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Flutter Dump

AnotherNewb

Well-known member
Joined
Apr 25, 2010
Messages
1,472
Location
Orlando, FL
Youtube

Set up:
14b turbo
2.5" IC pipes
Injen Intake with 2g MAF
HKS SSQV

1947 is exibiting these symptoms. It sounds like a horse whineying. After searching around I am unable to find a solid reasoning or solution to this problem (better BOV is not a solution). All the Vacuum lines are new, and the BOV is authentic. Also it is being recirculated with no noise insert. Has anyone had this problem with their car?The flutter dump is worse at part throttle but at wide open nearly nonexistant. The car has 17-20hg of vacuum so that isn't the problem and the BOV has a dedicated vacuum line to it (it might be tee'd off the line for the BC/WG).


Please discuss.
 

Diego

Well-known member
Joined
Dec 9, 2007
Messages
2,132
Location
In a van down by the river, Iowa
Isn't Flutterdump from compressor surge, allowing the flapper on the WG to open slightly undrer boost, not making a complete seal?

Matt didn't tell me he was having these problems. But ^ that is how I believe flutterdump happens.
 

AnotherNewb

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Joined
Apr 25, 2010
Messages
1,472
Location
Orlando, FL
Yeah, this one isn't adjustable. Is it from too stiff or too soft of a spring, I am getting mixed info on it.
 

I'm having the exact same issue! Thought it was from my HKS, but after swapping back to a stock BOV, it continues. Even under very low boost (0-3psi) while cruising down the road
 

curtis

Well-known member
Joined
May 4, 2003
Messages
11,892
Location
Clarksville TN
You might be able to put a stiffer preload on the wastegate actuator. It could be coming from the exhaust side instead of the BOV. All hks sound the same and do have some surge. Its a balance of BOV, which type boost controller you have exhaust etc but if you remove the two bolts on the actuator and stack a couple washers under each and reinstall it put more of a load on the actuator and makes for a tighter seal.

This is the reason I went to the synchronic bov for mine
 
Last edited:

2of9

Well-known member
Joined
Aug 29, 2007
Messages
869
Location
IGH, MN
This is how mine sounds:
click

I always though it was bov related but never really thought about the wastegate actuator deal. When I went with the 2g mas setup, it still sounds like this. Not sure if the BOV is even functioning because I currently have a knock off right now /ubbthreads/images/graemlins/frown.gif Checked the turbo for any shaft play and there is EXTREMELY little play in and out(probably not even notable but still...), no side to side movement. I remember when I was boosting it'd would actually do it like what the video did (flutter-dump). It would flutter and then dump. the car still flutters even under vacuum.
 

I had the same problem with a greddy type S. With that bov i could actually adjust the spring and it fixed the issue. I'd be down to try that washer issue. Get ahold of me and we can see if this will solve the problem.




Jesse


BTW i had a friend that had a mazda speed6 with the HKS and had the exact same problem.
 
Last edited by a moderator:

turbowop

Well-known member
Joined
Apr 29, 2001
Messages
11,971
Location
Yakima, WA
My HKS flutters on rare occasion. Depends on throttle position, load, and how into the throttle I was before partially letting off. Mostly it works just fine.

Does anybody have actual proof of a fluttering BOV damaging a turbo? I haven't actually ever heard of it happening, just a rumor that it's bad.
 

KiNgMaRtY

Well-known member
Joined
Apr 8, 2008
Messages
835
Location
Corona, CA
Get rid of the knock off and get a real one. They just DON'T function correctly unless you mod it.
 
Last edited:

Barnes

Well-known member
Joined
Feb 9, 2003
Messages
6,249
Location
Richland, WA
Quoting turbowop:
My HKS flutters on rare occasion. Depends on throttle position, load, and how into the throttle I was before partially letting off. Mostly it works just fine.

Does anybody have actual proof of a fluttering BOV damaging a turbo? I haven't actually ever heard of it happening, just a rumor that it's bad.



Flutter seems to occur at lower boost(from my experience), so I would suspect at such low turbo shaft RPMs any bov flutter(bov opening and closing several times after throttle is lifted) would not be able to cause damage.

However this 'flutterdump' sounds like it is not a great thing. If I'm reading this right, and looking at the video correctly, it means the BOV is opening late. Therefore allowing a pressure spike in the IC piping, thus causing the compressor to surge creating the funny noise. It would seem to me this is due to an overly strong BOV spring, or perhaps a damaged or sticking BOV valve. Or perhaps leaky BOV vacuum lines.
 

AnotherNewb

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Joined
Apr 25, 2010
Messages
1,472
Location
Orlando, FL
A lot of great info in this thread, I take it everyone used the computer at work to replie to it. Anyways I believe I will start with a dedicated vacuum line for the BOV since it can't be adjusted. I'm not really sure how the waste gate would tie into this problem, but "shimming" it is another viable test.

BTW, thanks for the title... I guess its better than "special needs". /ubbthreads/images/graemlins/grin.gif
 

onesickcrx

Well-known member
Joined
Jun 3, 2007
Messages
1,076
Location
NY
Quoting AnotherNewb:
Youtube

Set up:
14b turbo
2.5" IC pipes
Injen Intake with 2g MAF
HKS SSQV

1947 is exibiting these symptoms. It sounds like a horse whineying. After searching around I am unable to find a solid reasoning or solution to this problem (better BOV is not a solution). All the Vacuum lines are new, and the BOV is authentic. Also it is being recirculated with no noise insert. Has anyone had this problem with their car?The flutter dump is worse at part throttle but at wide open nearly nonexistant. The car has 17-20hg of vacuum so that isn't the problem and the BOV has a dedicated vacuum line to it (it might be tee'd off the line for the BC/WG).


Please discuss.



My car did exactly that when I had the HKS on it once I installed my Tial it stopped... not pointing fingers but /ubbthreads/images/graemlins/uhh.gif
 

onesickcrx

Well-known member
Joined
Jun 3, 2007
Messages
1,076
Location
NY
Quoting 2of9:
here's is about 1 hour ago. /ubbthreads/images/graemlins/dunno.gif

click



Can you get video of the inside of the blowoff valve? At the end of your video you can see inside but you didn't make it stumble. I am interested to see if it's actually moving or not and if it is does it go with the sound
 

2of9

Well-known member
Joined
Aug 29, 2007
Messages
869
Location
IGH, MN
the bov has two vacuum hoses. top hose on bov is goes to the intake manifold and the lower one is open. maybe i just need to plug the bottom one.

click
 

turbowop

Well-known member
Joined
Apr 29, 2001
Messages
11,971
Location
Yakima, WA
Quoting 2of9:
here's is about 1 hour ago. /ubbthreads/images/graemlins/dunno.gif

click



So you barely rev it and it flutters? /ubbthreads/images/graemlins/uhh.gif My HKS doesn't do anything when free revving it quickly in neutral since it doesn't build boost.

Mine is one of the older ones that is adjustable. I think I remember tightening it a hair when I first installed it, but this was back in '03 or so.
 

beaner

Well-known member
Joined
Jun 22, 2005
Messages
1,562
Location
b'ham, mi
@2of9 it sounds like compressor surge. looks like your bov isn't working at all. sort those vacuum lines out or jump ship to another bov.
 
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