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????

 

[CRiXman]

Hey turbo people,

I just built my first cheap boost leak tester, by following the instructions as per VFAQ linked below.

After some research here is what I have understood:

1) Remove the intake from the turbo
2) Tighten my home built boost leak tester to the turbo inlet.
3) Pump about 17 to 20psi of air using a compressor.
4) Listen to hear any leaks anywhere

I just wanted to ask you people that are familiar with boost leak testing, whether I should do anything more to the above mentiones steps.

I am expecting to find leak/s in the couplers I installed whilst changing the UIP. If I do find such a leak how would you advise repairing it besides trying to tighten the clamps further?

Also I am not to clear about how long the intake should hold 17 - 20 psi of boost, after I switch the compressor off.

One other thing.. I shall pump about 20 psi into the intake according to the compressor's gauge. Should my manual boost gauge also read 20 psi? i.e should the compressor's gauge and my autometer boost guage show the same pressure? Or will I have to expect a difference.

Thanks in advance

 

[dave99gst]

if you have a bleader type MBC - ya can lose that also .

 

[Black95TSIawd]

do what dave says and also pull the pvc line off the valve cover and cap it off somehow. big ass boost leak.

 

[Strm Trpr]

do what dave says and also pull the pvc line off the valve cover and cap it off somehow. big ass boost leak.

If your PCV is letting boost into the valve cover from the intake manifold
then your PCV is not funtioning properly.

Replace it with a new OEM unit.

To test if your PCV is not working, remove it and blow into it.
It should flow freely from the threaded end.
It shouldn't flow at all from the hose barb end....
It's basically a check valve.
It's designed to allow Positive Crank Case Pressure
to be vented into your intake tract to be burned during combustion...

To get by for now and to test your car, you can pull the line off of the PCV
and plug the line with a drill bit to make a snug fit, zip tie it if you have to.

 

[CRiXman]

Thanks for the feedback guys!

I forgot to mention I did not have a MBC yet..

Also I got one of the answers to my question AM question...: 'does the compressor gauge read the same pressure as my autometer boost guage?' The answer is YES more or less, but if someone could kindly confirm that would be ideal...

So...First trial... first results...

Either my air compressor is shite, or I have a boost leak somewhere at around 8-9 Psi, cause I cannot pump more than that... Most Importantly, even though I could not get a little more than 8psi I did not hear any sort of leak anywhere.. Just I heard like drops of oil (i think) inside the engine. Also once the compressor pumped 8.5 psi and stopped the boost guage slowly gradually dropped to around 1-2 psi.. This is normal right?

I have previously pumped bike tires easily up to 50 psi with this compressor.. so most probably I have a leak somewhere which can't hold more than 7psi... <---Is this logic?

I also notice when I drive, (usually) that when I WOT almost on anygear the car pulls but sluggier than If I gently, gradually push the gas pedal.. Is this due to a boost leak? FYI When I WOT My gauge reads 14psi (this is stock boost with my listed Mods... Maybe due to 95 octane?)

P.S Whilst the intake pipe was off (for the first time) I checked if there was any shaft play... According to me and what I have seem to have understood about shaft play I think there is no play at all.. I tried nudging it in every direction, and it only spun smoothly...

 

[steve]

Also I got one of the answers to my question AM question...: 'does the compressor gauge read the same pressure as my autometer boost guage?' The answer is YES more or less, but if someone could kindly confirm that would be ideal...

If they don't two thing could be going on. The gauges are off or it's leaking. It's easy to tell if the boost gauge reads higher than the compressor.

As far as how long it should hold pressure, the longer the better. It really should hold it forever but that doesn't happen in reality. A couple of mins would be fine.

Steve

 

[Strm Trpr]

You really need to try and get more psi out of your compressor.
20psi should be adequate to give you more time to track down your leak.

Did you test your PCV like I mentioned.
If it's bad, just plug the line going to it with something to get by for now.

The oil sound you're hearing is air rushing past your turbo seal down your oil return line into your oil pan and making the oil in your pan bubble.

Don't worry this is normal for a cold turbo.
When the turbo is operating and hot, the oil pressure helps seal the turbo seal while boosting, but during a static test, like you're doing, there isn't any oil pressure in the turbo.

