oem dv leaking at idle

hawkm3 · 01-18-2015, 09:16 PM

Hey guys, I'm running oem DV vent to atmosphere and I've noticed that at start up and idle they are blowing air, at start up its bad to the point where it feels like a fan and then when the car warms it they leak, if you put your hand you can barely feel it. Here's a picture with a shop towel that I placed in the front, you can see where the towel is being blown compared to the right side. Is this normal or did I damage them running higher boost.

https://flic.kr/p/qRDLzr

hawkm3 · 01-19-2015, 01:03 PM

Anyone?

Dackelone · 01-19-2015, 01:23 PM

I bet your vacuum res lines are melts near the valve cover/solenoids area.

hawkm3 · 01-19-2015, 07:29 PM

Check them and nope

Pig Farmer · 01-19-2015, 08:23 PM

Are you sure it is not the intake sucking air? If you put a small amount soapy water on the DV plug can you see bubbles?

Miko226 · 01-19-2015, 09:08 PM

Quote:

Originally Posted by Pig Farmer

Are you sure it is not the intake sucking air? If you put a small amount soapy water on the DV plug can you see bubbles?

+1

hawkm3 · 01-19-2015, 10:17 PM

Quote:

Originally Posted by Pig Farmer

Are you sure it is not the intake sucking air? If you put a small amount soapy water on the DV plug can you see bubbles?

Which plug exactly? Also if it was sucking air, why when I put a paper or small towel it blows out rather than suck in? Because at start up it blows like a damn fan haha

Pig Farmer · 01-20-2015, 06:45 AM

Quote:

Originally Posted by Ralph1M

Which plug exactly? Also if it was sucking air, why when I put a paper or small towel it blows out rather than suck in? Because at start up it blows like a damn fan haha

I may have viewed the picture wrong. If you're venting to atmosphere, you need to cap the hole where the flex tube from the DVs plug into the recirculation plumbing. I assumed you felt the air rushing out of those holes. Is the air coming out of the DVs?

hawkm3 · 01-20-2015, 09:54 AM

Those holes are plugged, both of them, and yes the air is coming out if the dvs, I can feel it on both of them at start up and idle, unless they were to close when I hit bpost and then open up when I let off?

e82passion · 01-20-2015, 07:43 PM

Perhaps a video would help illustrate your problem better?

e36addict · 01-21-2015, 07:36 AM

Quote:

Originally Posted by Ralph1M

Those holes are plugged, both of them, and yes the air is coming out if the dvs, I can feel it on both of them at start up and idle, unless they were to close when I hit bpost and then open up when I let off?

Engine is sitting in a vacuum state at idle, so it's normal for them to be pulled open at idle. Once you get on the throttle at all they should seal right up. Completely normal. I was concerned about this with the BOV on my M3, until I put all the pieces together and it makes sense.

hawkm3 · 01-21-2015, 02:14 PM

Quote:

Originally Posted by e82passion

Perhaps a video would help illustrate your problem better?

Lol didn't think of that

hawkm3 · 01-21-2015, 02:15 PM

Quote:

Originally Posted by e36addict

Engine is sitting in a vacuum state at idle, so it's normal for them to be pulled open at idle. Once you get on the throttle at all they should seal right up. Completely normal. I was concerned about this with the BOV on my M3, until I put all the pieces together and it makes sense.

I've read that before but I don't remember if it was true or not, that's why I had asked

Pig Farmer · 01-21-2015, 05:21 PM

^
The fact the manifold is in a state of vacuum is what has me puzzled? I would expect to feel air being sucked into the open DVs. I may have to pull my DV hose this weekend and see if it blows air at cold start-up.

hawkm3 · 01-21-2015, 05:50 PM

Quote:

Originally Posted by Pig Farmer

^
The fact the manifold is in a state of vacuum is what has me puzzled? I would expect to feel air being sucked into the open DVs. I may have to pull my DV hose this weekend and see if it blows air at cold start-up.

