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  335i Free BOV DIY
Red Star Rising
04-06-2007
Since Active Autowerke insists that their BOV is worth $750, I think this little DIY is great. Not extremely loud. But noticible, and nice. Member JOEVISTA clued me in on exactly how to do it. Thanks!
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  #66  
By teknochild on 04-07-2007, 09:13 PM
Quote:
Originally Posted by ///Matt View Post
If you say so. What do I know?
i think one of the points hes trying to make is that the aim of this is for people who want a BOV but dont want to spend the money, and since it has the same effect as a BOV mechanically that theres no reason for your stance

dont get me wrong im against BOVs on these cars and i agree that they shouldnt be installed, but your targeting this independantly of the BOV, syaing get the BOV instead, even though everything you have said has applied to them aswell

i think you could call the hypocrisy
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  #67  
By Raider on 04-07-2007, 09:15 PM
Hhaah that dont' sound too bad at all...
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  #68  
By Edman951 on 04-07-2007, 09:30 PM
Using stock diverter valves as BOV doesn't work.
Why you ask.

The dump side stays open when under vacuum.
So when you drive DIRTY unfiltered air goes into your motor via the dump tube tru the diverter valve.
BIG NO NO.

Didn't you notice the vacuum suckting on the pipe you disconnected?
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  #69  
By boostedtwin on 04-07-2007, 09:36 PM
M3to335 - Free some space for PM's...
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  #70  
By teknochild on 04-07-2007, 09:40 PM
Quote:
Originally Posted by Edman951 View Post
Using stock diverter valves as BOV doesn't work.
Why you ask.

The dump side stays open when under vacuum.
So when you drive DIRTY unfiltered air goes into your motor via the dump tube tru the diverter valve.
BIG NO NO.

Didn't you notice the vacuum suckting on the pipe you disconnected?


you do realize that whats in every car is the same thing as a BOV it just sends the air back to the intake rather then outside right? it does not "suck" air in from that tube
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  #71  
By Edman951 on 04-07-2007, 10:00 PM
Not true Teknochild.

A BOV has a stronger spring so the valve doesn't open under vacuum.

A diverter valve is design to run open to help bypass the turbo when its not spooled yet. Making the motor work less at low rpm to get air into the motor.
Once on boost the valve is closed untill the vacuum is released when you get of the throttle.
The diverted valve open under vacuum, and the small spring inside it help it stay closed under boost.

Just undo the return tube and see for your self.
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  #72  
By teknochild on 04-07-2007, 10:31 PM
that doesnt make sense, even at idle the turbo will be spooled enough to eliminate the manifold vacuum, and if not, theres no way that the hugly small vacuum present would lift the spring unless it was so light that, i cant imagine it would ever close
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  #73  
By Walked U on 04-07-2007, 10:36 PM
Dude thats pretty fucking good hahaha.

Good job meltdown
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  #74  
By Red Star Rising on 04-07-2007, 10:45 PM
Quote:
Originally Posted by Walked U View Post
Dude thats pretty fucking good hahaha.

Good job meltdown
Haha you know me from E46!!!

Its too bad the camera doesn't really catch the BOV as much as just engine noise....

The pressurized side of the intake does not suck in air through the diverter valve. It only feeds excess pressure to the pre-compression side. The valve is triggered by a vacuum line from the manifold/TB. I have checked it and it never sucks air in.Any suction would be coming from the pre compression intake ducts. That is why when you disconnect the diverter valve hose, you must cap those plugs. Its all explained on page 1.
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  #75  
By boostedtwin on 04-07-2007, 10:47 PM
Red Star Rising - I sent you a Pm.
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  #76  
By Edman951 on 04-07-2007, 10:51 PM
Quote:
even at idle the turbo will be spooled enough to eliminate the manifold vacuum,
,

Teknochild
Don't take this the wrong way.
But you really don't know much about how a motor works do you???

A motor canot run without vacuum.
At idle any car, and the 335 runs at about 18 inch of vacuum.
Thats more then enogh to open the valve.
The car will always run under vacuum until you creat enough load to build boost.

See this video i did back in December.
Notice the vacuum my car has will driving.
Then I push in the clutch and rev it out to hear the HKS BOV.
0 boost is at the 11:30 positin on the gauge. And 20 inch of vacuum at 9:00.



Just go pop the hood on you 335, undo the return tube from the diverter valve and see for yourself instead of saying thing you don't know.
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  #77  
By Edman951 on 04-07-2007, 10:57 PM
Red Star,
I wasn't refering the the turbo inlet side.

Double check it by using a paper to see if the diverter valve is sucking in air under vacuum..
You will be suprized.
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  #78  
By lkraven on 04-07-2007, 11:01 PM
While you're at it, you can tape one of these to the valve:

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  #79  
By Red Star Rising on 04-07-2007, 11:04 PM
Quote:
Originally Posted by Edman951 View Post
,

Teknochild
Don't take this the wrong way.
But you really don't know much about how a motor works do you???

A motor canot run without vacuum.
At idle any car, and the 335 runs at about 18 inch of vacuum.
Thats more then enogh to open the valve.
The car will always run under vacuum until you creat enough load to build boost.

See this video i did back in December.
Notice the vacuum my car has will driving.
Then I push in the clutch and rev it out to hear the HKS BOV.
0 boost is at the 11:30 positin on the gauge. And 20 inch of vacuum at 9:00.



