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Speed Sensor update

Discussion in '308/328' started by Rich in Panama City, Apr 3, 2015.

  1. mwr4440

    mwr4440 Three Time F1 World Champ
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    Jun 8, 2007
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    Bavaria, The 'Other' Germany
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    Mark W.R.
  2. mwr4440

    mwr4440 Three Time F1 World Champ
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    Jun 8, 2007
    38,216
    Bavaria, The 'Other' Germany
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    Mark W.R.
    #27 mwr4440, Jun 18, 2019
    Last edited: Jun 18, 2019
    Question: is there a difference between MPH Speedo/Odo cars and KPH Speedo/Odo car's SENSORS of the same year?

    Would say a 1981 GTSi with an OEM fitted MPH Speedo/Odo, have a different sensor from a 1981 GTSi with a OEM fitted KPH Speedo/Odo?

    I once put a KPH Speedo in my MPH car and it didn't work properly.

    Is the difference in the Sensor or the Speedo unit itself?
     
  3. Brian A

    Brian A Formula 3

    Dec 21, 2012
    1,989
    SanFrancisco BayArea
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    1983 US 308 GTS QV
    I received my sender board in the mail today!

    The board is tiny! (What did I expect?)

    Will report back after I install and test (which is after I get my darned valve covers back on and the engine back together).

    Look forward (hopefully) to finally having a speedometer that is reliable and doesn't require frequent replacement of the $280 sender!

    … love the post office's new high tech way of cancelling stamps!

    Image Unavailable, Please Login
     
    alhbln likes this.
  4. alhbln

    alhbln Formula 3
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    Mar 4, 2008
    1,651
    Berlin, Germany
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    Adrian
    Only difference between mph and kph of same type (1 or 2/3) is the faceplate and a different gear part inside the Speedo for the ODO.
    The sensors itself are independent of mph or kmh versions.
     
  5. mwr4440

    mwr4440 Three Time F1 World Champ
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    Jun 8, 2007
    38,216
    Bavaria, The 'Other' Germany
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    Mark W.R.
    Ok.

    Any Idea why my KPH Speedo didnt seem to work properly?

    Seemed to 'read' way too fast.

    Both Speed and ODO.



    Or, am I ..... "seein' things?"
     
  6. alhbln

    alhbln Formula 3
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    Mar 4, 2008
    1,651
    Berlin, Germany
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    Adrian
    The speedo sensor is always the same (Type 1 or Type 2, requires the matching Speedo), but the Speedos itself are different between kmh and mph (different gear inside the Speedo), and there are different Speedo PCBs to cater for normal aspirated cars as well as turbo cars which have a different trigger wheel in the gearbox.
    If you have the correct gearbox/sensor setup and the factory Speedo then everything should be fine. Difference of speed by the factor 2x would indicate the wrong sensor/gearbox and Speedo configuration. Difference of 1.6x is a wrong Speedo gear/faceplate combination.

    The different sensors are documented here:
    http://www.dinoplex.org/instruments/vegliaspeedosensor/index.html

    If you want to you could ship me your Speedo for a test run on the bench to check the displayed speed and configuration.
     
  7. Brian A

    Brian A Formula 3

    Dec 21, 2012
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    1983 US 308 GTS QV
    I hope to install my board in a few weeks when I have the car back up on jack stands.

    Regarding the "potting" process, is there any specific epoxy that is best? I also notice on the other thread that Adrian questions using "PU compound" rather than epoxy.

    If you could post a link to Amazon for the recommended potting product I would appreciate it since it eliminates lack of clarity. I have never bought a product like this before.
     
  8. alhbln

    alhbln Formula 3
    Owner Consultant

    Mar 4, 2008
    1,651
    Berlin, Germany
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    Adrian
    I have used PU (Polyurethane) potting compound for electronics quite often with very good results, but there is no problem with using epoxy resin for the potting.

    With epoxy resin try to avoid the super fast "5 minute epoxy" as it might be difficult to process if you don't have the routine to work with epoxy. Industry grade epoxy usually cures within 24 hours at room temperature but there is also express epoxy which cures within 30 minutes. If you raise the outside temperature by using an oven the epoxy will cure much faster. The epoxy/hardener bottle sizes at Amazon are quite large, maybe you can find something smaller/cheaper at a local hardware store?

    Polyurethane potting, example:
    https://www.amazon.com/MG-Chemicals-Urethane-Potting-Compound/dp/B07R18G154/

    Epoxy resin potting, example
    https://www.amazon.com/Epoxyseal-Electronic-Grade-Potting-Epoxy/dp/B00VXV9YZ2/
     
  9. Brian A

    Brian A Formula 3

    Dec 21, 2012
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    1983 US 308 GTS QV
    Thank you for the detailed reply. It has the exact information I need.
     
  10. Brian A

    Brian A Formula 3

    Dec 21, 2012
    1,989
    SanFrancisco BayArea
    Full Name:
    1983 US 308 GTS QV

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