However one thing that would make sense is that they are open and im feeling the air from the turbos spinning at idle, because at cold start they blow alot! (I.e because the turbos are spinning faster) can you try it and let me know

hawkm3 · 01-21-2015, 05:51 PM

Still kinda confused tho!

e36addict · 01-21-2015, 08:29 PM

Quote:

Originally Posted by Ralph1M

However one thing that would make sense is that they are open and im feeling the air from the turbos spinning at idle, because at cold start they blow alot! (I.e because the turbos are spinning faster) can you try it and let me know

Yep. Intake is pulling vacuum on the diverter diaphragm, thus opening it. Air from the turbos blowing into the throttle is escaping through the valves..

hawkm3 · 01-21-2015, 09:03 PM

Quote:

Originally Posted by e36addict

Yep. Intake is pulling vacuum on the diverter diaphragm, thus opening it. Air from the turbos blowing into the throttle is escaping through the valves..

Wait no, because the way diveter valves open is when boost forces them to open after boost can't go into the TB, thus oping the valve, if vacuum is opening them up, how is that working since the valve can't be opened from sucking the valve in, that wouldn't make no sense because how would the air be going out yet have enough vacuum to open the valve up

e36addict · 01-21-2015, 09:37 PM

Quote:

Originally Posted by Ralph1M

Wait no, because the way diveter valves open is when boost forces them to open after boost can't go into the TB, thus oping the valve, if vacuum is opening them up, how is that working since the valve can't be opened from sucking the valve in, that wouldn't make no sense because how would the air be going out yet have enough vacuum to open the valve up

Any time you let off throttle, there's a vacuum in the intake. This is what opens the diverter valves. Simple as that.

hawkm3 · 01-21-2015, 10:13 PM

Quote:

Originally Posted by e36addict

Any time you let off throttle, there's a vacuum in the intake. This is what opens the diverter valves. Simple as that.

hmm? boost pressure is what opens them up, when boost needs to escape it is either shot out or recirculated back into the intake, or i am wrong, unless a dv works differently than a bov

Pig Farmer · 01-21-2015, 10:50 PM

When you lift off the throttle, the throttle plate shuts but the engine still acts as an air pump creating suction (i.e a vacuum in the space between the back of the throttle plate and manifold). This vacuum opens the DV. Since the turbos are still spinning and creating boost, the open DVs allows the boost to recirculate through the intake system or in your case vent to atmosphere. If the DVs did not open, the boost would slam into the face of the closed throttle plate and cause a pressure wave to bounce back against the turbos' compressor wheels causing them to slow or even stop. This can seriously damage the turbos.

hawkm3 · 01-22-2015, 02:18 AM

Quote:

Originally Posted by Pig Farmer

When you lift off the throttle, the throttle plate shuts but the engine still acts as an air pump creating suction (i.e a vacuum in the space between the back of the throttle plate and manifold). This vacuum opens the DV. Since the turbos are still spinning and creating boost, the open DVs allows the boost to recirculate through the intake system or in your case vent to atmosphere. If the DVs did not open, the boost would slam into the face of the closed throttle plate and cause a pressure wave to bounce back against the turbos' compressor wheels causing them to slow or even stop. This can seriously damage the turbos.

turbo surge right, do the oem dvs act differently than a standard bov? I've dealt with bovs my whole life but never dvs, the turbo kits that I've build I've used turbosmart, synapse, tial etc never paid to much attention of the build structure of the dvs

