Speedo for Soarer with BMW gearbox trouble :/

Thread in 'Technical Questions' started by The Duncan, Mar 13, 2018.

  1. The Duncan

    The Duncan New Member

    Apr 7, 2016
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    Hi all, I'm putting together a 1jz Soarer drift car and have got to the point of a manual conversion. I've been searching on here, and all of the rest of google for a solution to this issue and can't seem to find anything. Using a 330d 5 speed for strength and cost, with a PMC adapter and flywheel. My understanding is that the auto box and factory speedo/ecu uses 2 speed sensors, 1 mechanical drive and 1 magnetic, (from what I can tell). The BMW box has no mechanical speed sensor. Issue is I want to be able to keep the stock gauges working as long as possible, with as few errors as possible until I go full standalone ecu. So I somehow need to be able to send two correct speed signals to the speedometer. I had a mad thought that the speed sensors could be cannibalised from the auto box and somehow frankensteined to the bmw box... i may just be completely off the mark here though. Has anybody on here done this swap successfully in a road car and kept the speedo working yet? Any help much appreciated with this specific issue - any thread I've found on this so far just talks about the r154 swap, or about how to go about the physical installation of the BMW swap and whether or not it's worth the ballache. Thanks!
  2. Wolfgang Schelhammer

    Apr 18, 2019
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    I have the same Problem on my jzx90. Tried some things.
    Im using the magnetic speed sensor. I tried a trigger Hand made trigger wheel. Problem here were the Vibrations on the gearbox. The trigger wheel Was mounted on the hardened prop shaft coupler. The speed sensor 2 Was mounted by the side on the gearbox. The Signal was modulated to get a 0v and a 5v Signal.
    As far as i know you will only need the speed sensor 1 Signal which is 1 Signal per Rotation of the prop shaft.
    BUT this didnt work.
    Next Thing i tried Was a metal Ring pressed on de coupling with a hole drilled Into. Didnt work either because the Ring jumped off the coupling.
    The Next Thing im going to try is:
    Building a New prop shaft whith a trigger wheel on the end towarts the diff. Mount the speed sensor 2 on the diff and modulate IT to speed sensor 1 Signal again. There should be less Vibrations and more space to mount the damn Thing.
    Hopefully my failures were usefull to you
  3. Zammish24

    Zammish24 Member

    Nov 19, 2016
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    may sound crude but could you cut the speedo worm gear off the auto box, then have that gear driled to match the diameter of the bmw output shaft so it would slide onto it with an interference fit?, from there its just modifying the casing to accept the original speedo drive i guess?

    I did the same thing putting a alfa romeo v6 into a lancia beta, instead i had the speedo drive gear from the lancia box bored out to push onto the alfa diff, then had a aluminium boss welded to the diff casing to attach to it.
    #3 Zammish24, Apr 18, 2019
    Last edited: Apr 18, 2019

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