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Old 12-04-2011, 01:15 PM   #1
DreksSTI
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Default Does anyone actually know the Proper steps to a boost leak test?

I hate to beat a dead horse here, But I have been searching and reading the threads here about Boost testing and just about every thread says or does something different.

I know I need to Block off the 4 lines including the Purge valve so I dont get the Buzzing sound. But what about the oil cap? does that need to removed so the cam seals are not toasted. And some guys says to pressurize to 5-10psi max, some say do 15+psi but no more than 20psi. Can you guys please help me out with a more straight forward answer, I am trying to get this done today since my car is running lean at WOT.

Thanks in advanced, Its really appreciated!
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Old 12-04-2011, 02:29 PM   #2
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bump it up
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Old 12-04-2011, 03:28 PM   #3
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Bump it up
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Old 12-04-2011, 07:17 PM   #4
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Where is my Purge Valve Because I sure as hell couldnt find it today while attempting the test?


And is this the PCV hose? If so, How do you remove it, Arent those the permanent style clamps?
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Old 12-04-2011, 09:08 PM   #5
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Anyone?
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Old 12-05-2011, 01:20 AM   #6
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night bump
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Old 12-05-2011, 08:17 AM   #7
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in the first pic, purge valve line comes off that shiny curved nipple just to the left of the alternator, line goes to purge valve, then continues to the turbo inlet. remove both lines (from intake mani and from turbo inlet) and cap them.

in the second pic, yes that's your PCV hose and yes, that's a permanent clamp (oetiker clamp). look a little left of that clamp to where the rubber hose connects to the plastic piece, that plastic piece can be removed from the turbo inlet nipple (has a press button to release thing like a wiring harness connector). remove it and you can cap the plastic nipple deal on the turbo inlet (needs a pretty big cap, can't remember the exact diameter).

removing the oil cap: some say do it, some say it's not necessary. it takes 3 seconds, just do it.

basically, remove all the hoses that go to the turbo inlet and cap them, cap the purge valve nipple on the intake mani as well, remove oil cap, and giv'er.

personal opinion: checking for leaks at 5-10 psi is pointless. i wouldn't try to push 40 psi in there, but my tune has me running 18psi so if my setup can't hold 15-20, i wanna know about it while i have my head under the hood, not while i'm driving


hope that helped

-sean

Last edited by blame; 12-05-2011 at 08:25 AM.
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Old 12-05-2011, 09:55 AM   #8
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Quote:
Originally Posted by blame View Post
in the first pic, purge valve line comes off that shiny curved nipple just to the left of the alternator, line goes to purge valve, then continues to the turbo inlet. remove both lines (from intake mani and from turbo inlet) and cap them.

in the second pic, yes that's your PCV hose and yes, that's a permanent clamp (oetiker clamp). look a little left of that clamp to where the rubber hose connects to the plastic piece, that plastic piece can be removed from the turbo inlet nipple (has a press button to release thing like a wiring harness connector). remove it and you can cap the plastic nipple deal on the turbo inlet (needs a pretty big cap, can't remember the exact diameter).

removing the oil cap: some say do it, some say it's not necessary. it takes 3 seconds, just do it.

basically, remove all the hoses that go to the turbo inlet and cap them, cap the purge valve nipple on the intake mani as well, remove oil cap, and giv'er.

personal opinion: checking for leaks at 5-10 psi is pointless. i wouldn't try to push 40 psi in there, but my tune has me running 18psi so if my setup can't hold 15-20, i wanna know about it while i have my head under the hood, not while i'm driving


hope that helped

-sean

Thanks alot my friend, That helped me out. If anyone else has any input, they are more than welcome to chime in. Thanks
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Old 12-05-2011, 04:39 PM   #9
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WRX specific, but perhaps useful: http://www.3gwrx.com/forum/index.php?topic=20671.0
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Old 12-05-2011, 04:59 PM   #10
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That link was one of the links I had been lookin at. Just needed some things clarified. thanks tho
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Old 12-05-2011, 08:30 PM   #11
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Anyone else have any input?
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Old 12-05-2011, 09:16 PM   #12
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What are you using to pressure the inlet? I bought a 5 gallon air tank for like $25 which works well. All the cheap air compressors would either not be strong enough to pressurize, or they would keep cycling making it hard to hear the leaks. It was cheaper for me just to buy the air tank than an a larger compressor.

