Boost leak test

[DMCTurbo]

When doing a boost leak test is in normal for it to slowly bleed off? I can hear it slowly bleeding out my CAI. Is this normal? I searched but didn't find what I was looking for.

Thanks.
DMC

 

[sledding rocks]

from what i can remember , yes it bleeds off slowly , check those charge tubes closely , i found the clamp that were given with the aftermarket charge tubes leak above 18-20 psi , i changed mine to the normal triton hose clamps with better results

 

[DMCTurbo]

I found a leak at the little plastic T next to the fuel rail that goes to the regulator. The hose TD supplies with the regulator has an ID that is to big for the T. Replaced with a smaller ID hose and now it's all good.

 

[DMCTurbo]

Plugged the crankcase vent to CAI as per yamamarc and all is good. Thanks yamamarc for your help and lending me your tester! Much appreciated!

 

[NYTurbo]

Spray with soap and water

 

[DMCTurbo]

Spray with soap and water

Yes did that.

 

[NYTurbo]

Cool. Make sure you spray intercooler , throttle body boots, BOV etc. Exhaust side should be checked as well

 

[Turboflash]

No matter where your crankshaft is when doing boost leak test, you've got at least a few valves open or partially open. So some air is going to pass through head and cylinder out exhaust. Plus, piston ring seal is not perfect either so some air gets past rings too. Need to have an air supply through a regulator that continues to supply air at set pressure as one searches with the soapy water for leaks. Then there's crankcase vent as mentioned above. Would help to close/block exhaust outlet completely to check exhaust side.

 

[SPM]

I found a leak at the little plastic T next to the fuel rail that goes to the regulator. The hose TD supplies with the regulator has an ID that is to big for the T. Replaced with a smaller ID hose and now it's all good.
View attachment 164222

I found a big leak by fuel reg too. All factory stuff in that area on my sled and I've owned it since new. There's nothing even close to do any damage to this hose!

 

[REDLINE 1]

I replaced most of the smaller hoses up front with high temp silicone vacuum hose. Nice upgrade over stock

 

[aquaticlaker]

2018 LTX sidewinder with 8k miles. Thought I would check the boost pressure sense I have not for 6k. Prior to test I found that all clamps need tightening. Then I made a tester as seen in the photo. Soap tested and tightened where needed. Does the slow bleed off seem normal? I could not find anymore issues.

I have a short video but the file is too big to load.

Mike

 

[THEPASMAN]

Did a leak down test and mine when pumped up to 20psi takes 22 seconds to leak down to 15psi
And I can hear it seeping out of the cai. No soapy bubbles anywhere
Tested two sleds and have the same results

I’m guessing this is normal?

 

[Fleecer]

Did a leak down test and mine when pumped up to 20psi takes 22 seconds to leak down to 15psi
And I can hear it seeping out of the cai. No soapy bubbles anywhere
Tested two sleds and have the same results

I’m guessing this is normal?

Yes, can't get much better than that.

 

[Turboflash]

Very good. Leaks/bleed-down may come from BOV (should be no leaks below 20 psi) and from pressure in cylinder(s) being relieved by ring leakage. There isn't any crank position where there aren't some valves open/partially open (even a crack). This is why when we start to do boost leak test, often the crank starts to rotate (and someone should be holding clutch to prevent reverse rotation). Pressure is pushing down on piston(s). Some pressure leaks past rings, some escapes into exhaust manifold. Most of what you are hearing should be pressure leaking out of cylinders past rings. Ring leakage is normal. Boost leak test is to make sure there are no leaks at throttle bodies, intercooler tubes, intercooler, even up pipe clamps.

 

[THEPASMAN]

thanks for the reply’s


The reason I’m testing is my sled was/is only producing 14ish lbs if boost on a 270 hurricane tune

I haven’t run it yet since thawing it out and pressure testing it. I’m hoping that something was iced up. I was running in lots of over the hood cold crystallized snow in warmer air temps. Sled was an icy mess. The under hood cai sock was covered in snow dust. Is it possible that the filter itself iced up and caused this condition. Afr reading were normal

Anyone else experience this