club.liberty.asn.au

Okay dont shoot me down with this question. First time owning a turbo charged car. Was getting sick of the noise my BOV was making so decided to take it off (yes i've researched the myth of damaging turbos with no BOVs, etc). Gave it a rev and makes the exact same sound, reinstalled the bov and tried again and noticed the tiny little psst noise the valve would make but was overpowered by whatever is going on. I have a front mount kit installed and a pod filter. Do subaru have there own valves installed somewhere? I uploaded a video to better explain. Thanks in advance.

https://www.youtube.com/watch?v=BjRpqyY ... e=youtu.be

What you are hearing is .. the pressure releasing.. it's just releasing out the way it came in, because it has to go somewhere, The 'tsu tsu tsu' is the compressor stalling as it tries to pump air into the intake piping which is closed.

Your problem here is not related to blow off valves really, but your intake. When you were using the reciruclating BOV, which btw you shoudl refit right now, you could hear the same air coming out the intake, it was just taking a different route to get there.

Replacing the airbox with a pod filter will almost always result in this sort of noise - You can fix this by making up an airbox for your pod, replacing it back with a factory airbox, and a few other things.

"Why do I still sound like a wanker?" Gold!!!

thats a sexy sounding lib

HardwareBoB wrote:What you are hearing is .. the pressure releasing.. it's just releasing out the way it came in, because it has to go somewhere, The 'tsu tsu tsu' is the compressor stalling as it tries to pump air into the intake piping which is closed.

Your problem here is not related to blow off valves really, but your intake. When you were using the reciruclating BOV, which btw you shoudl refit right now, you could hear the same air coming out the intake, it was just taking a different route to get there.

Replacing the airbox with a pod filter will almost always result in this sort of noise - You can fix this by making up an airbox for your pod, replacing it back with a factory airbox, and a few other things.

HardwareBoB wrote:What you are hearing is .. the pressure releasing.. it's just releasing out the way it came in, because it has to go somewhere, The 'tsu tsu tsu' is the compressor stalling as it tries to pump air into the intake piping which is closed.

Your problem here is not related to blow off valves really, but your intake. When you were using the reciruclating BOV, which btw you shoudl refit right now, you could hear the same air coming out the intake, it was just taking a different route to get there.

Replacing the airbox with a pod filter will almost always result in this sort of noise - You can fix this by making up an airbox for your pod, replacing it back with a factory airbox, and a few other things.

Well basically that BOV is a VTA, no plumb back. It makes absolutely no difference with it on or off. As if the BOV doesn't open at all. Do you think maybe the spring is too tight or something? Basically i want to eliminate that sound. Not that i dont like it, but ill shift at 2k trying to drive like an old lady and it still makes the tssttssttssttsstt noise. Cops love it.

That BOV in your hand from what I could see was a plumbback valve, it just wasn't plumbed back
You want to put the output of that back into the intake at some point - the stock point is in the section of piping that goes under the intake manifold. That said - if it's not making any difference, it might not be adjusted properly, or more likely, you haven't got it connected to the right vacuum line.

This is a plumb back BOV, boost goes in bottom, vents to the side, which plumbs back into intake piping, vacuum line comes from the intake manifold (anywhere post throttle really) so it knows when to open.


This is a vent to atmo BOV, boost goes in bottom, vacuum on top as before, but air goes PSCHHH.


This is an adjustable BOV with two outlets, that you can adjust between the two - same crap, just adjustable.


The all perform the same function, and it's important- if you don't have a BOV you're putting unnecessary stress on your turbo, and losing precious turbo spool on gearchange.

It is a dual port bov. I plumbed it back the other day, blocked off the other port but made no difference. I have my boost gauge connected just before the vac line to the bov and shows vac as well as boost so that must be right correct?

if you have an aftermarket bov and the spring is too tight at low rpms it will flutter, and at higher rpms it will blow off.

Stevo1111 wrote:It is a dual port bov. I plumbed it back the other day, blocked off the other port but made no difference. I have my boost gauge connected just before the vac line to the bov and shows vac as well as boost so that must be right correct?

I think as mentioned it might be slightly off adjustment, causing flutter at lowish pressures, however even adjusted right, the noise here is the hard intake path and the pod, you'll get crazy intake and pressure release noise until you change it.

So i just need to fit an airbox? Any suggestions on how to do that with intercooler pipes being in the way etc?

You could just put a softer spring the BOV. I had a recirculated one on my old set up and it made no noise at all.

kiahatsiu wrote:You could just put a softer spring the BOV. I had a recirculated one on my old set up and it made no noise at all.

Ah yeah nice, will get on the hunt for that. Thanks for your help guys ill let you know how i go.

So fixed the issue with a contraption i got off ebay for $60. Heres a another video of the success so you all know how it sounds.

https://www.youtube.com/watch?v=YDpl5xi ... e=youtu.be

Thanks for your help.

Iirc you need a speed/density tune, eg map not maf sensor based tune to reliably support vta bov?