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  • #31
    For those who have experienced failed stock mounts (S14 or 740i), I wonder if the failure was due to many years of service. I'm thinking if I replace the stock mounts every year or two (treat it as regular maintenance item), the mounts may not degrade much in performance and it is still cheaper than buying a grp N mount.

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    • #32
      Originally posted by M-tinker View Post
      For those who have experienced failed stock mounts (S14 or 740i), I wonder if the failure was due to many years of service. I'm thinking if I replace the stock mounts every year or two (treat it as regular maintenance item), the mounts may not degrade much in performance and it is still cheaper than buying a grp N mount.
      it will be nowhere near as good as Grp N mounts.


      Goodbye M3, you served me well.

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      • #33
        while on the subject, can someone give me the part # for the group N motor and transmission mount please

        thanks

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        • #34
          Originally posted by JS154 View Post
          Gruppe N mounts are stupid expensive. And they will break just like a stock one too. But they are stupid expensive.
          I have not seen any evidence the BMW Motorsport Gr.N mounts break. They will eventually wear out but not break. There is a big difference in the potential damage it can cause ... The high initial price is offset by their longer life cycle. It is a well tested item over the course of +20 years of racing ...

          The only other valid option for track use are the Gr.A replica aluminum mounts Conrad is making. We had Gr.A magnesium mounts as well but decided to sell them.
          1986 BMW E30 M3 CF airbox & Alpha N
          2007 Audi RS4 sedan

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          • #35
            Originally posted by kengarchow View Post
            while on the subject, can someone give me the part # for the group N motor and transmission mount please

            thanks
            You have it in the pictures I posted a couple of days ago. The p/n is engraved on the cup:

            11811417407 N
            Last edited by MMMM; 02-15-2011, 08:36 PM.
            1986 BMW E30 M3 CF airbox & Alpha N
            2007 Audi RS4 sedan

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            • #36
              Lee,
              Your ireland thread was the first thing I thought of when I saw that pic of the failed AKG mount.
              Amazing they just "re-made" the same mistake / design flaw
              jimmy p.
              87 E30 M3 Prodrive British Touring Car
              88 E30 M3 Zinnoberot - Street
              88 E30 M3 Lachsilber - Race (#98 SCCA SPU)
              92 E30 M Technic Cabrio - S14 POWERED!
              98 318Ti M44, Base - Morea Green
              04 Ford F350 - V10

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              • #37
                If anybody here wants to make engine mounts, I would gladly collaborate and submit ideas.


                [email protected]

                1969 2002 racecar
                1989 M3 racecar
                e39 Touring

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                • #38
                  MMMM thanks, saw the photo but not the #'s, how about the transmission mount #

                  so group n vs conrad's
                  any clear choice
                  is one or the other easier on the frame?
                  thanks

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                  • #39
                    Originally posted by jimmy p. View Post
                    Wow,,,, I am shocked at the failure mode of the AKG mount.
                    How the f*ck could they not expect that to fail.
                    Thats a horrible design.
                    So glad i didnt buy a set of those.


                    Still cant believe the AKG mount has so little meat into the mount.
                    Thats just designed to fail. Shame.
                    That was my initial thought, but then think of it this way....

                    I would rather have a sacrifical mount fail under impact stress like I mentioned, which I can swap out in 10 minutes in the paddock, versus having the ears on the tranny break off, or have the trans crossmember fail.

                    Kinda the same reason the two-piece driveshaft makes sense - in a similar situation, it;s just going to slide apart, instead of a single piece design putting all sorts of stresses on guibos, diff and diff mounts and subframe mounts etc...

                    all the stress has to go somewhere, best to sacrifice an easy to replace mount.
                    sigpic
                    2010 BMW Club Racing E30 M3 Touring Car Champion
                    2011, 2013 SCCA Runoffs Super Touring Under 3.0L Bronze Medalist
                    2011 SCCA Jim Fitzgerald Rookie of the Year
                    2012 SCCA Northeast Divisional STU Champion
                    2015 SCCA Runoffs STU Polesitter

                    Comment


                    • #40
                      Originally posted by MMMM View Post
                      I have not seen any evidence the BMW Motorsport Gr.N mounts break. They will eventually wear out but not break. There is a big difference in the potential damage it can cause ... The high initial price is offset by their longer life cycle. It is a well tested item over the course of +20 years of racing ...

