How to find a boost leak

[silvapain]

Originally Posted by broncojd78 if your pcv is leaking, then you will see air come through the valve cover vent. if your bpv is leaking, you'll see air come out of there. those both recirculate. so if you want to see only if you're losing air out of the system, then you could leave those in place. then, you could address any potential BPV and PCV leaks after. is that correct?

The BPV recirculates into the intake, which is also under pressure.

I have proven the valve cover vent pressure does not come from the PCV system, as I have opened the drain on my catch can with the intake pressurized and nothing came out (verifies my check valve from @MATT DAMOND seals).


Tapadatass

[silvapain]

What I'd like to do when I have the time is pull the valve cover and do a boost leak test. With the cover off I could better pinpoint where the air is escaping.


Tapadatass

[8.5MS3]

i would imagine that a small amount of air escaping the VC is normal

minor blowby past the rings gets down into crank case, pcv valves are forced shut due to pressurized intake, so air naturally travels up through the valvecover vent since during normal operation it would never be under pressure, only vacuum

i verified this by leaving my valvecover vent in the intake and shooting my dipstick about 30 feet into the air along with half my oil

[jack_hammer]

wait, wait, wait... if you leave the valve cover open and it leaks air, and then the pressure will drop... so how do you tell if you have a boost leak?

[8.5MS3]

the rate of flow out the valvecover is very minimal, half a pound every 3 seconds or so

pressurize the system, listen for hisses and/or spray with soapy water

repeat if pressure drops too low

[DarkPasseng3r]

Great write up. Will be doing this soon.

[silvapain]

Originally Posted by broncojd78 wait, wait, wait... if you leave the valve cover open and it leaks air, and then the pressure will drop... so how do you tell if you have a boost leak?

I stick my thumb over the valve cover vent when I boost leak test.


Tapadatass

[jack_hammer]

Originally Posted by silvapain I stick my thumb over the valve cover vent when I boost leak test. Tapadatass

what's the difference between that and just leaving it connected to the TIP?

[8.5MS3]

pressure in valvecover/crank slowly creeps up as opposed to being pressurized to whatever your testing at immediately

let it linger too long at too high a pressure and the dipstick will want out tho

[bigriver]

Gonna try this this weekend as i think i have a leak in my cpe nano intake near the maf. The o-ring is fine but could be the maf housing.

So to clarify, you disconnect pcv hose at the intake and cap off the nipple at the intake? Dont want any oil ejac. = )

And to test bov/bpv you disconnect recirc hose at the bov/bpv and fold the hose over to cap off the hose?

Thanks!

Btw for the 1/4" threaded brass nipple on the 2" pvc cap, i used my 1/2" drill bit to make the hole and screwed in the threaded nipple in the hole. Then applied jb weld at the top. Saved a couple of bucks for the brass nut. Not a big deal. Thanks for a great writeup!

[event]

Does anyone else's leak tester invariably blow off the intake tube at around 16-18psi? I can see it start slipping at 16psi and then it violently blows off above that. I need to check my bpv for leaks above 16psi but I can't hold the pressure long enough before it blows off...

[8.5MS3]

get a man to tighten shit down?

[Pedal-Force]

Originally Posted by event Does anyone else's leak tester invariably blow off the intake tube at around 16-18psi? I can see it start slipping at 16psi and then it violently blows off above that. I need to check my bpv for leaks above 16psi but I can't hold the pressure long enough before it blows off...

I think without a bead rolled edge, the rubber is just too slippery. I was using a t-bolt clamp and it would still blow off eventually. The intake just wasn't meant for that kind of pressure, so it doesn't have the necessary edge.

[86AmishMs3]

Putting all your ghetto leak testers to shame. Food grade 304 stainless with quick connect fitting.

[dooderek]

[breakfstincluded]

showoff

[Pedal-Force]

Should've rolled the lip. The only problem with mine was getting it to stay on under boost, since none of the pieces before the turbo are meant to have boost, they aren't rolled.

[86AmishMs3]

Originally Posted by Pedal-Force Should've rolled the lip. The only problem with mine was getting it to stay on under boost, since none of the pieces before the turbo are meant to have boost, they aren't rolled.

Too thick of stainless to roll. If i have issues i'll just put a weld a bead all across.

[himurax13]

Subbed for later.

[8.5MS3]

Originally Posted by himurax13 Subbed for later.

really? theres a menu option to subscribe to a thread. nub

[m4tic]

If you have a Cobb Sri check it... Mine has a nice crack in it. I know pressure doesn't flow through it and I can easily seal it... But still wtf

[dacrowshadow]

I know a stupid question, but I'm just making sure...
Wait but we also need a air compressor correct?

[silvapain]

Originally Posted by dacrowshadow I know a stupid question, but I'm just making sure... Wait but we also need a air compressor correct?

Yes, it is a stupid question, and yes, you need some sort of compressor for this. Im sure something like a bike pump would work, as long as you're willing to pump the fuck out of it.


Tapadatass

[dacrowshadow]

Originally Posted by silvapain Yes, it is a stupid question, and yes, you need some sort of compressor for this. Im sure something like a bike pump would work, as long as you're willing to pump the fuck out of it. Tapadatass

LOL Thanks. Im also just trying to get my post count up.

[franz]

I plan on building one of these since I cant track down a leak in my FMIC setup. How did you guys block off the BPV and VC tubes? I am going to measure them and try to find some rubber stoppers, but I wanted to see what you guys used first. My biggest concern is the rubber stoppers blowing out and killing someones cat or something.

[blackms3_71]

i just put this kit together and will be checking for leaks tomorrow, thanks op.

[BrandonRKD]

So everything should be completely sealed when pressurizing the tip using this method? I can blow into it without much pressure at all and hear air coming from behind the intercooler. Also my stock bpv has no rubber seal and air comes out through the square hole on the side.

[blackms3_71]

Originally Posted by BrandonRKD So everything should be completely sealed when pressurizing the tip using this method? I can blow into it without much pressure at all and hear air coming from behind the intercooler. Also my stock bpv has no rubber seal and air comes out through the square hole on the side.

If u hear air behind the intercooler it could be the ebcs lines but u need to pressurize the system to know and yes stock bpv should have rubber gasket

[Tiner]

Hi.

If I wanna test the whole system DO I need to take out the oil cap?

Just to avoid pressurising that place.

Thank you.

Enviado desde mi SM-G935F mediante Tapatalk

[Tiner]

Originally Posted by Tiner Hi. If I wanna test the whole system DO I need to take out the oil cap? Just to avoid pressurising that place. Thank you. Enviado desde mi SM-G935F mediante Tapatalk

No one?