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Why does my Boost fall?

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    Why does my Boost fall?

    What are the reasons that could cause my boost to hit 8psi then fall to 6 or 5 almost right away? I have an internal waste gate.
    Too small? Blood Sweat and Tears Build:
    http://www.r3vlimited.com/board/showthread.php?t=202389

    #2
    Leaky wastegate. Leaky boost pipes. Leaky BOV.
    BimmerHeads
    Classic BMW Specialists
    Santa Clarita, CA

    www.BimmerHeads.com

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      #3
      wastegate lag whats is the wastegate set to?

      exhaust piping, manifold design, there is alot of things at work here.

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        #4
        Originally posted by mr 325 View Post
        leaky wastegate. Leaky boost pipes. Leaky bov.
        +1

        1986 335is-1988 335ist -1991 335istsigpic

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          #5
          sounds like a boost leak test is needed. In my experience if you look at your car wrong you will get a boost leak

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            #6
            Originally posted by Toadleg View Post
            sounds like a boost leak test is needed. In my experience if you look at your car wrong you will get a boost leak
            Haha i would agree, ok thanks guys. I had a feeling that it was one of those things, but i figured i should ask incase there was something i missed. I will go tighten things up and then go from there.

            Whats the best way to test for a leak?
            Just doing the whole block off both sides and use an air compressor?
            Last edited by Lrutts; 07-17-2011, 02:00 PM.
            Too small? Blood Sweat and Tears Build:
            http://www.r3vlimited.com/board/showthread.php?t=202389

            Comment


              #7
              On one of my cars I take the intake off the turbo and attach to that With whatever works for you size intake. For me it was a 2 inch mission band with pvc cap and thread in a schrader valve. Get a compressor and pump it up and you will hear the leaks or spray soapy water on pipes and bubbles will appear. You will have to cap off a couple lines that will just leak air I dont know your set up mine is one of those turbo neons.

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                #8
                Try and get it to hold 15lb for as long as possible you will get some leak by in the head

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                  #9
                  On my car i switched to an external waste gate and that seemed to help with boost spike also

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                    #10
                    classic boost leak
                    my build here ---> http://www.r3vlimited.com/board/show...ht=lemans+blue

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                      #11
                      Are you able to hear any faint rattling during boost?

                      1991 325iS turbo

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                        #12
                        Originally posted by ak- View Post
                        Are you able to hear any faint rattling during boost?
                        No it sounds fine, i can't even hear a wine or anything like that. I went to home depot to get the stuff i need to make a home made boost leak test kit, they had nothing.....
                        Too small? Blood Sweat and Tears Build:
                        http://www.r3vlimited.com/board/showthread.php?t=202389

                        Comment


                          #13
                          Whats yor wastegate supposed to be set to?
                          Your signature picture has been removed since it contained the Photobucket "upgrade your account" image.

                          www.gecoils.com
                          My euro 316 project Transaction Feedback

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                            #14
                            8psi, ebay turbo
                            Too small? Blood Sweat and Tears Build:
                            http://www.r3vlimited.com/board/showthread.php?t=202389

                            Comment


                              #15
                              what size ebay turbo?

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