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29I harness connector for speed sensor

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  • 29I harness connector for speed sensor

    Where exactly is 29I?
    I'm Looking for connector 29I for speed sensor signal wire:

    Is this it? white-top

  • #2
    I seem to remember yanking one out of the body cavity above/behind the ecu.... but I don't remember the size/colour/shape, just that one was a pita to get out


    • #3
      Red/White wire is what I'm trying

      I'm going to try the red/white wire.
      This wire is suppose to pulse 5 volts, 24 times per revolution. The output from the digi to ecu Pin 29 is 5 volts 2 pulses per revolution.

      Anybody know MPH to speed sensor revolutions ecu or otherwise?

      Anyway it matches the diagram. right to left: Red/Black Red/White White/Blue


      • #4
        I've been planning on digging that signal out and feeding it to Megasquirt so that I can log it.

        If I can log speed sensor alongside tach, should be relatively trivial to calculate horsepower and torque; not valid numbers, but something that'll show increases and decreases better than the butt dyno does.
        88ss, MegaSquirted.
        t3/t4 60-1 cold, stage 3 hot, FMIC
        450cc DSM injectors, walbro 255 Boost gauge and MS info


        • #5
          Power/torque Calculations

          This is the Innovative calc provided with inputs RPM ACCEL SPEED :
          I've adapted to z31 weight, Cd :

          #mlb is mass in lb
          mlb = 3410
          #dia is tire diameter in inches
          #?Vehicle weight in kg = m
          m = mlb * 0.4536
          #?Tire diameter in cm = td
          td = dia * 0.3937
          #?i Name of RPM channel = dl32_1
          rpm = dl32_1
          #?i Name of Acceleration channel = dl32_5 {g}
          ACCEL = dl32_5
          #?i Name of speed channel = v {m/sec}
          vmph = dl32_3
          v = vmph * 1609.3 / 3600
          #Frontal area of vehicle (sqm) = Ar[2]
          Ar = 1.865
          #Drag coefficient = Cd[0.45]
          Cd = 0.380
          # ?Current atmospheric pressure (millibar) = atmp[1013.2] # sea level 29.92"Hg
          atmp = 1013.2
          #?Current temperature (degC) = temp[15]
          temp = 15
          #SAE correction factor
          SAEcf = (1.18 * ((990/atmp) * sqrt((temp + 273.15)/298)) )- 0.18

          #air density
          density = 0.0412236 * atmp/ (temp + 273.15)

          R = td / 200 #tire radius in m

          # aerodynamic draq in Newton
          Fa = 0.5 * density * (v^2) * Ar * Cd

          F = (m * ACCEL/9.81) + Fa
          powr =v * F * SAEcf/745.7
          MC(RWHP;hp;0) = powr
          MC(RWtorque;Nm;0) = powr * 7121/rpm

          This is one is based on just RPM and ACCEL:

          #m is mass in lb (assuming 150lb Driver)
          m = 3410
          #dia is tire diameter
          r=dia/(2*12) # radius in feet
          #final diff ratio
          gear_ratio=1.000 # assume 3rd gear pull, no overdrive
          F = m * dl32_5 # dl32_5 is accelerometer channel
          trq = F * r / (gear_ratio * finaldrive)
          MC(torque;lbft;0;500) = trq
          MC(power;hp;0;500) = trq * dl32_1 / 5252
          #dl32_1 is the RPM channel

          My z31 specs:

          z31 curb weight: 3260 lbs + driver 150lb = 3410 lb

          tire diameter in inches : 25.03

          finaldrive 3.7

          Automatic Gears:
          1st gear: 2.458
          2nd gear: 1.453
          3rd gear: 1.000
          4th gear: 0.686

          Cdrag: 0.380

          Vehicle Year and Model Cd Area(m2 ) Area (ft2 ) Cd x m2 Cd x ft2
          '86 300ZX Turbo 0.380 1.865 20.08 0.71 7.63


          • #6
            DL32 Log session with hp/torque example

            Shows shift changes result in torque/HP spikes. Notice 0.4 g at shift.


            • #7
              Got the speed sensor wired R/W wire

              It was the Red/white wire in the first photo I showed.
              Need to calibrate the speed, but just for fun here is my first log with it:
              Speed seems close but the HP/torque calculations don't look correct to me. I had to multiply the resulting RWHP and RWLBFT by 100 to get these results.

              15 psi run rolling start up a freeway ramp. PSI drops off from 15 to 10.

              This getting to be fun. Still need the WB O2 installed.


              • #8
                dbruce- what are you logging with?

                I can imagine its fun. I can hardly wait to be able to log and street tune. 8) I am jealous.
                Just stand back and throw money.
                Performance costs money.
                Reliable performance costs more.


                • #9
                  Corrected MPH/ACCEL/RPM RWHP/RWTorque

                  Found correct HP/torque calcs using speed sensor.
                  In logworks Preferences you need to select U.S standard , it defaults to metric.

                  Here is the corrected formula:

                  ?Vehicle weight in lb = m[3410]
                  ?i Name of RPM channel = rpm [DL32_1]
                  ?i Name of Acceleration channel = ACCEL {g}[DL32_5]
                  ?i Name of speed channel = v{ft/sec}[DL32_3]
                  ?Frontal area of vehicle (sqft) = Ar[20.08]
                  ?Drag coefficient = Cd[0.38]
                  ?Current atmospheric pressure (inHg) = atmp[29.92]
                  ?Current temperature (degF) = temp[70]

                  #SAE correction factor
                  SAEcf = (1.18 * ((29.235/atmp) * sqrt((temp + 459.67)/536.67)) )- 0.18

                  #air density
                  density = 0.0412236 * atmp/ (temp + 459.67)

                  # aerodynamic draq in lbforce
                  Fa = 0.5 * density * (v^2) * Ar * Cd

                  F = m * ACCEL + Fa
                  powr =v * F * SAEcf/550
                  MC(RWHP;hp;0) = powr
                  MC(RWtorque;lbft;0) = powr * 5252/rpm

                  More real world numbers:


                  • #10
                    Update on my DL-32 installation/Configuration

                    Hi!, I'm still around....
                    Anyway I got back into my car . I have the LC-1 WB O2 installed and working.
                    Want to log the Cyl Head temp sensor . Using all the dl32 channels now , need an SSI-4 I guess...

                    Speed sensor line worked fine, I've set it to a max speed of 140MPH@ 5volts. Anyone know how high the digital speedo will read? Probably runs over 5 volts ?
                    RPM is from Tach Output from MSD Digital 6 Plus, very smooth precise/accurate

                    Here are some links to my DL-32 configuration setup doc file and firsts logs....

                    Channel Configuration and HP/Tq U.S. calcs
                    Logworks log:

                    Pic of First log run with LC-1 WBO2 :