Just go pop the hood on you 335, undo the return tube from the diverter valve and see for yourself instead of saying thing you don't know.
The diverter valve opens with vacuum dependent on the pre compression intake duct. Why would the valve OPEN with a post compression vacuum situation? You would not be able to build up pressure again with the valve open. The point of a valve is for it to open only one way.
I have checked it and at idle, its blowing out just a tiny bit. I'll film it for you tomorrow if you like.
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  #80  
By boostedtwin on 04-07-2007, 11:14 PM
Red Star - Do you want to test a TT?
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  #81  
By teknochild on 04-07-2007, 11:18 PM
Quote:
Originally Posted by Edman951 View Post
,

Teknochild
Don't take this the wrong way.
But you really don't know much about how a motor works do you???

A motor canot run without vacuum.
At idle any car, and the 335 runs at about 18 inch of vacuum.
Thats more then enogh to open the valve.
The car will always run under vacuum until you creat enough load to build boost.

See this video i did back in December.
Notice the vacuum my car has will driving.
Then I push in the clutch and rev it out to hear the HKS BOV.
0 boost is at the 11:30 positin on the gauge. And 20 inch of vacuum at 9:00.



Just go pop the hood on you 335, undo the return tube from the diverter valve and see for yourself instead of saying thing you don't know.

you seem to be confusing idle with, driving along with no throttle.... nowhere in that video are you at idle, you have vacuum because the engine is spinning with the throttle body closed (you took your foot off the gas)


dont put words in my mouth, i never said an engine doesnt develop vacuum, i said at idle there is most likely none, and by that i meant there is not less pressure on one side of the spring then the other, and if there is it would not be enough to lift it no matter how light it was

idle = open throttle body = close to equal vacuum on both sides of the spring, no lift

getting off throttle = vacuum on manifold side = ifted spring = diverter open = doesnt matter because there is positive pressure



once the throttle body is opened (idle) it does not matter if vacuum is created, it will not effect anything since it will be present on both sides of the spring, and if the throttle body is closed and the vacuum is presentm sur ethe spring will lift like normal, but its not going to suck air in on the exit line, because the vacuum isnt on that side of the throttle body
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  #82  
By itsbrokeagain on 04-07-2007, 11:20 PM
Quote:
Originally Posted by Edman951 View Post
Not true Teknochild.

A BOV has a stronger spring so the valve doesn't open under vacuum.

A diverter valve is design to run open to help bypass the turbo when its not spooled yet. Making the motor work less at low rpm to get air into the motor.
Once on boost the valve is closed untill the vacuum is released when you get of the throttle.
The diverted valve open under vacuum, and the small spring inside it help it stay closed under boost.

Just undo the return tube and see for your self.

+1. You make perfect sense my friend. Second Generation DSMs run the same BOVs as we do, and Im assuming by your name you have or do own a 951. I used to have one as well, and the cheapo BOVs (same ones we have) stay open at idle, and will stay open under vacuum until it hits 0, or goes positive.

I dont understand why dont people just make some pipe and attach a BOV and flange to it and call it a day. THAT DIY would still be cheap as well.
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  #83  
By Edman951 on 04-07-2007, 11:27 PM
Correct,I have a Porsche 944T (951) its making over 400whp.
Factory It uses the same DV as the 335. Just 1 doo.
Happy to see you get how it works to.
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  #84  
By teknochild on 04-07-2007, 11:28 PM
Quote:
Originally Posted by lkraven View Post
While you're at it, you can tape one of these to the valve:

too expensive, like i said cut up straw, or the opening of a baloon
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  #85  
By Edman951 on 04-07-2007, 11:47 PM
Teknochild,
I'm always refereng to manifold vacuum and pressure.

Vacuum is always present, unless overcome by the boost.

I have another video from idle and reving in the garage.
I will load it on youtube and post it when its available.

You will see how much vacuum is present unless boost is built.

Good night
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  #86  
By Edman951 on 04-08-2007, 12:15 AM
OK its loaded, here's that video,


Since that gauge readying aint so good.
From left to righ
It start at the bottom at 30 inch vacuum, then 20, 10. and 0 at the 11:30position, then 5,10,15 and 20 psi all the way right.
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  #87  
By teknochild on 04-08-2007, 12:18 AM
Quote:
Originally Posted by Edman951 View Post
Teknochild,
I'm always refereng to manifold vacuum and pressure.

Vacuum is always present, unless overcome by the boost.

I have another video from idle and reving in the garage.
I will load it on youtube and post it when its available.

You will see how much vacuum is present unless boost is built.

Good night
your missing the point, it does not matter if their is a vacuum in the manifold; during idle the TB is OPEN both sides of the spring occupy the same pressure zone, there would be no forces on the spring

edit: and dont tell me that theres a pressure diffrence because the throttle body is a restrictive point either because then the spring would load under boost; and leak boost (to clarify, understand there would be a diffrence, but for the spring to open under that diffrence it would also have to open under boost)

also another quick pre-empt, dont try and say the throttle body is partially closed during idle because thats not true either


did YOU ever do your little paper test?


if you can give me some other reason to believe that the spring would be loaded i will go pull off the hose myself and check
Last edited by teknochild; 04-08-2007 at 01:39 AM.
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