20v keep blowing turbo, help please

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  • twoqu
    S2Forum Possessed
    • Sep 2003
    • 3103

    #76
    If its possible I would go back and measure the oil pressure cold and hot again and see whether its dropped compared to what you had before.
    I would also remove the wastegate cap and physically examine the spring. Either post a pic or measure the total height and ideally the wire thickness so we can determine whether it is a stock one.
    Shouldn't really have a strong smell of petrol in relatively fresh oil so that might indicate an injector issue which for piece of mind might warrant a test session for leaking and flow.
    Of course none of this might be the cause of your problem. The boost profile for that Volvo turbo according to PRJ is a 1.9 bar peak and 1.7 bar redline! How marginal that is I don't know but of the two turbos surely the one with the smaller turbine would be more likely to overspeed. Whether the extra 0.3bar base is necessary to achieve that I am unsure as the profile was quoted on a 1.9 bar spring and a flat out N75 by the look of it!
    The K27/26 also has a similiar profile. So in theory neither should have been knackered at the boost levels you have quoted. We know that the stock oil system is adequate for most needs and that the KKK turbo are usually pretty durable.
    As for the fuel pump, essentially it is the wrong spec for a 20V. The 10V pumps are biased towards high pressure for the K-jet and less volume whereas the Motronic wants higher flow with less pressure. At sometime might be worth looking at say a 044. Can't see a connection between this and the turbo issue!

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    • george21
      S2Forum Addict
      • Aug 2007
      • 226
      • Home: Lithuania Current: United Kingdom

      #77
      Oil pressure with new 10/40 semi.
      On cold 5.5 bar
      On hot 1.8-1.9 bar
      When throttle aplyed pressure goes up to 5.5 bar with revs.
      I think it is possibility that wrong fuel delivery can cause that .
      Injectors overflows
      Cleans cylider bores
      Makes blowby and thins oil
      Oil can not flow from the turbo to the sump fast enough
      Oil with petrol lubricates turbo bearing not enough and bang
      turbo ****ed.

      Is any logic there, is that possible?
      How do i do a test on injectors?
      I know on k-jet it's easy, 5 coke bottles, jumper wire and clock.
      I guess here it is a bit harder?

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      • twoqu
        S2Forum Possessed
        • Sep 2003
        • 3103

        #78
        Oil pressure sounds more reasonable than before.
        I would have thought that fuel diluting the oil would have made it thinner but it certaintly would effect its lubricating propieties. Then again your oil pressure seemed higher and you were using a thicker grade oil!
        The only test you can do really with the injectors is to see whether they leak when pressurised by connecting them up to the fuel rail out of the head and pressurising the system. It might be obvious which if any leaks. Due to the potential hazzard it might be better to have then looked at by someone with the proper kit (ASNU)! Bit frustrating to have to spend money on something that might be ok but what price piece of mind?

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        • mac2226
          S2Forum Extremist
          • Jun 2008
          • 1289
          • Country: United Kingdom

          #79
          Hi George did you find the problem why it was killing turbos?

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