01-18-2015, 09:16 PM	#1
hawkm3 Lieutenant 57 Rep 477 Posts Drives: 2009 135i Join Date: Jun 2014 Location: Central Cali iTrader: (4)	oem dv leaking at idle Hey guys, I'm running oem DV vent to atmosphere and I've noticed that at start up and idle they are blowing air, at start up its bad to the point where it feels like a fan and then when the car warms it they leak, if you put your hand you can barely feel it. Here's a picture with a shop towel that I placed in the front, you can see where the towel is being blown compared to the right side. Is this normal or did I damage them running higher boost. https://flic.kr/p/qRDLzr __________________ FBO 09 135i Space Grey Metallic ///M Sport/Premium Package JB4 40% E85 / BMS Intakes / VRSF FMIC / Berk Resonated Midpipes / Custom Muffler Delete / N54 tuning downpipes / VMR v710 Wheels
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01-19-2015, 01:03 PM	#2
hawkm3 Lieutenant 57 Rep 477 Posts Drives: 2009 135i Join Date: Jun 2014 Location: Central Cali iTrader: (4)	Anyone?
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01-19-2015, 01:23 PM	#3
Dackelone European Editor 10523 Rep 22,992 Posts Drives: N54 e82 Join Date: Feb 2010 Location: Bayern, Germany iTrader: (1)	I bet your vacuum res lines are melts near the valve cover/solenoids area. __________________ Dackel's European Delivery Museum Guide
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01-19-2015, 07:29 PM	#4
hawkm3 Lieutenant 57 Rep 477 Posts Drives: 2009 135i Join Date: Jun 2014 Location: Central Cali iTrader: (4)	Check them and nope
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01-19-2015, 08:23 PM	#5
Pig Farmer Major 340 Rep 1,293 Posts Drives: E92M Join Date: May 2010 Location: Florida iTrader: (0)	Are you sure it is not the intake sucking air? If you put a small amount soapy water on the DV plug can you see bubbles?
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01-20-2015, 09:54 AM	#9
hawkm3 Lieutenant 57 Rep 477 Posts Drives: 2009 135i Join Date: Jun 2014 Location: Central Cali iTrader: (4)	Those holes are plugged, both of them, and yes the air is coming out if the dvs, I can feel it on both of them at start up and idle, unless they were to close when I hit bpost and then open up when I let off?
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01-20-2015, 07:43 PM	#10
e82passion Enlisted Member 2 Rep 35 Posts Drives: 2008 M3 MT Coupe Join Date: May 2014 Location: Hong Kong iTrader: (0)	Perhaps a video would help illustrate your problem better? __________________ 2008 135i 6MT \| Alpine White \| Coral Red Leather \| Sport \| BMW Performance Brakes \| BMW Performance CF Spoiler\| BMW Performance CF Rear Diffuser \| BMW Performance CF Mirrors \| MTech CF Front Lip \| Blackline LCI Tail Lights \| Black Kidney Grilles \| 18" BMW Performance 269 \| Michelin PSS \| Bilstein PSS10 \| BMW Short-Shifter \| BMW Performance Steering Wheel \| BMW Performance Exhaust \| JB4\| //M3 Front & Rear Control Arms\| ECS Trailing Arms
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01-21-2015, 05:21 PM	#14
Pig Farmer Major 340 Rep 1,293 Posts Drives: E92M Join Date: May 2010 Location: Florida iTrader: (0)	^ The fact the manifold is in a state of vacuum is what has me puzzled? I would expect to feel air being sucked into the open DVs. I may have to pull my DV hose this weekend and see if it blows air at cold start-up.
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01-21-2015, 05:51 PM	#16
hawkm3 Lieutenant 57 Rep 477 Posts Drives: 2009 135i Join Date: Jun 2014 Location: Central Cali iTrader: (4)	Still kinda confused tho!
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01-21-2015, 10:50 PM	#21
Pig Farmer Major 340 Rep 1,293 Posts Drives: E92M Join Date: May 2010 Location: Florida iTrader: (0)	When you lift off the throttle, the throttle plate shuts but the engine still acts as an air pump creating suction (i.e a vacuum in the space between the back of the throttle plate and manifold). This vacuum opens the DV. Since the turbos are still spinning and creating boost, the open DVs allows the boost to recirculate through the intake system or in your case vent to atmosphere. If the DVs did not open, the boost would slam into the face of the closed throttle plate and cause a pressure wave to bounce back against the turbos' compressor wheels causing them to slow or even stop. This can seriously damage the turbos.
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