Problems running above 2bars of boost

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  • Faheemo
    S2Forum Maniac
    • Feb 2005
    • 544
    • Country: South Africa

    #1

    Problems running above 2bars of boost

    My car has been running 1.9bar boost for awhilst ,but i decided it is time to up the boost for more FUN.
    I've got all the necessary hardware required to Run 2.2bars or so i taught.
    I started off slowly by adding more fuel to the map and raising the boost controller to 2.0 bars at first then 2.05 bars. This was no problem.
    Once i tried to go above 2.05 to 2.1 bars the car would just not boost above 2.05 bars.
    It just held 2.05 bars till redline, with AFR knock and EGT in check.
    I cranked the boost controller up to 2.2 bars to see if the boost controller would raise the boost but it stayed at 2.05 bars for a few runs then all of a sudden the car would not boost more then 1 bar.
    I suspect the DV or wastegate to be stuck, but i would really would like to know why the car would not boost more then 2.05 bars.
    The wastegate is Stock Audi , boost controller is GReddy and the Dv is forge.
    Are ther any previous issues with the wastegate maybe not being able to hold the boost?
    Map sensor on the ECU is VMAP D.
    any ideas ?

    S2 Coupe fully built.
    10.9 1/4mile 0-100 in 3.5secs
    Precision 6262 turbo
    The Green Monster
  • GazzaG60
    S2Forum Freak
    • Mar 2007
    • 4133
    • Country: United Kingdom

    #2
    whats the boost limit on the controller?

    some have map based boost limit. others x amount over can pressure.

    id expect creep if the gate was flooded.

    Comment

    • Faheemo
      S2Forum Maniac
      • Feb 2005
      • 544
      • Country: South Africa

      #3
      Greddy Profec B - The spec says max of 43Psi.
      thats 2.9bar boost.

      S2 Coupe fully built.
      10.9 1/4mile 0-100 in 3.5secs
      Precision 6262 turbo
      The Green Monster

      Comment

      • s2_bo
        S2Forum Zealot
        • Oct 2005
        • 6067
        • Home: United Kingdom Current: France

        #4
        Is the turbo capable of 2.2 bar?
        Could be that the ECU is restricting it. Just upping the boost with out altering the ignition map could course a few issues as your already running so much boost.
        91 S2 coupé - RIP
        98 S8 - Luxury barge

        Comment

        • Jamo
          Retired OG Mod
          • Mar 2004
          • 21750
          • Country: United Kingdom

          #5
          Turbo can do 2.2 no problem

          Comment

          • A80Avant
            S2Forum Obsessed
            • Sep 2005
            • 10873
            • Country: Greece

            #6
            he is using a boost controller so the ECU is not controlling boost anyway

            Comment

            • Jonas_R
              S2Forum Possessed
              • Jan 2004
              • 3780
              • Country: Denmark

              #7
              is the 43 psi relative or absolute?
              Sleeper S2 Avant +450

              A6 Avant 2.7t Stage 3

              Audi S2 Coupe RS2'ed

              Comment

              • Jamo
                Retired OG Mod
                • Mar 2004
                • 21750
                • Country: United Kingdom

                #8
                Originally posted by Jonas_R
                is the 43 psi relative or absolute?
                The manual doesn't state it whether its relative or absolute

                Comment

                • Jonas_R
                  S2Forum Possessed
                  • Jan 2004
                  • 3780
                  • Country: Denmark

                  #9
                  If it was absolute, then 2.05 bar seems just on the money
                  Sleeper S2 Avant +450

                  A6 Avant 2.7t Stage 3

                  Audi S2 Coupe RS2'ed

                  Comment

                  • Rocco
                    S2Forum Zealot
                    • Aug 2007
                    • 6393
                    • Country: Spain

                    #10
                    good luck partner, i am having more or lees the same problems as you....

                    i cant rearch 2.0bar like in the past...and now only i can manage 1´3bar and the AFR numbers are much bad than before
                    RED Mitsubishi Lancer Evolution VI TME nº 16 of 250
                    BLACK Mitsubishi Lancer Evolution VI TME nº 189 of 250
                    LWB Audi Sport Quattro project

                    Comment

                    • Faheemo
                      S2Forum Maniac
                      • Feb 2005
                      • 544
                      • Country: South Africa

                      #11
                      Problem sorted out !
                      The Greddy uses both chambers on the wastegate - top and bottom.
                      The Boost pipe to the wastegate was cracked and leaking underneath the heatproof fibre insulation i have on them.
                      The cause of the 1 bar (wastegate spring) boost was that the electrical cable to the greddy boost solenoid frayed and broke off at the connector they supply.
                      I removed the connector and soldered the cables and insulated them well.
                      Did a log, car boosted to 2.1bar as required.

                      See how the car knocks when 2.1 bar of boost hits.
                      The User1 signal is the Knock sensor. The spikes indicate knock.
                      I will correct timing and fueling and try again.

                      BTW: i think the logging system i have is Brilliant !
                      Recommend it to others that are doing self tunes.
                      Attached Files

                      S2 Coupe fully built.
                      10.9 1/4mile 0-100 in 3.5secs
                      Precision 6262 turbo
                      The Green Monster

                      Comment

                      • Jonas_R
                        S2Forum Possessed
                        • Jan 2004
                        • 3780
                        • Country: Denmark

                        #12
                        What knock system are you using? Btw Zeitronix have realeased a new version of the Datalogger box so know it can take two inputs. I believe they are running a upgrade sale at the moment.
                        Sleeper S2 Avant +450

                        A6 Avant 2.7t Stage 3

                        Audi S2 Coupe RS2'ed

                        Comment

                        • Faheemo
                          S2Forum Maniac
                          • Feb 2005
                          • 544
                          • Country: South Africa

                          #13
                          I run, Phormula KS3 Knock system.

                          Zeitronix costing too much money every time to upgrade to new functionality !
                          I did the last upgrade for the ZAVT alarm.
                          Should have bought a innovate with that money.

                          S2 Coupe fully built.
                          10.9 1/4mile 0-100 in 3.5secs
                          Precision 6262 turbo
                          The Green Monster

                          Comment

                          • A80Avant
                            S2Forum Obsessed
                            • Sep 2005
                            • 10873
                            • Country: Greece

                            #14
                            megalogviewer is similar in doing logs and viewing them

                            how accurate is this knock sensing system? Have you tried comparing it to the simple headphones systems?

                            also, if you delay the boost a bit you will get away with not having any knock.

                            Comment

                            • EspenW
                              S2Forum Extremist
                              • Apr 2007
                              • 1534
                              • Country: Norway

                              #15
                              Interesting. What is your timing at the onset of knock?
                              What octane fuel are you getting down in SA? Access to ethanol at all?
                              1995 RS2 on Alcohol (6.8sec 100-200km/h)
                              1994 80E Avant
                              1986 2L Golf 2 on Alcohol

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