You really need more psi out of your compressor.
Make sure all of the thin Vac lines from your turbo are all zip tied nice and tight.
I had two leaks there once.

Next step is to remove the coupler at your turbo outlet elbow and put your boost leak tester on your LICP and boost leak test all the way thru your intake system.

Once some clown removed his LICP and instead of testing his intake tract towards the engine thru the IC and so on, he connected it to the turbo outlet and pressurized the turbo only. Basically against the flow of air the turbo would produce .

When doing your next test, get a clean spray bottle and put a mixture of dish soap and water in it.
This will help pin-point the leak cuz it will bubble.
Start at the coupler on your SMIC inlet and spray that soapy water all around your coupler.
Once you have that sorted out, do the SMIC outlet coupler and work your way up to the Throttlebody and eliminate all of your couplers and your BOV.

There is more to this of course, but just get those done and post results.

 

[Attoir]

When doing a boost leak test, how fast is the air supposed to leak out? When i do a boost leak test, I'll pressurize it to 20psi and it will all be gone within 15 seconds or so. Should it last l onger? How much longer?

Is the goal really 100% air tight?

 

[Black95TSIawd]

If your PCV is letting boost into the valve cover from the intake manifold
then your PCV is not funtioning properly.

Replace it with a new OEM unit.

To test if your PCV is not working, remove it and blow into it.
It should flow freely from the threaded end.
It shouldn't flow at all from the hose barb end....
It's basically a check valve.
It's designed to allow Positive Crank Case Pressure
to be vented into your intake tract to be burned during combustion...

To get by for now and to test your car, you can pull the line off of the PCV
and plug the line with a drill bit to make a snug fit, zip tie it if you have to.

I dont think even an OEM pvc is a good unit and can stop ALL the air coming out of the intake mani. The only way i see this working out perfectly is if you purchase those check valves that dejontool sells. Supposedly can hold 1000 or 100 psi or something, cant remember exactly. On another note, if you rid the pvc and run the catchcan setup like i stated, it helps A LOT better with venting the crankcase. I guarantee if your having problems with your dipstick popping out, it will stop that from happening.

 

[GST with PSI]

i boost leak tested my system from the compressor outlet on at 20 psi. my system held pressure for a good 3 minutes. after that long i was satisified that it had no leaks so i don't know exactly how long it would have held. however i do know that 15 seconds is no where close to long enough. try this:

if you have a manual boost controller block it off because it will leak. charge the system and repair all the leaks you can hear. if your system is still leaking but you can't hear the actual leak, mix up a little bottle of what i like to call SEE-A-LEAK. take any spray bottle and fill it full of soapy water. spray anywhere that could be possibly leaking. common places missed are around the injector seals, idle screw, and around throttle body. mine was leaking around the intercooler outlet. i tried to tighten the clamp but still had a leak. turns out the upper intercooler elbow had actually corroded all the way through making a seal impossible. a new intercooler (old one couldn't even be repaired) and a bottle of SEE-A-LEAK fixed me right up.

 

[steve]

I dont think even an OEM pvc is a good unit and can stop ALL the air coming out of the intake mani.

Some of them are pretty good. When I check them before using one, I feed it 20+ psi on the barbed end and if any air leaks out I toss it.

Back when the car was new I could count on the OEM part working even when none of the aftermarket ones did but not anymore. That's why test them.

Steve

 

[ddavisaf]

You should hold pressure for at least 30 seconds.

Follow GST's "SEE-A-LEAK" instructions.

GST, you didn't actually label the bottle of soapy water "SEE-A-LEAK" did you? !
You could probably sell it on ebay and make some money if ya did.

 

[DSMvroom]

yea he did. I bought a case of it only to find out it was soap and water! negative feedback!

ddavisaf at least you are getting yours to pressurize, i can't seem to get mine to go up at all. I'm using an electric pump and the damn thing could sit at zero all day if i let it.

 

[ddavisaf]

Could you explain how you're doing the test, maybe I can help.

