How do I make / buy / use / troubleshoot a boost leak tester? [merged]

[Turbo Monk3y]

All boost leak tester threads are combined here.

i read somewhere maybe the Vfaq about making or buying a boost leak tester of some sort but never found it.... the reason being my acceleration seems slower than normal and all ive done to my stock car so far is take out the air box put on a K&N filter and cut the dump tube i have my boost guage sitting in a box not hooked up yet. and since those 2 mods it when i go wot on the car i can hear the turbo spool up and it sounds nice but i can also hear a sound as my rpm increases the SHHHHHHHHHHHHHHHHHHHHHH sound does too. the sound comes from the same area as the BOV i think maybe i got a #@%#@%#@%#@% stock bov and it cant handle over 11-13 psi??? Then i shift and it makes the nice BOV sound WHOOOOSHHHH... but my car seems to be a little slower.. any ideas before i go check every tube clamp and tube????

 

[kicknurass4fun]

I also bought my valve stem at ace-hardware. The boost tester works great I use it all the time. Although i don't know if that is a good thing.

 

[RamenPride]

I got a pair of valve stems at Autozone for $2 to make the boost leak tester.

same here. I used that, a 2" to 1.5" Fernco coupling from Lowe's (came with clamps), and a 1.5" plastic pipe cap. drill hole in cap, pull valve stem through, done.

 

[90gsxmesaaz]

When doing a boost leak test there is air coming out of the valve cover breather. I should mention that my head recently had the valve seals replaced and since I got the car back I just noticed that the hose normally that comes out of the valve cover breather is missing.
1) Because of the hose missing is normal for air to be coming out of here? Is this supposed to be blocked off when doing a boost leak check?
2) Where is the valve cover breather supposed to go to? Is is suppose to route to the intake before the turbo? I have an aftermarket intake piping before the turbo and there is no where to route back into the turbo.
3) Should I just make a catch can or in-line filter and if so where should I route it to?

Sorry for all the questions. Hope someone can help.

 

[heppm01]

OHMYGOD! A boost leak post without Oldman chiming in? Can somebody call his house and make sure he's alright?

M

 

[SBstar]

Yes you should probably get a catch can for that, you can just get a filter but you'll be replacing it at every oil change. Might as well just get the catch can and not worry about it for a while. Your pcv valve might need to be replaced as well. I blocked off the hose on my car and my oil dipstick blew out when I did the boost leak test. I was told it was the pcv valve.

 

[Kewltalon]

OHMYGOD! A boost leak post without Oldman chiming in? Can somebody call his house and make sure he's alright?

M

!!! I would like to thank Oldman, evan though i never asked him for help, because reading his comments on boost leaks help me diagnos my leaks. Kudo's to Oldman and GTM! This thread here should help you answer all your questions. hope this helps u too.

http://www.dsmtuners.com/forums/showthread.php?t=174682&page=1&pp=25

 

[oldman]

What's going on here?? my ears have been ringing all morning.

When doing a boost leak test there is air coming out of the valve cover breather.

This means you have intake to crankcase pressure leak. What lead you the boost leak test? Here's a similiar thread that will get you started so we don't spent another 20 posts going over the basics. http://www.dsmtuners.com/forums/showthread.php?t=174682

1) Because of the hose missing is normal for air to be coming out of here? Is this supposed to be blocked off when doing a boost leak check?

NOOOO! In fact now that you know you have crankcase boost leak, you want to open the oil cap every time you pressure test so no more seals will get blown out.

 

[90gsxmesaaz]

Thank you! I will try the suggestions in the other posts.

 

[90gsxmesaaz]

Oldman,
Thanks for your suggestions. To answer your question, the reason why I decided to do a boost leak test is that whenever I was hitting 7psi I would get knock on my datalogger.

 

[90gsxmesaaz]

Wise Oldman, I sent you a PM for another question I had regarding boost leak testing. Thank you again!

 

[oldman]

PM answered. Post your follow up questions here so others who searched can also benefit from it, don't worry no one will laugh.

 

[90gsxmesaaz]

Thanks oldman!

To understand the concept of the boost leak test I wanted to know when pressurizing the turbo intake where is the air supposed to go and stay pressurized in? For example, air on my test was pressurizing the crankcase which apparently it is not supposed to. Thanks again for all your excellent posts and helping us all with our boost leak questions!!!
Maybe eventually all your good information can be put in the tech section under the FAQs!

 

[oldman]

Eventually.

 

[90gsxmesaaz]

oldman,
did you have an answer for my question yet or are you still busy?

 

[ddavisaf]

Thanks oldman!

To understand the concept of the boost leak test I wanted to know when pressurizing the turbo intake where is the air supposed to go and stay pressurized in? For example, air on my test was pressurizing the crankcase which apparently it is not supposed to. Thanks again for all your excellent posts and helping us all with our boost leak questions!!!
Maybe eventually all your good information can be put in the tech section under the FAQs!

Crankcase pressure is bad you're correct.
Your air should stop at the intake manifold.
The most common reason for crankcase pressure is a bad pcv. Try replacing that, but make sure you test them first. OEM is the way to get with pcv's.
In order to pinpoint crankcase leaks better, test from the throttle body elbow. Use soapy water and spray down everything in the area. Injectors, intake manifold, etc.

 

[90gsxmesaaz]

Great! Thank you!
I already was calling this morning to the dealers to get a PCV valve. I will be picking up an OEM one today.

