PD100 has variable intake manifold...

Pelican18TQA4

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6 - EGR valve
9 - Anti-shudder valve
13 - Lower section of intake manifold (with shift rod)
17 - Vacuum actuator
19 - Intake Manifold Runner Control Valve (N316)

This is the first I'm hearing of this and this explains what the vacuum actuator is for that can be seen on the passenger's side of the engine. I know the one on the driver's side is for the bypass valve for the EGR cooler.

Anyone seen or heard of this before??
 

DPM

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Item 9 looks like the "changeover valve" in this application. There's certainly some kind of dual port/ siamesed setup in item 13...
 

Pelican18TQA4

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Item 9 (anti-shudder valve) is what closes off the intake when you shut the engine off and also what creates vacuum in the intake manifold to allow more EGR gasses to flow into the intake. Item 13 has its own vacuum actuator (Item 17 in the first pic), seen in the pic below as Item 1 which explicitly states that it's for the variable intake manifold.




Also, here are some quotes from the Bentley manual regarding the intake:

"Engine code BEW:
  • The variable intake manifold is switched depending on engine speed and accelerator pedal position."

"Disassembling and assembling variable intake manifold:
  • Note: Tighten the variable intake manifold in the described sequence to avoid distortion.
  • Remove variable intake manifold.
  • Loosen connecting bolts.
  • Disconnect upper and lower parts of intake manifold. Separate both parts with light blows of a rubber-headed hammer if necessary.
  • Clean contact surface.
  • Replace seal.
  • Put upper and lower parts of intake manifold together and tighten all connecting bolts hand-tight.
  • Tighten all securing bolts in indicated sequence to 10 Nm.
  • Install variable intake manifold."
Now, where's all the TDI experts, we need to figure out more about this variable intake manifold as found on the BEW.
 

whitedog

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Thanks for the pictures. I have been trying to find it and I finally have. It looks to me like if there is any intake clogging, it will be in a place that is hard to detect by just pulling off a hose, and if it does get clogged, it appears to be fairly easy to clean. Well, relatively easy since things come apart and you can get into more kooks and nannies. Er... nooks and crannies...
 

Sooch

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This reminds me of the IMRCs on the Ford Mustang Cobra 4V's. Usually you just take off the throttle plates or get the delete kit, and change a single 1 to a zero in the ECU. We used to have GTGs to clean them out if you wanted to keep them.

They are usually there to promote higher velocity intake air at low revs, for more torque, or switch in the long intake runner at low revs. Not sure why that's needed on a diesel?
 

DPM

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In this case, I'll bet it's used to alter the speed/ angle of the inlet air's swirl.
While it's a 16v, the later PSA HDI has dual runners; these are configured to promote swirl...
 

Pelican18TQA4

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Resurrecting a thread from the dead!

Browsing new posts today, I came across a pic posted by Birdman353 in a PD EGR thread:



You can clearly see here the variable intake manifold and how different it is from the ALH and prior TDI manifolds. There are clearly two intake passages for each intake port. I'm still very curious about this and how/when exactly it's utilized on the PDs??
 
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PDJetta

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Thank you for the picture. Very interesting! I've been for a while trying to figure out what the heck the vacuum diaphragm down low, near the turbo actuated, and according to the under hood diagram, it is for the "Variable intake runner changeover valve". This evidently is NOT the throttle plate (which is electrically actuated on the PDs). That picture explains it, but why is it there? Maybe for high EGR flow rates (light load operation) the small openings are open and the large ones are closed to create faster air velocities to prevent intake plugging (via the vacuum diaphragm in the picture). Both ports must be open during high boost/load/no EGR conditions. I'd suspect there is a butterfly valve over each of the large intake ports on the end (in the manifold) that bolts to the head, and these butter fly valves (4 of them) are all on a commpn rod, pivoted by the vacuum diaphragm. Just my guess.

For those of us with non-functioning EGR systems on the PDs, I wonder if the intake manifold changeover valve should just be locked in the position to cause the largest air flow all the time (through the large ports). I think this set-up has to be EGR related only (and to combat intake clogging). Is this on the European PDs?

--Nate
 
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Pelican18TQA4

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I don't know that is has anything to do with the EGR system though. As you can see from the Bentley quotes I posted above pertaining the the variable manifold:

"The variable intake manifold is switched depending on engine speed and accelerator pedal position."

That leads me to believe it's a performance-enhancing feature, though perhaps not as extreme as Honda's VTEC. In my opinion, the narrower intake passages are probably low-end runners (narrower passage speeds up the air) which enhances low-end torque and the larger intake passages allow more air to flow at higher RPM to enhance top-end hp. Or, I could be totally wrong!!

Point is, VW didn't spend the engineering Euros on something that doesn't serve a purpose.
 

NathanMSL

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I had no idea all that junk was down there in the intake. It should be pretty interesting to see what happens when I put the PD150 intake on with none of that fancy flapper stuff. :)
 

andreigbs

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you can "hear" the intake manifold flaps being tested if you do a "output test" with VAG-com. it will go through the tests, shut off the car at a point, then do bank 1 of the intake manifold. You'll hear something flipping open/shut. It's probably good to do the test once in a blue moon, to make sure it's not gummed/crudded up. Works just fine on my PD.
 

