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2016 GEN 2
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Discussion Starter · #1 ·
So I have a boost leak I cannot seem to pin point. After leak testing with air at 20 psi I hear air leaking seems like towards the throttle body area. It takes less than 10 seconds to go from 20psi to below 10 psi. Anyone have any ideas if there is some common spots on these LE2s that leak? It like my boost is barely 2-4 psi, and car falls flat on its face. I just did plugs today, I am at 59,000 miles and plugs weren't terrible, but service interval states at 60k so they got replaced. I have had the car since 42k and its not the same. Oh and further note I already replaced the Wastegate actuator with a mamba and yellow spring so im positive it isnt that. Thanks!
 

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2013 Cruze LT
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You may find this article helpful: How to Test for Boost Leaks

It lists common places to check. I find a bottle of simple green and a little dawn dish soap filled with water bubbles real well. soak around the throttle body and look for bubbles. GL!
 
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Discussion Starter · #3 ·
Completed a boost leak test, I definately have a leak, so I am going to build a smoke machine because its to hard to figure out where its coming from with just compressed air.
 

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2013 Cruze LT
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Completed a boost leak test, I definately have a leak, so I am going to build a smoke machine because its to hard to figure out where its coming from with just compressed air.
Do you think a smoke machine will work under 20 PSI of testing?
 

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Does the boost leak affect performance of the vehicle?

To a certain extent, every turbocharged vehicle has boost leaks. The air squeaks out in small quantities, in multiple locations, but it's not enough to really affect anything. The permanent solution for these small leaks is the turbocharger maintains proper boost pressure by just adding some more to compensate for the leaks. It's not much, so it's not really noticeable.

If you had a leak that was slightly bigger than what you might see on the regular, the turbocharger can still keep up to a certain extent. The turbo is sized for some excess boost and the wastegate (if so equipped) vents excess boost into the exhaust, or our cars use the VNT vanes to dial in boost that is optimal. If there is a leak, those VNT vanes just crank it up a little bit more to compensate and it's not a problem.

It only becomes a problem if the leak is such an orifice size that more boost leaks out than the turbocharger can generate to keep it peaked right where it's supposed to be. Drill a pinhole in your air intake and the turbo can probably keep up without problems. Drill a hole the size of a half-dollar and that's where you have a problem of too much pressure leaking out faster than the turbocharger can spool it up.

So, if you think you have a boost leak and the car is running fine (the turbocharger still responds, builds boost, and keeps it peaked right where it's supposed to be), maybe you could ignore the leak?
 

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2013 Cruze LT
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Does the boost leak affect performance of the vehicle?

To a certain extent, every turbocharged vehicle has boost leaks. The air squeaks out in small quantities, in multiple locations, but it's not enough to really affect anything. The permanent solution for these small leaks is the turbocharger maintains proper boost pressure by just adding some more to compensate for the leaks. It's not much, so it's not really noticeable.

If you had a leak that was slightly bigger than what you might see on the regular, the turbocharger can still keep up to a certain extent. The turbo is sized for some excess boost and the wastegate (if so equipped) vents excess boost into the exhaust, or our cars use the VNT vanes to dial in boost that is optimal. If there is a leak, those VNT vanes just crank it up a little bit more to compensate and it's not a problem.

It only becomes a problem if the leak is such an orifice size that more boost leaks out than the turbocharger can generate to keep it peaked right where it's supposed to be. Drill a pinhole in your air intake and the turbo can probably keep up without problems. Drill a hole the size of a half-dollar and that's where you have a problem of too much pressure leaking out faster than the turbocharger can spool it up.

So, if you think you have a boost leak and the car is running fine (the turbocharger still responds, builds boost, and keeps it peaked right where it's supposed to be), maybe you could ignore the leak?
Kind of, depends on how big it is. My Forge Atmospheric BPV leaks a little bit (bubbles sometimes on boost tests) but I have no big issues and boost test still passes.
 

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2014 LT program car, Pull Me Over Red
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Kind of, depends on how big it is. My Forge Atmospheric BPV leaks a little bit (bubbles sometimes on boost tests) but I have no big issues and boost test still passes.
Didn't you put some Teflon tape on the outlet of the BPV actuator to fix that?
 

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Didn't you put some Teflon tape on the outlet of the BPV actuator to fix that?
It was fixed for a little bit, but is leaking again. I just gave up.
 
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