For those of you out their with the 3.7 and have installed a cold air intake, have any of you came across your intake making a pretty loud whistling noise at certain rpms when cruising? I've heard that it could be the butterfly valve, then why does it only whistle in lower liter engines and or V6's and lower? I know 2 people who have an intake on there 4.7 and another on there 5.7 but they both sound good! lolanyone else with information about it would help too....thanks!

 

My intake (4.7l) whistles at some cruising speeds and when cold. Its not unusual for them to do it. My whistle actually comes from the throttle body, and it went away when I put my fastman on. If the whistle is coming from the intake, you're fine; if the whistle is coming from a vacuum leak, then you have an issue.

 

Ohhhh ok ok and yea mine has been whistling since the day I put it on my truck a couple months back so im assuming its my intake haha

 

I am 98% sure it is. When you get vacuum behind a blade where air is getting sucked past, you will get a whistle. The whistle is just covered up normally by your stock intake.

 

I have a whistle on my 4.7 but im not sure if its my intake. hopefully it is because i dont feel like doing with any problems right now and shes running great

 

on mine when i built my cai at first i had it real short and had a whistle to it then i extended it down more and the whistle went away is yours a kit or a home made one

 

My whistle is very loud... but I like it hehe.

 

Mine does it too. It's the TB. If you pull off your CAI and run the truck as you manually operate the tb the air passing over the butterfly valve causes it to whistle.

Drives me up the wall. Hopefully the TB I put on this weekend gets rid of it.

 

the whistle with the cai is normal and nothing to worry about. mine does it alot around 1500-1800 rpms

 

Mine whistles. This is completely normal. The only reason you don't hear it with a factory intake pipe is because of the sound baffles and tubing. This muffles the whistle so that you can't hear it. I wasn't really used to having a whistle, you can't even hear it on the race car, which used to be my DD. See? N/A stuff can be fun, folks.