[335boston]

Hello all! Have had this question o not mind ever since I did the m3 cowl mod on my n54 ever since the mod the turbo noise and induction sounds from the dci increased dramatically and the car actually sounds twin turboed lol. ! But what also was louder was the blow off of the dv. On wide open throttle the dvs will work perfectly and just give that nice "pshhh" sound to recirculate the air . But on medium throttle the car with actually flutter , not to the extent of say a Supra or r34 skyline but you can definitely hear it . My question is through all my research everyone uses the stock dvs and have no issues but I haven't herd anyone talk about this semi flutter action I'm getting . Wondering if anyone had gone through this and what they did about it !

[nicky dj]

Originally Posted by 335boston

Hello all! Have had this question o not mind ever since I did the m3 cowl mod on my n54 ever since the mod the turbo noise and induction sounds from the dci increased dramatically and the car actually sounds twin turboed lol. ! But what also was louder was the blow off of the dv. On wide open throttle the dvs will work perfectly and just give that nice "pshhh" sound to recirculate the air . But on medium throttle the car with actually flutter , not to the extent of say a Supra or r34 skyline but you can definitely hear it . My question is through all my research everyone uses the stock dvs and have no issues but I haven't herd anyone talk about this semi flutter action I'm getting . Wondering if anyone had gone through this and what they did about it !

My experience is depends on how much boost you're pushing. If I switch maps to be conservative say 10- psi my bov flutters. 15+ psi and up it swooshes top. My bro's subi with DV's flutters all the time.

[Jeff@TopGearSolutions]

Do people still use stock DV? JK

It seems normal if you are not releasing full boost through them.

[Bimmer_Bro]

Its normal to hear a little bit of flutter on medium throttle or whatever. Some throttle positions might be on the edge of boost vs vacuum hence the flutter sound.
If you are tuned at all, honestly get rid of those plastic junk BOVs. They are the worst.

[335boston]

Thanks everyone for the reply's! I've been trying to get my hands on some turbo smart diverters for months but not manny people seem to have them on the forums lol. Herd some nightmares about the forge dvs and that they require maintenance every so often from them to run properly . Are these my only 2 options ? Don't want to go BOV at all as I don't really think I want the sound lol . Thanks again everyone !

[nicky dj]

Originally Posted by 335boston

Thanks everyone for the reply's! I've been trying to get my hands on some turbo smart diverters for months but not manny people seem to have them on the forums lol. Herd some nightmares about the forge dvs and that they require maintenance every so often from them to run properly . Are these my only 2 options ? Don't want to go BOV at all as I don't really think I want the sound lol . Thanks again everyone !

Get a Tial BOV very subtle sound compared to a Synapse or HKS. Can't even hear it boost under 10psi.

[dpaul]

Originally Posted by Jeff@TopGearSolutions

Do people still use stock DV? JK

Yes. DPs, intercooler, inlets/outlets, PE exhaust and custom tune with stock turbos at 20psi peak on 93 octane but still running the original 2009 plastic chargepipe and plastic BVs. I've been waiting for 7 years for them to explode or malfunction in some way but they continue to work perfectly.

[studio54]

Originally Posted by dpaul

Yes. DPs, intercooler, inlets/outlets, PE exhaust and custom tune with stock turbos at 20psi peak on 93 octane but still running the original 2009 plastic chargepipe and plastic BVs. I've been waiting for 7 years for them to explode or malfunction in some way but they continue to work perfectly.

Yes i was surprised, I just swapped Forge DV with stock DV to make some maintenance on the Forge ones (service kit). Did not noticed any difference in logs (~18 psi).

So people should not throw them or qualify them as shit, it works quite good !

[Bimmer_Bro]

Just because you are still hitting your boost target does not mean the stockers are working good. At 18 psi they are most likely still leaking. Your turbos are probably just working a little harder to keep the boost at 18 psi. So yes you may not be losing power, but you may be working your turbos a little harder than needed. I admit I ran them
For a long time too but glad I upgraded.

I was worried about Forge Dvs also when I was shopping around. Ended up going with the forge anyway because I got a great deal. They have worked perfectly running stage 2+. They are so simple to service too. ( I haven’t had to yet). The top cap screws off and easy to lube internals up.

I run mine venting to atmosphere with some small breather filters to keep dust and such out. Capped off the original return holes. Sounds awesome !

[studio54]

Originally Posted by Bimmer_Bro

Just because you are still hitting your boost target does not mean the stockers are working good. At 18 psi they are most likely still leaking. Your turbos are probably just working a little harder to keep the boost at 18 psi. So yes you may not be losing power, but you may be working your turbos a little harder than needed. I admit I ran them
For a long time too but glad I upgraded.

I was worried about Forge Dvs also when I was shopping around. Ended up going with the forge anyway because I got a great deal. They have worked perfectly running stage 2+. They are so simple to service too. ( I haven’t had to yet). The top cap screws off and easy to lube internals up.

I run mine venting to atmosphere with some small breather filters to keep dust and such out. Capped off the original return holes. Sounds awesome !

Hehe cool, you made some home made Blow off with Forge DVs, i wanted to do it too

I agree but i watched WGDC on logs, and it's the same, so i do not think turbos are working harder. The OEM DV have probably more chances to leak if you are still using the stock chargepipe cause stock connectors (grey/black plastics) are maybe a weakness. With a metal chargepipe with tight silicone couplers should be fine.

