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Boost Increases in gear

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  • Boost Increases in gear

    I got my Sy out for the first time this year for preparation for upcoming spring and summer racing. In short, I noticed under WOT first gear tops about 16 psi. 2nd goes to 18 psi and 3rd gear hits 20 psi. I have not adjusted the wastegate arm yet. Just drove it. Last year I did change the spring in the forge wastegate to a 18-22 psi spring. In order for it to have consistent boost pressure in each gear, what should I be looking into to fix this issue?

    Turbotweak chip, forge wastegate, and stock turbo

    I'll also post this on the facebook group too just in case more are watching it.
    Syclone #380 71mm Turbo Fast XFI
    Syclone #463 13k Original and Stock
    Syclone #1385 Stock Turbo Class Competitor
    '17 Civic Type R #965 AutoX and PDX
    '16 S3 APR Stg 1 DD 12.03 @ 112

  • #2
    Start with lengthening the wastegate rod by 2-3 turns.
    Justin "RealFastV6"
    1991 GMC Syclone
    1993 GMC Typhoon

    Comment


    • #3
      Thanks for the response. So lengthening the rod will help with producing consistent boost pressure due to the higher spring in the wastegate?
      Syclone #380 71mm Turbo Fast XFI
      Syclone #463 13k Original and Stock
      Syclone #1385 Stock Turbo Class Competitor
      '17 Civic Type R #965 AutoX and PDX
      '16 S3 APR Stg 1 DD 12.03 @ 112

      Comment


      • #4
        Short answer, "kinda".

        Longer answer; the wastegate's total movement and ability to bleed exhaust manifold pressure is limited mechanically by the travel of the wastegate actuator. The more overlap (preload) you have on the wastegate flapper, the less the flapper can open in total. The full fix is going to be something like letting the flapper open MORE by reducing the wastegate preload, and then you should have more consistent boost between your gears (which will eliminate the 3rd gear creep), and then you use the boost control to dial up the total boost in all the gears; but right now I suspect you're overrunning the ability of the boost controller because the flapper can't move enough.

        Hope that makes sense.
        Justin "RealFastV6"
        1991 GMC Syclone
        1993 GMC Typhoon

        Comment


        • #5
          I have a turbo tweak chip. So, I have been adjusting the rod in the past before I went to the higher spring. I added more boost in the turbo tweak chip by 2 lbs, but I didn't see a difference when making a pass and watching the data log. I might have to use a manual boost controller to get the boost up where I want all while adjusting the rod to be consistent.
          Syclone #380 71mm Turbo Fast XFI
          Syclone #463 13k Original and Stock
          Syclone #1385 Stock Turbo Class Competitor
          '17 Civic Type R #965 AutoX and PDX
          '16 S3 APR Stg 1 DD 12.03 @ 112

          Comment

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