Quick Links

MegaSquirt-III EMS System with MS3X Expansion V3.57 - Assembled Unit
MegaSquirt-III EMS System with MS3X Expansion V3.57 - Assembled Unit
MegaSquirt-III EMS System with MS3X Expansion V3.57 - Assembled Unit
MegaSquirt-III EMS System with MS3X Expansion V3.57 - Assembled Unit
MegaSquirt-III EMS System with MS3X Expansion V3.57 - Assembled Unit
MegaSquirt-III EMS System with MS3X Expansion V3.57 - Assembled Unit
MegaSquirt-III EMS System with MS3X Expansion V3.57 - Assembled Unit
MegaSquirt-III EMS System with MS3X Expansion V3.57 - Assembled Unit

MegaSquirt-III EMS System with MS3X Expansion V3.57 – Assembled Unit

5.00 out of 5 based on 10 customer ratings
(10 customer reviews )


In stock

SKU: MS3X357-C_BL Category: Brand:


Complete, ready to run MegaSquirt-III ECU with the MS3X expansion board. 2.5 bar MAP sensor is standard equipment.

The MS3 daughter card on its own will give you all these features and more:

  • VE and ignition tables are both 16 x 16 with full interpolation.
  • 0.1% steps on VE table, 0.1 degree steps on ignition table
  • Socket for an onboard SD card – no laptop required for data logging  (SD Card not included)
  • Built in USB port
  • GM stepper IAC control
  • Closed loop idle and mixture control
  • CANBus communications for interface with GPIO Board, IO Extender, or other devices
  • Staged injection
  • Native support for many different OEM trigger patterns

This MS3 EMS already has the MS3X expansion board installed, enabling the following features:

  • 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 external module or coils with internal ignitors.
  • 6 Medium current outputs. Use for 2 stage progressive nitrous, boost control, tach output, 3 wire 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 (Hall sensor or VR with external conditioner), and more.
  • 1 Cam sensor input. Can be used with VR, Hall, or optical sensors.

The MS3X has all these circuits on it, just ready for you to wire up and use them. No mod kits, no setting up custom special order ECUs, just plug in and enable it in TunerStudio.

For complete MS3 documentation and more see http://www.msextra.com/

Customers' review

Rated 5.00 out of 5 stars
10 reviews
4 stars 0 0 %
3 stars 0 0 %
2 stars 0 0 %
1 star 0 0 %

10 reviews for MegaSquirt-III EMS System with MS3X Expansion V3.57 – Assembled Unit

  1. 5 out of 5

    Best Bang for you Buck!This is the second MS ecu I have owned. Once again, it surpassed my expectations. First unit was a MSPNP2. Now on the MS3 version and the system is great. I swapped in a VQ35DE - 350z motor into my S13 240sx. Using stock crank and cam sensors, stock Coil on Plug with Bosch 2200cc High Impedance injectors on E85, this ecu has great idle, drive ability, etc. The feature set works great and I am ecstatic with the results. The next best thing is support from DIY. I can get a response in less than 24 business hours which is a plus. Keep up the good work!

    Was this review helpful to you? 0 of 0 people found this review helpful

  2. 5 out of 5

    Affordable, Reliable, and Packed with Features!We have installed 4 of these ECU's on 2JZ powered vehicle (2x Supra's , 2x S14) all running strongly and reliably for a few years now, and just order another one for installing on an FD rx7. Most of those cars have been used as daily drivers, and its nice to be able to get into a car, turn the key and drive away without worry of ECU issues/bugs. I've attached a dyno chart of the last supra we dyno'd running one of these ECU's and while achieving about double the factory HP, we were also able to achieve higher MPG of about 30 MPG on top of that! Will always recommend these ECU's!

