BOV Setup for your N54

TheFixer

Corporal
Aug 16, 2020
242
128
0
Tennessee
Ride
2008 535i, my wife
I did the orange first. That was the lightest one I have. Stays open. Then purple. Stays open. Blue.... closed, but too stiff. I'm going to try a combo when I get more springs. I'll pick whatever matches my vacuum reading.

Well it is purple (9in hg) and pink (4in hg) for me. I'm running 14 in hg of vacuum. Works fantastic.
 

Mon54ster

Lurker
Aug 15, 2020
18
6
0
Would a stiffer spring and oem nipple at manifold cause the car to not reach boost target? Got a z4 with a turbosmart bov, boost target is 19.5 and only reaching 14psi. No codes for boost leak, boost is constant at 14psi throughout the pull.
 

Mon54ster

Lurker
Aug 15, 2020
18
6
0
What Martymil said. I'd check connections first to see if there's any loose clamps.
Turbos are New upgraded td04 turbos. Forgot to tell. I made a post on troubleshoot, could you guys check the datalog I uploaded there? Had problems reaching boost target on the oem turbos as well 2 weeks before upgrading.
 

Jeffman

Captain
Jan 7, 2017
1,498
549
0
Check for boost leaks. I had similar behavior (Only reaching 15psi, yet targeted 22psi) until I noticed I forgot to install the meth plugs on my new charge pipe LOL! Crazy thing is I drove around for weeks like this:fearscream:

Before: 15psi max boost
8E13586E-8858-4033-B815-23D774E4AF39.jpeg


After: 22psi (What an amazing mod! Haha)
84AE0094-4CC6-4AC7-8293-502F3F2F97F1.jpeg
 

NoQuarter

Major
Nov 24, 2017
1,605
1,003
0
Indiana, USA
Ride
Z4 35is, 535xi, X5 35i
Check for boost leaks. I had similar behavior (Only reaching 15psi, yet targeted 22psi) until I noticed I forgot to install the meth plugs on my new charge pipe LOL! Crazy thing is I drove around for weeks like this:fearscream:

Before: 15psi max boost
View attachment 44167

After: 22psi (What an amazing mod! Haha)View attachment 44168
Thats the kind of upgrade I can fully support!

No error codes with that?
 

TheFixer

Corporal
Aug 16, 2020
242
128
0
Tennessee
Ride
2008 535i, my wife
Thats the kind of upgrade I can fully support!

No error codes with that?

You'd think there would be a low pressure boost code....however at 14 psi maybe it isn't low enough to throw a code.

For mhd its just not reaching target. For the car ecu it's good enough.
 

derekgates

Lieutenant
Feb 23, 2018
727
348
0
NW FL
derekgates.us
Ride
2011 335is
Check for boost leaks. I had similar behavior (Only reaching 15psi, yet targeted 22psi) until I noticed I forgot to install the meth plugs on my new charge pipe LOL! Crazy thing is I drove around for weeks like this:fearscream:

Before: 15psi max boost
View attachment 44167

After: 22psi (What an amazing mod! Haha)View attachment 44168

Damn that will get ya. I've done similar things. I'm shocked the car drove like that!
 

IQraceworks

Specialist
Jul 7, 2020
77
25
0
Missouri
Ride
07' BMW 335i
So I've read through all pages of this thread....but I still have some questions on some recent BOV issues I've been having. I will try to keep this short....I have two main questions.

So...some background. I've been running an MHD OTS stage 2+ E40 tune for 6 months now. I'm still on stock turbos, and I'm running a Tial BOV with the standard 10psi spring. Car runs great, logs look fantastic, no issues. Nice "WOOOOSH" sound when I get out of the throttle and the boost dumps. Very happy with the entire setup. All is good.

Recently I noticed that there was a crack in the flange of the rear oem inlet where it hooks to the turbo. I decided to install some VRSF 1.75" silicone inlets. Install went fine......car runs great, but now I have this horrible screeching parrot/squealing noise every time the BOV dumps pressure. (see attached video).

So...after finding this thread, and seeing some of VCC's suggestions....I swapped the 10psi spring that the Tial BOV came with for the black 7psi spring. It's slightly open at idle (spring can't overcome vacuum from engine), but it sounds like that's not a big deal

So...here are my questions.

1. The screeching parrot sound is still there....even with the 7psi spring in the Tail BOV and new 1/4" ID line going to it from the BMS adapter. What can I do to get rid of that horrible sound? Is that just a product of the silicon inlets? If so, why?

