Help sorting my underboosting S2?

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  • gunman
    S2Forum Maniac
    • Jan 2009
    • 660
    • Country: Northern Ireland

    #31
    Back from the garage now and the test was somewhat inconclusive. We could see no smoke form anywhere, tested the IM on it's own and the IC. The machine was showing a flow though when connected up to the entire system, although no smoke was seen. His theory was that the turbo seals had gone and it was leaking into the exhaust. He reckoned that we weren't seeing smoke in the exhaust as the cats stopped it.

    we checked the play in the shaft in the turbo and there was a bit, even put the boroscope in there to take a look. TBH, the car does use a bit of oil and there was oil in the intercooler when I had it off last week.

    So not sure what the best option is now, I have a spare turbo but don't believe it to be any better than whats on there. Do I go recon or look for another turbo?

    Any before anyone starts mentioning RS2 spec here, be advised.... I cant afford that right now
    1996 Audi S6 Avant.
    1994 80 TDI - Daily Driver

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    • AndyP
      S2Forum Zealot
      • Feb 2004
      • 6049
      • Country: England

      #32
      Whe the seals on my turbo had gone the boost was leaking down the oil return line and into the sump. Try removing the oil reurn line and pressure testing it again, you should be able to hear the leak if there is one.
      sigpic
      1991 Audi S2 3B - 2.5 Stroker engine
      1997 A6 2.5TDi quattro avant - C4
      1976 RD250E / 350LC cafe racer

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

        #33
        Pressurize with proper pressure.
        That smoke machine probably does like 2 psi if that.

        You need to get at least 7-8 in there.
        http://tuner.ee - http://www.facebook.com/tuner.ee

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        • gunman
          S2Forum Maniac
          • Jan 2009
          • 660
          • Country: Northern Ireland

          #34
          Originally posted by prj
          Pressurize with proper pressure.
          That smoke machine probably does like 2 psi if that.

          You need to get at least 7-8 in there.
          It was tested at over 0.5bar.
          1996 Audi S6 Avant.
          1994 80 TDI - Daily Driver

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

            #35
            Originally posted by gunman
            It was tested at over 0.5bar.
            Meh. You are going to boost at least 1.2 Bar stock so test at that level. 0.5 bar proves nothing.
            RS2'd 93 UrS4 5 spd sedan
            94 UrS4 V8 6 spd manual avant

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            • gunman
              S2Forum Maniac
              • Jan 2009
              • 660
              • Country: Northern Ireland

              #36
              7 or 8 psi not going to tell much either then. I don't know what to do then, i tried a boost leak test myself and found nowt, the smoke test showed nothing so I am non the wiser and out of options .
              1996 Audi S6 Avant.
              1994 80 TDI - Daily Driver

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              • stocious
                S2Forum Maniac
                • Jul 2012
                • 838
                • Country: Ireland

                #37
                did you test your gauge ? shot in the dark but i would test if mine!! would a blocked cat/cats do this also. MAYBE and im not sure on this but id also remove wastegate and check what pressure it open at with a compressor and regulator, watch it open/close and make sure its not sticking. if im wrong in any of what i said im sure someone will put right, just trying to help and good luck
                1991 S2 3B Coupe, KW v1, solid sub frames, poly bushed, chipped, about 260 ish

                Comment

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

                  #38
                  Originally posted by gunman
                  7 or 8 psi not going to tell much either then. I don't know what to do then, i tried a boost leak test myself and found nowt, the smoke test showed nothing so I am non the wiser and out of options .
                  How long did it hold 0.5 bar after you put it in?
                  http://tuner.ee - http://www.facebook.com/tuner.ee

                  Comment

                  • gunman
                    S2Forum Maniac
                    • Jan 2009
                    • 660
                    • Country: Northern Ireland

                    #39
                    Originally posted by prj
                    How long did it hold 0.5 bar after you put it in?

                    It held pressure constanly as it was hooked to an air line, there's 2 gauges, one shows pressure and the other shows flow, there was a constant flow shown in order to maintain pressure. If we turned down the air supply the pressure dropped fairly quick (few secs).
                    1996 Audi S6 Avant.
                    1994 80 TDI - Daily Driver

                    Comment

                    • murat
                      S2Forum Enthusiast
                      • Oct 2005
                      • 167
                      • Country: Turkey

                      #40
                      Originally posted by gunman
                      It held pressure constanly as it was hooked to an air line, there's 2 gauges, one shows pressure and the other shows flow, there was a constant flow shown in order to maintain pressure. If we turned down the air supply the pressure dropped fairly quick (few secs).
                      You have a leak then
                      Cheers

                      Murat

                      Comment

                      • gunman
                        S2Forum Maniac
                        • Jan 2009
                        • 660
                        • Country: Northern Ireland

                        #41
                        Originally posted by murat
                        You have a leak then
                        Yes, I know that, but I can't find it. We reckon'd that it could be leaking at the turbo seass, possibly into the exhaust or the oil returun.
                        1996 Audi S6 Avant.
                        1994 80 TDI - Daily Driver

                        Comment

                        • stocious
                          S2Forum Maniac
                          • Jul 2012
                          • 838
                          • Country: Ireland

                          #42
                          pressure test it again, whole system and then in sections and surely that will show up where the pressure loss is occouring, if not at least youl know that its elsewhere. how did you test the IM? engine will always have a valve open, cant see logic in that ! or im missing something .
                          1991 S2 3B Coupe, KW v1, solid sub frames, poly bushed, chipped, about 260 ish

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                          • gunman
                            S2Forum Maniac
                            • Jan 2009
                            • 660
                            • Country: Northern Ireland

                            #43
                            yes, there was loss but no smoke coming out anywhere so we assumes no leaks (externally anyway).
                            1996 Audi S6 Avant.
                            1994 80 TDI - Daily Driver

                            Comment

                            • murat
                              S2Forum Enthusiast
                              • Oct 2005
                              • 167
                              • Country: Turkey

                              #44
                              try blocking turbo outlet. And pressurize it slowly, see if it holds without flow
                              Cheers

                              Murat

                              Comment

                              • stocious
                                S2Forum Maniac
                                • Jul 2012
                                • 838
                                • Country: Ireland

                                #45
                                and listen through filler cap/exhaust pipe.
                                1991 S2 3B Coupe, KW v1, solid sub frames, poly bushed, chipped, about 260 ish

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