BOV Flutter

[Zufelt]

What's up guys, I can't seem to solve my problem. I stated getting flutter recently on my 1g BOV at around 25 pounds. I have no boost leaks, replaced all vaccum lines and reseated my BOV just to make sure it was all good. I'm at a loss of what I can do to get rid of this flutter, it's only when I'm WOT then let off the gas. Here is a video, you would have to listen as it's faint. I apologize in advance for my cousins choice of words.

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My mod list is up to date and I'm currently running e85.

 

[codym]

Are you having drivability problems when the BOV is releasing pressure or are you just bothered by the sound?

 

[Zufelt]

Are you having drivability problems when the BOV is releasing pressure or are you just bothered by the sound?

Neither, just when I hear this sound I relate it to compressor surge, I can't afford to replace my turbo in a couple hundred miles. If it won't affect the turbos life then all is well. I just didn't want to keep driving it as is if it was gunna hurt the turbo.

 

[codym]

Well I couldn't view the video, it took me to a photobucket page with nothing but pictures so I wouldn't be able to tell you if it sounds like the BOV is operating properly.

Here is a quote from another similar thread..

http://www.youtube.com/watch?v=nCj6Spwl1CU

Surge happens any time the turbo is making airflow the engine is not using. If your BOV is too stiff or not opening when the throttle plate is closed and the engine is on vacuum, the turbo is making airflow the engine is not able to use....causing compressor surge. In the example shown above, certain compressors will surge while under boost by providing more air than the engine can use. This is commonly found on turbos with large compressors mated to small turbines.


Did the problem seem to come on all at once, or did it occur after you modded the valve? Have you tried swapping a non-modded valve in place?

The few Dodge-Garage 1G valves I've been exposed to would indeed cause a little flutter on vacuum when letting off at a low boost level, when the boost in the piping was not high enough to "force" the valve open....although there was never an issue while on boost.

You can have a valve that opens fast at low boost or holds high boost pressure- you can't really have both.

Is your 1g BOV crushed ?

 

[Zufelt]

Well I couldn't view the video, it took me to a photobucket page with nothing but pictures so I wouldn't be able to tell you if it sounds like the BOV is operating properly.

Here is a quote from another similar thread..




Is your 1g BOV crushed ?

It's uncrushed, I actually read the page your talking about. Mine only happens at WOT with my boost above 20 pounds it also happens ONLY when I shift, I can still hear the psst like normal but with a flutter following it. I don't seem to hear it as much in third. Here is a direct link, hopefully it works better.

4680553B-6683-40BB-A37A-2517D9A2E86E_zpskx7dc7ae.mp4 Video by idcmanwhatever | Photobucket

If this is compressor surge this is not it

[ame]http://m.youtube.com/watch?v=nCj6Spwl1CU[/ame]

My car sounds like this shifting at 20psi + usually in second gear, it's not as loud as this one and still has a Pshhht sound still while having this


[ame]http://m.youtube.com/watch?v=1-cxhvbP_zA[/ame]

I don't mind the sound, I just don't want to ruin my turbo.

 

[bjjnerd85]

That sounds just like mine bro. Itll also do it if you feather the throttle in higher RPM's I wouldnt worry about it. It isnt surge. Ive heard it in alot of turbocharged engines.

 

[codym]

I can still hear the psst like normal but with a flutter following it.

I say as long as your not having any issues while on boost, and as long as it is relieving the pressure properly you won't have any issues with compressor surge. The flutter you're hearing may just be the spring not opening all the way after the majority of the pressure has already been released.


If you have access to another working BOV, you might try swapping them to see if there is any difference. If you had access to a dyno you would clearly be able to tell if the sound is coming from the BOV or the turbo itself, but being in the car it might be difficult to distinguish between the two.

 

[Seamus]

Bov noises are not compressor surge. That only happens when your compressor moves too much volume spooling up from having a big compressor on a tiny turbine. Like putting a 20g or larger on a td05h.

 

[JusMX141]

Oddly enough, it sounds exactly like my buddy's old Dodge Garage-modded 1G valve did at the same boost level on his 2G when the quick release function was disabled.

