Dull roar through airbox

[BK24]

Getting this at what I would call the very minimum vacuum. Sometimes when I start it it does it, while its sitting I can force the throttle under the hood and the second before it is at normal idle like the last breath of vacuum it does it. Pulled the filter off and it still does it up in the assembly. Cant pinpoint exactly where the sound is originating but its somewhere around the throttle body. Any ideas?

 

[4a7191a]

i can hear my eaton whine and suck through my fipk on startup. id say its a normal noise as long as it doesnt sound like a coffee can full of bolts rattling around.

 

[BK24]

Its not a whine, only thing I know to compare it to is the apu on my helocopter when it first starts up. No rattling, just the slight roar.