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December, 2011

  1. Megasquirt modifications

    December 31, 2011 by frank

    Honda connectors removed and wires soldered in. I always use the oem Mazda color codes (an old wiring loom is super handy for this kind of thing) as it's easier to spot mistakes.
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    Honda connectors removed and wires soldered in. I always use the oem Mazda color codes (an old wiring loom is super handy for this kind of thing) as it's easier to spot mistakes.

    The Honda connectors are removed and new wires soldered in.  I always use the oem Mazda color codes (an old wiring loom is super handy for this kind of thing) as it’s easier to spot mistakes.  I also made sure to have a stress relief for the wires should I ever accidently rip out the connectors.  It’s not pretty, but it does the job just fine.
    As always, more pictures in the S2000 album.

     

    The NB miata gearbox has a VR sensor which outputs an 4000 ppm AC waveform.  The miata instrument cluster has a built in VR conditioner to convert that signal to a square wave signal which drives the miata speedo.  This square wave is also used as an input for the megasquirt.

    MX5 circuit board installed with some stick on spacers to prevent it touching the S2000 pcb.
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    MX5 circuit board installed with some stick on spacers to prevent it touching the S2000 pcb.

    The problem is that when I remove the miata cluster, I’ll no longer have the VR conditioner.  Since the megasquirt cannot directly accept the AC waveform, I’d have to build a new VR conditioner in the proto area.  I found it easier (and faster) to remove the small pcb/display (with VR conditioner) from the miata cluster and install it inside the S2000 cluster.  Just like before, the output of the miata pcb goes to the megasquirt and the megasquirt output will be used to drive the S2000 speedo.

    Modifry ECT module glued to the MS3X module
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    Modifry ECT module glued to the MS3X module

    I installed the Modifry ECT module inside the Megasquirt.  This module takes the signal from the coolant temp sensor and converts it to a format that the S2000 cluster understands.  The input of the module taps into the sensor wire, the output goes to the S2000 cluster.  The module is fully programmable and even has an adjustable alarm output (as a warning for overheating for example).

     

    For my own reference:
    ECU pin 1G is Modifry CLT out to S2000 cluster 2A (V/W) via an additional wire
    ECU pin 2D is MS3 VSS input from MX5 module 2L (W/B)
    ECU pin 2A is MS3 VSS output to S2000 cluster 2O (P/L) via an additional wire

    Category Westield build diary | Tags: , | No Comments

  2. Progress with the instrument cluster

    December 29, 2011 by frank

    this is what the S2000 cluster will look like in the westfield (miata) housing.
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    this is what the S2000 cluster will look like in the westfield (miata) housing.

    The S2000 cluster is a lot smaller than the miata cluster (that was the reason of doing the swap all along), so I’ll have to make a template out of plexi to make it fit.  Shouldn’t be too hard to do though.  A bit of plexi and some paint or vinyl sticky stuff should do it.  I haven’t yet decided which color, probably matte black.

     

    I don’t have the S2000 connectors and I don’t want to cut the wiring of the car, so I decided to remove the S2000 connectors from the pcb and replace them with the connectors from the miata cluster.  Removing the S2000 connectors proved to be a bit challenging and in the process I managed to let my dremel slip and touch the pcb in one or 2 places.  It took me quite a while to repair the damage.  As Murphy would want it, I cut right in the middle of a bunch of very thin traces.  Luckely i managed to avoid cutting into components.

    The problem with the miata connectors is that they are part of the instrument cluster, so I had to cut them out.  It looks worse then it is really.

    S2000 cluster with cutouts for the miata connectors (bottom).I cut these out of the miata cluster.
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    S2000 cluster with cutouts for the miata connectors (bottom).I cut these out of the miata cluster.
    Miata connectors glued in and circuit ready to be soldered.It looks messy, but everything is pretty firmly glued in.
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    Miata connectors glued in and circuit ready to be soldered.It looks messy, but everything is pretty firmly glued in.

    I cut some holes in the S2000 cluster and glued the miata connectors in.  The left one was a straight fit, the right one needed enlarging and the middle one is an all new hole.  I’ll probably add a couple of screws to make sure they don’t come loose.
    I used the corresponding bits of the circuit board layer and will solder the wires straight on them.

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  3. New instrument cluster

    December 18, 2011 by frank

    Luckely, I can still see the most important part of the tacho, but I'd like to see more of the odo.
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    Luckely, I can still see the most important part of the tacho, but I'd like to see more of the odo.

    As I can’t really see all my dials, I decided to buy a Honda S2000 instrument cluster today.  It’s a lot smaller and should be entirely visible through the steering wheel.
    The cluster is a bit of a pain to connect because the S2000 has a 156000 ppm (pulses per mile) speed sensor, while the miata has a 4000 ppm.  I’ll have to come up with a way to multiply the stock signal by 39.

    Also, the coolant sensor does not just measure the resistance (voltage) of the coolant sensor.  Instead, the ecu measures it and sends a 5V signal that has a 30ms high pulse and a 150ms to 1500ms low pulse, relavite to the temperature, so that’ll require some modifications as well.
    Oh, and I’ll have to reprogram the km reading, because I only have 12K kms, not 142K!

    I have no idea yet if it’ll fit inside the Westfield dash as the upper part of the cluster is rather high.  I’ll make it fit if necessary.

    the color filter can be easily replaced with a different color
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    the color filter can be easily replaced with a different color

    I’m also planning on changing the color of the display because I don’t like the yellow/orange backlight.  It’s just a piece of plastic, so it shouldn’t be too hard to swap it with a different color.  The bulbs are a bit yellow-ish as well, so I’m going to look into replacing them with bright white leds.

     

    More pics in the S2000 album.

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