I have 1500 miles on my 07, and last night after flooring it from about 20mph-80mph I noticed a sound coming from the engine bay the rest of the night. It's a faint whistling/hissing sound that gets higher in pitch as the RPMs increase. It's most noticeable in first and second gear. I'm guessing it's just the intake making normal noises but I've never noticed it before. If I rev it from a stop it still makes the noise but it's much harder to hear. Performance seems the same as before so I'm assuming there's nothing wrong. Really hoping it's not a leak somewhere. Any ideas?

 

its your intake takin in air

 

I noticed my '06 intake used to make a slight whistling noise. JWT popcharger makes an even more prominent whistling noise. I believe it is caused by the Venturi ring contour that exists in both the stock and the JWT intake designs that causes the whistling. Or it may just be a characteristic of the length and surface roughness of the intake tube from the filter to the throttle body, I'm not sure. The JWT popcharger certainly allows more of the engine noise to get out, so maybe the whistling happens happens just as much witht he OEM setup but is contained by the airbox enclosure.

Anyways, it's normal like the other guy said.

 

for the millionth time it's normal, top 100 questions thread FTW