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  • #16
    James @ Redish has a plan, but not having the technical verbal knowledge to explain I'd end up making a hash of what he's planning. I'm expecting another video off him at the end of the week which should explain what he's attempting to do.
    Last edited by ROCKAPE; 14-03-2017, 10:38 PM. Reason: Spelling mistake

    Comment


    • #17
      Originally posted by ROCKAPE View Post
      Hi Tony

      Just the installation has cost £3,000 + £550 for the kit.
      Ouch... Still, peace of mind from knowing top job done. Shame about the exhaust fiasco! That's a ridiculous situation.

      Thanks for sharing the info. Really useful for us all to know
      Not actually in the least bit fat

      2000 S50 Titanium Silver / Black
      ACS Suspension, Exhaust & Type III Wheels
      Simota carbon air intake | Strong Strut Front Brace

      Comment


      • #18
        Hi guys,
        James @ Redish Motorsport here.

        Myself and customer James thought it would be good to show my plan/workings and if it's possible to alter the OEM Z3M Rear Silencers in such a drastic way (video below) to clear the new 'dual ear diff mount'.

        Here's a video of my plan.
        I purchased a set of replacement exhausts so we didn't have to cut up the customer's silencers to 'learn' about this internal layout.
        I like to think of it as a practice run.

        There's still no guarantee this can even be done, or even if it is done, I'm not sure how the acoustics will change.

        I'm no exhaust specialist, and don't claim to be, so this is why I thought it might be useful/interesting for the community to discuss this exhaust plan and show my workings as we go.
        There might be something I've missed which someone can point out.

        From reading above, there are some knowledgabe members on here, especially with previous exhaust modification experience like Jon_Bmw, and Randy Forbes - so thanks for sharing your information already.

        Anyway, here's the most recent video:
        https://youtu.be/lCuOUxhZY8w

        Feel free to discuss.

        Best regards,
        James :)

        Comment


        • #19
          Originally posted by Dakar View Post
          Hi guys,
          James @ Redish Motorsport here.

          Myself and customer James thought it would be good to show my plan/workings and if it's possible to alter the OEM Z3M Rear Silencers in such a drastic way (video below) to clear the new 'dual ear diff mount'.

          Here's a video of my plan.
          I purchased a set of replacement exhausts so we didn't have to cut up the customer's silencers to 'learn' about this internal layout.
          I like to think of it as a practice run.

          There's still no guarantee this can even be done, or even if it is done, I'm not sure how the acoustics will change.

          I'm no exhaust specialist, and don't claim to be, so this is why I thought it might be useful/interesting for the community to discuss this exhaust plan and show my workings as we go.
          There might be something I've missed which someone can point out.

          From reading above, there are some knowledgabe members on here, especially with previous exhaust modification experience like Jon_Bmw, and Randy Forbes - so thanks for sharing your information already.

          Anyway, here's the most recent video:
          https://youtu.be/lCuOUxhZY8w

          Feel free to discuss.

          Best regards,
          James :)

          Welcome to the forum

          Comment


          • #20
            Originally posted by Dakar View Post
            From reading above, there are some knowledgabe members on here, especially with previous exhaust modification experience like Jon_Bmw, and Randy Forbes - so thanks for sharing your information already. )
            I'm sure forum member 'exdos' would have some useful insight to share. He's not as active on here as he once was though unfortunately

            Some of his existing posts may be useful if he doesn't see this thread
            Last edited by Fat Tony; 16-03-2017, 11:28 AM. Reason: Added link to exdos profile page
            Not actually in the least bit fat

            2000 S50 Titanium Silver / Black
            ACS Suspension, Exhaust & Type III Wheels
            Simota carbon air intake | Strong Strut Front Brace

            Comment


            • #21
              James,

              I will have a look at the video tonight / tomorrow.

              By the way, fair play for doing such a good job on the video for the customer on the issues. That is proper service.

              I suspect Randy might be well placed for the 'best' advice because it is his kit and he HAS to have come across this problem before.

              Thanks

              Jon

              Comment


              • #22
                Great video James, I'm not sure there's such an detailed dissection of Z3M silencers out there!
                Once the end plates have been swapped is there a need to fabricate tubing within the 1st compartment to channel the gases to the entry point of the 2nd compartment? Would placing a plate (yellow line) at 45% at the new entry point and removing the perforated tube (red lines) in compartment 1 be enough to guide and allow the gases (blue lines) to move freely through the first compartment?
                I've just looked at the picture again and realised that another plate at 45% on the other side of compartment 1 would furthermore help channel the gases into compartment 2.
                Last edited by ROCKAPE; 06-04-2017, 07:05 PM.