    Was this review helpful to you? 10 of 10 people found this review helpful

  3. 5 out of 5

    Well this is just great. I remember making fun of megasquirt maybe 10 or so years ago. Now it's just simply a beast. I run this in conjunction with a stock 2jz is300 ecu so I wired in one thing at a time progressivly using more and more features from the megasquirt. Combined with tablet tuning, custom tablet gauge layouts, auto tune, ability to use any kind of sensor inputs, and all kinds of tuning options this is really impressive. Dollar for dollar it puts other Ecu's to shame. If you can deal with the diy type of install then there's really not a better deal on the market.

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

  4. 5 out of 5

    I purchased this unit, added the Mapdaddy 4 Bar Map sensor and Realtime clock. I had the unit in a couple weeks and had the car running a couple weeks after that. Granted, this was just the first build and a year later I have redone things a few different times (trying to clean up the factory wiring).

    Email support has been great plus the good support at MSextra and Corral have made this a very good experience. After-market ECUs are a lot of work and I have learned a lot about Engine Management from what I have done.

    This system replaced an Accel Gen 6 ECU that quit working. I'd recommend this system to anyone who wants to isn't scarred about learning new things and will spend the time to make the most of their engine through proper management

    Was this review helpful to you? 2 of 2 people found this review helpful

  5. 5 out of 5

    quiero comprar un megasquirt para un motor ls 6.0 chevrolet no mas para instalar cual sería el mejor

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

  6. 5 out of 5

    Si señor la ms3 te sobra es mas te podría decir que es mucho ya que varias cosa quedarían sin utilidad en ella, particularmente en ese modelo que no tiene distribución variable ya con la ms2 estas bien sobrado.



    Was this review helpful to you? 0 of 0 people found this review helpful

  7. 5 out of 5

    La daughter Zeal Engineering Daughterboard with Dual VR Conditioners leer el manual de MSextra y mucha paciencia.

    Was this review helpful to you? 0 of 0 people found this review helpful

  8. 5 out of 5

    Cualquier megasquirt te funciona 1,2 o 3 en tu corolla

    Was this review helpful to you? 0 of 0 people found this review helpful

  9. 5 out of 5

    Yo quiero montarla en mi rx7 turboII que necesito.

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

  10. 5 out of 5

    Yo quiero saber si me funciona y que necesito para montarla en un corolla 95 con motor 1.6
    La mega squirt III

    Was this review helpful to you? 0 of 0 people found this review helpful

Add a review

What harness do I need with this?

  • You need both the MegaSquirt harness and the MS3X harness.

What inputs and outputs is the MS3 V3.57 with MS3X set up for?

  • It is set up for sequential fuel control and eight channel logic level spark output, with the following inputs and outputs:
    • Coolant temperature
    • Air temperature
    • MAP sensor (built in)
    • Throttle position sensor
    • O2 sensor - narrow band or external wideband controller
    • Crank and cam position sensor input - Hall, optical, or VR
    • On/off, stepper, or PWM idle control - unused idle control outputs can be repurposed as general purpose relay control outputs
    • Fuel pump relay
    • Eight fuel injector banks plus two fuel injector outputs for a second stage or general purpose outputs
    • 3 analog 0-5V inputs
    • Flex fuel input
    • 6 on/off or frequency inputs
    • 0-12V tach output
    • 5 general purpose on/off or PWM outputs
    • 8 5V logic level spark outputs
    • CANbus

What firmware does it have?

  • The MS3 V3.57 ships with the latest MS3 code. The code it initially shipped with will be indicated on a sticker on the underside of the unit.

Is the V3.57 board available in kit form?

  • The V3.57 is essentially a V3.0 that has been changed for machine assembly with very few differences. Consequently, it is not offered in kit form.

What connections are on the DB15?

  • By default, it only has a couple extra reference voltage and ground pins for sensors. The DB15 can be used for adding optional I/O if you run out of pins on the main connector.

Where is it built?

  • The components are assembled at various locations in the US, with final assembly completed in Suwanee, Georgia.

What is the warranty?

  • We provide a one year limited warranty against manufacturing defects.

