Buffeting Explanation

[FJ40INTOW]

This is the best explanation yet on Buffeting.
http://jalopnik.com/why-do-slightly-opened-car-windows-make-that-awful-soun-1447498738

I guess I need to brush guard or a bug shield?

 

[adventurenali92]

That's an excellent explanation. I thought it was going to explain what causes the new trucks to have that issue when the windows are all rolled up though....

 

[2011SSVHOE]

makes sense to me.

 

[FJ40INTOW]

My guess is with this assumption, any air leak into cab can cause the buffeting. The leak may only appear once the vehicle is in motion.

 

[Danny3737]

I wonder if anyone has tried experimenting with hood deflectors, vent visors, different side view mirrors to see if that made a difference with buffeting when the windows are up. I had a buddy who complained of buffering after he installed some aftermarket roof racks on his Cherokee and eventually ended up taking them off because of that.

 

[AngelXL]

I wonder if anyone has tried experimenting with hood deflectors, vent visors, different side view mirrors to see if that made a difference with buffeting when the windows are up. I had a buddy who complained of buffering after he installed some aftermarket roof racks on his Cherokee and eventually ended up taking them off because of that.

Seen I don't know what I'm looking for... I can't tell.
And of course I know about cracking one of the other windows when you open one up.
Opening the sunroof seen fine to me.

 

[nj16yukon]

My guess is with this assumption, any air leak into cab can cause the buffeting. The leak may only appear once the vehicle is in motion.

The buffeting that occurs is a form of resonance, and only occurs when the conditions are just right. The size of the opening, the turbulence of the air outside the opening, and the volume of the air inside the car all play a factor as to whether or not resonance occurs.

As the article points out, the car behaves like a Helmholtz resonator. The system is hitting a resonant frequency where a small driving force has the ability to produce large oscillations (think opera singer shattering a wine glass). When you open another window, you change the resonant frequency of the system, and the buffeting stops. An acoustic guitar is another type of Helmholtz resonator.

 

[Danny3737]

The article made perfect sense. Without a wind tunnel, the only DIY that I could think of doing would be trying to change the airflow outside the vehicle. That type of buffeting could be coming from anywhere, even underneath the vehicle. It's hard to believe with all the complaints that somebody hasn't figured out what's causing it. It would drive me insane, especially after spending that much money.

Trying to solve it when you only get it when the windows are open is another story. I had a 2008 Highlander and you could not drive over 20 MPH with the rear windows down without the buffeting getting unbearable.

 

[nj16yukon]

I think there are multiple different issues at play here. Buffeting is a resonance effect that you hear as a "whoomp-whoomp" with a rear window open. Many cars do this. I believe that the sensation people are feeling in their ears is a different issue, where something with the aerodynamics of the car (and possibly related to the vent system) is affecting cabin pressure in a negative way.

 

[FJ40INTOW]

The GMC offers the Active Noise Cancellation. If I remember Lotus developed this technology. It would detect a "Noise" and reproduce said noise out of phase to cancel it out. You may not be able to notice the noise but it raises the sound pressure in the cabin. I remember hearing about this when installing car stereos, If you had no bass it could be that one of the 6x9 speakers was wired backwards.

 

[Blueinterceptor]

When driving your trucks, can you look at the door seems (weather stripping ) and see daylight?
Maybe this noise can be canceled out by a redesign of the weather stripping around the doors.

 

[funkdoobiest]

It sucks that the GM's have buffeting even when the windows are up. The issue has kept me from getting one. Like mentioned earlier, the issue could be occurring anywhere, under the car, wheel wells, etc. On a side note, the best SUV I ever had that solved the issue with rolling the windows down was a Toyota 4runner. The rear view windows are motorized like side windows and retract into the hatch (actually a tailgate on the 4 runner). Roll that baby down and the buffeting stopped. The rear view window on the 4runner (and old wagons) are awesome, I don't know why more companies don't do this.

 

[nj16yukon]

I came across an interesting thread on a Tesla forum. In one of the hatchback models, people were experiencing odd pressure sensations and ear popping with the windows up. They traced the problem to a loose section of the hatch, that was bouncing up and down on uneven road surfaces. The hatch was essentially acting like a large speaker, compressing the air inside the cabin and causing discomfort to passengers. Wasn't there a known issue with the roof de-laminating in our trucks? It would take a fairly large surface oscillating to create this speaker effect.