Replacing worn wastegate acuators

Discussion in 'Technical' started by J3bba, Jul 10, 2017.

  1. J3bba

    J3bba He Who Struggles

    Hello all,

    So I finally went and got the Z on the dyno. Mixed results. It didn't explode so there's that :thumbup: . I was aiming for 16 PSI but the boost curve maxed out at 14ish @ 4200 rpm and then quickly dropped. Mechanic said it was most likely worn wastegate actuators, which makes sense.

    The other strange thing was that his dyno boost reference and my boost gauge were saying dramatically different things. While the dyno was saying 14 PSI the boost gauge was saying 18. The references for each reading was on different sides of the engine.

    So, my questions are:

    1. Due to worn springs is one turbo producing THAT much more boost that the balance bar can't balance it? or is my boost gauge just rubbish?

    2. Am I able to replace the actuators engine in or am I going to have to pull it? Having a look I might be able to get to the passenger side one but the drivers side looks a tad tight. Anyone done it engine in?

    Thanks in advance :D
     
  2. MagicMike

    MagicMike Moderator Staff Member

    More info needed, like turbos and other mods.
     
  3. J3bba

    J3bba He Who Struggles

    Stock turbos, using a gfb g force 2 as a boost controller. Boost controller works by setting a duty cycle. Boost gauge is plumbed into same line as stock gauge. Dyno boost reference was teed into fuel pressure line.
     
  4. MikeZ32

    MikeZ32 das Über member

    I'd be more inclined to trust the tuner's boost gauge.

    Where is your boost controller getting input from? Is the output split via a T or Y into both actuators?

    If one of the waste gates is off then it will affect the total boost as one turbo is working harder than the other. It should still balance out but will limit total boost.

    Assuming everything is working correctly could just be back pressure preventing you from building any more boost. Auto or manual stock turbos? Stock exhaust?

    Stock dumps and auto turbos are good up to 12psi.

    You might get to 16psi on manual turbos but even then it's already out of efficiency range and they're happier around 14psi.
     
  5. J3bba

    J3bba He Who Struggles

    The boost controller solenoid goes from the passenger side hard pipe and then tees off to the wastegates. The actual controller takes its boost reference from the stock gauge line.

    It's an auto to manual conversion so auto turbos, I've got 3 inch turbo back though so I wouldn't think back pressure would be too much of an issue.

    Yeah, I might need a new gauge. I did get a cheapie.
     
  6. MagicMike

    MagicMike Moderator Staff Member

    Sounds like there isnt much wrong with the setup. Stock auto turbos aren't going to see any more boost than you are now.
     
  7. Tektrader

    Tektrader Z32 Hoe, service me baby

    You where always likely to have blow by with the stock actuators at 16 PSI, They are not quite good enough even when new.
     
  8. J3bba

    J3bba He Who Struggles

    I had a bit more of a fiddle and the wastegates are definitely worn, waste gate pressure is only 6 psi.

    So I suppose I'm just wondering if it's still safe to drive with the turbos making different boost levels and if I have to pull the engine to replace them.

    What would be the max boost from auto turbos? If I get manual compressor/exhaust (I can't remember which one is different) housing would that increase the max level much?


    I was looking at the adjustable ones from Z1 (https://www.z1motorsports.com/force...ed-adjustable-wastegate-actuators-p-5550.html) to replace them which hopefully should get around that issue.
     
  9. IB

    IB ?????

    That's not far off the stock 7 psi, could be just a gauge difference?

    Watergate actuator change is essentially an engine out job (driver's side at least). It might be worth upgrading turbos while you're at it?
     
  10. J3bba

    J3bba He Who Struggles

    Yeah, I was thinking about it. But turbos are so expensive. Anyone have 2 turbos better than stock that I can have for less than a grand? :p
     
  11. IB

    IB ?????

    For under a grand each you can get the hypergear rebuilds...
     
  12. SRB-2NV

    SRB-2NV #TEAMROB

    $800 each plus $240 for high pressure actuators.
     
  13. J3bba

    J3bba He Who Struggles

    Yeah, kinda hoping I won't need new turbos though :p
     

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