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Discussion Starter · #1 ·
Hi all, this is my first post but I have lurked here for a while. I bought a 2014 Focus ST with pretty much every performance modification that you can do to the car without going the built motor route. Big turbo (unsure on it, 2867r or 2971r most likely), intake, downpipe, full exhaust. The only modification that I added was a 4 port aux fuel kit.

When Brian at JST started to get the hang of the turbo that was on the car and I started making appropriate boost for my setup, I noticed that around 4500-6000 RPM I hear this extremely loud and god awful tea kettle boiling/flutter sound. I figured it was probably a boost leak but my car makes and holds boost just fine. (About 24psi on 93 octane currently). Did a boost leak test today and fixed a few areas here and there that had small leaks. I even took the intake side coupler off of the turbo and checked for shaft play. Didn't notice anything out of the ordinary with that. There also isnt any damage to the compressor wheel fins or the housing itself from what I can tell.

Anyone have any ideas on what this awful noise could be caused by? I haven't been very successful in finding anyone else with the same issue besides one post made a few years ago.


Here are some videos that I took of the sound in action.


Any help appreciated! :)
 

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Maybe an exhaust leak near the turbo and your hearing noise from the wheel on that side of the turbo? Either that or I'd be curious if there's something in the intake tract that is creating an odd noise when under boost because it's sitting in just the right way in the path of airflow. Does the noise change with higher or lower boost levels?
 

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Discussion Starter · #3 ·
Maybe an exhaust leak near the turbo and your hearing noise from the wheel on that side of the turbo? Either that or I'd be curious if there's something in the intake tract that is creating an odd noise when under boost because it's sitting in just the right way in the path of airflow. Does the noise change with higher or lower boost levels?
It seems to get louder the higher my boost is. I didn't have this noise when I was previously ironing my tune out and saw less than 20psi. Once Brian got a feel for my turbo and bumped it above 20, I started to hear it a WOT.

It's funny that you mentioned the exhaust leak near the turbo as I was just thinking that myself. The downpipe is currently missing a bolt and another one might be pretty loose as it keeps backing itself out.

I just got word from Brian that I have no more boost leaks, so it definitely seems to be pointing in the direction of some kind of exhaust leak.
 

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2014 ST3. Garrett GTX2860R Gen 2. FBO
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To build off what Dman said, im thinking it might just be turbulence in the intake tract.

Does your turbo have a round flange that you could remove the pipe and elbow from and temporarily slap a conical filter directly on to rule out the intake pipe? On a dry day, obviously. If the noise goes away, you know thats all it was.
 
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