# Flutter noise when backing off throttle



## Guest (Jan 6, 2003)

Hi guys, does anyone know how to get that flutter noise when you back off the throttle like those 1000hp GTR's in japan. I was told the flutter noise is made by having an external wastegate.
Does anyone know exactly what it is?


Thanks for reading guys


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## jbanach77 (Jun 11, 2002)

my car does it all the time. the sound comes from the wastegate and the bov letting low air levels escape from charge pipes.


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## Guest (Jan 6, 2003)

JIMMY!!!! You hang out here too? Long time no talk.


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## morepower2 (Apr 19, 2002)

B-Real said:


> *Hi guys, does anyone know how to get that flutter noise when you back off the throttle like those 1000hp GTR's in japan. I was told the flutter noise is made by having an external wastegate.
> Does anyone know exactly what it is?
> 
> 
> Thanks for reading guys *


Actualy the noise is compressor surge which isnt too good for the turbo. If you adjust your BOV right you can minimize it. Its not good to tune your BOV to make it louder because it can make the turbo lag more when you get back on the gas and its not good for the turbo in general.

Mike


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## jbanach77 (Jun 11, 2002)

yeah B, just trying to learn as much as possible. the more I know the better off my car will be.


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## Guest (Jan 7, 2003)

Hi morepower2, I believe you're right. Compressor surge making the flutter noise makes sense because the Janpanese boys with 1000hp GTR's dont have BOV's at all.

Sorry morepower2,
I didnt understand when you said
"if you adjust your BOV right you can minimize it".

do you mean minimise "loud BOV noise" or "compressor surge"


Thanks very much morepower2, I appreciate it


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## Guest (Jan 7, 2003)

Turbo Chatter...ouch  

Good way to kill your turbo. A properly tuned BOV is the only way to get rid of that.


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