(07-23-2013, 04:09 PM)OM616 What pump are you running?

Did it die while you were increasing RPM, or did you "snap" the throttle and it died when the throttle was returned to the idle position?

(07-23-2013, 04:20 PM)OM616 Is this something it just started doing all of a sudden?

I assume you have checked the tank vent, (no vacuum in the tank), also the filters, (not plugged), and the post lift pump pressure?

(07-23-2013, 03:33 PM)Syncro_G Hi,
Life has largely kept me absent from STD for the last two years. However, I've had a back burner project that is now nearly finished and is in need of a little advice.

background:

Some of you might recall me trying to improve on Forced Induction's (vacuum controller). Instead of using three fixed pressure dawse valves controlled by vacuum switches on the throttle linkage, I came up with a variable pressure valve that is directly controlled by the throttle position.

However, to keep things interesting, I also replaced the automatic transmission with a 5-speed manual gearbox (Getrag 717.421), replaced the head gasket, and pulled out a pile of vacuum control devices and the wiring harness that were put in to support the automatic ('85 722.4) transmission.

problem:

Engine appears to idle fine but dies after a little while. idle doesn't seem to be that consistent.
Engine also dies if I give it too much throttle. as if it's fuel starvation. I don't think it's the controller. I can remove it completely from the vacuum system and engine still dies.

Here's a clip on Youtube

descriptions of system:

VNT controller overview
(seems straight forward enough)

vacuum system overview
(this shows my assumptions - are these correct?)

(07-24-2013, 03:24 AM)offroaddieselhu Hi,
Can you writte me what kind of turbo you have?
What car it's on?
What pressure do you want to use it?
What is th e aim? (to use for...)
I try to help you if you writte me the basic data.
Offroaddieselhu

• a little more low end torque
  
• better economy at lower throttle positions
  
• a little more hp at higher speeds
  
• preserve reliability
  
• smoother boost curve at low speed
  

(07-24-2013, 05:58 AM)Syncro_G

(07-24-2013, 03:24 AM)offroaddieselhu Hi,
Can you writte me what kind of turbo you have?
What car it's on?
What pressure do you want to use it?
What is th e aim? (to use for...)
I try to help you if you writte me the basic data.
Offroaddieselhu

Thanks! The problem turned out to just be air in the fuel.
The controller isn't sorted out yet. I still need to tune spring pressure and orifice between the device and the vacuum source. I also need to verify I'm getting the desired pressures at the actuator.

This is a GT 2256V turbo. I'm planning to operate it at 1 to 1.2 bar range when under load at full throttle with a stock MW pump.

My initial goals are simply to improve on the stock Garrett turbo without tearing apart my engine compartment.

• a little more low end torque
  
• better economy at lower throttle positions
  
• a little more hp at higher speeds
  
• preserve reliability
  
• smoother boost curve at low speed
  

Once I have that figured out, I will likely be tempted to add fuel.

(07-24-2013, 06:09 AM)offroaddieselhu How big the engine? (cm3)
The turbo would like to work on min. 1,4 bar not on 1 bar if your engine can bear it.
The air is for free you should trade on it! And your car will go better!

(07-24-2013, 12:04 PM)Syncro_G Just took the truck for a hill climb. it feels nice though is only making about 4.5 psi (3.1 bar).

I tuned the valve for 17psi in atmospheric environment. However, since the valve has 20mmHg vacuum on the other side, I need to compensate with more spring pressure.

next step is to have a new exhaust made and fit an air cleaner.

(07-24-2013, 12:56 PM)AlanMcR Correction: 3.1 bar is 45psi.

(07-24-2013, 02:52 PM)raysorenson Not sure if this makes any difference because I don't know exactly how that part works or what it does, but the green thing is not what I understand to be a vacuum restrictor. Dieselgiant calls it a transmission vacuum dashpot. The restrictors, which are color coded by size look like this:

(07-24-2013, 02:52 PM)raysorenson Thanks for sharing your idea with us. I think it rawks. Did you have the block the dawes valve threads into fabricated or is it an off the shelf thing?

(07-24-2013, 04:49 PM)Syncro_G ...still need to figure out an air cleaner solution. the stock G can doesn't work.

(07-26-2013, 05:02 PM)AlanMcR Consider putting in 463 fender liners and using the area behind the headlight and between the fender liner and the fender. There is quite a bit of room. On mine that area is used for the fan-driven oil cooler.

(08-05-2013, 11:16 PM)Syncro_G Does anyone know what the proper vacuum levels are needed to move the actuator?

this is a GT2256V garrett from a T1N sprinter (before they switchted to the hella actuator)

measuring with a mightyvac, I see the following:
0 to 5 mmHg does nothing to vanes
then 5 - 17 mmHG moves vanes to maximum.
is this normal?

(08-05-2013, 11:16 PM)Syncro_G Does anyone know what the proper vacuum levels are needed to move the actuator?

this is a GT2256V garrett from a T1N sprinter (before they switchted to the hella actuator)

measuring with a mightyvac, I see the following:
0 to 5 mmHg does nothing to vanes
then 5 - 17 mmHG moves vanes to maximum.
is this normal?

(08-05-2013, 11:38 PM)AlanMcR If you are saying that it behaves in an on/off manner, then that desn't sound right to me. Maybe the mechanism is just sticky? Try the test again while shaking/tapping the housing.

(10-31-2013, 06:17 AM)cjcosta Lot of guys use the sprinter motor in the Gwagen.

I am also curious about the VNT controler.