[Bimmer_Bro]

Originally Posted by studio54

Hehe cool, you made some home made Blow off with Forge DVs, i wanted to do it too

I agree but i watched WGDC on logs, and it's the same, so i do not think turbos are working harder. The OEM DV have probably more chances to leak if you are still using the stock chargepipe cause stock connectors (grey/black plastics) are maybe a weakness. With a metal chargepipe with tight silicone couplers should be fine.

Haha thanks! It definitely on the louder side lol.
Sounds like your Dvs held up better than mine did! Yes those plastic connections suck!

[studio54]

Originally Posted by Bimmer_Bro

Haha thanks! It definitely on the louder side lol.
Sounds like your Dvs held up better than mine did! Yes those plastic connections suck!

Yeah it must sounds good Can you mention the size for those small filters ?

Yes the stock ones can probably fail with time. I just run them temporarly now because i want to service my Forge DVs (i ran them for 2 years now without servicing them). I will certainly order one these service kit soon that Forge are selling.

[Bimmer_Bro]

Originally Posted by studio54

Yeah it must sounds good Can you mention the size for those small filters ?

Yes the stock ones can probably fail with time. I just run them temporarly now because i want to service my Forge DVs (i ran them for 2 years now without servicing them). I will certainly order one these service kit soon that Forge are selling.

I believe the filters have a 1 inch opening (flange). The breather filters seem to be mostly the same size, just the connection size varies. Found them on amazon.

[studio54]

Originally Posted by Bimmer_Bro

I believe the filters have a 1 inch opening (flange). The breather filters seem to be mostly the same size, just the connection size varies. Found them on amazon.

Okay thanks, i will probably order them (and plugs) at the same time i order the Forge service kit. It will avoid the Forge DVs to spray some oil in the engine bay.

[Bimmer_Bro]

Originally Posted by studio54

Okay thanks, i will probably order them (and plugs) at the same time i order the Forge service kit. It will avoid the Forge DVs to spray some oil in the engine bay.

Nothing has ever leaked out of mine. I was more worried about dirt getting in there . Don’t forget to cap off the old return holes. You will
Need 1 inch rubber caps as well.

[studio54]

Originally Posted by Bimmer_Bro

Nothing has ever leaked out of mine. I was more worried about dirt getting in there . Don’t forget to cap off the old return holes. You will
Need 1 inch rubber caps as well.

Yes plugs are mandatory

If i understand correctly, and if DVs are not failing, it should not suck dirts from here cause it's meant to blow off the pressure on let off, it's more to filter some oil that will be spray when you went to atmosphere. Anyway thanks for your informations, i will probably make a setup like yours for sounding fun

[Bimmer_Bro]

Originally Posted by studio54

Yes plugs are mandatory

If i understand correctly, and if DVs are not failing, it should not suck dirts from here cause it's meant to blow off the pressure on let off, it's more to filter some oil that will be spray when you went to atmosphere. Anyway thanks for your informations, i will probably make a setup like yours for sounding fun

Yes exactly. I was thinking it would probably be a safe way to keep dust out of the DV even tho that’s the exhale side. Give it a try! Sounds cool.

[bimmerguy1210]

I hear whoosh sounds constantly with stock dv’s after swapping to BMS cowl filters. Made my desire for an aftermarket bov go away.

[studio54]

Originally Posted by bimmerguy1210

I hear whoosh sounds constantly with stock dv’s after swapping to BMS cowl filters. Made my desire for an aftermarket bov go away.

Yeah when you take out the main engine cowl you can hear more engine bay sound and it sounds good.
But remember that the cowl is here for a thing, personnaly i prefer to run the stock cowl cause there is some air pressure at the windshield base at speed, and i am not sure it's a benefit to run without it for IATs.

Honnestly i am not a big fan of the DCI + Cowl filters setup, it's a thing made by sellers to sell more DCI and cowl filters, i tested both DCI and stock air box with no difference in logs, and moreover, i found the car more smooth with the stock airbox than with DCI in low RPM and trust me i am a maniac. I tend to believe it's only business.

All sellers are saying "throw away stocks DVs", "airbox can't handle the PSI if you are tuned" "your chargepipe will break" etc etc honnestly i just trust in downpipe and upgraded intercooler, the rest for me is not true cause i tested it by my self with a lot of logs.

[Julian2485]

I believe if anyone has leaking oem dvs just change the orings with slightly bigger ones and all should be fine.

[335boston]

How would someone know if their stock dv's are leaking at higher boost levels such as 18 psi? Someone mentioned wastegate duty cycles but Is there a base number I should go off of ? I have the jb4 and have many logs to see but confused at how to compare .

Also that serviceable o-ring , is that the main cause for the "leak" at higher boost levels or is it an internal problem where the dv won't seal at the high boost level ? I have a Cobb charge pipe with the silicone adapters for the dv's so atleast that takes care of one potential problem! Thanks everyone for posting !

[streetpro]

I had oem DVs that looked fine (I could make them move with my mouth vacuum easily, no diaphragm was torn) however after replacing them w Forge´s the engine pulls way harder, boost builds smother and sooner...