Noise from Under Driver's Footwell? Sounds like Wind Buffeting @ Highway Speeds

[WillieFlo]

Fellow Gen 2 Pilots,
I installed Soundskins Pro in the doors, on the back wall, and parts of the floor of my truck and it's MUCH quieter in there now when the radio is off and I'm on the highway. The problem is now I seem to notice that when I:

1) Have cruise control set to any speed 75 mph or up
2) Start to approach an overpass or an incline upward
3) Accessport is indicating 2-6 lbs of boost

I'll start hearing this increasing sputtering psss....pssss...pss....psssss.......(like a strong fluttering in the wind or erratic air turbulence) below my(driver's) footwell.
THEN, when I'm over the top of the overpass going downhill(in negative boost pressure/vacuum) I hear like a small actuated door slam shut with a "thud", and everything is quiet again.......

- No CEL
- No issues at all under WOT, or if I step on it while the noise is happening, the door/wastegate shuts and noise is gone........
- No noise at all below highway speeds
- Accessport indicates boost topping out around 21 lbs and over 510 hp in short WOT test hits.

Is this normal noise from the turbos/wastegate now that I can't hear my road noise, or is the driver's turbo wastegate starting to act up? I did not notice any loose hoses or air escaping from anywhere or anything out of the norm after inspection.

Any feedback is appreciated.

 

[XSTNKT]

Race wastegate making race wastegate noises? Your turbos are upgraded, right?

 

[WillieFlo]

Nope, factory turbos. I am tuned though. If it’s normal, for the irregular wind buffeting, hissing sound to be happening, then I’m happy with it. However, it does not sound at all like a consistent releasing blow off valve sound. The fluttering sound doesn’t bother me that much, but the heavy thud/pop when the air is no longer being released gives me concern.

 

[XSTNKT]

Nope, factory turbos. I am tuned though. If it’s normal, for the irregular wind buffeting, hissing sound to be happening, then I’m happy with it. However, it does not sound at all like a consistent releasing blow off valve sound. The fluttering sound doesn’t bother me that much, but the heavy thud/pop when the air is no longer being released gives me concern.

It is odd. And if you’ve pinpointed the sound to that location, it would make sense to be turbo related because it’s right adjacent to that area.

 

[WillieFlo]

It is odd. And if you’ve pinpointed the sound to that location, it would make sense to be turbo related because it’s right adjacent to that area.

Yes, BUUUT, then I found this thread, and wondering if this may be the culprit instead.....https://www.fordraptorforum.com/threads/strange-noise-and-clunk-at-highway-speeds.99859/page-2
His symptoms are almost identical to what I am experiencing.....BUUUUT, this evening I drove home on my 50 mile trek home, and I didn't experience any sound at all the whole way home......VERY odd.

 

[WillieFlo]

Yes, BUUUT, then I found this thread, and wondering if this may be the culprit instead.....https://www.fordraptorforum.com/threads/strange-noise-and-clunk-at-highway-speeds.99859/page-2
His symptoms are almost identical to what I am experiencing.....BUUUUT, this evening I drove home on my 50 mile trek home, and I didn't experience any sound at all the whole way home......VERY odd.

Well, problem solved thanks to @PTobias ' article that described his problem as he did. I knew when I read his description, that had to be my problem as well. So, I bought the new IWE check valve tube assembly and the IWE solenoid, and changed the check valve assy this evening. Went for a 30 minute test drive and no issues. Hoping the violently crumbling paper sound is gone for good!

Thanks to this community for sharing all the info that you do! While this site has cost me alot of money with all the great ideas and goodies I see on here, I've also saved a ton of $$$ with the diagnosis many provide on what the issues they encounter when things break/break down on these trucks. THANKS!