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

[IQraceworks]

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?

 

[zaw111]

there is a suspicion of a boost leak from the video. Like something with a vacuum line to the valve and it is open for a long time

 

[IQraceworks]

I didn't have a boost leak before the inlets, not sure why I would have one after the inlets. Also, even at low boost level at part throttle....the BOV makes that same crying turkey type high pitched noise. Car runs awesome.....just sounds embarrassing when I get off the gas.

 

[zaw111]

I didn't have a boost leak before the inlets, not sure why I would have one after the inlets. Also, even at low boost level at part throttle....the BOV makes that same crying turkey type high pitched noise. Car runs awesome.....just sounds embarrassing when I get off the gas.

IMHO such a sound when the valve is open longer than necessary. Therefore, instead of phhhhhhh , the sound is slightly stretched.

 

[NoQuarter]

Seems to me you are too fixated on what caused it. You need to open up a bit more and consider other possibilities.

 

[RuskiRacer]

Yeah but he should be fine from BMS. They're good guys.

Op: take it apart completely and clean/inspect it especially the diaphragm when your black spring comes in. Lube it all up and reinstall.

Myself, I'm ditching my Tial soon and going to TS raceport or Gofast Bits SV50.

With you there on the gfb

 

[ShocknAwe]

With you there on the gfb

Do you have one already?

 

[IQraceworks]

Seems to me you are too fixated on what caused it. You need to open up a bit more and consider other possibilities.

That's kind of the whole idea....figure out what's causing the problem so that you can make the chnages needed to get rid of the problem. What other possibilities?

 

[IQraceworks]

Well, I put the new 7psi spring in the Tial BOV last night. It's definitely lighter, it's fully open at idle, which I'm not sure I'm a big fan of....but I can always switch it back to the 10psi spring.

Long story short......same screeching owl/chicken noise when I'm in boost and let off the throttle and the BOV opens. Larger 1/4" ID line, and 7psi spring.....no change at all. Kind of frustrating...it used to sound so good with the stock inlets on the car.

At this point, I guess I will just have to chalk it up as some strange resonance caused by the silicone inlets....I can't think of any other explanation. I guess I will just leave it until I get some different turbos later this summer....probably just put some PR relocated inlets on the car while I do the turbos. From everything I've read, they will get that nice "whooosh" sounds back from the BOV.

 

[KClemente]

Reviving this thread because something clicked in my brain and the sneeze started pissing me off again lol

I did a test with the stock box and filter, and what do you know, the noise completely disappeared. Though even at high boost I could barely just barely hear my beautifully normal sounding TiAL.

Watch this video @nyt put up on n54tech and listen to the first vent. You can hear the sneeze from the intakes, and the classic tial noise immediately after. You can't deny the video. The sneeze happens up to 1/8th of a second before the bov opens.
TiAL after VTT Inlets

Now here's my conspiracy theory. The reason why I could barely hear my TiAL vent with the stock airbox on was because much of the positive pressure was recirculating all the way back into the airbox. Obviously not all the air because there is still that quiet little bov making its signature noise. Even my friends Tial on his WRX is 10x as loud as any N54 mounted one I've heard.

Why is the Tial so delayed you might ask? Well on our cars, the throttle body pretty much never closes whenever the engine is running. And with just a little critical thinking, if the throttle body is still slightly open, there is still positive pressure entering the intake manifold thus delaying the vacuum reference from properly working as quickly as it should. That's why there are people out there recommending such a light spring, because the lighter the spring, the easier it is for the piston to be actuated.

I have the yellow -11psi spring and a true 1/4 vacuum reference. I'm going to try bumping down to a -7 spring like Terry and few others recommended. @IQraceworks I know you've already tried the -7 but did you change your inlets yet?

 

[nyt]

Reviving this thread because something clicked in my brain and the sneeze started pissing me off again lol

I did a test with the stock box and filter, and what do you know, the noise completely disappeared. Though even at high boost I could barely just barely hear my beautifully normal sounding TiAL.

