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

MegaSquirt-III MS3X Expansion Card & Connector Kit

5.00 out of 5 based on 2 customer ratings
(2 customer reviews )


In stock

SKU: MS3Xpander Category: 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.

Customers' review

Rated 5.00 out of 5 stars
2 reviews
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2 reviews for MegaSquirt-III MS3X Expansion Card & Connector Kit

  1. 5 out of 5

    WowThis has to be the greatest expansion ever. Rock solid idle at 15.1 afr. I got this and the ms3. Initially i was going to go with aem but then i read more about what the latest iterations of megasquirt could do for half the price. Car is an is300 (1jz vvti) with the MS running in parallel with the stock ecu. Runs like a stock car.

    Was this review helpful to you? 1 of 1 people found this review helpful

  2. 5 out of 5

    Wow great product, I added this to my MS3, added one jumper s12c to js9 plugged in two ribbon cables and just like that added more inputs and outputs than I will ever need enabling fully sequential spark and fuel. Awesome it fired my ez30D right up.

    Was this review helpful to you? 3 of 3 people found this review helpful

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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
  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.