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  • Slats in front of rear tyres

    Noticed that the slats in front of my rear tyres look a bit battered. How are they supposed to look like new? Are they much bigger?
    Also has anyone tried a mod of putting slats infront of all 4 tyres to improve the aerodynamics?



    Cheers

    Greenbat

    Ex MC Owner

  • #2
    Greenbat,

    The OEM things all get knackered and are an absolute waste of money. I've made my own rear aero slats out of aluminium and rubber, because my experiments with ABS plastic show that it just breaks off.

    Likewise, at the front I've modified my ACS front flippers so that less air gets under the wheels and goes around the sides.

    I'll post some photos into this posting tomorrow.
    /// Exdos ///
    "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

    Comment


    • #3
      Originally posted by exdos
      Greenbat,

      The OEM things all get knackered and are an absolute waste of money. I've made my own rear aero slats out of aluminium and rubber, because my experiments with ABS plastic show that it just breaks off.

      Likewise, at the front I've modified my ACS front flippers so that less air gets under the wheels and goes around the sides.

      I'll post some photos into this posting tomorrow.
      Thanks Exdos looks forward to it as I am looking into improving the aerodynamics of the MC.

      Was just browing here http://www.globalcar.com/datasheet/B...8BMWMCoupe.htm and just realised how bad the aerodynamics (Cd) is on the MC. The good thing is that there is a huge scope for aerodynamic improvement.

      Cheers

      Greenbat

      Ex MC Owner

      Comment


      • #4
        Greenbat,

        Below is a photo of the rear wheel slat I've made out of aluminium plate and rubber. This is the third prototype I've made, having experimented with an all-aluminium design and an aluminium and ABS plastic design. The design as presently fitted is the most durable design and has been on my car for several months now.


        The photo below is my own addition to my ACS front flippers.



        The idea is as a result of my doing a lot of research of literature on car aerodynamics earlier this year. Ideally, it would be a full airdam across the width of the front of the car but it would be impractical for a road car and unsightly made out of rubber (which these things are). As it is, these additional devices lie in the shadow of the ACS flippers and so are hardly visible unless you look for them. They've been fitted on my car since about February this year. You mustn't have noticed them at our Welsh weekend, although they were fitted then. Interestingly, the BMW 1 series have similar flaps in front of the front wheels. When I use a pressure washer as my "poorman's wind tunnel" the pressurised spay shows that these devices do exactly what I hoped they would do with moving air passing in front of them.

        Likewise, the increase in air pressure in front of my front flippers has been harnessed to convert the N/S front brake duct into an "air scoop" as per the thread here:
        http://www.z3mcoupe.com/forum2/viewt...r=asc&start=15

        As regards to the aerodynamics of the MC, it does have a poor Cd figure. I've also been at work on the underside of the car and fitted some blanking to the back end of the car to form a primitive diffuser between the rear silencers as below:



        I've additionally fitted a wing device which I've made out of aluminium and which fits onto the central blanking plate, therefore it doesn't need attaching to any bodywork. Hopefully these devices will increase downforce at the rear.

        /// Exdos ///
        "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

        Comment


        • #5
          Thanks Exdos for the info. Hope you havent patented any of those designs as I think i will be pinching some ideas.

          Have you done any 'pratical' tests at all? Eg something like a couple of high speed runs at all?

          Maybe we need to organise our own V-max or similar.

          Cheers

          Greenbat

          Ex MC Owner

          Comment


          • #6
            Greenbat,

            I'm quite happy for anybody to copy any of my ideas except for commercial gain. I very much enjoy examining how things work and devising possible DIY ways of tweaking OEM parts to get an improvement. There are far too many rogues selling "snake oil" products to gullible motorists, which I despise. Consider all my ideas like Freeware or Sharware.

            I'm afraid that my "butt dyno" is my major test tool. :wink: All I know is that my MC seems to have got better and better with each of the mods and changes over the past 18 months.
            /// Exdos ///
            "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

            Comment


            • #7
              Flippers, Diffusers & Professor Exdos

              Originally posted by exdos
              Greenbat,

              I'm quite happy for anybody to copy any of my ideas except for commercial gain. I very much enjoy examining how things work and devising possible DIY ways of tweaking OEM parts to get an improvement. There are far too many rogues selling "snake oil" products to gullible motorists, which I despise. Consider all my ideas like Freeware or Sharware.