Watch this video @nyt put up on n54tech and listen to the first vent. You can hear the sneeze from the intakes, and the classic tial noise immediately after. You can't deny the video. The sneeze happens up to 1/8th of a second before the bov opens.
TiAL after VTT Inlets

Now here's my conspiracy theory. The reason why I could barely hear my TiAL vent with the stock airbox on was because much of the positive pressure was recirculating all the way back into the airbox. Obviously not all the air because there is still that quiet little bov making its signature noise. Even my friends Tial on his WRX is 10x as loud as any N54 mounted one I've heard.

Why is the Tial so delayed you might ask? Well on our cars, the throttle body pretty much never closes whenever the engine is running. And with just a little critical thinking, if the throttle body is still slightly open, there is still positive pressure entering the intake manifold thus delaying the vacuum reference from properly working as quickly as it should. That's why there are people out there recommending such a light spring, because the lighter the spring, the easier it is for the piston to be actuated.

I have the yellow -11psi spring and a true 1/4 vacuum reference. I'm going to try bumping down to a -7 spring like Terry and few others recommended. @IQraceworks I know you've already tried the -7 but did you change your inlets yet?

When I converted to ST, the sneeze is gone. I almost miss it lol.

 

[KClemente]

When I converted to ST, the sneeze is gone. I almost miss it lol.

If you still have it, how does the tial sound?

 

[nyt]

If you still have it, how does the tial sound?

Still using it. It's quiet unless higher intake pressure. I also have cams/head work, so a little less intake vac, I think that helps it open faster/more since I can run a lower pressure spring and it won't open at idle.

 

[CantSitStill]

Reviving this thread because something clicked in my brain and the sneeze started pissing me off again lol

I did a test with the stock box and filter, and what do you know, the noise completely disappeared. Though even at high boost I could barely just barely hear my beautifully normal sounding TiAL.

Watch this video @nyt put up on n54tech and listen to the first vent. You can hear the sneeze from the intakes, and the classic tial noise immediately after. You can't deny the video. The sneeze happens up to 1/8th of a second before the bov opens.
TiAL after VTT Inlets

Now here's my conspiracy theory. The reason why I could barely hear my TiAL vent with the stock airbox on was because much of the positive pressure was recirculating all the way back into the airbox. Obviously not all the air because there is still that quiet little bov making its signature noise. Even my friends Tial on his WRX is 10x as loud as any N54 mounted one I've heard.

Why is the Tial so delayed you might ask? Well on our cars, the throttle body pretty much never closes whenever the engine is running. And with just a little critical thinking, if the throttle body is still slightly open, there is still positive pressure entering the intake manifold thus delaying the vacuum reference from properly working as quickly as it should. That's why there are people out there recommending such a light spring, because the lighter the spring, the easier it is for the piston to be actuated.

I have the yellow -11psi spring and a true 1/4 vacuum reference. I'm going to try bumping down to a -7 spring like Terry and few others recommended. @IQraceworks I know you've already tried the -7 but did you change your inlets yet?

I know this is an old thread however I have developed the same noise recently, here is my post from another site asking for help:

Really hoping someone has seen this before and I can help me…

I have been having a strange problem for some time now that I can’t find any information on, maybe because it’s hard to describe or take a recording of. Basically what is happening is when I’m under moderate boost/acceleration at say 20-40mph, if you lift off the pedal quickly (instantly straight off) the car will make a short (split second) cough noise almost like the turbos are stalling (it sounds like someone making a crap fake coughing noise). It does not do it at higher boost levels, and it does not happen all the time.

Now here is what I have tried:

1. Upgrading trial tial BOV with a weaker spring and giving it a bigger vacuum hose tail in the manifold – this helped the bov react quicker but not the noise
2. Adjusting the wastegates – I had tightened these on my old turbos, so I loosened them a bit – this helped a little, but it was still there
3. Upgrading my turbos to 19t’s – wastegates were properly calibrated and noise is still there
4. Upgrading to an RB PCV valve – made no difference but old one was leaking bad
5. Adjusting the base duty cycle (menu 12) on the JB4 – this seems to help/cure but I need to lower the setting way down (to like 1500) so I think its masking the issue rather than it being directly related to the wastegate position
6. Using a different tune (MHD/Wedge custom) – worse with flash only as JB4 settings are not masking the issue

To me it almost sounds like the turbo’s stalling a little in the split second before the BOV reacts, so MAYBE either the throttle body is closing too fast or the wastegates not reacting fast enough for coming off the boost. They need a lack of vacuum (atmosphere) to open the wastegates so im thinking boost solenoids next??

