New Inlets and catch can installed...now Tial BOV sounds horrible?? Why?

IQraceworks

Corporal
Jul 7, 2020
208
121
0
Missouri
Ride
07' BMW 335i
I just got finished installing my new silicon inlets, and BMS OCC. I took my car for a drive, and it runs great.....but the Tial BOV sounds horrible now for some reason.

It used to have a nice and deep "Whoooosh" sound when getting out of the throttle when it dumped the boost.........but now, it's got this high pitched squeal to it that just sounds horrible! And it's crazy loud now. It's almost as if the valve isn't opening as fast as it used to, and instead of it dumping all of the boost in a hurry....not it just squeals and the air is forced out of the valve.

I checked the manifold adapter that the 1/4" line comes off of, and followed the line to were it connects to the BOV...no problems, no leaks, all is good.

Could some crap have gotten into the BOV somehow? Why would new inlets and OCC cause the BOV to sound so high pitched and horrible? Ideas?
 

CantSitStill

Specialist
Jul 22, 2022
79
25
0
And my theory on why it “only started happening” with upgraded inlets is because of their ability to flow much more than the stock ones. More flow means that it’s even easier for positive pressure to force its way back through the turbo and out the filters.

Multiple videos on youtube showing that the “hoot noise” is coming from the filters themselves, as the bov is visibly delayed in response
Great advice and good to know im chasing a "normal" issue. I think the synapse BOV has an option to include boost pressure from a hose tail on the high-pressure side, which could be the hot side. I wonder if this would solve the issue.

Edit: Needs to be the old v1 one: http://synapseengineering.com/support/Blow-Off-Valve-c1-p.html?ipp=25

I have that one
 

CantSitStill

Specialist
Jul 22, 2022
79
25
0
Great advice and good to know im chasing a "normal" issue. I think the synapse BOV has an option to include boost pressure from a hose tail on the high-pressure side, which could be the hot side. I wonder if this would solve the issue.

Edit: Needs to be the old v1 one: http://synapseengineering.com/support/Blow-Off-Valve-c1-p.html?ipp=25

I have that one
Hello,

So short story is i have completely solved my issue and returned the instant whoosh of my tial BOV. Its completely transformed it. The turbo back pressure noise is gone and BOV reacts instantly when you have the foot off the gas. Its also back to working at lower RPM's/Speed again. Boost and WGDC are the same (20psi) so i assume its not leaking boost as well. To say im happy is an understatement!

I did try to synapse connected to 2 vacuum sources and one boost source and it was still crappy.

Anyway here is how i modded the bov:

1. The piston was not able to travel up all the way and was only ever half open - i opened is up and shave off 5mm from the internal guide pin, i had to take a bit off the guide pin and the outer sleeved the guide pins moves up and down. This enabled the BOV to open much wider
2. The outer sleeve inside the BOV has 2 holes in it to allow air vacuum to suck the BOV open. I drilled these holes bigger with a 5.5mm drill
3. The banjo i drilled with a 5.5 MM drill to make the hole bigger and the banjo bolt i drilled as well bigger
4. I shorted the spring by about 20mm by hacksawing a bit off - you might not need to do this so i would try the above first
5. When i put the banjo bolt back on i made sure the large hole i drilled was perfectly lined up with the banjo bolt
6. As before i have 2 separate vacuum sources coming from the manifold to the BOV ensuring you have a fat T piece being used.

Its important there are no bottlenecks for the vacuum source.

Anyway, as i say im shocked at the difference this has made and has fixed all my issues. BOV sounds amazing again and so do my new turbos.

I assume a real Tial bov would not have these issues, pretty sure mine is fake. What i would say if you have a real one buy a cheap fake one, make the mods and see if its any better.

Cheers
 

KClemente

Sergeant
Nov 26, 2019
284
147
0
Ride
E90 335i
Hello,

So short story is i have completely solved my issue and returned the instant whoosh of my tial BOV. Its completely transformed it. The turbo back pressure noise is gone and BOV reacts instantly when you have the foot off the gas. Its also back to working at lower RPM's/Speed again. Boost and WGDC are the same (20psi) so i assume its not leaking boost as well. To say im happy is an understatement!

I did try to synapse connected to 2 vacuum sources and one boost source and it was still crappy.

