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Old 06-13-2003, 01:41 AM   #1
Cusco
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Default WHat causes BOV "flutter" noise

WHat causes the flutter noise from the BOV? Is it the pressure meaning how much PSI you are pushing or is it a certain type of BOV that is making the sound because I know that the SR20DET's, i.e. silvias, are known to have the flutter BOV sound. Also I have noticed some Supras have a chirping noise. How can I get a flutter noise or whatnot?
Thank you.

John
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Old 06-13-2003, 02:34 AM   #2
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hks super sequential is what you're looking for IIRC.
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Old 06-13-2003, 01:21 PM   #3
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Smile thank you

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Old 06-14-2003, 10:02 AM   #4
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Some BOV you can give less spring tension/less shims and will do the same effect. sound is determined buy the builder of the BOV. just be sure not to get a BOV the is too small may cause Turbo falure later down the road or even power loose.
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Old 06-23-2003, 02:15 AM   #5
dza360
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Default I got flutter and don't want it

I have an HKS SS and it quit working I also have an annoying flutter noise between shifts when there is supposed to be a Whoosh from my BOV....I checked the forums for explanations...checked all hoses...it all checks out. Took it to the dealer and they are really cool about it, I told them to check the wastegate and noticed that it wasn't moving at all...but I never noticed a change in boost ever...but this little sllver wastegate is stuck and doesn't move. So they ordered me an entire new turbocharger and its all covered under warranty. Too bad they couldn't put an STI turbo in there.

Flutter is bad.

D
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Old 06-23-2003, 11:06 AM   #6
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yes

flutter = compresser surge = death screams of a turbo
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Old 06-23-2003, 11:27 AM   #7
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Yeah I figured it was compressor surge when you hear a flutter noise. My BOV only does this and has more of a whomp sound than a woosh sound when I shift hard at high rpms. Under normal driving or light boost it makes a nice woosh sound that sounds oh so sexy. A crushed BOV and 4psi don't get along to well I guess...
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Old 06-24-2003, 05:56 AM   #8
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flutter = not good at all.

A chirp is actually what you are after (should sound like a sneeze)

Adam
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Old 06-24-2003, 03:16 PM   #9
dza360
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Default flutter bad, new turbo good.

I took off my HKS SS BOV, put my stock BOV back on so that i could take it in and have the Turbo replaced without questions. To my surprise, the flutter between shifts was gone after I put the stock BOV back in. I think its a HKS defect, not necessarily a turbo defect...but I am not going to tell them....they get the warranty work and I get a new Turbo, even if i didn't need it. But they put a loss of boost on the work order, so...I just don't know if I should put the HKS back in....has anyone had their HKS BOV for over a year and a half? I might have to get another BOV. or leave the stock in....although I love being able to hear my engine, any suggestions?

D
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Old 06-25-2003, 04:42 AM   #10
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So you are saying ALL BOV flutter is the cause of a wastegate failure? that woudl mean half of teh turbo'ed cars in Japan are having wastegate failure. my thread was not asking "what is wrong, I have BOV flutter noises coming form engine bay.." the thread was about what type of BOV intentionally makes the flutter noise, not a noise that comes from a faliure. hehe

SO then the HKS SSQV is no good? or it is more of a chirping noise rather then a flutter noise. and is this only possible with high boost pressures? meaning more than 13 psi?

I have an XS type-h BOV and it soinds great but I wanted somethign more unique in sound. so then I guess the better question is, "What kinds of differnet sounds do different BOV's make and which brands."

thank you

John
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Old 06-25-2003, 11:11 AM   #11
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Quote:
So you are saying ALL BOV flutter is the cause of a wastegate failure
no no no
flutter aka compresser surge is caused but a bov that is set to tightly or broken, nothing to do with the wastegate

it makes for better throttle resonce but will kill your turbo in the long run

Quote:
what type of BOV intentionally makes the flutter
any misadjusted BOV will do this at the expense of your turbo longevity.. like say a crushed stock bov
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Old 06-25-2003, 03:08 PM   #12
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Doesn't the flutter noise come from too much pressure or too hard of a spring? Some BOV making a turkey noise kind'a...
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Old 06-25-2003, 06:02 PM   #13
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Default so where should we be. ?

All of us HKS'ers should have the valve adjusted all the way out? so that we don't choke our turbo? Maybe buying a BOV wasn't such a good idea. I have only had mine on for a matter of months, maybe six months.
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Old 06-25-2003, 07:08 PM   #14
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I always assumed that if the fluttering is coming from the BOV and not from the turbo side, its just an issue with the BOV not getting enough pressure to open the valve. Turboxs confirms that this is normal operation...

Even though, I lubed my valves and put a softer spring into my Type-H BOV (which is all for show and sound; I have an AT), and it doesn't have an issue opening now and doesn't flutter anymore (well at 2-3psi only).

-jlee
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Old 06-26-2003, 02:05 AM   #15
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To my understanding, the fluttering sound can come from the Wastegate (known on some high hp and high boost GT cars). This is normal for turbo cars, due to boost and how the car release the boost pressure (both intake and exhuast side). Intake side taken care by the BOV and the wastegate controls the boost by regulating the amount of the exhuast gas should go through the turbine (the mechanical/solenoid boost controllers give the feed back from the intake side that boost level is achieved.. the wastegate does all the dirty work).

you can hear the fluttering from a stock wrx setup, by just unbolting the air intake and letting the turbo spool up and slowly letting the throttle off... it's how you let off on the throttle that would trigger it. Basically the turbo is winding down, and the butterfly valve in the throttle body isnt completely closed.. so the air going into the throttle body doesn't create a backpressure for the BOV to go off. At this effect, the ECU reads off that the the throttle is letting off and air intake boost levels are climbing.. this is where the wastegate comes in and just completely let off the boost by slowly leaking it out in a fluttering noise, so that way when you let off the gas, the car slows down, and boost goes down.

