Squeal when adding OEM PCV flapper

pysical

Sergeant
Jun 16, 2017
461
107
0
Ride
2009 335xi E90
I have the VTT billet valve cover and dual catch can setup and this is my current setup:


except I am not using the breather.

I removed the filter from the high side catch can and ran a line to my turbo inlet. In line, I added the pcv flapper. Since doing that I get a squeal when idling. Should I run it without the flapper? I was trying to put it back to as close to the RB/BMS setup I had on the stock valve cover since I think I am experiencing some turbo oil drain issues. My bottom mount single drain has some oil buildup around it.
 

Tuppidsay

Corporal
Aug 3, 2017
115
63
0
Seattle, WA
Ride
2008 535i
best bet is to restrict the line from the manifold or remove the flaper. Either options will work but restricting the vacuum line will stop issues with what is essentially a "vacuum" leak. Tuning can overcome that if u want to just delete the flapper. I run the same vtt system but without the aftermarket cover without a flapper valve. been fine for 75k miles
 

pysical

Sergeant
Jun 16, 2017
461
107
0
Ride
2009 335xi E90
best bet is to restrict the line from the manifold or remove the flaper. Either options will work but restricting the vacuum line will stop issues with what is essentially a "vacuum" leak. Tuning can overcome that if u want to just delete the flapper. I run the same vtt system but without the aftermarket cover without a flapper valve. been fine for 75k miles
What do you mean by restrict? I removed the flapper and so it goes VC -> CC -> Inlet.
 

Tuppidsay

Corporal
Aug 3, 2017
115
63
0
Seattle, WA
Ride
2008 535i
Your post said you installed the pcv flapper and got a squel. That's caused by too much vacuum in the crank case. It's literally air being drawn in around the crankshaft seals. Either remove the flapper (may cause not enought vacuum at idle, ie turbo drainage issues) or leave the flapper and lower the amount of vaccum to the crankcase by restricting the vacuum hose from the manifold to the catch can. This problem is why VTT came out with the vaccum relief valve accessory. I personally run the vtt setup with no flapper and it's fine but I have a factory cover and twins. I have a client that is single with the bms/rb setup with the flapper and hasn't had issue either. Your mileage may very. Id suggest getting yourself a cheap manometer, making an oil filter cap adapter, install the flapper, and then "tune" the amount of crankcase vacuum to near stock levels via restricting orafices inserted into the manifold vaccum line to the catch can. OR buying the vtt vacuum releaf valve that vtt sells and adjust it to where you get the stock levels of crankcase vacuum.

Good Luck
 

TheLittleOne

New Member
Apr 26, 2020
1
0
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30 Jahre M3
Your post said you installed the pcv flapper and got a squel. That's caused by too much vacuum in the crank case. It's literally air being drawn in around the crankshaft seals. Either remove the flapper (may cause not enought vacuum at idle, ie turbo drainage issues) or leave the flapper and lower the amount of vaccum to the crankcase by restricting the vacuum hose from the manifold to the catch can. This problem is why VTT came out with the vaccum relief valve accessory. I personally run the vtt setup with no flapper and it's fine but I have a factory cover and twins. I have a client that is single with the bms/rb setup with the flapper and hasn't had issue either. Your mileage may very. Id suggest getting yourself a cheap manometer, making an oil filter cap adapter, install the flapper, and then "tune" the amount of crankcase vacuum to near stock levels via restricting orafices inserted into the manifold vaccum line to the catch can. OR buying the vtt vacuum releaf valve that vtt sells and adjust it to where you get the stock levels of crankcase vacuum.

Good Luck
Hey man Im trying to run the same setup as you but im having trouble. Im trying to use the VTT dual cans with the stock valve cover stock twins recirculating into the inlet. I set everything up and the car is idling super rough with a couple vacuum codes. Was wondering if you had the same problems and how you fixed it.
 

pysical

Sergeant
Jun 16, 2017
461
107
0
Ride
2009 335xi E90
Your post said you installed the pcv flapper and got a squel. That's caused by too much vacuum in the crank case. It's literally air being drawn in around the crankshaft seals. Either remove the flapper (may cause not enought vacuum at idle, ie turbo drainage issues) or leave the flapper and lower the amount of vaccum to the crankcase by restricting the vacuum hose from the manifold to the catch can. This problem is why VTT came out with the vaccum relief valve accessory. I personally run the vtt setup with no flapper and it's fine but I have a factory cover and twins. I have a client that is single with the bms/rb setup with the flapper and hasn't had issue either. Your mileage may very. Id suggest getting yourself a cheap manometer, making an oil filter cap adapter, install the flapper, and then "tune" the amount of crankcase vacuum to near stock levels via restricting orafices inserted into the manifold vaccum line to the catch can. OR buying the vtt vacuum releaf valve that vtt sells and adjust it to where you get the stock levels of crankcase vacuum.

Good Luck
I just wasn't sure why adding the flapper would cause it when it didn't do it with the stock valve cover. The setup was the same.

Stock:
VC -> Flapper ->CC -> Turbo Inlet

VTT:
VC -> CC -> Flapper -> Turbo Inlet
 

Tuppidsay

Corporal
Aug 3, 2017
115
63
0
Seattle, WA
Ride
2008 535i
The adapters to connect the factory valve cover and the internal passages provide enough vacuum restriction to keep things happy. One of the advantages to the aftermarket covers is the larger more free flowing connections for pcv operation. Thus more vacuum getting to the crank case. This is great for during boost and situations that would cause high crankcase pressure. But creates more work when trying to implement a vacuum and pressure type system like factory.
 
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pysical

Sergeant
Jun 16, 2017
461
107
0
Ride
2009 335xi E90
The adapters to connect the factory valve cover and the internal passages provide enough vacuum restriction to keep things happy. One of the advantages to the aftermarket covers is the larger more free flowing connections for pcv operation. Thus more vacuum getting to the crank case. This is great for during boost and situations that would cause high crankcase pressure. But creates more work when trying to implement a vacuum and pressure type system like factory.
Thanks. I think I am going to go back to the stock valve cover and RB/BMS catch can setup. This VTT shit has been nothing but oil leaks, oil consumption, and 2D2E. I had no issues with the stock cover.
 
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