                Comment


                • #23
                  Originally posted by Dakar View Post
                  Hi guys,
                  James @ Redish Motorsport here.

                  Myself and customer James thought it would be good to show my plan/workings and if it's possible to alter the OEM Z3M Rear Silencers in such a drastic way (video below) to clear the new 'dual ear diff mount'.

                  Here's a video of my plan.
                  I purchased a set of replacement exhausts so we didn't have to cut up the customer's silencers to 'learn' about this internal layout.
                  I like to think of it as a practice run.

                  There's still no guarantee this can even be done, or even if it is done, I'm not sure how the acoustics will change.

                  I'm no exhaust specialist, and don't claim to be, so this is why I thought it might be useful/interesting for the community to discuss this exhaust plan and show my workings as we go.
                  There might be something I've missed which someone can point out.

                  From reading above, there are some knowledgabe members on here, especially with previous exhaust modification experience like Jon_Bmw, and Randy Forbes - so thanks for sharing your information already.

                  Anyway, here's the most recent video:
                  https://youtu.be/lCuOUxhZY8w

                  Feel free to discuss.

                  Best regards,
                  James :)
                  I've been following your work over the past couple of months and I'm fascinated. Awesome attention to detail. I fear we may need to have a conversation in the not too distant future!

                  Build thread: https://www.z3mcoupe.com/forum/showthread.php?t=19347

                  Comment


                  • #24
                    Hi James,

                    I am answering your video as I go along. My brain capacity is too small to watch it all and try and answer your questions / thoughts, so by the end of the video you may have answered all my points below, sorry!

                    The stainless wrap around the perf muffler inlet pipe in chamber one is the protect the wadding from being burnt into 'balls' which will rattle.

                    You can see despite this wrap the wadding is most damaged close to the perf. Normal, this isn't a result of your grinding in my opinion.

                    To me the muffler will be designed like this;

                    Muffler perf pipe is expanded up a size to accept the muffler inlet (diff pipe). The perf pipe will be expanded up to the inlet end plate size. The muffler would be manufactured in one area and then the diff pipes welded as part of a final assessment, by operation. All three parts would then get rotary welded in one weld (diff pipe, end plate, perf pipe)

                    Where it gets complicated is the inner 60mm pipe within the 70mm section. I have a theory that this maybe due to heat. They probably wanted to keep the black paint on the silencer and diff pipes for visual reasons (due to low slung muffler). The amount of influence styling guys have within OEMs is ridiculous, well them and NVH guys! So potentially the inner pipe keeps the heat from burning the paint off during the design verification testing or overheating something under the body . How it is retained so it doesn't rattle I am not sure!


                    Right I watched some more of the video to the end now!

                    The reason it is expanded quite tight is to stop the rattle.

                    Ok so onto to your idea, yes that is what I was thinking at work the other day. To me I would try and and seperate the 3 parts I said earlier (good luck!). Then fit a 1D 90 degree that you capture in the muffler inlet weld. Then sleeve over a perf pipe the same length as the current one fitted in chamber one (most forward one in car line). Make this nice and tight and overly long. Slide it over the inlet 90 deg straight leg, then get another 90 degree and insert it into the cut original inlet perf pipe. slide your perf pipe so it now goes tightly over the top of both bends straight legs. Only stitch weld the perf to the second bend. This will allow a small amount of expansion on the muffler inlet pipe to stop things breaking. Use stainless wrap over the perf and lock wire in place.

                    Then you add your wadding back in over the top. Tig weld the silencer back together. Try to keep the heat from really building up around the lockseam part of the end plate. As this is a mechanical join, excess heat tends to unravel the lock seam and then they can leak a bit from here...not that you or anyone would notice to be honest!


                    One other option was to try and replicate the muffler inlet pipe in the new position but I am not sure there is enough room to do it or get a hole saw to the baffles? Then you would just blank the original muffler inlet perf pipe. You would lose a small amount of expansion volume but nothing serious.

                    Rock ape I think you are in fairly safe hands here, they come across in the videos as people who think like engineers first rather than just fit things like most dealerships. Christ I should be on comission


                    I hope this helps confirm you are on the right path?? Sorry for lots of typos I suspect....bloody tablet and autocorrect!

