Why does my Tial 50mm BOV sound like a turkey when blowing off?

[tom04841]

Just as the title says? When i let off the gas after boosting, it flutters and sounds like a turkey. I have a good vac source, and the BOV doesn't leak at all.

It has been doing it ever since my rebuild and upgraded cams. Before the rebuild to you blow off fine.

 

[olmytsi]

Do you have a dedicated line for the bov? I used to have other things tapped in the bov line and i was getting surge. After i switched to a bigger vacum line straight to the bov with nothing else tapped in it, it works much better.

 

[tom04841]

The only thing i have on the line with it is my 3 bar map sensor for my speed density setup. It has been this way for a while, and up until the rebuild, i didn't have any issues, so i know it isn't that

 

[T9S1i]

Kind of the same thing happened to me, i had a hks SSQV and it made a normal WOOSH like a cleaner 1g bov before i blew my motor. I think rebuilt the motor, added forged internals with higher compresson pistons and now my BOV flutters. I noticed that its mosty at lower boost though around 10psi, once i turned it up to 15psi, the old sound was almost back, but still a little different. I also have a dedicated line to my bov, nothin "T'd" off of it.

TOM, are you still breaking in the new motor or driving around at low boost?

 

[tom04841]

TOM, are you still breaking in the new motor or driving around at low boost?

Nah. motor is fully broken in, and i am running 20 psi

 

[94Jettameowpsst]

its normal.....tials sound different from everything else.....it also depends on what turbo you're runnin as well

 

[danyz250f]

My greddy knock off did the same thing after the 60-1 install. A bigger vac line helped a bit but still have the turkey call.

 

[tom04841]

its normal.....tials sound different from everything else.....it also depends on what turbo you're runnin as well

Its not normal. It blew off fine before i rebuilt the motor and upgraded the cams.

 

[94Jettameowpsst]

I would say to change your vacuum source then.
The only other thing i can think of is your cams not pulling a lot of vacuum at idle but that wouldnt effect your blow off.

Does it happen at full or part throttle? Because i have a crushed 1g bov and it flutters at part throttle like crazy...it also surges at low rpm at full throttle.

 

[Reese92tsi]

Do you have a dedicated line for the bov? I used to have other things tapped in the bov line and i was getting surge. After i switched to a bigger vacum line straight to the bov with nothing else tapped in it, it works much better.

Exactly. I run a 1/4" ID vacuum hose to my Tial and it blows off very easily at very low boost even though I have other stuff tapped into it. I think Tial even recommends a minimum line diameter of 6mm ( 1/4") for their bov and WG.

 

[tom04841]

I am pretty sure my line is 3/16th. It bolws off at low boost too, just makes a fluttering sounds now, where as before it would open very smoothly.

Is it possible that the lower vac from the cams is causing this? My vac at idle with stock cams was 18, and now with the webcams, it is around 10.

Not sure which spring i have in there now, but you think switching to a lower pressure spring would help?

 

[olmytsi]

As long as you are not hearing any surge from the turbo, i wouldn't worry about it. BOV sounds change from setup to setup.

 

[tom04841]

As long as you are not hearing any surge from the turbo, i wouldn't worry about it. BOV sounds change from setup to setup.

I'm not sure i know what surge sound like.....never heard it before

 

[suprdave09]

if your idle vac is at 10 go with the 7lb spring. I had the same problem and when i went with my ffwd 272's i started to flutter. Also make sure the piping where the flange meets is opened to the diameter of the flange. This would also cause a flutter.

 

[tom04841]

if your idle vac is at 10 go with the 7lb spring. I had the same problem and when i went with my ffwd 272's i started to flutter. Also make sure the piping where the flange meets is opened to the diameter of the flange. This would also cause a flutter.

After i welded the flange to the pipe, i took a die grinder and made the hole flush. Will the flutter hurt anything, or do i need to dive in further?

 

[suprdave09]

After i welded the flange to the pipe, i took a die grinder and made the hole flush. Will the flutter hurt anything, or do i need to dive in further?

it could after time damage the turbo if it is compressor surge. If its bov flutter then no. I would still upgrade the spring its only around 25 bucks shipped.

 

[olmytsi]

I'm not sure i know what surge sound like.....never heard it before

Then you probably don't have it. It's really loud and it sounds really cool although it is bad for the turbo in the long run.

 

[94Jettameowpsst]

I'm not sure i know what surge sound like.....never heard it before

It happens when the ve of your motor isnt high enough and the turbo spools enough air to make the compressor surge....makes a chhh chhh chhh sound at lower rpms at full throttle

 

[olmytsi]

Well, there are 2 types of surge.

94 jetta, you are talking about true surge. We are talking about the surge you get when your bov doesnt open or it opens way too little and air travels back to the compressor and causes this noise. 2 totally different things.

 

[wishihadatalon]

I agree on the new spring. Setting the proper spring pressure is important to proper bov function.

 

[daren_p]

Sounds to me like you just have a little bov flutter, which isn't damageing like surge. More then likely the reduced vacuum is the source for the issue. As others have mentioned a dedicated line & one of a larger diameter may help your issue. You can usually stop the flutter by going to a lighter spring as well.