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Thread: Actuators for Z20 let engines......

  
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    Actuators for Z20 let engines......

    Ive been looking for an uprated actuator for the z20let engine, but have had no luck and am starting to give up!!

    Do any of you guys know where i should look etc?
    Corsa C LEH 4x4?

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    Why would you want one. They serve no purpose in upgrading from standard

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    so what are they there for then?
    Corsa C LEH 4x4?

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    They are there to limit the boost. They bleed pressure at a certain point.

    Uprated one will do nothing as the ECU and EM deal with the pressure bleed limit on the Z20let

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    so how do they bleed the pressure then? and how come some peoples engines peak and hold different pressures if its all governed by the ecu?
    Corsa C LEH 4x4?

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    Heres the answer ...
    " The wastegate now is a device that can control the boost by releasing (wasting) some amount of the exhaust gases to the exhaust BEFORE traveling to the Turbine Wheel. Therefore the Compressor Wheels is not driven that fast and boost is reduced. The wastegate is opened by a actuator, driven by air pressure. The actuator is preloaded with a spring and opens the wastegate when the pressure applied exceeds the springs load.

    Usually the Compressors output will be connected by a vacuum hose to the wastegate-actuator. Therefore the bigger the boost of the compressor the more the wastegate opens and the less boost will be produced."

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    The reason why you need an uprated wastegate actuator is when the boost pressure on the actuator forces it to open, against the action of the spring.

    This was a problem on the Cossie's and R5 GTT's (ie cranky old heaps)

    On a Z20LET, thanks to help from Saab (I believe) the engine is more hi tech and uses a solenoid controlled wastegate actuator, hence no wastegate creep leaking off the boost too early

    Welcome to the 21st century

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    I hear what your saying but.... This is how i have always percieved a turbo to work. The waste gate is not opened by an actuator its held closed by an actuator with a pre tensioned load on it, the boost is governed by the tension on the waste gate stopping exhaust gasses by passing the turbine. so when the turbo initially spins up it creates a load on the waste gate untill it opens(this is where you get your peak of boost) (which i believe people call overboost) once the gate is opened the pressure drops off and is then held. for example it takes more energy to to get a car moving than it does to keep it moving!

    and when i say that i mean that it takes more psi to open the waste gate than it does to hold it open!!

    So using this theory it would make sense to have an actuator with a higher tension on it.. that way instead of getting a peak of (for example) 10 psi then dropping off to 7psi you would get it to peak at 11 and hold 9-10.

    If you wind the actuator out on your turbo it will peak hold less boost.
    Corsa C LEH 4x4?

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    The solenoid controls the wastegate opening, hence winding or changing the actuator does nothing at all.

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    what solenoid?? do you mean, amal valve?
    Corsa C LEH 4x4?

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