                    Thanks

                    Jon

                    Comment


                    • #25
                      This is all interesting, if somewhat overtly technical for me.

                      As someone said earlier, a lot of design work (time and cost) will have gone into the original exhaust. Bottom line is what is the benefit (unlikely to be reliability) over OEM? Can't honestly see the point for a road car.
                      S54 Titan Silver metallic. Black leather, most factory options including sunroof, Becker Cascade and Becker Silverstone changer.

                      Comment


                      • #26
                        Originally posted by Jon_Bmw View Post
                        Hi James,

                        I am answering your video as I go along. My brain capacity is too small to watch it all and try and answer your questions / thoughts, so by the end of the video you may have answered all my points below, sorry!

                        The stainless wrap around the perf muffler inlet pipe in chamber one is the protect the wadding from being burnt into 'balls' which will rattle.

                        You can see despite this wrap the wadding is most damaged close to the perf. Normal, this isn't a result of your grinding in my opinion.

                        To me the muffler will be designed like this;

                        Muffler perf pipe is expanded up a size to accept the muffler inlet (diff pipe). The perf pipe will be expanded up to the inlet end plate size. The muffler would be manufactured in one area and then the diff pipes welded as part of a final assessment, by operation. All three parts would then get rotary welded in one weld (diff pipe, end plate, perf pipe)

                        Where it gets complicated is the inner 60mm pipe within the 70mm section. I have a theory that this maybe due to heat. They probably wanted to keep the black paint on the silencer and diff pipes for visual reasons (due to low slung muffler). The amount of influence styling guys have within OEMs is ridiculous, well them and NVH guys! So potentially the inner pipe keeps the heat from burning the paint off during the design verification testing or overheating something under the body . How it is retained so it doesn't rattle I am not sure!


                        Right I watched some more of the video to the end now!

                        The reason it is expanded quite tight is to stop the rattle.

                        Ok so onto to your idea, yes that is what I was thinking at work the other day. To me I would try and and seperate the 3 parts I said earlier (good luck!). Then fit a 1D 90 degree that you capture in the muffler inlet weld. Then sleeve over a perf pipe the same length as the current one fitted in chamber one (most forward one in car line). Make this nice and tight and overly long. Slide it over the inlet 90 deg straight leg, then get another 90 degree and insert it into the cut original inlet perf pipe. slide your perf pipe so it now goes tightly over the top of both bends straight legs. Only stitch weld the perf to the second bend. This will allow a small amount of expansion on the muffler inlet pipe to stop things breaking. Use stainless wrap over the perf and lock wire in place.

                        Then you add your wadding back in over the top. Tig weld the silencer back together. Try to keep the heat from really building up around the lockseam part of the end plate. As this is a mechanical join, excess heat tends to unravel the lock seam and then they can leak a bit from here...not that you or anyone would notice to be honest!


                        One other option was to try and replicate the muffler inlet pipe in the new position but I am not sure there is enough room to do it or get a hole saw to the baffles? Then you would just blank the original muffler inlet perf pipe. You would lose a small amount of expansion volume but nothing serious.

                        Rock ape I think you are in fairly safe hands here, they come across in the videos as people who think like engineers first rather than just fit things like most dealerships. Christ I should be on comission


                        I hope this helps confirm you are on the right path?? Sorry for lots of typos I suspect....bloody tablet and autocorrect!

                        Thanks

                        Jon
                        Hi Jon,

                        Thank you very much for your detailed reply.
                        Having had first hand experience with the insides of the Z3M silencers and posting your pictures of them has helped a lot. So thanks again.

                        Yes, I suspect the outer 70mm pipe is simply a heatshield too (probably to stop heat soak into the driveshaft cvjoint rubbers which are close), and paint finish like you also mention.

                        I'm thinking exactly the same things as you; directing the new inline pipe location through a 90/straight/90 into the original location at chamber wall 1/2.

                        I went ahead and ordered some stainless 57mm & 60mm straight solid and straight perforated, as well as a 2.25" donut which seems to provide tighter 90's than a traditional mandrel bender could offer.

                        Here's a quick update video:

                        https://www.youtube.com/watch?v=8Px-ylOIS_M

                        The challenge I face is not wanting to cut a huge opening in the outer skin sheet of the rear silencers (remember, these silencers in the video are replacements I bought for investigation only, so still have the proper process to carry out on Rockape's silencers).
                        I'm don't mind cutting a small window above chamber 1 to allow access for welding and re-stuffing, but hope to keep chambers 2,3,4,5 covered (especially now that I have a 'dummy run' to see whats inside C2,3,4,5).