              I'm afraid that my "butt dyno" is my major test tool. :wink: All I know is that my MC seems to have got better and better with each of the mods and changes over the past 18 months.
              Exdos, another well put together - high quality tech-talk. Much appreciated.

              Can you shed some MORE light on the: type of rubber used on your enhanced front flippers & the way they are attached.

              2ndly, the aluminium rear flat body diffuser: is that attached to the bottom of the battery case by way of nuts & bolts?

              Finally, just wondering about the last photographed item you were holding up; is that a Hamann diffuser-wing? Where are these available & how much

              Cheers mate.

              Comment


              • #8
                Re: Flippers, Diffusers & Professor Exdos

                Originally posted by ICU88R


                Finally, just wondering about the last photographed item you were holding up; is that a Hamann diffuser-wing? Where are these available & how much

                Cheers mate.
                He crafted this himself, so not an 'off the shelf' item :wink:
                Black S50

                Comment


                • #9
                  Re: Flippers, Diffusers & Professor Exdos

                  Originally posted by chippy
                  Originally posted by ICU88R


                  Finally, just wondering about the last photographed item you were holding up; is that a Hamann diffuser-wing? Where are these available & how much

                  Cheers mate.
                  He crafted this himself, so not an 'off the shelf' item :wink:


                  :shock: That is unreal ! Love to build a replica of that, & the aluminium venturi, front flippers, exhaust, EXDOS coilovers etc etc...

                  Hell, I'm gonna name my 1st born child EXDOS :wink: !!!

                  Comment


                  • #10
                    Re: Flippers, Diffusers & Professor Exdos

                    Originally posted by ICU88R
                    Can you shed some MORE light on the: type of rubber used on your enhanced front flippers & the way they are attached.

                    2ndly, the aluminium rear flat body diffuser: is that attached to the bottom of the battery case by way of nuts & bolts?

                    Finally, just wondering about the last photographed item you were holding up; is that a Hamann diffuser-wing? Where are these available & how much

                    Cheers mate.
                    ICU88R,

                    My rubber flippers are attached by self-tapping screws to the back of the AC Schnitzer flippers fitted to my MC. If you haven't got ACS flippers, then you could make some similar rubber flaps, which would attach to the underside of the front bumper using the existing fixing points, but you'd need to fabricate a metal bracket and fasten the rubber to it with rivets. They're just made from an offcut of some 10mm thick rubber sheeting I have lying around. The rubber needs to be sufficiently thick so as not to flap about, especially at higher speeds.

                    The central blank plate at the rear is attached to the battery housing. You need to remove the battery from its housing well and put a screw-head bolt facing downwards through the hole which is present in the battery well. When the battery is in place, the bolt remains in place so that you can simply attach the aluminium plate from the underside. The photo below shows the upper side of the plate. On the left the blank has been shaped to fit and sit inside the rear bumper and I've put silicone sealant on the contact point and also where it sits against the battery well to prevent rattling. I've found it necessary to drill various holes into the plate because when the weather is over 30degrees C, it gets a little hotter than I'd like above the plate.


                    I made the wing-diffuser out of some aluminium and a little bit of bodyfiller. It's attached to the central blanking with 2 bolts and is shaped so that that it fits closely around the exhaust system. The profile (cross-section as in my earlier posting) has been created from my understanding of how downforce might be best created by aerofoil shapes. The lowest edge of the rear diffuser wing has also been determined to be at the same level as the two side sections of the rear bumper, when attached to the car, so that it looks neatest to the eye. The photos below show the plan-section of the diffuser-wing and also show it fitted to the central blank. The diffuser and central blank can easily be fitted and removed form the car as a single unit by the one bolt attached to the battery well.




                    All of these home-made bits cost me virtually nothing in materials to make, just my time. I really enjoyed the additional time I spent researching the theory behind these things and I learnt a huge amount about car dynamics and had fun trying to make things that hopefully improve my MC's performance a little.

                    Originally posted by ICU88R
                    Hell, I'm gonna name my 1st born child EXDOS !!!
                    Poor b45t4rd :!:
                    /// Exdos ///
                    "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

                    Comment

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