a leak somewhere or bad bcs.
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Old 04-10-2013, 08:35 AM   #4
Turd Nugget
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Just look at your vac lines and check the bcs. Since it drops below 7psi, I'd check out the WG actuator too. I love all these answers "3 port" "protune". I'm guessing your looking for the car to perform like it was ment to be, and there is no need to spend 1k when you can just replace the defective part through thorough troubleshooting.

You are supposed to be seeing 15psi, although the spring in the wastegate mechanically regulates boost to 7psi, so electronicaly the ECU uses the BCS to bleed off boost from the source to the atmosphere until the ECU sees around 15psi. If boost is fluctuating under 7, id say there is a problem with the wastegate itself. Test it.
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Old 04-10-2013, 11:12 AM   #5
subaru505
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Quote:
Originally Posted by Turd Nugget View Post
Just look at your vac lines and check the bcs. Since it drops below 7psi, I'd check out the WG actuator too. I love all these answers "3 port" "protune". I'm guessing your looking for the car to perform like it was ment to be, and there is no need to spend 1k when you can just replace the defective part through thorough troubleshooting.

You are supposed to be seeing 15psi, although the spring in the wastegate mechanically regulates boost to 7psi, so electronicaly the ECU uses the BCS to bleed off boost from the source to the atmosphere until the ECU sees around 15psi. If boost is fluctuating under 7, id say there is a problem with the wastegate itself. Test it.
Sorry I'm kinda new what's a bcs and how do you test waste gates
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Old 04-10-2013, 01:55 PM   #6
HinshawWRX
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BCS= Boost control solenoid. It's located on the passanger strut tower, has 2 vaccuum lines coming off of it, follow them to your turbo.

You have one waste gate, it is on the turbo, and allows for the turbo pressure to be relased. (It's internal fyi) DO NOT ADJUST THE ARM.

First thing to do is replace the vaccuum lines, make sure there is a restrictor pill in the appropriate one, and see what happens.

Read this. http://forums.nasioc.com/forums/show....php?t=1190530

Refer to this image for help.

**Note that what is titled "wastegate control solenoid** is your BCS.
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Old 04-10-2013, 02:54 PM   #7
subaru505
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Could it be because of my intake ??
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