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Wastegate actuator

Discussion in 'A3/S3 Forum (8L Chassis)' started by Steve1, Jul 27, 2003.

  1. Steve1
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    Steve1 New Member

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    [Jul 27, 2003]
    If one were to adjust the wastegate actuator to increase boost slightly, would the ECU correct this increase and set it back to normal?(I am talking about 2 turns on the actuator rod).
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  3. RichA3Turbo
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    RichA3Turbo ...Watching you! Staff Member Moderator

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    [Jul 27, 2003]
    [ QUOTE ]
    20Vturbo said:
    If one were to adjust the wastegate actuator to increase boost slightly, would the ECU correct this increase and set it back to normal?(I am talking about 2 turns on the actuator rod).

    [/ QUOTE ]

    I think your asking for trouble doing that!

    Rich
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  4. Gambba
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    Gambba Active Member

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    [Jul 28, 2003]
    [ QUOTE ]
    20Vturbo said:
    If one were to adjust the wastegate actuator to increase boost slightly, would the ECU correct this increase and set it back to normal?(I am talking about 2 turns on the actuator rod).

    [/ QUOTE ]

    I don't think the ECU would reset it, but I'm not overly sure. I would think that your best option is to run this past someone like Jabbasport, who have probably tried this sort of adjustment in their quest for acheiving the best performance.
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  5. Crafty
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    Crafty Member

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    [Aug 3, 2003]
    unless you override the ECU boost control or the actuator is weak and is not holding proper boost doing what you suggest will make sweet FA difference because the ECU will detect the boost pressure and bleed off the excess...
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  6. Mo-S3
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    Mo-S3 Member

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    [Aug 3, 2003]
    Where exacty does it bleed the excess off to? Details plz
    /ubbthreads/images/graemlins/idea.gif
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  7. Crafty
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    Crafty Member

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    [Aug 3, 2003]
    someone correct me if Im wrong but it works like this:

    ECu uses a map sensor that can "see" boost.. this is reported back to the ECU, ECu processes this data along with everything else ( throttle position, RPM, ign advance, volume of air entering engine, knock detection etc ) and decides on a suitable boost level to run... it then closes or opens the N75 valve as it sees fit, the N75 valve controls the vaccuum line that goes to the actuator, when the N75 closes this line the actuator has to release.. opening the wastegate, thus bleeding off the boost straight through the exhaust.

    On old turbo cars you could pull the pipe off of the actuator, this gave you pretty much infinite boost ( depending on strength of the actuator ).. naturally most engines didn't survive this for too long /ubbthreads/images/graemlins/smile.gif AFAIK you could do this to a 1.8T and the ECU will detect something is wrong, possibily flag a light and give reduced boost.

    Similarly what the OP suggested would allow more boost to be sustained, its quite often done if the actuator has got weak and thus cannot hold proper boost, winding up up a few turns would restore the boost.. however on modern engines everything is under too much control..


    Edit: A alot of people fit the N75 valve from an S4 and this allegedly gives a couple more psi pressure before cutting vac.. however some have tried it and found it didnt work well at all...
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