What kind of boost leak tester do you have, does it have a pressure gauge to see how much is in the turbo inlet?
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Old 12-05-2011, 10:19 PM   #13
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I am using a Smallish compressor and tank that has a regulator on it. I have a valve attached to a PVC cap.
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Old 12-05-2011, 10:57 PM   #14
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You should spray soapy water on all the joints on the air intake and see if you can see bubbles. This way you can see even minor leaks, trying to hear leaks will only work for large leaks. its amazing how many small leaks you might find on a highly modified intake system sometimes.
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Old 12-05-2011, 11:25 PM   #15
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will be sure to spray soapy water. My intake is stock.
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Old 12-06-2011, 02:28 AM   #16
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+1 on the soapy water, lets you use your eyes to check for leaks as well as your ears
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Old 12-06-2011, 09:13 AM   #17
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Old 12-06-2011, 09:57 AM   #18
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^^thanks for that link. Thats helps me feel a lot better
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Old 12-06-2011, 10:19 AM   #19
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theres some good info in this thread. thanks to the people who posted links. i need to do one myself and wasnt 100% sure wich lines needed to be capped off and if i could do it from the intake pipe.

now does anybody know the exact size caps needed for this? i am not sure if my old testers will fit on this car or not and i would just prefer to buy some new parts to make a new setup anyhow. mine are pretty old and probably just need to be replaced anyhow.
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Old 12-06-2011, 07:44 PM   #20
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Well this is interesting, Been talking with [email protected] and he says they leave everything plugged in when they run their pressure test. If you remove the lines from the inlet hose then how will you know if one of lines has a leak or not? Makes since. So now I am back to being unsure lol
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Old 12-06-2011, 10:07 PM   #21
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Also he said if your lines on the inlet hose are popping off with only 5-10psi then they dont have a very good connection and need to be connected better.
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Old 12-06-2011, 10:18 PM   #22
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Quote:
Originally Posted by DreksSTI View Post
Well this is interesting, Been talking with [email protected] and he says they leave everything plugged in when they run their pressure test. If you remove the lines from the inlet hose then how will you know if one of lines has a leak or not? Makes since. So now I am back to being unsure lol
I'm pretty sure Chris misunderstood you!

If you leave them all connected it won't work, You will shoot pressurized air straight into your crankcase, and if your oil cap is off it will just blow out the filler neck. I have done this test on two of my cars, a WRX and an STI, like 100 times and it works very well. You are just plugging the crankcase breather, the tube that goes to the breather that splits to the heads and to the "kazoo" which is part of the fuel vapor line.

The lines to the boost controler will stay connected.

Just an idea/hint.... Get long bolts, the kind that have a smooth area between the head and the threads, Cut them down and use them to plug the hoses. You will need a couple different sizes that fit your lines along with hose clamps to keep them from shooting out.

Keep in mind you will want everything you are plugging to be tight! You need to be very careful, 15psi can really hurt if something goes wrong. I've destroyed a tester by it flying out of the inlet tube and exploding against the fender. So like I said BE CAREFUL!! I tested my sti up to 25psi when I was running E85, You should shoot for a couple psi above what you plan on running for boost.
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Old 12-06-2011, 10:31 PM   #23
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Quote:
Originally Posted by 2gnt2wrx View Post
I'm pretty sure Chris misunderstood you!

If you leave them all connected it won't work, You will shoot pressurized air straight into your crankcase, and if your oil cap is off it will just blow out the filler neck. I have done this test on two of my cars, a WRX and an STI, like 100 times and it works very well. You are just plugging the crankcase breather, the tube that goes to the breather that splits to the heads and to the "kazoo" which is part of the fuel vapor line.