Any advice what to try next welcome, I'm worried about my new turbos now especially if they are stalling



After reading this I realise that it was about the time I fitted the 2 inch inlets it started. As above to me it sounds like the compressor stalling ever so slightly for a split sec. I don't see many posts about it so its maybe something that's triggered by the inlets but not down to them. Maybe a slow throttle body? As in it's not closing off quick enough or reacting ever so slightly slow. That or maybe the wastegates not opening quick enough off throttle so boost solenoids not venting quick enough. Im going to try a different throttle body and report back.

Should also note on my last 335i with inlets this never happened but I had a synapse BOV. I tried a synapse on this 335i and it was worse, which makes sense since the synapse has boost pressure keeping it sealed, so to open it has to over come this. Good for high boost applications, bad for crappy vaccume.

 

[TheFixer]

After I finished my turbo upgrade I've got some odd hooting sounds when driving around lightly. I'll just barely push into the gas to speed up a little and get off it and there's this high pitched wooohooo sound.

Comes from the turbo side.

My kids think it's hilarious.

 

[CantSitStill]

After I finished my turbo upgrade I've got some odd hooting sounds when driving around lightly. I'll just barely push into the gas to speed up a little and get off it and there's this high pitched wooohooo sound.

Comes from the turbo side.

My kids think it's hilarious.

Haha thats the noise! What BOV do you have? Mine was this bad before I went with a lighter spring and a bigger vacuum hose into the BOV. It also helped to make sure the hose tail on the top of a TiAL bov is aligned correctly to allow air to pass without going round the fitting.

 

[TheFixer]

Haha thats the noise! What BOV do you have? Mine was this bad before I went with a lighter spring and a bigger vacuum hose into the BOV. It also helped to make sure the hose tail on the top of a TiAL bov is aligned correctly to allow air to pass without going round the fitting.

I have a turbosmart BOV. I changed springs around to see if that was the issue. Regardless of the spring type it stayed the same.

I think it may be not enough vacuum under light load to pull the plunger up and that creates slight back pressure making the weird sound at the turbos.

Under regular and hard acceleration there is no hooting sound. Just normal spooling and blow off.

 

[CantSitStill]

I have a turbosmart BOV. I changed springs around to see if that was the issue. Regardless of the spring type it stayed the same.

I think it may be not enough vacuum under light load to pull the plunger up and that creates slight back pressure making the weird sound at the turbos.

Under regular and hard acceleration there is no hooting sound. Just normal spooling and blow off.

Yes its the same with me except mine does go off well but right after a split sec of the noise. I have to give it boost and come off the throttle dramatically to get it to do it now. I would try the bigger hose tail in the manifold mod if you have not done it

 

[TheFixer]

Yes its the same with me except mine does go off well but right after a split sec of the noise. I have to give it boost and come off the throttle dramatically to get it to do it now. I would try the bigger hose tail in the manifold mod if you have not done it

I do have the bigger vacuum hose and adapter. I've also measured the vacuum to match the correct spring.

It's weird. Doesn't really bother me as it only happens under light acceleration.

I still have some tuning to do and an upgraded fuel pump to install. So, I'll probably fiddle with the noise issue more after that.

 

[KClemente]

@CantSitStill I can reproduce that sound fairly easily. It’s because it is most likely compressor stall. The best spot to place a bov on our cars is as close to the turbos as possible, so the outlet on the hot side.

When you let off the throttle, the pressure differential between the charge piping and the intake manifold is never 100:0. If you take logs, you can see the dashpot working and damping the throttle body and preventing it from closing fully

And within that split second, the bov doesn’t open fast enough and positive pressure makes its way back to the turbos.

This is one of the fundamental reasons why bmw chose 2 diverter valves for the n54 (able to handle low boost and respond very quickly) and in newer cars, use an electronic diverter valve mounted on the turbo or recirculate all that waste boost efficiently through the engine, keeping the turbo spooled.

 

[KClemente]

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