 

[oldman]

oldman,
did you have an answer for my question yet or are you still busy?

I was not aware you were still waiting for an answer , I thought I answered it via pm. Anyway, intake pressure extends from the turbo all the way to the intake valves, this will include the intake ports on the head which is where valve stem seals are, reason why intake pressure can leak through valve seals into your crankcase. With that said, since at least one set of intake valves will be open no matter the position of the crank, technically the answer is the piston.

 

[ddavisaf]

Yeah, I didn't put much thought into my answer and then forgot where the post was when I figured out I was wrong.
My appologies.

 

[90gsxmesaaz]

I was not aware you were still waiting for an answer , I thought I answered it via pm. Anyway, intake pressure extends from the turbo all the way to the intake valves, this will include the intake ports on the head which is where valve stem seals are, reason why intake pressure can leak through valve seals into your crankcase. With that said, since at least one set of intake valves will be open no matter the position of the crank, technically the answer is the piston.

Thank you for your reply! So if I understand the boost leak test correctly, if the PCV valve is good there should not be any air coming through the hose that runs from the intake manifold to the PCV valve. Then the air will go through the intake manifold, one set of intake valves that are open, and stop at the pistons. Once pressure is built and the PCV valve is good then won’t some air come out of the breather? Sorry for all the stupid questions. I just really want to understand the concept completely. Thank you for your answers and patience with me!

 

[oldman]

So if I understand the book leak test correctly, if the PCV valve is good there should not be any air coming through the hose that runs from the intake manifold to the PCV valve.

What is a book leak test? There should still be pressure in the hose to the pcv valve, a functional pcv will stop air from entering the crankcase. Crankcase = oil pan + area under the valve cover and all internal passages that connects both areas.

Then the air will go through the intake manifold, one set of intake valves that are open, and stop at the pistons. Once pressure is built and the PCV valve is good then won’t some air come out of the breather? Sorry for all the stupid questions. I just really want to understand the concept completely.

If you hear hissing from the breather valve on the passinger side of the valve cover, you have crankcase leak at either pcv, valve seals or piston rings.

 

[90gsxmesaaz]

Thank you!
By the way, I did a boost leak test before and after the turbo and I was still getting air out of the breather hose. However it did seem that I was getting slightly less after the turbo. I tried blocking off where the air comes from the intake manifold to the PCV valve (doing test on the throttle body) and I still had some air coming out. It is frustrating because I just had my whole head cleaned and new valve seals put it and also had the piston rings replaced (less than 1,000 miles ago). Does that sound right to you? (I ran the spell check this time )

 

[oldman]

By the way, I did a boost leak test before and after the turbo and I was still getting air out of the breather hose. However it did seem that I was getting slightly less after the turbo. I tried blocking off where the air comes from the intake manifold to the PCV valve (doing test on the throttle body) and I still had some air coming out. It is frustrating because I just had my whole head cleaned and new valve seals put it and also had the piston rings replaced (less than 1,000 miles ago). Does that sound right to you? (I ran the spell check this time )

I don't think the spell check will pick up "book leak test".

Let's re-group a little. Are you blowing smoke? Boost problems? What lead you to the pressure test?

1. How much holding pressure and time at the turbo?

2. At the TB with pcv connected?

3. At the TB without pcv?

Do not go by how you feel, go by actual numbers. You have followed directions pretty well so far but you keep ignoring the part about pressure level. Do you not have a boost gauge.

 

[90gsxmesaaz]

I don't think the spell check will pick up "book leak test".

Let's re-group a little. Are you blowing smoke? Boost problems? What lead you to the pressure?

1. How much holding pressure and time at the turbo?

2. At the TB with pcv connected?

3. At the TB without pcv?

Do not go by how you feel, go by actual numbers. You have followed directions pretty well so far but you keep ignoring the part about pressure level. Do you not have a boost gauge.

I am not blowing smoke (that sounds funny) and I do have a boost gauge (one in the car and one on my boost leak tester).
The problem I was having is that I was getting 10+ counts of knock anytime I get over 7 psi. Now that I have replaced the PCV valve I can get to about 9-10 psi without getting any knock.
1. At the turbo I can build pressure but as soon as I get to 7psi it starts hissing out of the breather. If I test from the throttle body it starts hissing of the same area but not as much at 7psi as well. I can get to about 10psi while letting air come out of the breather hose.
2. Lastly I tested at the throttle body with the intake manifold hose plugged and nothing on the PCV. I was also able to build to 10 psi (before my by bike pump broke ) It still was leaking out of the breather hose about 7 psi (again slowly)

 

[oldman]

Bike pump might be part of your problem right now, buy a $70 compressor from Walmart and return it after you're done , A compressor will give us a better gauge of the damage. Also, spray soapy water on every gasket and vacuum connection, including the injector seals, you need to take care of all the small leaks first before you know how serious the crankcase leak is. Oh, leave the pcv off during these tests.

 

[90gsxmesaaz]

Bike pump might be part of your problem right now, buy a $70 compressor from Walmart and return it after you're done , A compressor will give us a better gauge of the damage. Also, spray soapy water on every gasket and vacuum connection, including the injector seals, you need to take care of all the small leaks first before you know how serious the crankcase leak is. Oh, leave the pcv off during these tests.

That sounds like a good idea. Thank you for all your help! I will test it later this week or this weekend and let you know what happens.