The lines to the boost controler will stay connected.

Just an idea/hint.... Get long bolts, the kind that have a smooth area between the head and the threads, Cut them down and use them to plug the hoses. You will need a couple different sizes that fit your lines along with hose clamps to keep them from shooting out.

Keep in mind you will want everything you are plugging to be tight! You need to be very careful, 15psi can really hurt if something goes wrong. I've destroyed a tester by it flying out of the inlet tube and exploding against the fender. So like I said BE CAREFUL!! I tested my sti up to 25psi when I was running E85, You should shoot for a couple psi above what you plan on running for boost.
Thanks for your info.

I am pretty sure Chris didnt misunderstand me tho, since he was the one who told me to do the pressure test.

This is straight from Chris

"Sorry for not getting back to you yesterday, you will actually want to leave all of the spigots installed on the inlet hose when you do the pressure test. Taking them off will mask problems with the stock inlet hose if there is a leak there. Just leave everything the way it is, put the plug at the end of the inlet hose, and pressurize the system. "

And I replied what about the lines popping off and what about capping the PCV valve and this was his response,

"They should stay on if they have a good connection. If they pop off, then they're need a better connection. The PCV doesn't need to be capped off either. 20 psi isn't enough to cause any damage. We've done this on a lot of cars in the past."
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Old 12-06-2011, 10:32 PM   #24
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Quote:
Originally Posted by DreksSTI View Post
I hate to beat a dead horse here, But I have been searching and reading the threads here about Boost testing and just about every thread says or does something different.

I know I need to Block off the 4 lines including the Purge valve so I dont get the Buzzing sound. But what about the oil cap? does that need to removed so the cam seals are not toasted. And some guys says to pressurize to 5-10psi max, some say do 15+psi but no more than 20psi. Can you guys please help me out with a more straight forward answer, I am trying to get this done today since my car is running lean at WOT.

Thanks in advanced, Its really appreciated!
EIDT: Nevermind, misunderstood "Boost leak" to mean only testing the pressurized side of the intake tract ignore below text becuase I'm stupid.

Pretty sure if you're running lean you don't have a boost leak. A boost leak will cause you to run rich. A boost leak means air that has been metered by the MAF is leaking out, therefore the ecu is putting in the fuel required for the all the metered air, yet some of the metered air is leaking, hence too much fuel for the actual am ount of air thats getting into the motor. Rich = slower but *somewhat* safe.

On the other hand a leak between your MAF and turbo inlet will cause you to run lean but this section of tract is under vaccum. In this case you're sucking in air in addition to what was metered so the ecu is not adding any fuel to compensate for the additional air hence you will run lean = dangerous.

Check all the connections between your MAF and inlet, stock inlet ends tend to rip if you've taken the turbo out/replaced it. Mine did, as did my friends during turbo swaps.

Last edited by Shef; 12-06-2011 at 10:39 PM. Reason: I'm not smart
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Old 12-06-2011, 10:40 PM   #25
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Quote:
Originally Posted by Shef View Post
EIDT: Nevermind, misunderstood "Boost leak" to mean only testing the pressurized side of the intake tract ignore below text becuase I'm stupid.

Pretty sure if you're running lean you don't have a boost leak. A boost leak will cause you to run rich. A boost leak means air that has been metered by the MAF is leaking out, therefore the ecu is putting in the fuel required for the all the metered air, yet some of the metered air is leaking, hence too much fuel for the actual am ount of air thats getting into the motor. Rich = slower but *somewhat* safe.

On the other hand a leak between your MAF and turbo inlet will cause you to run lean but this section of tract is under vaccum. In this case you're sucking in air in addition to what was metered so the ecu is not adding any fuel to compensate for the additional air hence you will run lean = dangerous.

Check all the connections between your MAF and inlet, stock inlet ends tend to rip if you've taken the turbo out/replaced it. Mine did, as did my friends during turbo swaps.
I meant a Vac/boost leak. Wasnt sure which it might be. And I am hoping that its somewhere on the inlet. Thanks for your input. All good man.
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