This is more of a morning turbo yawn i'd like to call it
I don't know if it has to do with being cold, and maybe the vanes need to do they're sweep but every morning when i'm driving to work during either a shift when the boost drops on its own (Without pedal interaction) the turbo makes a funny noise and then picks back up on boost.

I have no turbo issues, builds 28 PSI steady and nothing else is an issue, that i know of.

I can also make this happen if i speed up and then cut to half throttle or slowly let off the pedal for boost to drop.

Not that i think it's causing me any issues, but my trucks straight piped and its damn near louder than the boost itself

 

Stock or programmed?

 

Have you checked all the CAC boots for splits even though you are making boost there could be a hair line.

 

All stock truck, would a hairline crack or cut be apparent only when cold/first started? i certainly don't feel/hear any air leaking anywhere

 

My thinking is telling me yes because the statement when you speed up and cut to half throttle. a hair line will be hard to see almost have to pull the boot and squeeze it until you find it , only opens at min boost. are the boots original stock?

 

All boots are stock, i'm 2nd owner from new. I've had the boots off with the tubes for maintenance and didn't notice anything but i will inspect tomorrow when i do a tire rotation.

Why would it only happen under minimal boost, wouldn't i hear a increasing leak under more boost? and once the truck warms up, this "yawn" is gone under all circumstances

 

I meant it starts at Min boost to higher pressure, when driving you don't hear it ? under the second statement I thought you were driving with 28psi and could duplicate the sound. can you post Values for VGT , Boost at koeo , low , High 2500 rpm in park

 

I do hear it while driving, cannot duplicate it at 28 psi though :P happens mostly around 1-2 gear with lower boost (Under 10 mainly), doesn't happen with steady throttle, only when letting off or when it hit's a shift point for a short time.

But, it all clears up once warm, or has been running for a certain time, usually 10 mins or to 150 degrees EOT.

I have yet to program those into my Scangauge, but like said, i'm working on her a bit tomorrow so any values you that can help, let me know and i'll punch them all in

 

does it stop when Engaging the clutch? ( just a thought)

 

Does that still follow for an automatic transmission? It does follow that pattern when the transmission engages though, it never happens when accelerating, only letting off the throttle

 

Sorry dismantle that statement was thinking ya had a stick

 

I'll see If I can round up Mark K he is the Tranny Guy.

 

my bad misread the post

 

Mine does something similar. Only when it's cold (temps still below 120° or so). It's not as loud as the turbo fart example of the truck playing in the snow that's been posted here a couple of times. It happens only sometimes when I lift off the throttle after pulling a small hill at about 2000 RPM's. There's a stop sign at the top of the hill and truck is going slowly making a little boost and I lift the throttle just as it would have shifted and it will kinda quietly chuff two or three times.
I don't think there's anything wrong with the truck. It's only a just-right combination of throttle and load that can catch it like that. I've never thought about the fact it only does it when it's still cold. I have never heard it do that when it's warmed up.
The truck runs great and I watch the main stuff pretty close with a ScanGauge. All my boots are fresh and I put the metal cold side tube on it awhile back.

 

Watch or check the BARO sensor, a light tap should not change any values.