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    Wastegate spring vs boost

    I'm fairly new to the turbo scene. When i built my barra turbo a few people suggested i go to a 14psi wastegate spring in my turbosmart internal wastegate. I also went to a manual turbosmart boost tee.

    I understand the upgraded spring is to stop the internal gate blowing open. However. How do guys get almost double the psi?

    Say 7psi spring and 15psi at engine, or 14psi and 25-28psi. Without using co2 assistance to hold the gate steady
    Originally posted by 50RTD
    Dave, have you uploaded the data from the carby?

    #2
    Loose rule is spring should be half the pressure you want to run, but many variables obviously

    Means well but is skittled

    Comment


      #3
      External gate is like a poppet style, so pressure on the other side is reasonably irrelevant, on a flap style internal be pretty much the same deal?

      I've got a 16psi spring in my gate, and regulating it to 33 is no probs

      Sent from my Pixel 2 XL using Tapatalk
      This is a post i wrote by mistake, which is nice...

      Comment


        #4
        I understand a dual port or external gate is different.

        Sent from my Nexus 6 using Tapatalk
        Originally posted by 50RTD
        Dave, have you uploaded the data from the carby?

        Comment


          #5
          The taxi currently runs one spring in the internal wastegate and makes just over 16psi. I've got two more springs to put in it (it originally came with three in it, but we removed two)

          Sent from my SM-G950F using Tapatalk

          Comment


            #6
            Originally posted by GSRman View Post
            External gate is like a poppet style, so pressure on the other side is reasonably irrelevant, on a flap style internal be pretty much the same deal?
            Internal flapper gates I have seen are arranged so pre-turbine exhaust pressure will force it open, not closed. NFI about externals.

            Comment


              #7
              Originally posted by Roadsailing View Post
              Internal flapper gates I have seen are arranged so pre-turbine exhaust pressure will force it open, not closed. NFI about externals.
              yeah - walked out to the shed to check - essentially they hope that the surface area in the actuator is much larger than the flap - so a 16psi wastegate spring with no pressure being applied to it probably needs a fair bit more than 16psi against the flap (if 0 against the actuator diaphragm) to push it open.


              I assume they would prefer it to fail open than closed.
              This is a post i wrote by mistake, which is nice...

              Comment


                #8
                You can do some basic maths on valve vs diaphragm area and spring force to get a rough idea but it relies on turbine/compressor match to engine keeping EMP:IMP reasonable.

                Comment


                  #9
                  Originally posted by Dogsballs View Post
                  Say 7psi spring and 15psi at engine, or 14psi and 25-28psi. Without using co2 assistance to hold the gate steady
                  Because the wastegate diaphragm doesn't see any boost pressure until the ECU opens the boost control solenoid.

                  Comment


                    #10
                    Originally posted by GSRman View Post
                    I assume they would prefer it to fail open than closed.
                    My figuring also!

                    Comment


                      #11
                      That makes sense. If the wastegate is bigger than the internal flap it will generate more boost
                      Originally posted by 50RTD
                      Dave, have you uploaded the data from the carby?

                      Comment


                        #12
                        Originally posted by uuheels View Post
                        Because the wastegate diaphragm doesn't see any boost pressure until the ECU opens the boost control solenoid.
                        I run a manual boost t
                        Originally posted by 50RTD
                        Dave, have you uploaded the data from the carby?

                        Comment


                          #13
                          You transplanted the factory loom didn't you? Why not fit a solenoid and have it tuned. You can always add a switch on the positive power wire if you only want to run gate pressure. Less likely to do the overboost on transition that manual bleeds tend to exibit and give a wider control range.

                          Comment


                            #14
                            I have the loom there but factory boost solenoid was playing around, that's why we went boost t. Some say it's a crisper response

                            Sent from my Nexus 6 using Tapatalk
                            Originally posted by 50RTD
                            Dave, have you uploaded the data from the carby?

                            Comment


                              #15
                              I haven't looked into the ford and holden reflash stuff but I'm betting there are a heap of base duty, PID and per gear tables you can tweak so it comes on a bit harder than a stocker with electronic control.

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