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Tach Adapter - R2

Tach Adapter - R2

$ 119.95 $ 129.95

We have developed a simple, plug-and-play adapter that allows you to use your factory tachometer with your swapped engine in your Toyota. Plug in the tach adapter from the output from your new ECU then simply connect the output from the adapter to your original tachometer! This will provide perfect ignition timing for your factory tach to function how it should, at all RPMs, all the time. 

Not only does the Rat2 Tach Adapter effectively modify and change the signal for your original impulse tach, but being 100% digital it creates the ideal signal to drive the OEM tach and provides a smoother response than any other tach adapter available. (Analog adapters can have latency/frequency issues).

This is intended for cars equipped with older, high-impulse tachometers, such as the 85-89 AW11 MR2, 91-99 SW20 MR2, or any Toyota which uses a factory igniter as part of its ignition system.  The "4 cylinder" version is intended as a signal modification only- not a timing modifier. That means the RPM signal/timing signal is the same on the output as the input, This will also work converting older V6 chassis to newer V6 ECUs/engines, or older V8 cars running newer V8 ECUs to the dash. This part is on all of our RAT2 in-house Gen4/5 3SGTE builds. 

The "6 Cylinder" version is for converting a 6-cylinder ECU tach output signal into the older, 4-cylinder tachometer dashboards. This adapter not only modifies the signal style/but also interprets and recalculates the tachometer timing to correctly show the engine's true RP. These are on every 2GRFE and MZ V6 swap built here at RAT2 in-house.

 We have continued to improve on the original design to make it function faster, smoother, and with more reliability. First, the adapter boards are all now coated with water-resistant circuit board coating, eliminating any future issues with high humidity climates or water damaging any of the circuits. Extensive in-house testing of water resistance has proven to be a validation for this new design in even the most extreme scenarios.

Second, the output signal works more effectively with the factory AC wiring in the original SW20 body harness. We have also designed and built a new box style that provides a more robust body as well as protects the wire harness plug end when connected to the adapter. Finally, we have also improved the response programming to provide a smooth idle reading, with more intuitive sweep characteristics, along with a more accurately calibrated tach output.



V3 is now on its way! We have further improved the input filtering and signal sensitivity. The new version should be even more resilient to different ECU types and signal variability.



  • Silent operation - no annoying wine or humming
  • True RPM - Digital control means no approximation or 'tuning' is needed
  • True impulse signal
  • Easy to install screw lock wire terminal for easy installation
  • LED Indicator lights to show 12x power on, tach input, and tach output. 
  • Water Resistant


  • Rat2 Motorsports Tach Adapter
  • Connector
    Double Sided Adhesive for mounting on ECU
  • Instructions 

Overall Dimensions: 4x2x1

ECU pinouts for reference (Various Engines)


Part Numbers

  • 66012-57450
  • 66012-57451
  • 66012-57550
  • 66012-57551

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