I have purchased a older Maha Chassis Dynaometer previously used by a emissions testing shop. It has a 150 horsepower eddy current brake and a 2000 pound flywheel.  I’d like to upgrade the eddy brake someday so I can hold at set rpm’s for tuning but for now the heavy flywheel allows me to dyno larger hp motors just doing inertia pulls. I started by gutting the electronic control cabinet.  I purchased a YourDyno instrumentation kit and built a control for the eddy brake using a bridge rectifier and IGBT.  I replaced the analog roller rpm sensor with a digital one and re machined the trigger wheel so it had 18 teeth. I added a external 12 volt power supply for the wideband and other optional sensors.  To keep things tidy and the box connections from getting damaged I placed Aviation Plug Connectors and a panel mount micro usb male to type B 2.0 Female Extension in the cabinet cover.  I chose the usb type B for the cover because it is a little more robust connection. I for engine rpm’s I have Bluetooth obd  or a wired input using a dc-dc solidstate relay as a opto-isolator. 

Link to Photo’s and brake control schematic    Retro fit files


Last updated byadmin on June 23, 2019


  1. Daniel Johnson
    December 13, 2019 @ 3:07 am

    This is amazing. what kind of hp have you put through this? I just picked up this same dyno and am going to try and write a plugin to use the existing hardware since it is so well documented in the manual


  2. reichwaldtent
    December 13, 2019 @ 10:47 pm

    I’ve only done 300s so far. I’m helping a buddy with a Dodge aero with a 605 cu in Hemi. LOL, it will be the test of all tests. I’m not sure you can just use a plugin to control the existing hardware. You could possibly reuse the Mosfets board. Jostein’s little blue box works good and could control it, but you would need to have some additional hardware. I’d just gut it and start over. I tend to try to keep it simple.


    • Joe
      August 14, 2021 @ 5:00 am

      Any updates with your project?


  3. David Walmer
    May 2, 2020 @ 8:53 pm

    I have this dyno too. Want to increase HP
    I use a SUN 450 analyzer to run.


  4. Bowen1481
    May 14, 2020 @ 6:01 pm

    Just got the same dyno I emailed
    reichwaldtent about his dyno I will be following the same path as he has. I will keep you all updated to.


    • Joe
      August 14, 2021 @ 5:01 am

      did you end up doing the same retrofit? how did it work out?


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