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Discussion Starter #1
Hey everyone,

I have an 02 WRX and I have a boost gauge in it. I have only recently owned the car and installed the gauge. I am pretty confident that the gauge is working correctly, and it usually shows the car boosting up to about 15 psi, which is normal. However sometimes the car won't boost over 8 or 9 psi, and definitely feels slower. No matter how hard I "gun it" the car continues to only boost up to that range of psi. I'm wondering if that it normal or if I can even fix/change that. Other times the car boosts fine so it's kind of back and forth between the normal range and then back to 8/9 psi. The car isn't throwing any codes or anything either. Help?
 

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Pro Manscaper
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Where in the RPM range are you seeing it drop to that?

Also, is your WRX stock? Stock boost pressure is around 13.5 PSI give or take a couple tenths.

Check all your vacuum lines to make sure everything is connected properly and securely.
 

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Discussion Starter #3
It is stock. I've read somewhere that it should be 14.7 psi, and when its running properly it stops right around 15 psi. And it doesn't drop. When it revs up it just hovers right around 7-9 psi and then drops once I take my foot off the gas.
 

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Discussion Starter #4
Actually now some places are saying 14.7, and others are saying 13.5.. Is it bad if my car is running at about 15 psi's?
 

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Pro Manscaper
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Next question...what kind of boost gauge do you have?

Stock boost system on a 2002 WRX is only going to get to 13.5ish psi. 14.7psi is not correct. Stock will also taper down to below 10psi as it approaches redline.

Datalogging would be your best bet to figure out what exactly your boost is hitting and where.

15psi isn't that bad for your car...going stage 1 or stage 2 will increase boost. But if you are hitting a true 15psi on a stock WRX, there may be a slight over boosting issue.

But I also don't completely understand what you are saying that when it revs up it hovers around 7-9 psi. Revs up where? What RPM range are you talking about specifically?
 

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Captain James of the SS Impreza has gone down with
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Also, your gauge may not be accurate. Your ECU will tell you what boost levels you're hitting.
 

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Also, your gauge may not be accurate. Your ECU will tell you what boost levels you're hitting.
Ergo why I asked what kind of boost gauge the OP had, smart guy :p
 

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Captain James of the SS Impreza has gone down with
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Captain James of the SS Impreza has gone down with
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Discussion Starter #12
I'm going to keep driving it and then tell you guys exactly what is going on. but it seems like the max boost I am getting in any gear is either about 15 psi, or 7-9 psi, depending on the drive.
 

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I'm going to keep driving it and then tell you guys exactly what is going on. but it seems like the max boost I am getting in any gear is either about 15 psi, or 7-9 psi, depending on the drive.
7-9 PSI is mechanical wastegate pressure. There are some things you could check. Your ECU could either be pulling boost because of detonation or the issue could be entirely mechanical. Check to make sure that your vacuum plumbing is properly hooked up between your boost solenoid and the wastegate -- especially check for any boost leaks. Also, check to see if the restrictor pill is intact.
 

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I am really confused by that. The amount of boost you have is directly relevant to the amount of gas you give the car...

Like previously asked, what brand gauge do you have?

Or take and post a video of your cluster when you go for a drive so we actually know what you're talking about.
 

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Discussion Starter #15
Sorry I'm not being clear. The gauge is automated. And when I say that the car is boosting to 7-9 psi, that is with my foot flat to the floor. I think the car also needs plugs. Could that have something to do with it?
 

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So you never actually do hit 15psi.

Plugs *might* have an issue in contributing, but there's something else amiss. Wastegate pressure is around 7psi or so, which means you have some kind of a boosting issue. You need to start looking at the restrictor pill, the boost control solenoid, or vacuum leaks somewhere at this point.

For a reference of the WRX boost system, refer to this link.
 

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It be an exhuast leak. I had the same problem with inconsistant boost and couldnt figure it out. I used that sea foam treatment and found two exhaust leaks. One at the up pipe/turbo and another at the down pipe/turbo. I replaced those gaskets and its fine now.
 

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^^^That could definitely be a possibility...
 
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