Help! Loud Whistling Noise. Between 2000-3600 or so there is a loud whistling noise. It sounds like it is coming from the intake area. It does not happen off throttle, or at full throttle. It sounds like someone is whistling very loud. This is a new noise. Last few days. I'm running the K&N typhoon, and Forge recirculating. I put on the RNR full turbo-back a few weeks ago, but this sound is only happen in the last few days. It is REALLY loud, and thus I need help to fix it.
Does anyone have any ideas??? I'm thinking its the DV opening slightly, and somehow causing this whistling noise.

 

check the bolts to your turbo outlet. These will loosen and canuse a whisteling noise.

 

Hate to be the one to tell you but possible the transfer case.

Chris

 

does the sound vary under different engine loads, meaning if u push the gas harder and you build more boost does it get louder and vis versa?

 

Definitely not the transfer case. Nothing to do with drivetrain. Something with either the turbo, wastegate, or my guess the diverter valve. I am guessing that the computer is reading a little too much boost, and having the vacuum open, to oven the diverter valve just a bit. It is an air realted sound. Thus the whistle, just like someone whistling very loud. I think the DV is openinga little to let air back into the intake, and it is just making this noise. No idea why though?? No difference with loads, under full throttle no noise. No noise at idle. Just low revs. I am wondering if with the turboback it builds boost very quickly (as it does feel so) and then the DV has to open sooner to release the pressure back into the intake. But the noise is driving me crazy. Very loud but one of those this couldn't be good noises. It sounds like maybe the DV is not opening and closing properly.
Any ideas????

 

No one has any ideas?? Why would the vacuum pump be opeing the DV under throttle, and not just off throttle? Or is it just releasing boost?

 

I had the k&n typhoon and it gave me nothing but problems. I switche to the buschur intake and car runs way better.

 

Hey is this noise only at high boost??Are you using a MBC? My friend had a similar problem, he installed a mbc was running high boost and it would make a whistling sound at high rpms, we retightened all hoses, clamps, etc. Another thing we did was cap off the wastegate actuaror hose and the turbo hoses. After doing it it went away.

 

Mine does this all the time. If this is a soft whistle while your feathering the throttle or easing off of it slightly, it's probably your BOV bleeding off some air.

Pay attention to your boost gage. It probably happens while in vacuum only (just before/below 0) and disapears as soon as you get back into boost.

If I'm right and this bugs you, you can tighten your tensioner a bit. Don't tighten it too much, or it may cause your car to stall.

 

Put the stock one back in to eliminate the possiblity that this may be your cause. Along with what the other guys are saying, check all your hose connections.

 

I have a crushed 1G flange that whistles too.. It happens when there's equal pressure, or slightly greater pressure in the intercooler pipe than spring pressure to hold it closed tightly..

Its annoying as hell, but not harmful, assuming what your describing when the engine from part throttle, drops down, or when your driving around under very light load, at part throttle, when your Vacuum/boost gauge is almost at 0, or another time is when the engine is under vacuum, 15-17in or where it has enough vacuum in the intake manifold, and very little vacuum in the upper intercooler pipe to hold it closed..

 

Similiar problem....There is a whistling sound after full boost is achieved with the forge diverter, none at part throttle or idle. The boost wouldn't appear to drop, maybe one psi or so. I think it was the spring closing to soon, bleeding boost, but it never happened until the TT flash and lower IC pies by AMS, which do not require you to touch the dump off the turbo. I had the blue spring in, and changed it to the yellow, a softer one, and the problem seemed to go away.

What do you think?

 

Hey - I have the same problem (or very similiar). AEM intake with Apex filter, PINA TBE, and Dynoflash. Under part throttle and low boost it sounds as if the BOV opens (loud air sound) as rpm climb the noise gets louder until it fades out about midrange, no sound under WOT. I did not notice this before installing the intake and dynoflash. My best guess is the BOV has always opened prematurely, but I never noticed because I didn't hear it with the stock intake. Does this sound like what your are experiencing?

 

I'm having the same problem which I noticed after installing BR stage 2 UIC and intake pipes. Note that this does not happen under boost, but only at low rpm like at idle (as the OP said). Boost builds fine and only "normal" noises are heard when the BOV operates.

I got lucky today and it was consistent enough that I could listen for it and pinpoint the noise to the intake while the car idled. It's a different pitch than the 1g BOV (a bit lower) and sounds a lot like brake squeel to me. It is very noticable and quite annoying when driving around in traffic and it happens.

I don't know if it's coming from the turbo, or if it is simply air whistling through the MAF or across the metal junction that the BOV dumps to. I'm open to suggestions on what to check, I really want to get rid of this noise!

 

at low rpm, like what zeus and others said, at partial throttle or off the throttle, it sounds like whistling or gaggling sound (for stock intake box).

I think that's normal.

Some say it's the gears, some say it's the air traveling forward and backwards, trying to figure out what it wants to do.