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M42 Supersprint Fitment and Leaks

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    M42 Supersprint Fitment and Leaks

    I recently picked up a brand new Supersprint catback for my 318is and am having troubles getting the fitment correct. It’s slightly twisted and the tip is really close to the valence opening.

    I’m using Bosal stock mounting muffler clamps (which were a total bitch to install by the way, and also required welding of the bracket tabs to not separate on install).

    Also, when I started it up for the first time both connections were visibly leaking both vapour and condensation. No where can I find of these sections needed gaskets or not.

    Any help or insights appreciated!
    Steve • Toronto
    1991 318is • Brillantrot
    Build Thread

    #2
    Not sure if I can be of any help, would like to see pictures though.
    Supersprint fitment should be perfect, no welding. I adjust the muffler clamps to center the tail pipe. Badly leaking?, plugging the end of the tailpipe with your hand should show leaks in the system.
    Biggest question I have for you though, when it’s all finished-
    Is it louder than the old style supersprint? The new ones don’t have the resonator up front and I am wondering if the new style is louder. Thanks, good luck to you

    Comment


      #3
      Originally posted by SlickAlpinweiss View Post
      Not sure if I can be of any help, would like to see pictures though.
      Supersprint fitment should be perfect, no welding. I adjust the muffler clamps to center the tail pipe. Badly leaking?, plugging the end of the tailpipe with your hand should show leaks in the system.
      Biggest question I have for you though, when it’s all finished-
      Is it louder than the old style supersprint? The new ones don’t have the resonator up front and I am wondering if the new style is louder. Thanks, good luck to you
      The fitment is definitely top notch, which leads me to believe I am doing something wrong myself.

      How do you adjust the clamps for fitment? I thought you just tighten them up and thats that. Maybe thats where I am going wrong.

      The leaks were very apparent without even needing to block the tip with my hand. See attached pics showing the "vapour" leaking out when I started it up for the first time.


      You can also see the leaking condensation from both connections. This was only after 5 minutes of idling when I started it up for the first time after install.

      Steve • Toronto
      1991 318is • Brillantrot
      Build Thread

      Comment


        #4
        Wow those pictures show exactly what you were saying, but sorry I’ve got no idea why it leaks like that.
        Centering the muffler tip in the valance I meant to say adjust the muffler straps, but it could just be worn out rubber muffler hanger mounts.
        The leaking could just need more tightening, but too tight and your bolts will snap. I would try just covering the end with my hand and see how bad it leaks out from some point and just double check if there might be some hole or something.

        Comment


          #5
          So an update here - I was able to get the fitment for the tip in the valence opening close, but not 100% perfect. I was able to take the car for its first drive with the new exhaust last night and noticed that its still leaking at the joints, both condensation (to start) and fumes.

          Also noticed a hefty rattle coming from the exhaust, which might be it touching the heat shield.

          Any help or insights would be greatly appreciated! Like I've said, I have no doubts about the quality of the exhaust - I am almost certain it is me doing something wrong but I cant figure out what that is yet.
          Steve • Toronto
          1991 318is • Brillantrot
          Build Thread

          Comment


            #6
            Did you use exhaust sealant paste in the connecting joints? That will help seal up leaking and condensation. For fitment I hope someone else might have an explanation.
            I still want to hear what the new supersprint sounds like, this one without the resonator.
            I know the old ones are very quiet, post a video if you can.

            Comment


              #7
              Originally posted by SlickAlpinweiss View Post
              Did you use exhaust sealant paste in the connecting joints? That will help seal up leaking and condensation. For fitment I hope someone else might have an explanation.
              I still want to hear what the new supersprint sounds like, this one without the resonator.
              I know the old ones are very quiet, post a video if you can.
              Sorry - I updated this in my build thread but never updated this thread. See below.

              I did not use exhaust sealant, but now that its installed, I will probably use the sealant next time I take it off just to be sure its sealed.

              I will also record some video of the exhaust and post it here soon - I just haven't have the time to do it unfortunately. I haven't even heard it from outside the car yet, but from what others have told me when they've heard me driving, it sounds really good and matches the M42 well.

              FINALLY got my exhaust figured out. Turns out I couldn't get the slip over connection fully seated which is why it was leaking. I simply spread the 'slots' with a flat head screwdriver and it slips right on. Re-clamped it with some vice grips and boom, all good.

              Only issue I have now is that the tip hits the valence slightly, but once the brand new rubber hanger donuts wear in a bit it should droop enough to stop rubbing the valence.


              Here is where I had to spread to make it fit.

              Steve • Toronto
              1991 318is • Brillantrot
              Build Thread

              Comment


                #8
                Originally posted by SlickAlpinweiss View Post
                Did you use exhaust sealant paste in the connecting joints? That will help seal up leaking and condensation. For fitment I hope someone else might have an explanation.
                I still want to hear what the new supersprint sounds like, this one without the resonator.
                I know the old ones are very quiet, post a video if you can.
                I was finally able to get a sound clip, just an iPhone drive by clip but at least its something.

                https://www.youtube.com/watch?v=u_KkYd6liUY
                Steve • Toronto
                1991 318is • Brillantrot
                Build Thread

                Comment


                  #9
                  I fitted the same exhaust and I'm also experiencing fitment issues. The tip points up and goes very close to the valance. I wrestled with it for a few hours today and I finally got it to where it doesn't touch, but it's still very close. It's also very close to the heat shield at the first bend down from the cat. I expected better fitment from a Supersprint exhaust, but the quality is very good. It just appears that it wasn't designed quite right. It sounds very nice though. It's pretty quiet and I didn't hear any drone on the test drive I took it on today. This particular exhaust is E.C.C. homologated, which means it matches the original exhaust in noise and back pressure, which appears to be a requirement for road cars in Europe. It comes with a certificate. There is another one for the 318is with dual pipes that is not homologated, so it would be louder and may not have the correct back pressure. https://www.supersprint.com/ww-en/su...e30-318is.aspx. I'm still happy with the exhaust and I would buy it again. If I hear the exhaust hitting under the car I'll just have to take it to a shop that can correct the fitment.

                  Here's an FAQ on homologated exhausts: https://www.walker-eu.com/en-uk/walk...xhaust-system/





                  Plug and Play Wiring Harness Adapters for S54, S50, M54 and more.

                  Comment


                    #10
                    To achieve proper fitment at the valence, which is a 6 cyl one in your case, you should adjust/bend the wrap around hangers just below their rubber mountings. When I fitted my Stromung I started with the forward one for gross adjustment and moved to the aft one for fine tuning. A lift is a great help here if you can get some time on one.

                    Comment


                      #11
                      Originally posted by roguetoaster View Post
                      To achieve proper fitment at the valence, which is a 6 cyl one in your case, you should adjust/bend the wrap around hangers just below their rubber mountings. When I fitted my Stromung I started with the forward one for gross adjustment and moved to the aft one for fine tuning. A lift is a great help here if you can get some time on one.
                      2nd that!

                      Comment


                        #12
                        I bent down the exhaust hangers a little and it fits now. Thanks guys!
                        Plug and Play Wiring Harness Adapters for S54, S50, M54 and more.

                        Comment

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