                      The only other valid option for track use are the Gr.A replica aluminum mounts Conrad is making. We had Gr.A magnesium mounts as well but decided to sell them.
                      in an impact, even minor car to car - the Grp N mounts will break. I've seen it time and time again on other droivers cars that I refuse to spends the hundred$ of dollars when I can get a stiffer mount like AKG or Ireland for less.

                      Keep spares in the track bin. simple.
                      sigpic
                      2010 BMW Club Racing E30 M3 Touring Car Champion
                      2011, 2013 SCCA Runoffs Super Touring Under 3.0L Bronze Medalist
                      2011 SCCA Jim Fitzgerald Rookie of the Year
                      2012 SCCA Northeast Divisional STU Champion
                      2015 SCCA Runoffs STU Polesitter

                      Comment


                      • #41
                        Originally posted by JS154 View Post
                        That was my initial thought, but then think of it this way....

                        I would rather have a sacrifical mount fail under impact stress like I mentioned, which I can swap out in 10 minutes in the paddock, versus having the ears on the tranny break off, or have the trans crossmember fail.
                        Well,,, sadly,,, I'm pretty sure AKG didnt have that design intent of the sacrificial motor mount in mind when they made them, I think it was just bad design...

                        However Eric,,, I think your statement has merit in that I would also rather replace a motor mount than a subframe at the track (or even periodically as a service item).

                        I got so incredibly sick of replacing motor mounts at the track, I just went solid.

                        I think the AKG could be the "next best" design to Grp N if they just had a deeper / better anchor into the delrin.
                        Then in theory it could still sacrifice fail if needed in an impact, but not tear in half under aggressive service which is what happened.

                        I bit the bullet og the Grp A replica arms,,, once again making both cars more similar by the day, nut by nut, bolt by bolt haha.
                        jimmy p.
                        87 E30 M3 Prodrive British Touring Car
                        88 E30 M3 Zinnoberot - Street
                        88 E30 M3 Lachsilber - Race (#98 SCCA SPU)
                        92 E30 M Technic Cabrio - S14 POWERED!
                        98 318Ti M44, Base - Morea Green
                        04 Ford F350 - V10

                        Comment


                        • #42
                          Jimmy hows the noice and vibration with the solid mounts?

                          I suppose you could run solid mounts, and notch the trans crossbrace so that part fails first under high load, instead of the trans ears.

                          That bracket would be easy-peasy to swap out.
                          sigpic
                          2010 BMW Club Racing E30 M3 Touring Car Champion
                          2011, 2013 SCCA Runoffs Super Touring Under 3.0L Bronze Medalist
                          2011 SCCA Jim Fitzgerald Rookie of the Year
                          2012 SCCA Northeast Divisional STU Champion
                          2015 SCCA Runoffs STU Polesitter

                          Comment


                          • #43
                            Originally posted by JS154 View Post
                            Jimmy hows the noice and vibration with the solid mounts?
                            Fairly horrific.
                            I have a pretty high tolerance for NVH, I used to drive a fully solid mounted GTO drag car and enjoyed it many years ago,,, but yeah, its about as bad as you would expect it to be with a buzzy 4 cylinder solidly bolted to a solid everything else car.

                            Shit is constantly vibrating off.
                            Loctite red and blue and Nylock nuts everywhere are my best friends.
                            Quite literally if I cannot get a nylock nut on something, its got loctite on it because otherwise, it will fall off.

                            However,,, i wouldn't change a thing (for a dedicated race car).
                            its so direct.
                            Transition throttle is so much fun.
                            I couldn't go back.
                            I enjoy the benefits much more than I am annoyed by the downsides.
                            jimmy p.
                            87 E30 M3 Prodrive British Touring Car
                            88 E30 M3 Zinnoberot - Street
                            88 E30 M3 Lachsilber - Race (#98 SCCA SPU)
                            92 E30 M Technic Cabrio - S14 POWERED!
                            98 318Ti M44, Base - Morea Green
                            04 Ford F350 - V10

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                            • #44
                              ^ Jimmy is my effing hero. Probably the #1 E30 M3/S14 fan if there ever was one.

                              Jake

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                              • #45
                                Originally posted by Jake View Post
                                ^ Jimmy is my effing hero. Probably the #1 E30 M3/S14 fan if there ever was one.

                                Jake
                                Yup....

                                The mere thought of a solid mounted S14 scares me. I once tried a solid shift lever (no rubber insert) and it about drove me crazy in a mile.

                                I would also worry about actual fatigue that would occur by all that vibration transfered directly to the chassis.
                                Last edited by Ironhead; 02-16-2011, 07:08 PM.

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