If you hear a fluttering coming from the BOV (usually very loud), that is a very bad sign.. the BOV is either busted because the spring has no more static ability to keep the valves closed at normal boost levels, or the wastegate is busted and all the exhust gas is going into the compressor wheel.. meaning your turbo is spinning even at idle and you're not even moving.

Correct me if I am wrong people.

Thanks
Keefe
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Old 06-26-2003, 02:08 AM   #16
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Quote:
Originally posted by xenonk
To my understanding, the fluttering sound can come from the Wastegate (known on some high hp and high boost GT cars). This is normal for turbo cars, due to boost and how the car release the boost pressure (both intake and exhuast side). Intake side taken care by the BOV and the wastegate controls the boost by regulating the amount of the exhuast gas should go through the turbine (the mechanical/solenoid boost controllers give the feed back from the intake side that boost level is achieved.. the wastegate does all the dirty work).

you can hear the fluttering from a stock wrx setup, by just unbolting the air intake and letting the turbo spool up and slowly letting the throttle off... it's how you let off on the throttle that would trigger it. Basically the turbo is winding down, and the butterfly valve in the throttle body isnt completely closed.. so the air going into the throttle body doesn't create a backpressure for the BOV to go off. At this effect, the ECU reads off that the the throttle is letting off and air intake boost levels are climbing.. this is where the wastegate comes in and just completely let off the boost by slowly leaking it out in a fluttering noise, so that way when you let off the gas, the car slows down, and boost goes down.

If you hear a fluttering coming from a single spring or single drive BOV (usually very loud), that is a very bad sign..UNLESS you have a BOV that is designed with a dual drive or a sequential type (like HKS SSQV, or BLITZ DD, or SARD R2D2) the BOV is either busted because the spring has no more static ability to keep the valve closed at normal boost levels, or the wastegate is busted and all the exhust gas is going into the compressor wheel.. meaning your turbo is spinning even at idle and you're not even moving.

Correct me if I am wrong people.

Thanks
Keefe
I corrected a few things in there =P
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Old 06-26-2003, 03:52 PM   #17
dza360
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Default this is all good info....but I still don't get it.

Thanks for the info...but despite the mumbo jumbo...i still can't figure out why with all hoses intact, my BOV stopped working, I had a chokey flutter (not chirp) noise coming from the Right side of my engine, I guess my turbo really was dead if my wastegate wasn't providing the vacuum that the turbo needs to spool up and feed the BOV. So hopefully a whole new turbo will remedy things. But I am not sure if I should put my HKS back on...will I have the same problem again in six months? by that time my turbo will be out of warranty....

AHHHH i am a moron. I don't know what I am going to do. It sounded great when I first got the BOV in Sept. but it just quit. If all the hoses are intact and the valve on the BOV is open all the way, it shouldn't hurt my turbo right?
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Old 06-26-2003, 06:59 PM   #18
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You didnt over-tighten the BOV spring valve did you?? That's the easiest way to kill your turbo other than overboosting it. If you tighten the spring too much, the BOV isn't going to vent, causing the back pressure to force the wastegate to do a lot of expelling of the gases. (thank goodness for ball bearing turbos, roll forward, and roll back, you just hope that your fins are strong enough and your wastegate acts fast to get rid of the exhuast gas).


Keefe
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Old 06-26-2003, 07:12 PM   #19
dza360
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Default spring loosened

So unscrewed all the way out, that is the correct place to have it right? unscrewed all the way out before it actually falls out.?

thanks
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Old 06-26-2003, 07:42 PM   #20
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ALSO , if a blowoff valve has its vacuum line tee'd off any where then you will get that.you want a direct line to the valve.
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Old 07-03-2003, 03:23 PM   #21
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I swear that flutter sound isn't all bad...I mean go drive next to just about any Supra TT or RX-7 and you'll probably hear the butterfly valvish, flutter BOV sound...the sound is hard to explain, let alone write out...but its not the phssssst, whooooosh, or any of those sneezy sounds...I have a movie that explains exactly what I mean, but I can't figure out a way to post it since its on my harddrive. SO what I wanna know is...that sound is compressor surge, not just a special BOV?
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Old 07-03-2003, 03:36 PM   #22
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During the in-car of the Supra are two shifts that have the BOV sound that I'm talking about. I don't know if this like is going to work...sorry about it being zipped. I'll keep looking around.

Supra vs. GT-R


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Old 07-04-2003, 01:26 AM   #23
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Kinda sounds like...

"Pprrrrrrrphsssssssshhhh" (during the "rrrrrrr" roll your tongue." It takes some practice.

So add with engine noise during shifting and you have a

"VRRRRRROOOOOOOOOOOOM, Pprrrrrrrphssssssssh, VRRRRRRROOOOOOOOOOOM, Pprrrrrrphsssssssssh...etc.

hehhe

IMO it's a very distinct and beautiful blow off sound, almost as beautiful as the sound of your opponents car's engine behind in the backgorund te he


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Old 07-04-2003, 01:32 AM   #24
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Kinda sounds like...

"Pprrrrrrrphsssssssshhhh" (during the "rrrrrrr" roll your tongue." It takes some practice.

So add with engine noise during shifting and you have a

"VRRRRRROOOOOOOOOOOOM, Pprrrrrrrphssssssssh, VRRRRRRROOOOOOOOOOOM, Pprrrrrrphsssssssssh...etc.

hehhe

IMO it's a very distinct and beautiful blow off sound, almost as beautiful as the sound of your opponent's car's engine behind in the backgorund tehe


John
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