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Thread: T28r Actuator - help

  1. #1
    Guest mgf91's Avatar
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    T28r Actuator - help

    So, I lost all boost yesterday and found my actuator came off yesterday and it was a pain to connect back up (was incredibly stiff and had to use grips to actually get it to move). Once connected - still no boost.

    Assume something in the actuator has seized.

    Anyone selling a t28r actuator or can recommend one? I assume it's could be the same as the t28 actuator?

    If that's not the issue...what else could it be? New turbo time?

    Thanks.

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    Guest Jonnay's Avatar
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    It's the same as a T28 (or close enough to fit with no issues) but if it was siezed closed you would be overboosting rather than suffering no boost.. if it had failed and was easy to move and had no resistance, letting the penny open freely, you'd be loosing your boost.

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    the workshop manual shows how to test the actuator. you should be able to just use a foot pump.

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    Guest mgf91's Avatar
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    Quote Originally Posted by Jonnay View Post
    It's the same as a T28 (or close enough to fit with no issues) but if it was siezed closed you would be overboosting rather than suffering no boost.. if it had failed and was easy to move and had no resistance, letting the penny open freely, you'd be loosing your boost.
    Thanks.

    Sorry, forgot to add I got tiny boost at around 4k rpm.

    That's what's making me think it's seized as it's only under high pressure that I'm getting something.

  5. #5
    Yorkshire Rep CMR's Avatar
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    If you disconnect the actuator and move the wastegate arm on the turbo by hand can you hear the penny moving inside? You should hear it clink, if not the weld has gone.

    As for your theory - you are thinking of it in reverse, the actuator has to be stiff to hold the penny closed to build boost, then it bleeds off pressure allowing the penny to open to maintain a steady pressure. If the penny is allowed to stay open then boost won't be built at all until high in the rev range.

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    Guest mgf91's Avatar
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    Quote Originally Posted by CMR View Post
    If you disconnect the actuator and move the wastegate arm on the turbo by hand can you hear the penny moving inside? You should hear it clink, if not the weld has gone.

    As for your theory - you are thinking of it in reverse, the actuator has to be stiff to hold the penny closed to build boost, then it bleeds off pressure allowing the penny to open to maintain a steady pressure. If the penny is allowed to stay open then boost won't be built at all until high in the rev range.
    It doesn't move at all, it's too stiff

    Sent from my SM-G920F using Tapatalk

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    Guest Jonnay's Avatar
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    Quote Originally Posted by mgf91 View Post
    Thanks.

    Sorry, forgot to add I got tiny boost at around 4k rpm.

    That's what's making me think it's seized as it's only under high pressure that I'm getting something.
    If it's siezed stuck in (arm fully retracted) you would have too much boost, you'd be hitting fuel cut.

    Like someone said above, your penny flap may have come loose from the rod and be open, that will not allow it to build any boost. This is the part the actuator controls

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    Guest paresh521's Avatar
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    Sorry to hijack the thread.

    I had a similar problem, boost on the high end, very little on the low end. I have a HKS actuator but made no difference.

    If it is the penny flap, how do you change that? or is that a new turbo altogether?

    Thanks

  9. #9
    Guest mgf91's Avatar
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    Quote Originally Posted by paresh521 View Post
    Sorry to hijack the thread.

    I had a similar problem, boost on the high end, very little on the low end. I have a HKS actuator but made no difference.

    If it is the penny flap, how do you change that? or is that a new turbo altogether?

    Thanks
    Mine ended up being the penny flap. Mechanic I took it to just rewelded it. I thought it'd be new turbo time but only cost be 30 in labour in the end and boosts fine now 🐌



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