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Flutter sound?

DVS33T

By DVS33T,
in Engines & Forced Induction

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Steg33 Community Regular

Steg33

Posted
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Fluttering has everything to do with your BOV working or not. The sound is the air going back through your turbo. If you put a flat piece of tin under your BOV to block it off you will get the noise when off throttle at boost. If you adjust any BOV spring tension to tighter you'll get this sound because the BOV isn't opening at that boost level. Just means that air's going back into your turbo, not a good thing if you're running raised boost and want your turbo to last. You're better off with a pshh sound instead of the flutter.

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drifto Collaborator

drifto

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Anyone heard of wastegate chatter?????????????????????????????????????????????

Can one of the experts here explain why my Bro's old 31 with RB20 and no BOV had this "flutter"

Actually, don't bother cause I thinks it's been covered a thooooouuuuusand times before!

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Steg33 Community Regular

Steg33

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The HKS makes the POD filter flutter at low RPM's and at high RPM will Make a high picthed noise and then Flutter. Tightening it all the way will not make it just flutter.

Tightening the spring tension in your BOV 'will' produce this flutter, even more so at high boost because the BOV will be inactive if the spring is too tight and the air will resonate back in the turbo instead of being released. Any car without a BOV will give the same flutter sound as one that's got their spring too tight, eg: boosted VL's that didn't come out with BOV's.

As i've already said, if you want the sound just blank off your BOV or tighten the spring in it, but don't expect it to last a life time if it's been boosted.

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R31Nismoid Grand Master

R31Nismoid

Posted
Posted
Anyone heard of wastegate chatter?????????????????????????????????????????????

Can one of the experts here explain why my Bro's old 31 with RB20 and no BOV had this "flutter"

Actually, don't bother cause I thinks it's been covered a thooooouuuuusand times before!

ill say it again... for all those that CBF.

The flutter is caused by the air going back through the turbo.

This is due to:

1) NO BOV

2) A tightly sprung BOV, that at low PSI wont vent

3) A stuffed BOV.

4) Some ATMO BOV's do try to make the flutter, but they dont really.

The dependancy of how long/pitch etc:

1) The type of I/C

2) The size of the piping

3) The size of the turbo

- ash

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