 

[GST with PSI]

actually i did label it SEE-A-LEAK so i wouldn't get it confused with my wax as you dry bottle, they were both the same bottle. sorry about that misunderstanding vroom, you should have read the auction details better (especially the small print.). about your boost leak test though, a compressed air tank is best for testing for a boost leak. it charges you system instantly so that if you have a large leak, it will pump in air faster than it can leak out (be very careful NOT to overcharge the system, a very large leak may result.). also hearing an air leak over an electric air pump is near impossible. a portable air tank works pretty good. use it to find the large leaks. you'll have to charge it at a gas station (prefferably one with free air) or something. once you have fixed all your large leaks, you should be able to use your electric air pump to find the rest. the smaller leaks left won't dissipate pressure as fast as the large ones you fixed earlier, so charge, fix, charge, fix, charge, fix until your system holds pressure. don't forget to use the SEE-A-LEAK in the final steps.

 

[95dodgeavenger]

OK I'm a noob at this whole dsm world still but i thought i would post and help a few others out hopefully...


Do you have Power loss bad, gas mileage idle surge?


you've done boost leaks and covered the whole?


and nothing else leaks..


well thats what i did.. until about 8 hours of searching i found that my 2G bov.. you know the thing that looks like it was made by a child... yea. well it was leakin at idle all the way up..

i have a 95 with 98k and its auto meaning mine don't blow off as much a manual.. and its bad already alot of people here not gettin the best gas mileage or any other symptoms above might want to check there bov's out..


so this is to all people with stock 2g bovs CHANGE THEM! there garbage..

get a 1g at least which can be found on ebay cheap..

after changing mine i drove my car and HOLY Hell its fast... its like a free mod.. yet its not.. better gas mileage more power better idle... ! all because of a plastic part that mistu thought would cut it...



so i hope i solve someone Else's problems..

 

[Spookcorleone]

Yeah anyone that looks around should understand that they are crap. I think they start to leak after 12PSI (if they are working correctly) which is pretty weak. I think a 1G holds 30something'ish.... don't quote me on that. Not sure.

 

[95dodgeavenger]

12 PSI!! our cars spike higher then that stock!!!!!!!! deff should be the first mod.. like before washing it!

 

[oldman]

12 PSI!! our cars spike higher then that stock!!!!!!!!

That doesn't mean the bov isn't leaking rather the turbo working harder.

I think a 1G holds 30something'ish....

There are no set numbers for this but 1g bov should hold 18-22psi stock and 25psi modified, 30psi seem a little high.

 

[95dodgeavenger]

That doesn't mean the bov isn't leaking rather the turbo working harder.


There are no set numbers for this but 1g bov should hold 18-22psi stock and 25psi modified, 30psi seem a little high.

ok what you said to me i dont think makes sense... i was stating that the stock bov working could leak on people..

 

[oldman]

ok what you said to me i dont think makes sense... i was stating that the stock bov working could leak on people..

I thought you were stating that you disagree with this statement

I think they start to leak after 12PSI (if they are working correctly)

because 2Gs with stock bov have gone 12psi+ in this statement.

12 PSI!! our cars spike higher then that stock!!!!!!!!

 

[BudmannG]

I just went to a tire shop and bought one. It cost me 2 dollars.

And then I put in a regular air hose fitting (Male Adapter). Set my compressor to 20 PSI and started my boost leak test. This way works much better, If you are doing the work yourself. But you have to make sure your out going air is set to 20 PSI.

 

[-silencer-]

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

 

[Defiant]

You might tell the hardware stores you're looking for a Schraeder valve. Hit the rack at Wal*Mart, by the air compressors in the automotive department. On the rack with the tire repair kits.

Do not use "u" for "you".

 

[hellotbone]

I built mine a touch more costly but easier to use. Don't forget you need a compressor with a pressure regulator on it you can't just nail it with 100 psi of pressure.

I used a 2" to 3" rubber coupler with hose clamps on both sides from the hardware store. Then in the 2" side I used a plumbing cap just the black ones that threads onto the pipe and has the rubber O ring as the seal. You have a nice square flat nut shaped piece of plastic sticking up now. What I did was go to the compressor section and they have small lengths of hose usually with 3/8" NPT threads on each end. Get a 1' piece and the correct male fitting for your compressor line. Now drill a hole slightly smaller then the 3/8" npt fitting and thread it in. You want a tight fit and you can cover it with epoxy if you are worried about leaks. Thats it now just plug your compressor hose into the leak tester and test it.