Pelican18TQA4

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andreigbs said:
you can "hear" the intake manifold flaps being tested if you do a "output test" with VAG-com. it will go through the tests, shut off the car at a point, then do bank 1 of the intake manifold. You'll hear something flipping open/shut. It's probably good to do the test once in a blue moon, to make sure it's not gummed/crudded up. Works just fine on my PD.
Sure that's not the electrically actuated "throttle" butterfly? I ask because the actuator for the variable intake manifold is vacuum operated so it would be impossible to test it with the engine off except for the few seconds after the engine is shut off and vacuum is still available.
 
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andreigbs

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correct sir, which is why the output sequence test is done right after the engine is shut down, during sequence testing. you can hear the flap opening/closing, though you can't discern what mechanism is being used to make it open/close. The noise itself is a clacking-swooshing noise lasting a half-second or so, very swift, but with the windows down you can hear it.

that butterfly valve; i hear it every time i shut down the engine when i park, 2 seconds or so after shutdown, it's a different noise.

besides, the output test lists the order of events so you know what's being tested. try it with VAG-com on a PD; there isn't the option to test it on anything pre-PD.
 

andreigbs

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but soot is normal right? afer some thousands of miles it's expected. what about that gummy, sticky junk? how many miles on that intake? did it require cleaning? if so, was there a difference/improvement? thanks again, good pics too.
 

Pelican18TQA4

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Thanks Birdman353 for the heads-up on the additional pics. After seeing the pics of the complete manifold off the car, it looks an awful lot like a PD150 intake manifold. See below:

PD100



PD150



Of course, the PD100 manifold has the variable part, but overall the intake runners appear to be the same on both manifolds.

Something else I noticed is that the the default position of the variable intake has the small ports closed:



Perhaps we could do some testing with the vacuum actuator unplugged so it leaves the smaller ports blocked, and then some testing with constant vacuum applied to leave the smaller ports completely open??

*PD150 pics are courtesy of RWDdiesel*
 

JoeBleed

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2 questions to ponder.

1. When you chip a pd100 with pd100 manafold, are the actuation perameters changed?

2. If you just stick a pd150 manafold on a pd100 with no chip will you get an mil?

2 could probably be figured out very simply. just unplug it and see if it trigers a mill. and the sugested vacume test listed above should work. and prove to be interesting.
 

PDJetta

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andreigbs said:
you can "hear" the intake manifold flaps being tested if you do a "output test" with VAG-com. it will go through the tests, shut off the car at a point, then do bank 1 of the intake manifold. You'll hear something flipping open/shut. It's probably good to do the test once in a blue moon, to make sure it's not gummed/crudded up. Works just fine on my PD.
How do you do this test with the VAG-Com?

Thanks.

--Nate
 

PDJetta

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"that butterfly valve; i hear it every time i shut down the engine when i park, 2 seconds or so after shutdown, it's a different noise."

Ah Ha! That's the source of the after cut-off wheeze I hear! I used to think it was the throttle plate closing, but my throttle plate somehow disappeard right about the same time a foreign object found its way into the EGR pipe, blocking it:D

--Nate
 

PDJetta

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Birdman353 said:
I have more pictures in my photo album
http://pics.tdiclub.com/showgallery.php?cat=500&ppuser=36421

There was notably more soot built up in the smaller passages of the intake
Fascinating! So the flap just closes off and opens the smaller passages it appears.

What are the two small hose connections for on the backside of the EGR gas cooler for? (where do the hoses go that connect to them?).

--Nate
 

Birdman353

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PDJetta said:
Fascinating! So the flap just closes off and opens the smaller passages it appears.

What are the two small hose connections for on the backside of the EGR gas cooler for? (where do the hoses go that connect to them?).

--Nate
The two smaller hoses are for the coolant expansion. One goes from the egr cooler to the head, the other from the egr cooler travels under the tandem pump and into the larger hose out of the radiator
 

PDJetta

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Birdman353 said:
The two smaller hoses are for the coolant expansion. One goes from the egr cooler to the head, the other from the egr cooler travels under the tandem pump and into the larger hose out of the radiator
Thanks. Good to know in case I want to remove the cooler permanently.

--Nate
 

andreigbs

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using VAG-com, with car running, go to Engine-01, then go down to Output Test. It will ask you if you want to start the test sequence. At this point I open my front windows. Then I click next, it goes through a few tests then gets to the intake manifold bank 1, then the car shuts off. This intake manifold bank continues being tested with the engine off and you hear the flaps open and close, there is a mechanical noise that tells you they're operating. The output test cycles on/off for as long as you leave it on that particular test. (I'm afraid maybe later on it cold dislodge built-up crud from the intake into the motor?! Is that possible or am I going crazy?) It runs this intake manifold flap test only on my PD; on the AHU it never had any test like that. I am unsure whether it's cycling the smaller intake ports/flaps or if it's cycling the whole intake, but I do think it's the smaller ones from the pictures so kindly posted. Thanks a lot, btw, to you guys with great pics. Interesting what you find...

How come no smaller ports on the PD150 intake? And why the extra dirtiness? Or is it just my eyes...
 
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andreigbs

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interesting how it has those baffles even in the head ports. so would anyone still think to "gain" something by installing a PD150 intake on a PD100 motor? Wouldn't that cause problems with EGR flow and therefore MAF readings/adjustments? I cannot see how this would be beneficial in any way.
 

Birdman353

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32k on it. It didn't need to be cleaned, but I wanted to tear it apart and take pics anyway so I cleaned it. The mess on the last port was from a gummy piece sitting on the narrow part of the canal. Seemed like 3 & 4 were gummy and 1 & 2 were mostly soot.
 
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