MK2 GTD 1.9 VNT History of a SWAP(s) - page 2 - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• #15 by rallydiesel on 06 Nov, 2007 16:49
• So does the throttle cable override the boost can or the other way? I can't quite make out how the throttle cable and the boost can are connected. Is that rod with the two nuts on it the vnt actuator rod or is it on the other side of that plate?
• #16 by Apsik on 06 Nov, 2007 17:17
• So does the throttle cable override the boost can or the other way?
  The other way - cable pulls vnt actuator but when the boost increase the can just push actuator back. Other words: on full throttle the cable holds (up) the actuator (vanes CLOSE) but the preasure can can push it back (down) because of the spring.
  
  I can't quite make out how the throttle cable and the boost can are connected.
  They are not connected They work together ... cooperation
  
  Is that rod with the two nuts on it the vnt actuator rod or is it on the other side of that plate?
  Yes - that rod with two nuts just under the can is the vnt actuator rod (on the top I added a piece of plate to connect the cable). There is nothing else on the other side of the plate
• #17 by rallydiesel on 06 Nov, 2007 18:01
• So the black rod underneath the boost can is the old wastegate stem? It looks like it isn't touching the vnt actuator, is that right?
  
  Do you mean that on full throttle, the vanes are closed and as boost builds the boost can opens the vanes?
  
  One last question, are the vanes open or closed without a controller. Is there a spring that keeps the vanes in a certain position?
• #18 by Apsik on 07 Nov, 2007 00:57
• Do you mean that on full throttle, the vanes are closed and as boost builds the boost can opens the vanes?
  You are right! Sorry m8 that's my mistake - it was 2:30am when I was writing that and I mixed up some facst. My posts are already corrected.
  
  So the black rod underneath the boost can is the old wastegate stem? It looks like it isn't touching the vnt actuator, is that right?
  That's right. The old wastegate steam is touching the vnt actuator only on full throttle when vanes close and by increasing boost = steam is pushing the actuator down (opening vanes).
  
  One last question, are the vanes open or closed without a controller. Is there a spring that keeps the vanes in a certain position?
  Vanes are OPEN on the neutral/start position (like on the picture). It doesn't need any spring because the cable controls that.
  
  .... and libbybapa have noticed my mistake too
• #19 by rubadubdub on 07 Nov, 2007 09:50
• Quote

  Is that rod with the two nuts on it the vnt actuator rod or is it on the other side of that plate?
  Yes - that rod with two nuts just under the can is the vnt actuator rod (on the top I added a piece of plate to connect the cable). There is nothing else on the other side of the plate

  
  
  I cant quite get my head round this. If the cable is attached to the plate welded to the actuator rod then surely when the wastegate rod presses against it to move the vanes back under high boost it will also move the cable with it, and pull the arm on the pump.
  
  Im sure im missing something as it makes sense that the plate moves and compresses the spring below the plate, rather than tugging on the cable. If this is the case i just cant figure out how the cable is attached to pull on the vanes during acceleration but can still allow the spring to compress under high boost. Or am i just being thick!?
  
  Care to elaborate a little? Thanks
• #20 by Apsik on 07 Nov, 2007 16:07
• Please don't comment my paint skills but this may help:
  
  The plate is mounted to the GT20 with 2 stock screws M6 (hot part) Solid orange part is the bushing that holds vnt actuator rod vertically. On the picture you can see that it's much thinner than on my drawing
  Preasure can is welded to the "orange" plate
  VNT arm (the solid brown part allows to adjust the rod position - higher/lower)
  VNT actuator rod with a piece of "metal" welded on the top and there is a whole just to let the cable go through
  Cable from mountain bike front disk break attached behind the pomp to the arm and on the other side to the vnt actuator rod but it has a lock above the actuator than goes through a whole in the actuator than through a spring and a lock on the end - this way fixing is flexible
  spring from a pen (double in my case) allows to push the vnt actuator rod down on high boost on full throttle
  
  Guys my english is't as good as yours but I hope you can understand that.
  It took me 2 months to find "in my opinion" the simplest solution (base - tintin's vnt control).
• #21 by Slave2School on 07 Nov, 2007 16:39
• That is a GREAT picture!  I fully comprehend it now, I was wasn't sure where the boost can came into play in the other pictures since it looked like it was broken, but now I see the shaft comes and hits the flat plate to push it back to open when the desired boost is met.  Very nice.
• #22 by rallydiesel on 07 Nov, 2007 21:08
• Simple question for any of the VNT people: Is there a spring in the vnt actuator that keeps the vanes open unless something acts on it or do the vanes just flop around if the actuator isn't hooked up to anything? In other words, is the cable coming from the throttle the only thing that closes the vanes?
• #23 by Apsik on 08 Nov, 2007 00:21
• Quote from: "rallydiesel"

  In other words, is the cable coming from the throttle the only thing that closes the vanes?

  
  Yes in my case it is. I think it's the point of the system.
  Only the throttle can close the vanes and increase boost. Without the cable I had hudge turbo surge because it also opens vanes when throttle released.
  
  Another picture:
  
  colors match the previous drawing
  Yellow stripes - locks on the cable
  Orange circles - mounting points/screws M6
  Orange U - bushing that keeps the actuator vertically