Anyway here is how i modded the bov:

1. The piston was not able to travel up all the way and was only ever half open - i opened is up and shave off 5mm from the internal guide pin, i had to take a bit off the guide pin and the outer sleeved the guide pins moves up and down. This enabled the BOV to open much wider
2. The outer sleeve inside the BOV has 2 holes in it to allow air vacuum to suck the BOV open. I drilled these holes bigger with a 5.5mm drill
3. The banjo i drilled with a 5.5 MM drill to make the hole bigger and the banjo bolt i drilled as well bigger
4. I shorted the spring by about 20mm by hacksawing a bit off - you might not need to do this so i would try the above first
5. When i put the banjo bolt back on i made sure the large hole i drilled was perfectly lined up with the banjo bolt
6. As before i have 2 separate vacuum sources coming from the manifold to the BOV ensuring you have a fat T piece being used.

Its important there are no bottlenecks for the vacuum source.

Anyway, as i say im shocked at the difference this has made and has fixed all my issues. BOV sounds amazing again and so do my new turbos.

I assume a real Tial bov would not have these issues, pretty sure mine is fake. What i would say if you have a real one buy a cheap fake one, make the mods and see if its any better.

Cheers
I'm jealous of you now lol.

I have a real tial but may consider buying a fake one and modifying it similar to your synapse
 

Torgus

Brigadier General
Nov 6, 2016
2,671
2,194
0
Boston
Ride
ACF 6466 E92 + METH
I'm jealous of you now lol.

I have a real tial but may consider buying a fake one and modifying it similar to your synapse

If only someone had a fake tial lying around they don't want(it was a friend's who bought a legit one) and was about to it throw away...
 

Sausage

Private
Jul 12, 2022
31
8
0
4. I shorted the spring by about 20mm by hacksawing a bit off - you might not need to do this so i would try the above first

So you change the PSI rating of your spring essentially putting in a softer spring. Yes that will make it behave very differently.
 

CantSitStill

Specialist
Jul 22, 2022
79
25
0
Hello,

So short story is i have completely solved my issue and returned the instant whoosh of my tial BOV. Its completely transformed it. The turbo back pressure noise is gone and BOV reacts instantly when you have the foot off the gas. Its also back to working at lower RPM's/Speed again. Boost and WGDC are the same (20psi) so i assume its not leaking boost as well. To say im happy is an understatement!

I did try to synapse connected to 2 vacuum sources and one boost source and it was still crappy.

Anyway here is how i modded the bov:

1. The piston was not able to travel up all the way and was only ever half open - i opened is up and shave off 5mm from the internal guide pin, i had to take a bit off the guide pin and the outer sleeved the guide pins moves up and down. This enabled the BOV to open much wider
2. The outer sleeve inside the BOV has 2 holes in it to allow air vacuum to suck the BOV open. I drilled these holes bigger with a 5.5mm drill
3. The banjo i drilled with a 5.5 MM drill to make the hole bigger and the banjo bolt i drilled as well bigger
4. I shorted the spring by about 20mm by hacksawing a bit off - you might not need to do this so i would try the above first
5. When i put the banjo bolt back on i made sure the large hole i drilled was perfectly lined up with the banjo bolt
6. As before i have 2 separate vacuum sources coming from the manifold to the BOV ensuring you have a fat T piece being used.

Its important there are no bottlenecks for the vacuum source.

Anyway, as i say im shocked at the difference this has made and has fixed all my issues. BOV sounds amazing again and so do my new turbos.

I assume a real Tial bov would not have these issues, pretty sure mine is fake. What i would say if you have a real one buy a cheap fake one, make the mods and see if its any better.

Cheers

Just to update here a little. I have the same BOV in place working spectacularly 4 months on. The BOV is wide open at idle in case anyone is wondering - i know there are a lot of people who this is should be shut, half open, and fully open. With mine fully open at idle it still holds 24psi to the red line OK. In terms of anything that could fall off into the manifold - there is actually nothing in the design that could allow that to happen as the piston is one piece, the only thing that screws into the piston is from the inside so even if it came loose it would come apart inside the bov - to avoid that i used thread lock and made sure is was very tight. The spring shortening would have made a difference for sure but the extra diameter on the vacuum feed would make it react faster as well. Same principle applies to anyone who has improved this bov by adding a bigger hose tail to the intake manifold - its just an improvement on that mod