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    E30 brake temperature monitor

    Any interest in a group buy if I develop a stand-alone brake temperature monitor system? Considering this for my Turbo M20 build.

    Looking at monitoring rotor temperatures with non-contact IR sensors, and presenting data on an in-dash display.
    11
    Analog gauge x4
    9.09%
    1
    LEDs (BLUE:Cold, GREEN: Ok RED: Hot)
    27.27%
    3
    LCD Numeric
    63.64%
    7
    "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

    1987 E30 3L Turbo Stroker Das Beast
    2002 E39 M5

    #2
    In.

    RISING EDGE

    Let's drive fast and have fun.

    Comment


      #3
      I'm interested to see where this goes.
      My Garage
      2001 Z3 2.5i Steel Gray/Black (Lexi)
      1988 325ix Diamond Schwartz/Black (Izzy)
      1989 325i Cirrus Blue/Houndstooth (Stitch)
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      Instagram: Stone.Hopkins

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        #4
        IR measurements are typically inaccurate on shiny, varying surfaces like the braking surface of a disc. You may be able to get more consistent results by painting the outer edge of the disc with high temp black paint and measuring there. You won't be getting braking surface temps though, which is what's most important.

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          #5
          What sort of sensor are you going to use? First google search came up with this sensor,



          Recommends cleaning the sensor every day with alcohol, Which on a race car would be fine, on a street car might be quite tedious. It does suggest an accuracy of 3% which at 800 degrees is +/-24deg which is pretty damn good i would have thought for an IR sensor. Only price i can find is 199 English pounds each, not much change from 1000USD for 4!

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            #6
            Pete: "Shiny" is what you see in visible light, not what the IR sensor sees. But point taken. I need to look into what wavelength would work best for this application. I have access to some interesting sensors via a Rep, so stay tuned.

            Davie: Yep. It's gotta be cost effective.
            "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

            1987 E30 3L Turbo Stroker Das Beast
            2002 E39 M5

            Comment


              #7
              Interesting project... ;-)

              Monitor front and rear temps ;-)
              Brake harder. Go faster. No shit.

              massivebrakes.com

              http://www.facebook.com/pages/Massiv...78417442267056





              Comment


                #8
                Infrared Research

                Progress so far ............

                Melexis has an 1800F IR thermopile MLX90616 which is perfect for this application. Unfortunately it seems to be unobtanium, even at Mouser. And expensive, at $30 even through a shady Aliexpress listing. Finally Melexis seems a bit flaky. They only have one sales office in the USA with a listed phone number, and they don't answer the phone! Ugh. Probably not the road to take.

                Most other common IR thermopile sensors max out at 700F, which is not high enough to measure brake temperature for racing. I'm sure a sensor manufacturer would make one OEM, but that takes cubic dollars.

                Speaking of Cubic Dollars, there ARE brake temperature monitor systems on the market, but they are expen$ive. For just the sensors:

                Electron Controls $540/each
                IZZE Racing $300/each
                Texense $600/each
                Renvale $550/each
                Datron $$$$/each (F1)
                FirstSensors $?/each

                So ............. thinking about a different direction.

                Thermocouples can be had for $10 each and easily measure up to 1500F. I'm thinking of drilling a small (1/8") mounting hole in the back of a brake pad, tapping in the probe and going from there. Should work fine.

                Yes, I know it's not rotor temperature, but pads will get pretty damn hot as well. We may even rather know the pad temperature than rotor anyway.

                Lee any comments?
                "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

                1987 E30 3L Turbo Stroker Das Beast
                2002 E39 M5

                Comment


                  #9
                  Chances are that pads may even get hotter than rotors as rotors are cooled by air and radiant heat dissipation while pads aren't. In fact, it is also the brake fluid that cools the pads by absorbing its heat thru the caliper pistons. With the effect we all know ;-) hence the importance of getting stainless pistons. One-piece or two-piece.

                  BTW Darrin, once you start fitting brakes that don't get heat soaked as easily, rotor temp becomes less a worry. ;-)
                  Brake harder. Go faster. No shit.

                  massivebrakes.com

                  http://www.facebook.com/pages/Massiv...78417442267056





                  Comment


                    #10
                    Well then, Full Speed ahead with a thermocouple solution. This should be interesting.
                    "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

                    1987 E30 3L Turbo Stroker Das Beast
                    2002 E39 M5

                    Comment


                      #11
                      Added poll to choose display type
                      "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

                      1987 E30 3L Turbo Stroker Das Beast
                      2002 E39 M5

                      Comment


                        #12
                        Need to scale the sensors correctly, so here are some brake pad temperature charts.

                        Hawk


                        Wilwood


                        PAGID


                        PFC doesn't know how to spell "graph"


                        Looks like we need an 1800 - 2000F thermocouple.
                        Last edited by dvallis; 02-15-2017, 04:41 PM. Reason: image
                        "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

                        1987 E30 3L Turbo Stroker Das Beast
                        2002 E39 M5

                        Comment


                          #13
                          If you are using thermocouples in the pad, you'll want to get them as close to the braking surface as possible, as the friction material is somewhat of an insulator. At some point you'll wear through the thermocouple, but it should be pretty accurate right before you wear through! Obviously you won't get much information when the brakes aren't applied.

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                            #14
                            Could drilling into the pad compromise it's strength?

                            RISING EDGE

                            Let's drive fast and have fun.

                            Comment


                              #15
                              7420 pad is 4.74" x 2.34" or 8.2 in2. We're drilling a 1/8" hole into the pad, which is 0.0123 in2. So you are compromising 0.2% of the brake pad area. Should be fine.
                              "And then we broke the car. Again." Mark Donohue, "The Unfair Advantage"

                              1987 E30 3L Turbo Stroker Das Beast
                              2002 E39 M5

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