If it's an uncrushed valve without the Dodge Garage Mod done to it, there are a couple things to look into- if you recently had the valve off and used RTV on the gasket (or RTV as the gasket), it's possible some of the RTV is clogging the quick-release port on the bottom of the valve. Another thing to check if you're recirculating is that the recirc tube is not pinched shut anywhere.

If these two possible remedies check out OK, try using a vacuum tester to draw vacuum on the valve from the port on the top and see if it holds. If the diaphragm has a small hole, it can cause slow response from the valve when it opens.

Bov noises are not compressor surge.

If the throttle plate is closed and the BOV is not opening for whatever reason, then it's absolutely compressor surge as the turbo is generating airflow that the engine is not using. This can and will harm a journal bearing turbo over time with enough boost.

Tough to distinguish a difference in the two at times.

 

[Seamus]

I didn't know that had a name.
I guess it's the same end result though. Pressurized air is unable to get where it needs to be.

 

[Zufelt]

Oddly enough, it sounds exactly like my buddy's old Dodge Garage-modded 1G valve did at the same boost level on his 2G when the quick release function was disabled.

If it's an uncrushed valve without the Dodge Garage Mod done to it, there are a couple things to look into- if you recently had the valve off and used RTV on the gasket (or RTV as the gasket), it's possible some of the RTV is clogging the quick-release port on the bottom of the valve. Another thing to check if you're recirculating is that the recirc tube is not pinched shut anywhere.

If these two possible remedies check out OK, try using a vacuum tester to draw vacuum on the valve from the port on the top and see if it holds. If the diaphragm has a small hole, it can cause slow response from the valve when it opens.


If the throttle plate is closed and the BOV is not opening for whatever reason, then it's absolutely compressor surge as the turbo is generating airflow that the engine is not using. This can and will harm a journal bearing turbo over time with enough boost.

Tough to distinguish a difference in the two at times.

I thought the exact same thing with the RTV, except that wasn't the case. I suppose I can try another BOV. If the noise persists even with another uncrushed BOV should it be something to worry about?

 

[codym]

If the noise persists with another BOV than that one is bad too, or something is obstructing it's way back into the intake. Your a lot less likely to get compressor surge with a properly operating BOV.
Just for S&G's tell me.. is anything T'd into the BOV line?

You said you noticed the issue after you replaced all the vacuum lines, did you perhaps use a smaller diameter?

 

[johneclipse]

Am I wrong in saying I thought a stock 1g bov needed to be crushed to hold 20+ psi correctly?

 

[codym]

Mmm I don't know that off the top of my head, I want to say yes, but I don't want to give you the wrong info. I'll have to do some research about it and get back to you, but I do know the 1g bov's are extremely reliable .

 

[Seamus]

Am I wrong in saying I thought a stock 1g bov needed to be crushed to hold 20+ psi correctly?

Yea typically they need to be crushed or dodge modded.

 

[johneclipse]

Yea typically they need to be crushed or dodge modded.

I coulda swore my stock started leaking at 18ish.

So, couldn't this simply be his problem? Stock unmodified bov running 20+ psi.

 

[Seamus]

I coulda swore my stock started leaking at 18ish.

So, couldn't this simply be his problem? Stock unmodified bov running 20+ psi.

It's happening when he lets off the gas.

I will say this I've heard plenty or race cars with no bov and the sound they make from this "compressor surge" is not a faint flutter. It sounds like rapid queefing from the fiercest vagina in the world.

I've also had really bad traditional compressor surge before experimenting with 20g configurations combined withor piggybacked on aggressive boost control. It's a more violent sound than a flutter too and it only happens at wot as boost starts to get high

In my experience bov just flutter sometimes and nothing is wrong. I've had a greddy type r, a vortex, 1g, and tial over the years and they have all made different sounds and fluttered sometimes.

 

[jlaw12]

My Greddy flutters all the time.

 

[pacn91]

I crushed my stock bov and it started fluttering....now that someone mentioned it when i pulled it off for replacement, I did find where i used to too much rtv on the gasket. like JUSMX said, it was clogging the quick release port. I had just purchased a greddy bov so i went ahead and switched. little to no fluttering now.