Boost test (leaking turbo)

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  • nip
    S2Forum Extremist
    • Apr 2006
    • 1786
    • Home: United Kingdom Current: Abu Dhabi

    #1

    Boost test (leaking turbo)

    Well ive boost tested it yet again today but all i hear is air p155ing out of the turbo cant feel any air but can hear it, also it wont hold any pressure what so ever.
    My car being suffering with being down on power it boosts to 20-25psi but has no real go to it(feels like just blowing hot air). Also running standard power turbo ect.
    Any ideas???
    cheers nip
    Last edited by nip; 5 August 2012, 15:11.
  • martinws
    S2Forum Maniac
    • Oct 2008
    • 917
    • Country: Scotland

    #2
    Have you blanked of the small diameter hose going to the Lower wastegate chamber before testing?

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    • nip
      S2Forum Extremist
      • Apr 2006
      • 1786
      • Home: United Kingdom Current: Abu Dhabi

      #3
      Originally posted by martinws
      Have you blanked of the small diameter hose going to the Lower wastegate chamber before testing?
      I tested it with it still on, then blanked if off but still was the same

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      • driftin jo
        S2Forum Fiend
        • Sep 2007
        • 2222
        • Country: United Kingdom

        #4
        Originally posted by nip
        Well ive boost tested it yet again today but all i hear is air p155ing out of the turbo cant feel any air but can hear it, also it wont hold any pressure what so ever.
        My car being suffering with being down on power it boosts to 20-25psi but has no real go to it(feels like just blowing hot air). Also running standard power turbo ect.
        Any ideas???
        cheers nip
        Your running a standard turbo ? At 20-25 psi ? Thats way over what chipped standard
        set up should do !

        Standard RS2 is only 21 psi .

        Comment

        • nip
          S2Forum Extremist
          • Apr 2006
          • 1786
          • Home: United Kingdom Current: Abu Dhabi

          #5
          Originally posted by driftin jo
          Your running a standard turbo ? At 20-25 psi ? Thats way over what chipped standard
          set up should do !

          Standard RS2 is only 21 psi .
          It's also chipped (forgot to add that) , it always run about 20-25 psi

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          • UrS4boy
            S2Forum Obsessed
            • Feb 2006
            • 11859
            • Country: Canada

            #6
            Originally posted by driftin jo
            Standard RS2 is only 21 psi .
            But it can be chipped to run 28 psi.
            RS2'd 93 UrS4 5 spd sedan
            94 UrS4 V8 6 spd manual avant

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            • driftin jo
              S2Forum Fiend
              • Sep 2007
              • 2222
              • Country: United Kingdom

              #7
              Originally posted by UrS4boy
              But it can be chipped to run 28 psi.
              Yes but this is a stock S2, so chipped will only do 21-22 psi max before it's just a
              furnace of hot air.

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              • newsh
                S2Forum Obsessed
                • Aug 2003
                • 16226
                • Country: United Kingdom

                #8
                Check the bolts holding the cold side on, mine were loose. I took them all out and re-fitted with blue loctite. Also check the hose from the cold side to the WGFV is not split and the WGFV is not cracked or broken, I've had this too. Best to pull the hose of the WGFV and plug the end to test (don't drive it like this though!)

                Blowing like mad and not making power can also be the MAF connector corroded and the vac line to the ECU leaking.

                S2 Coupe 3B Project


                Ur quattro restoration

                S2 Avant

                Boost is the new rock and roll!
                sigpic

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                • nip
                  S2Forum Extremist
                  • Apr 2006
                  • 1786
                  • Home: United Kingdom Current: Abu Dhabi

                  #9
                  Originally posted by newsh
                  Check the bolts holding the cold side on, mine were loose. I took them all out and re-fitted with blue loctite. Also check the hose from the cold side to the WGFV is not split and the WGFV is not cracked or broken, I've had this too. Best to pull the hose of the WGFV and plug the end to test (don't drive it like this though!)

                  Blowing like mad and not making power can also be the MAF connector corroded and the vac line to the ECU leaking.
                  Cheers newsh, il check them tomorrow I also took the pipe from the n75 to the turbo off pressure tested it then put my finger over the turbo nipple and it held pressure, it seems like its leaking somewhere in the middle of the turbo I can hear the air bubbling in the sump.

                  Comment

                  • newsh
                    S2Forum Obsessed
                    • Aug 2003
                    • 16226
                    • Country: United Kingdom

                    #10
                    Ok, if it's bubbling the oil then that's fairly normal Could mean your turbo is getting tired though..

                    S2 Coupe 3B Project


                    Ur quattro restoration

                    S2 Avant

                    Boost is the new rock and roll!
                    sigpic

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                    • nip
                      S2Forum Extremist
                      • Apr 2006
                      • 1786
                      • Home: United Kingdom Current: Abu Dhabi

                      #11
                      Originally posted by newsh
                      Ok, if it's bubbling the oil then that's fairly normal Could mean your turbo is getting tired though..
                      If it bubbles the oil in the sump so that means air is escaping through the turbo seals then, also if the air is leaking surely that can't be normal can it?

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                      • nip
                        S2Forum Extremist
                        • Apr 2006
                        • 1786
                        • Home: United Kingdom Current: Abu Dhabi

                        #12
                        Pressure tested it again today, still the same it seemed as the turo was leeking before, its more like the bottom of the wastegate, if I block the pipe going into the wastegate from the n75 it doesn't leak so does that mean the gate is knackered?

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                        • newsh
                          S2Forum Obsessed
                          • Aug 2003
                          • 16226
                          • Country: United Kingdom

                          #13
                          It does mean there's air getting through the wastegate valve guide, however this is less of a problem when driving as there's boost pressure one side and exhaust pressure the other side to balance it somewhat. I would just take the top off the wastegate (6 small nuts) and see how much you can wobble the top of the valve from side to side. If it's really bad then get it refurbed. The leak will tend to make the car boost more than it should.

                          S2 Coupe 3B Project


                          Ur quattro restoration

                          S2 Avant

                          Boost is the new rock and roll!
                          sigpic

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                          • nip
                            S2Forum Extremist
                            • Apr 2006
                            • 1786
                            • Home: United Kingdom Current: Abu Dhabi

                            #14
                            Originally posted by newsh
                            It does mean there's air getting through the wastegate valve guide, however this is less of a problem when driving as there's boost pressure one side and exhaust pressure the other side to balance it somewhat. I would just take the top off the wastegate (6 small nuts) and see how much you can wobble the top of the valve from side to side. If it's really bad then get it refurbed. The leak will tend to make the car boost more than it should.
                            Cheers newish, I did that today it does wobble allot, il replace the gate and see if it cures it.

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                            • prj
                              S2Forum Zealot
                              • Mar 2010
                              • 6308
                              • Country: Estonia

                              #15
                              Every single one of these gates leak to the exhaust and it doesn't matter because it seals up when hot.
                              Just make sure the membrane is not shot.

                              I would measure the compression in the engine, because it's been knocking like crazy if it's running 25 psi on standard turbo.
                              I'd say the rings are shot because of det and it needs a rebuild.
                              http://tuner.ee - http://www.facebook.com/tuner.ee

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