Just got my AFE 2 stage air intake on the 5.4 the other day, and after driving it for a few days, I notice a lot of noise under the hood when you get on it. Do all of the intakes make this extra noise, and is there anything you can do to quiet it down? I assume this noise is coming thru the cone filter, or is the plastic tube intakes noisier than rubber or metal ones?

 

Any intake that provides a more direct route for sound to escape the intake is going to make the growl you are describing. I would guess that most people that buy aftermarket intakes like that growl. That's part of why the OE intake is so restrictive, to get rid of the noise. Good 'ol EPA.

Now you need a louder exhaust to out-growl your intake.

 

Have changed the exhaust system too, so between the two, its not a "stealth" truck anymore. Intake sound reminds me of my 4bbl on the old truck with the air cleaner off. I bought the new intake with maybe the hope of a little more power and mileage, but could do with less noise. But I will get used to it. Let 'er rip.