                        Also, I wasn't planning on putting exhaust wadding back into Chamber 1. It's extremely tight access (approx 80mm deep), and once has 3 pipes in there it's even harder to get your hands in to put the 1st layer of stainless wrap and lock wire.
                        The downside is nobody knows how this is going to work out or sound, so we only get 1 go at it.
                        I'll certainly take on board your suggestion of the stainless wrap and wadding for Chamber 1 and try to come up with a way to get it back in place (new).

                        The quickest way to do this would be to cut holes in Chamber Wall 1/2 and let the new inlet pipe location just feed straight into the twin outlet pipes, but then there is literally no silencing, and who knows what that will sound like or feel like for performance.
                        So it's worth investigating this 'S' bend idea in Chamber 1 to help feed the gas into it's original route.

                        Thanks for your input again.

                        Best regards,
                        James
                        Last edited by Redish; 21-03-2017, 12:52 PM.

                        Comment


                        • #27
                          Originally posted by Dave P View Post
                          Welcome to the forum
                          Thanks Dave

                          Comment


                          • #28
                            Originally posted by ROCKAPE View Post
                            Great video James, I'm not sure there's such an detailed dissection of Z3M silencers out there!
                            Once the end plates have been swapped is there a need to fabricate tubing within the 1st compartment to channel the gases to the entry point of the 2nd compartment? Would placing a plate (yellow line) at 45% at the new entry point and removing the perforated tube (red lines) in compartment 1 be enough to guide and allow the gases (blue lines) to move freely through the first compartment?
                            I've just looked at the picture again and realised that another plate at 45% on the other side of compartment 1 would furthermore help channel the gases into compartment 2.
                            Thanks James,

                            That's right, directing the flow of gas to the other side of the silencer (original inlet pipe) is the key I think).

                            It could well work just letting it enter chamber 1 and finding it's way to the other side naturally, but nobody knows, so it's better that we come up with a way to direct the gas flow from it's new inlet pipe to the original inlet pipe in chamber 1.

                            Thanks for the picture. That's the sort of thing I was thinking with pipe.
                            I've just replied to Jon's helpful post, and put an update video in there which shows the similar thing with pipe.
                            It's tight in there!

                            Thanks,
                            James :)

                            Comment


                            • #29
                              Originally posted by mnbrennan View Post
                              I've been following your work over the past couple of months and I'm fascinated. Awesome attention to detail. I fear we may need to have a conversation in the not too distant future!
                              Hi Martin,

                              Thanks for the kind words.
                              I remember seeing your M at Wellsway meet last year - I was with Roger's Phoenix and Mike's E30, but also saw a few customer's cars there: Rhys' Laguna, Pete's, 320ci etc.

                              Sounds good to me, feel free to call or email anytime.

                              Best regards,
                              James :)

                              Comment


                              • #30
                                Originally posted by ian View Post
                                This is all interesting, if somewhat overtly technical for me.

                                As someone said earlier, a lot of design work (time and cost) will have gone into the original exhaust. Bottom line is what is the benefit (unlikely to be reliability) over OEM? Can't honestly see the point for a road car.
                                Hi Ian,

                                Thanks for the question.
                                It's more of an investigation to see if an alteration can be made to keep the exhaust appearing OEM, to use with the Randy Forbes Dual Diff Cover Kit.

                                Usually when using the Dual Diff Cover (after Boot Floor reinforcement) you have to cut off the outer 70mm pipe, and hit the exhaust pipe inwards to clear the new Dual Diff Cover.
                                Or you stump up and buy an aftermarket exhaust system known to fit like Eismann for example.

                                We're investigating the possibility of making an internal and external 'swap over' of the OEM Rear Silencers to see if it allows them to be used for Dual Diff Cover upgrades.

                                It might not yet be able to be done, and if so we'll hold our hands up and say, but know that we at least tried.

                                However, if it is possible then there's a new option for people that want to retain the OEM Rear Silencers (certainly in look, we're still yet to know what it will sound like, and if there will be any downside with performance).
                                Early stages yet.

                                I do agree with you, BMW would have spent probably 10's of thousands (if not more) just on the Z3M exhaust development, and we are certainly not likely to better it.

                                It's just about getting over a challenge and seeing if it can be done.

                                Best regards,
                                James :)

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