2000series8

Hi all

Anyone who has faced this issue before, your feedback would be so very much appreciated.

Installed an Apexi air intake system on a FD yesterday- but when revving between abt 2500 and 3500 RPM, it is humming reallllly loud.. like a droning type sound and it doesnt sound good at all. Ive seen and heard this setup on another FD, and there is no way this intake is supposed to produce such a humming sound. Sounds like its coming from the top air intake.. but i cant be too sure since they are both so close together.


What could be causing this??
Any suggestions on fixing it would be great

Thanks guys

KKMpunkrock2011

iTrader: (5)

post a video of what it sounds like

moconnor

iTrader: (14)

Search for the word 'moo'.

hsitko

iTrader: (1)

it could be your air pump.

MR_Rick

iTrader: (7)

+1


The old moo sound under the hood.

grimple1

iTrader: (1)

had the same thing happen to me.... sorta. mine was creating a low whistle sound. Turned out that it was the UIM. Had to put another one on it.

There was nothing wrong with it, per say. It just so happened that the construction of the LIM/UIM the tubing and everything else was creating a resonant frequency. When I heard it, I knew it immediately. It's a phenomenom that occurs in nature. Air pressure creates it (sound waves = air pressure).

Don't know if this is what you're experiencing but my gut says it is. Essentially every object has a frequency that it naturally amplifies. This is most commonly found in rooms with parallel walls or in tubular shapes. When wind/sound reaches the objects resonant frequency it will be amplified... and will produce audible sounds -- or in some cases case the object to deconstruct. A good example is of a singer finding the resonant frequency of a crystal glass and shattering it by singing that pitch.

In your case, I'm betting that the wind at that rpm range is causing your intake to hit its resonant frequency thus producing an amplified hum.


Course others could be right too in that it's the "moo"... I just suspect otherwise in this case.

2000series8

Thanks guys.
the moo is exactly what they refer to it as being.
But im not sure where to plug it up using the chair caps with small holes. doesnt that mean that a pipe on the intake itself would also need to be blocked off?
Thanks in advance

2000series8

UPDATE:
-chair cap used as directed with small holes in it.
-but the moo STILL persists. :/

Any other suggestions guys?

DaveW

Can you route that hose to one of the air-filter-to-turbo-intake pipes? That would muffle the sound.