Sound Generator Mod to Kill Ghost Whistle

[Zukunft]

The past 6 months have included thousands of hours of internet research, 5 different mechanics, and two different BMW dealerships…but now I've accepted the fact that the god-awful "Ghost whistle"(AKA the vacuum/fluid/swooshing sound that occurs when accelerating between 1700-2200 RPMs with no reason why) is something I must come to terms with.

So here is my question….I know that the foam removal/sound generator mod is popular….but has anyone done it to "drown" out the ghost whistle? I know the sound can't be "fixed" (trust me, I've tried everything) so is there a way to "hide" it?

Any other SI owners(Specifically fellow coupe owners) out there who suffer from that terribly annoying sound who have done that mod? Does it do anything to the ghost whistle?

I assume the new noise level in the cabin would either:
A) sort of drown out the swooshing sound
B) make it worse

Anyway, I thought id ask before trying myself…

Thanks guys

if you don't know what the "ghost" whistle is….here are some of the many unsolved forum posts about it…

http://www.bimmerfest.com/forums/sho...d.php?t=330173
http://forums.bimmerforums.com/forum...e-accelerating

[the dink]

The other board is talking a lot about intake issues. Have you removed the air cleaner element and drove it just to see if that changes the noise?

[unluky]

I was thinking the same thing as randyf when I was reading this. I have never heard this sound before, but the description sounds a lot like the problem we have on the 300zx forums when we put pop chargers on those cars. They call it the "goose honk" there though. After putting the pop charger on, you are removing the sound restricting OEM air box which let's this sound (which is always there) make it out where it can be heard. It is heard only under medium acceleration in the area you stated. I like Randy's idea to see if the sound changed at all.

[jeebus87]

Subscribing to this thread because i HATE THIS SOUND with a passion and will try anything to get rid of it. I've been to a couple dealer and indy shops and no one seems to know the cause. Smoke test doesn't show any intake leaks...

[wolfman1807]

My 2002 Ford F150 has a whistle at 1700 RPMs. It all started when I put a K&N filter in it. If I remove the filter the sound goes away. It a has something to do with the filter design as they have changed the filter for my truck since then.

[3002 tii]

OP your car is 100% stock? Any way you can record a video?

Maybe you should remove foam to make the intake noise louder and it'll drown out the whistle lol

[douggreglas]

I have a coupe, and did the foam delete shortly after I got the car. I have never heard this sound. Either my car doesn't have it, or the foam delete fixed it.

Taking out one of the foam pieces is quick, easy, and makes the car sound better. Give it a try!

[Zukunft]

Originally Posted by 3002 tii

OP your car is 100% stock? Any way you can record a video?

Maybe you should remove foam to make the intake noise louder and it'll drown out the whistle lol

Bone stock.

I will record a video once I have a chance. And yes! I'm doing the foam delete this weekend to see if it'll kill the noise.

I've done everything, including messing with the intake box, but the sound is always there.

Originally Posted by randyf

The other board is talking a lot about intake issues. Have you removed the air cleaner element and drove it just to see if that changes the noise?

This there a DIY for this?

Originally Posted by jeebus87

Subscribing to this thread because i HATE THIS SOUND with a passion and will try anything to get rid of it. I've been to a couple dealer and indy shops and no one seems to know the cause. Smoke test doesn't show any intake leaks...

Me too. I've come to the conclusion there is no fix…just a flaw with the specific model/year..sadly. I smoke tested too…nothing.



Sorry for the late response! Ill update everyone next week...

[Zukunft]

Hey friends,

I just did the sound generator mod. I gotta say, with all the hype surrounding this mod, I am disappointed at how little of a difference it makes.

Once I did the mod, I noticed that my car(only one previous owner, who I know) only had these two pieces of foam in the sound generator. I was expecting three….did anyone else experience this?

1) The black/spongy one was from the front of the generator(the side you have to unclip)

2) The marshmallow/hard gray one came from the firewall side.

3) ?


I read somewhere that the black spongy piece should NOT be removed because it acts as a filter….can someone verify this so I can pop it back in before i do damage?

Thanks

SO I guess the answer to this thread is;

The Sound generator mod did NOT kill the ghost whistle(except maybe when you floor it)

[bucko521]

I have a mystery whistle as well... really notice it with top up. Can't locate it. But in the end, with top down or radio on, the issue is less. Still annoying as heck.

[jeebus87]

I swear mine is getting louder, or that my ears have become trained to hear it. Either way, taking her in for an oil change in the next week so I will ask my indy to poke around some more. I'll update it anything comes of it.

[Z4fortom]

A few years ago I chased a 'ghost whistle' down to the 't-shaped idle regulating valve' (as it is called on realoem)

It's a silver cylinder on the driver side under the intake manifold.
you can simply disconnect the plug from the valve and see if the sound goes away.

My fix was as simple as removing, cleaning and lubricating the valve.

Hope it's that simple for you!

[jeebus87]

Well, another trip to the mechanic, another diagnosis of "normal." I saw some people on the x3 forum talking about a similar issue, and they traced it down to microcracks in the intake tubing. Since my smoke test is negative, not sure that's the problem with ours. At this point, I'd be willing to test out their theory.

[jeebus87]

My indy did say something about the throttle body being a potential cause of the issue as well, in case someone wants to try that out. He was skeptical that it would work, plus it's an expensive job.