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DIY...another boost leak tester

74K views 19 replies 12 participants last post by  dfaudi 
#1 · (Edited by Moderator)
ok there are a couple designs out there for one of these but i havent seen one like this.....


parts you need:
(2) 1/4" male air line fittings
(1) 1/4" female air line fitting
(1) 1/4" to 1/4" male connector
(1) 1/4" regulator with gauge
(1) 1/4" air reel lead in line
(1) 2" to 1/2" pvc reducer (threaded)
(1) 1/2" to 1/4" threaded reducer
(1) thread seal tape

my total cost from home depot was about 40$






another thing i would recommend getting is a set of these:

nomex sleeves....i got mine from matco tools, these are what you see the ALMS guys wearing when they swap brakes during a race...they work that good!

ok you have made your boost leak tester now disconnect your IC piping from your turbo and put the pvc fitting in its place and tighten the clamp:



now connect your air line with the regulator turned ALL the way down
now very slowly open the regulator until you hear air hissing into the system...go check your boost gauge and slowly increase your pressure until you hear a loud hissing...it will be very obvious if you have a leak
make sure you dont exceed 20 psi unless your system is designed to handle it....i started to pop vacuum lines off at 22 psi

other things to check:
cap your intake pipe off, the vacuum lines will bleed air into the pipe and you will think you have a leak
watch where you put your hands and head, if something pops off it comes off with authority
you can tighten the piping if you have a leak with the system pressurized, just listen for the leak to stop

any other questions feel free to ask or pm me

btw i found 4 leaks with this setup that i couldnt find with a normal evap smoke test machine

good luck be safe
 
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#2 ·
Extremely good wright up! Now for those of us that still have a tmic and may find it hard to sneak that coupling to the turbo outlet hose, Can we do this same test threw the inlet and just cap off the bretaher hose lines? Just the breathers since the PCV will not allow air going into the crank case. I know that the inlet is not desing to hold say 20 psi "or any psi at all" but to find leaks on a top mount setup it would be nice to do this.

So to re cap my quesiton, would you think that this would work on an stock inlet tube with the properly capped off hoses?
 
#3 ·
you could do it that way however it may not work as well, you could loosen the elbow and turn it slightly to allow you to get the tester in there, as you said the inlet isnt designed to hold pressure, i wouldnt recommend it it would be easier to just loosen the elbow since its just an elbow with a hard pipe instead of plastic like the wrx...its been ages since i have looked under a top mount but i seem to remember there being room in there
 
#6 ·
Same question for me:).
 
#7 ·
sorry i didnt see this sooner, if you dont take off the air filter and cap the end of the pipe the vac. lines going to it will bleed off the pressure your putting into the pipe and you will have a constant pressure drop, when you put the intercooler piping under pressure your pressurizing the whole motor so you just have to look for all the spots that the air could escape from so you dont misdiagnose a leak
 
#8 ·
Ok, so you're saying pressurized air from the intake manifold, etc. will bleed back into the intake and turbo inlet through vaccum lines when doing this, thus the requirement to cap off the intake at the air filter? If this is the case doesn't that mean the intake/turbo inlet will see the same pressure as the rest of the system when doing the test?

This is what I'm wondering (assuming I'm on the right track), if you have to cap the intake at the air filter wouldn't it make more sense to make a pressure tester that connects to the afta MAF tube or turbo inlet, or am I missing something?
 
#11 ·
^^^Thanks for posting. It was kind of unclear also. The op of that thread says you need to cap the lines coming off the turbo inlet (like the one going to the pcv valve for instance), but the the guy who did the write up in that thread didn't mention capping anything. The same guy who did the write up says to go up to 20psi in the actual write up, but at the end of thread (after he was called out) says you should be able to go up to 5psi, wtf?



Sorry to keep asking question 1loudsti, but I just though of something else. You said you need to cap of the intake at the air filter because air will still make into the intake with your method. But wouldn't you also need to cap the turbo compressor outlet as well? Did you do this? If not, would air just leak out the turbo compressor outlest since air gets into the intake?
 
#12 ·
well next time i do one ill make a checklist and see, it could have just been the way i had everything ran but ill try to get some clear cut answers for everyone
 
#15 ·
ok maybe im not reading this right now...or maybe i wasnt then but the pipe im referring to pressurizing is the CHARGE pipe of the intercooler piping right at the turbo...doing it this way all you have to do is hook up to the pipe and slowly increase the pressure going off your boost gauge in the car....this will pressure check everything that sees BOOST pressure so you can go up to what your motor is tuned for as far as i know...i go to 21 psi when i do my tests

now if you choose to test at the elbow by the air filter then i cant speculate on proper maximum pressure since those lines do not see the same pressures as your charge piping...i hope this answered some questions if anyone has any more feel free to ask and i will try to help
 
#16 ·
if i understand correctly you are only charging your intercooler unless your butterfly is open in the throttlebody yes ?no?If you charging the whole motor would'nt the air be going passed the open valves and out the exhaust like when you do a leak down and your not at tdc?I may be confused i will reread.I would very much like to do this as i have struggled in the past with vacum leaks.
 
#17 ·
can i just hook the boost leak tester up to the turbo inlet HOSE where the aftaMAF elbow would normally go or just remove the entire airbox and elbow and begin to pressurize the turbo inlet HOSE from there? and in theory if im correct that should pressurize everything pre and post turbo( intercooler BPV and all lines to and from turbo) Or am i doing this wrong...i found a huge leak this way where the inlet HOSE meets up with the turbo the inlet hose had a rip. Fixed that with a perrin inlet but im still only hitting 14.5 psi when i should be hitting 21. so this makes me think i may be doing this boost leak test wrong MAF voltage is in the 4.4v - 4.5v range which is high and indicates i still have a fairly large leak somewhere
 
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