2. With the lighter spring, I'm getting what sounds like BOV flutter at low rpm/low load/low boost situations.....it's annoying. I never had this with the 10psi spring. What's causing this?

WOT logs still look great, car runs great, no issues at all....just some flutter at mid boost, and the hoot-owl sound from the BOV that's embarrassing.

Any advice would be a huge help!! Thanks!


 

NoQuarter

Major
Nov 24, 2017
1,605
1,003
0
Indiana, USA
Ride
Z4 35is, 535xi, X5 35i
The sound is definitely coming out of the blow off valve? You are able to cause this while reving and sitting still?
 

TheFixer

Corporal
Aug 16, 2020
242
128
0
Tennessee
Ride
2008 535i, my wife
So I've read through all pages of this thread....but I still have some questions on some recent BOV issues I've been having. I will try to keep this short....I have two main questions.

So...some background. I've been running an MHD OTS stage 2+ E40 tune for 6 months now. I'm still on stock turbos, and I'm running a Tial BOV with the standard 10psi spring. Car runs great, logs look fantastic, no issues. Nice "WOOOOSH" sound when I get out of the throttle and the boost dumps. Very happy with the entire setup. All is good.

Recently I noticed that there was a crack in the flange of the rear oem inlet where it hooks to the turbo. I decided to install some VRSF 1.75" silicone inlets. Install went fine......car runs great, but now I have this horrible screeching parrot/squealing noise every time the BOV dumps pressure. (see attached video).

So...after finding this thread, and seeing some of VCC's suggestions....I swapped the 10psi spring that the Tial BOV came with for the black 7psi spring. It's slightly open at idle (spring can't overcome vacuum from engine), but it sounds like that's not a big deal

So...here are my questions.

1. The screeching parrot sound is still there....even with the 7psi spring in the Tail BOV and new 1/4" ID line going to it from the BMS adapter. What can I do to get rid of that horrible sound? Is that just a product of the silicon inlets? If so, why?

2. With the lighter spring, I'm getting what sounds like BOV flutter at low rpm/low load/low boost situations.....it's annoying. I never had this with the 10psi spring. What's causing this?

WOT logs still look great, car runs great, no issues at all....just some flutter at mid boost, and the hoot-owl sound from the BOV that's embarrassing.

Any advice would be a huge help!! Thanks!



My tial knock off sounded like that. I have a Turbosmart now and it sounds alot better.
 

doublespaces

Administrator
Oct 18, 2016
9,050
4,158
0
AZ
Ride
2009 E93 335i
2. With the lighter spring, I'm getting what sounds like BOV flutter at low rpm/low load/low boost situations.....it's annoying. I never had this with the 10psi spring. What's causing this
Do you have a log of this exact instance? That would help narrow down the reasons.

Here is another thread that talks about this same problem: https://www.spoolstreet.com/threads/compressor-surge-flutter-16t-hybrids.6836/

The consensus there is this is caused by a tuning issue. I think you said you're using OTS maps, so perhaps you need a custom tune?
 

IQraceworks

Specialist
Jul 7, 2020
77
25
0
Missouri
Ride
07' BMW 335i
The sound is definitely coming out of the blow off valve? You are able to cause this while reving and sitting still?
Nope....only does it when the turbos build boost and the BOV opens and dumps it. I can't get it to do it when just reving the motor.
 

IQraceworks

Specialist
Jul 7, 2020
77
25
0
Missouri
Ride
07' BMW 335i
Do you have a log of this exact instance? That would help narrow down the reasons.

Here is another thread that talks about this same problem: https://www.spoolstreet.com/threads/compressor-surge-flutter-16t-hybrids.6836/

The consensus there is this is caused by a tuning issue. I think you said you're using OTS maps, so perhaps you need a custom tune?

Honestly, the BOV flutter concerns me less than the horrible noise the BOV is making. If I put the slightly heavier BOV spring in (10psi), the flutter goes away. It's not compressor flutter. The car ran great with the heavier 10psi spring in the BOV.....it opened with just a slight about of pedal input and decrease in vacuum. This lighters 6-7psi black spring is wide open and idle, and technically...it's to light. I could probably try shimming it a bit to get it just slightly closed at idle. Who knows, a little more pressure on the spring might get rid of the fluttering also.

That horrible screeching sound from the BOV is what I really hate.....