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A strange result on adjusting wastegate-actuatorbracket. Very surprising

Discussion in 'Daytona and Laser' started by torgtoe, May 23, 2017.

  1. torgtoe

    torgtoe Active Member

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    Hey again
    Im really not a turbo-expert, - i hardly understand how they work. This i s what happened to my turbo lately:
    A couple of weeks ago i noticed that my turbo stopped giving boost, not strange since my aktuatorbracket had popped of the valve where it is mounted.
    I thougt this would be an easy job, but no it wasnt at first.
    I found a "reasonable" adjustmentpoint to mount it back. The result was bad boost, and week acceleration. I tried 4-5 different setting, and suddenly landet right and i got my 7 psi. Speed was now very good.
    So i thougt i had to try an experiment: I turnet the bracket only halv a turn, notice only half a turn -clockwise, -result; car run very bad.
    I stopped the car, and turned the bracket only half a turn the opposite way back to where i first set it: Now car runs great again?? How is this possible? Can the setting be so sensitive? I dont understand this? What happens? I would like to understand.
     

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  2. GLHS60

    GLHS60 Well-Known Member

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    The actuator has an internal spring that keeps the wastegate closed.

    As boost increases, boost pressure acts against the spring to open the wastegate and prevent overboosting.

    It's a very delicate balance that normally maintains about 7 psi when directly connected to a vacuum/boost source.

    The waste gate solenoid bleeds off some pressure to the actuator to enable higher boost.

    Most actuators aren't adjustable but obviously yours is.

    You need the wastegate closed until about 7 psi.

    Closed is some spring pressure pushing the actuator rod towards the wastegate arm, Engine off.

    Too little spring pressure allows the wastegate to open before 7 psi, or possibly remain open.

    An open waste gate at low Engine speed will reduce power considerably.

    Sounds like you are about right.

    Thanks
    Randy
     
    boblonben likes this.
  3. torgtoe

    torgtoe Active Member

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    Good reminder -im trying to learn. Thing is i still need 1 psi - gaugeneedle stoppes at 6. Where is my last psi lost on its way?
    And needle is unstable : suddenly coming from dead posistion to approx 3, then it moves correct.
     
  4. paullybob

    paullybob Well-Known Member

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    A little boost goes a long way!! The gauge may be faulty as its probably the factory original right?? Order a new gauge from Ma MOPAR, the new gauges are way more accurate and don't get too hung up on that 7 psi number...as GLH said, your boost solenoid will (should??) take care of those little spikes along the way. Don't get crazy with your adjustment, like 10 psi, or you'll be looking at parts instead of a new gauge, lol. Also wouldn't hurt to replace all the vacuum lines with good quality silicone vacuum hose and ziptie all the end points good and snug. You need to keep that vacuum as clean and stable as possible.

    I miss my turbo MOPARS.....Wonk, wooonnnkkkkkk!!
     
  5. ImperialCrown

    Level III Supporter

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    The factory shop manual gives no procedure for wastegate adjustment or calibration. No wastegate service is given other than turbo assembly replacement. The factory adjustment should not have changed unless a previous owner messed with it.
    The initial 'lack of boost' problem likely wasn't your wastegate. It should have been left where it was.
     
  6. GLHS60

    GLHS60 Well-Known Member

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    I think he said the actuator arm popped off the wastegate lever which will cause a lack of boost.

    The fact that it has a threaded shaft indicates a jobber replacement??

    Agreed, the shaft length shouldn't be changed, sounds like his is still a little long.

    Boost control happens on the other end of the actuator.

    A very simple method of boost control is to run a hose directly from the actuator to a pure vacuum source.

    Normally boost runs about 7 psi without any electronic intervention.

    Simplifies the vacuum harness as well.

    Thanks
    Randy
     
  7. torgtoe

    torgtoe Active Member

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    ""Agreed, the shaft length shouldn't be changed, sounds like his is still a little long.""

    Funny -This is just what i did som days ago -gave the bracket another halv turn, and i got the one lost psi back. Good quess here.

    Thanks for all answers - im still surprises how accurate this adjusting is. Well now the lockring is placed on my act-bracket. I may have i thicker vac-line to turbo but it seems ok.
     
  8. GLHS60

    GLHS60 Well-Known Member

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    Good guess, LOL, I prefer accurate diagnosing !!!

    Getting greedy yet, say 8, 9 even 10 psi ;)

    Thanks
    Randy
     
  9. torgtoe

    torgtoe Active Member

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