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MegaSquirt-III MS3X Expansion Card
MegaSquirt-III MS3X Expansion Card
MegaSquirt-III MS3X Expansion Card
MegaSquirt-III MS3X Expansion Card
MegaSquirt-III MS3X Expansion Card

MegaSquirt-III MS3X Expansion Card & Connector Kit

4.8571428571429 out of 5 based on 7 customer ratings
(7 customer reviews )
MegaSquirt-III MS3X Expansion Card & Connector Kit


SKU: MS3Xpander Category: Tags: , , , , , , , , , , , , , Brand:


Put this small circuit board in your MegaSquirt-III to unlock its full potential! This board installs in the MS3 case with no soldering; just connect it with the included ribbon cables. Install the MS3X board to add this whole list of inputs and outputs to the MS3 ECU:

  • 8 Sequential fuel injection outputs. Each can drive a high impedance injector, and unused injection outputs can be put to other purposes.
  • 8 Logic level 5 volt ignition outputs. Works with many types of ignition modules and coils, including LSx coils and our IGN-1As. Requires exteranl module or coils with internal ignitors.
  • 6 Medium current outputs. Use for 2 stage progressive nitrous, boost control, tach output, 2 or 3 wire PWM idle speed control, general purpose PWM or relay control, or many other potential applications.
  • 3 Analog inputs. Use for an external MAP sensor, second O2 sensor, fuel pressure, accelerometer, or general data logging.
  • 4 Switch inputs. Can be used to start data logging, arm a nitrous system, switch tables, launch control, VSS input (with external conditioner), and more.
  • 1 Cam sensor input. Can be used with VR, Hall, or optical sensors.

The MS3X has all of these circuits on it, ready for you to wire up to your engine and use them. No mod kits, no setting up custom special order ECUs, just plug it in and configure TunerStudio to use the new outputs!

The MS3X is intended for use with the MS3 daughter card only.

Customer reviews

Rated 4.8571428571429 out of 5 stars
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7 reviews for MegaSquirt-III MS3X Expansion Card & Connector Kit

    Only logged in customers who have purchased this product may write a review.

    What advantages are there to adding the MS3X to the MS3?

    • This is the easiest way to add the extra I/O allowed by the MS3 processor. Without the MS3X, an MS3 will be like an MS2 except for adding data logging and a faster processor. This card allows using the MS3 to its full potential.

    Where is this board made?

    • It is built in the USA.

    Questions & Answers

    1. 0 votes

      The knock module solders to the white MS3 daughter card. You can use it with or without the MS3X board, although without the MS3X board you will have a limited number of spark output options.

    2. 0 votes

      Please see section 3.6.3 of the MS3X V3.0 hardware manual for how to configure this ECU for V12 sequential support.

    3. 0 votes

      Yes, this card has the needed inputs and outputs for using the MS3's A/C control functions.

    4. 0 votes

      Most aftermarket tachs will have no problem with the signal. Only a few older tachs (particularly OEM units) driven off the coil will have a problem.

    5. 0 votes

      6 is no problem. Any unused fuel or ignition outputs can be turned off in software or repurposed for other uses.