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Old 07-29-2021, 07:39 AM   #1
600hpSTI
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Default How Do I Make the Turbo "Flutter"???

I have a built 2008 STI. I want the turbo to flutter. I don't want compressor surge under boost just when I let off the throttle. I have a TurboSmart BOV and a Tial 38mm EWG. I have tried closing the BOV and also blocking it off completely, to no avail. When I blocked off the BOV in my 2005 WRX, the turbo fluttered like crazy but not in my hatch. I believe it has something to do with the EWG. If I block off or close the BOV, the boost pressure has no where to go besides back through the compressor or out the EWG, so it must be escaping through the EWG, right?? What do I have to change for the turbo to flutter? Help me out!

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Last edited by 600hpSTI; 07-29-2021 at 10:05 AM.
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Old 07-29-2021, 09:47 AM   #2
K3rm1tth3fr0g
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Your compressor housing is not connected to your wastegate, so no, it isnt "escaping through the EWG"
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Old 07-29-2021, 10:02 AM   #3
600hpSTI
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Understood, then why is the turbo not fluttering when I close or block off the BOV?
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Old 07-29-2021, 10:58 AM   #4
K3rm1tth3fr0g
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Good question. I would ask your tuner.

But to be honest, chasing compressor surge is pretty silly.

I get that it sounds cool, but off throttle compressor surge is still a surge, and while its most likely harmless, the less surging the better IMO.

And not to mention you lose compressor speed when it stalls and surges....
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Old 07-29-2021, 11:12 AM   #5
Waddlz
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Ditch the turbosmart, and buy a Tial 50mm BOV.
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Old 07-29-2021, 11:13 AM   #6
K3rm1tth3fr0g
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Quote:
Originally Posted by Waddlz View Post
Ditch the turbosmart, and buy a Tial 50mm BOV.

Disagree. Turbosmart is top tier
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Old 07-29-2021, 11:16 AM   #7
Waddlz
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Quote:
Originally Posted by K3rm1tth3fr0g View Post
Disagree. Turbosmart is top tier
I'm not disagreeing

Simply saying if he wants flutter, the Tial will do that no issue with a stiff spring.

Is that a reason to buy a BOV? not in my opinion, but some people like different things.
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Old 07-29-2021, 03:02 PM   #8
umscooby
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Ouch the first post hurts. So much fail I didn't want to post. First we have a 600hp STi with a 20g. And go ahead a block off your BOV, that's a great idea.


Quote:
Originally Posted by Waddlz View Post
I'm not disagreeing

Simply saying if he wants flutter, the Tial will do that no issue with a stiff spring.

Is that a reason to buy a BOV? not in my opinion, but some people like different things.
Now for the reason I posted. I'm not sure that switching to a TIAL is gonna do squat for him. I say this because I see you live Colorado like me but the OP is in CA at, I'm assuming, close to sea level. I have a TIAL on my EJ setup and here in CO it flutters like hell between shifts etc., probably like yours. But, when I take my car to CA at sea level all I EVER get is a super crisp and sharp chirp, no flutter to speak of. I have no idea the science as to why but I actually prefer the way it sounds/functions down at sea level, the flutter annoys me.

Maybe there is something behind this and maybe not, just posting my personal experience.
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Old 07-29-2021, 11:13 PM   #9
600hpSTI
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[quote=umscooby;46605640]Ouch the first post hurts. So much fail I didn't want to post. First we have a 600hp STi with a 20g. And go ahead a block off your BOV, that's a great idea.

First off, I have 3 subarus. Stock 05' WRX, FBO 400hp 08 STI hatch (dd), and a FBO 593hp 08 STI (dedicated track car). Track build has a closed deck ej257, Borg Warner EFR 83/74 TS turbo, JE FSR pistons with Manley I-beam rods, Kelford cam, 1/2" headstuds, if you want the whole build ill happily type it out.


I was simply wondering why my hatch doesn't flutter. My 05 and my 08 sedans both flutter like crazy and the 05 is stock, just bov block off plate. Im not concerned about the premature wear that may or may not be harmless caused by off throttle compressor surge. Although I do agree that chasing compressor surge/flutter is pretty silly, I just love the sound. The chirping of my EWG and the crisp whoosh of the TS BOV are both euphoric, I just want a change. I also do agree, the less surging the better, especially under boost. Boost surge make subie go boom
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Old 07-30-2021, 12:52 AM   #10
umscooby
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[quote=600hpSTI;46605925]
Quote:
Originally Posted by umscooby View Post
Ouch the first post hurts. So much fail I didn't want to post. First we have a 600hp STi with a 20g. And go ahead a block off your BOV, that's a great idea.

First off, I have 3 subarus. Stock 05' WRX, FBO 400hp 08 STI hatch (dd), and a FBO 593hp 08 STI (dedicated track car). Track build has a closed deck ej257, Borg Warner EFR 83/74 TS turbo, JE FSR pistons with Manley I-beam rods, Kelford cam, 1/2" headstuds, if you want the whole build ill happily type it out.


I was simply wondering why my hatch doesn't flutter. My 05 and my 08 sedans both flutter like crazy and the 05 is stock, just bov block off plate. Im not concerned about the premature wear that may or may not be harmless caused by off throttle compressor surge. Although I do agree that chasing compressor surge/flutter is pretty silly, I just love the sound. The chirping of my EWG and the crisp whoosh of the TS BOV are both euphoric, I just want a change. I also do agree, the less surging the better, especially under boost. Boost surge make subie go boom

I just want to know if the whole build incudes the plumbing you added to allow air from your intake track to escape out of your downstream exhaust.
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Old 07-30-2021, 12:56 AM   #11
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Quote:
Originally Posted by 600hpSTI View Post
... I believe it has something to do with the EWG. If I block off or close the BOV, the boost pressure has no where to go besides back through the compressor or out the EWG, so it must be escaping through the EWG, right??...
Right.
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Old 07-31-2021, 06:00 PM   #12
Norm Peterson
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Quote:
Originally Posted by K3rm1tth3fr0g View Post
But to be honest, chasing compressor surge is pretty silly.

I get that it sounds cool, but off throttle compressor surge is still a surge, and while its most likely harmless, the less surging the better IMO.

And not to mention you lose compressor speed when it stalls and surges....
This ^^^


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Old 07-31-2021, 06:01 PM   #13
lefty o
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agree with the above posts. i would do everything i could to eliminate flutter/surge in a turbo. no good comes from it.
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Old 08-01-2021, 11:36 PM   #14
Diavolo_
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Default

hmmm, since the "flutter" sound is your only concern, what about a throttle body block off plate, and an intercooler delete?

from what you describe its sounds like the problem is the charge of air is getting sucked into your intake manifold and mixing with fuel and combusting after being compressed.


let us know what your solution is when you figure out how to reverse the direction of the air flow.
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Old 08-02-2021, 07:03 AM   #15
K3rm1tth3fr0g
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Quote:
Originally Posted by Diavolo_ View Post
hmmm, since the "flutter" sound is your only concern, what about a throttle body block off plate, and an intercooler delete?

from what you describe its sounds like the problem is the charge of air is getting sucked into your intake manifold and mixing with fuel and combusting after being compressed.


let us know what your solution is when you figure out how to reverse the direction of the air flow.

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Old 08-21-2021, 03:05 AM   #16
lucytharex
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Just get an HKS bov
all the flutter you could ever want
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