Ever tried a pre filter. They slip over the actual filter and are used in dusty conditions and such to help keep the air filter clean. It will cut down on some air and maybe the whistle..Just a thought

 

The whistle is very very normal. My truck whistles more then it whines just because of how much throttle I give it during every day driving. You get use to it.

 

That box goes on the tube on your K&N the highest one that goes from the tube to behide the throttle body. i never put mine back on i cant hear the whisle over the truck but every now and then right around 2,000 rpm's i can hear it a lil bit. umm Jbrew had a picture of it some were. yeah dont scrap the CAI because it whisles its normal for them to do that...what K&N intake do you have?

 

mhm i think im going to go buy some silicone tomorrow and put it around the MAP sensor throttlebody and filter and see if that helps

 

i just put some silicone around where the MAP sensor goes in the tube and around some of the rubber ring things, well see if that helps.

i think it comes from the filter though

 

i have the same problem with the whistle at low rpm. and i just siliconed aroud the air hose connection on both sides for pluged side to side with breather tube before the throtle body. i check the with water and they are not air tight and i tried sylicone and didnt really work. so i got some epoxy and really cover them air tight. ill let you know but it was on my truck before and didnt whistle when i put it bak on it whistled.so it can be tweek to not make the noise. ill let ya know

 

I have an AEM CAI on my S-crew and It doesnt whistle.

At higher RPM (2-3 k) It has a growl to it. But no whistle at low RPM.

 

All aftermarket intakes are louder, flow better and make the motor more efficient. The whole reason why the factory intake is so restrictive and less efficient is because its so quiet, its all about customer comfort. Same goes for exhaust

 

according to K & N techs, the whistling comes from the air rushing in across the throttle body blade. normally around 2000-2400 rpm's

 

I've had my K&N for about a couple of months, I don't hear any whistling at all (defining whistling as a high pitch sound made by a mass of air forced through a small hole). I hear a loud "whoosh" at low RPM when I hit the accelerator really quick, I hear the resonance of the plastic intake tubing from 3000rpm to redline (like the sound of a 350Z exhaust), and I hear the suction of air through the filter from idle to about 2500rpm, which some would consider to be the "whistle". Personally I think it's a neat series of sounds.

 

I've had this same whistle when I installed a K&N cai on my 2015 F150 5.0L around low RPMs (1K- 2K). I recently installed a throttle body spacer with some oil separators to clean up the recirc air and that whistle got louder and the range of RPMs where it could be heard increased slightly. I have gotten used to the noise and actually don't mind it, but I did chat with K&N directly to verify and they told me this:

"The noise you are describing sounds normal. This is probably the sound of air passing by the throttle body blade.Your vehicle’s original intake components may have been designed to muffle these noises, by using resonator chambers, convoluted tubing, and a closed air box. Your new performance air intake system, with its open filter and high flow tube, and the noises which occur naturally within your engine are free to pass out into the open air, and can be more audible. But yes, it is normal."