Questions & Answers

  1. 0 votes

    $692.00 MS3X357-C_BL: Assembled Megasquirt-III V3.57 with MS3X
    $99.99 JimStim-C: Assembled JimStim diagnostic board
    $17.00 StimPower: JimStim power supply
    $83.00 MSHarness: 8' main board wiring harness
    $86.00 MS3X-Hrn: 8' MS3X wiring harness
    $22.49 IATwPiggy: Intake Air Temperature Sensor
    $9.49 38NPT-Bung_A: Aluminum bung for IAT sensor (Also available in stainless steel)
    $7.49 MS3TuneCable: USB communications cable for MS3
    $1017.46 Subtotal without wideband

    The wideband oxygen sensor system is optional, but a very useful tuning tool. We carry the Innovate line.

    Wideband Options:

    $189.00 LC-2 without gauge (you can still view real-time AFR and datalog AFR through your laptop)
    $219.00 MTX-L Plus digital gauge system
    $219.00 LC-2 with DB digital gauge (available in red, green, or blue)
    $259.00 LC-2 with G series analog gauge 
    $349.00 LM-2 basic data logger with one sensor 
    $399.00 DLG-1 dual wideband package with digital gauge 
    $479.00 LM-2 deluxe kit with one O2 sensor 
    $669.00 LM-2 deluxe kit with two O2 sensors

  2. 0 votes

    This can run the setup you describe if you use the main board drivers to run the LPG injectors in two banks of three, or if you use external peak and hold drivers to run the LPG injectors sequentially.

  3. 0 votes

    While an MS3 V3.57 can control the VVTi system on this motor, this engine uses two VR type cam sensors. You'd need an external VR conditioner for the second cam sensor. Stepping up to an MS3Pro EVO will get you extra VR conditioner channels, so you won't need extra modules to run the VVTi.

    In either case, you'll need a cable operated throttle body.

  4. 0 votes
  5. 0 votes

    This system supports almost all ignition systems you could run on a Ford smallblock.

  6. 0 votes

    You will need wiring for two connectors - the main board connector, which takes a standard MS1 / MS2 / MS3 harness, and separate wiring for the MS3X. We have these harnesses in 8' and 2' lengths, but do not have any application specific harnesses for this particular ECU.

  7. 0 votes

    You could use our N52 DIYBOB breakout board to make an adapter harness for this ECU.

    The DIYPNP startup map can be loaded into an MS3, although some settings will not load over, and you will need to configure the output pins differently since the MS3 and DIYPNP output ports are not the same.

  8. 0 votes

    Double VANOS solenoids need 12 volt power instead of ground to trigger. You can use our HSD-4 high side driver module for this purpose.

  9. 0 votes

    This unit could run wasted spark ignition and semi-sequential fueling. Stepping up to an MS3Pro EVO will allow fully sequential fuel control, although the ignition will still be wasted spark. You could run twelve coils; they'd just be fired in pairs.

  10. 0 votes

    Pretty well - it can run the stock ignition, whether it's coil on plug or the earlier dual distributor version, with the factory sensors. In addition to sequential injection and individual cylinder tuning, this ECU can do boost control, traction control, and many other tuning features.

  11. 0 votes
  12. 0 votes

    If using LS1 coils, I'd recommend using a crank trigger, like the 36-1 trigger wheels we sell. You can make the distributor into a cam sensor by cutting the reluctor wheel down to one tooth.

  13. 0 votes

    You will need to use a cable operated throttle body with this system. The factory Gen III Hemi throttle bodies were drive by wire, but there are some aftermarket throttle bodies out there for this application that use a cable.

  14. 0 votes

    You would either need to have the stock ECU control the drive by wire or convert to a cable operated throttle body, and we'd also need to know the transmission details to see if anything is needed there. This ECU does have everything needed to run the engine with the exception of drive by wire; you would just need to add the two wiring harnesses and wire it up. A wideband O2 sensor is also a good idea as it makes tuning the fuel a lot easier.

  15. 0 votes

    There's very little difference. The V3.57 is essentially just a machine assembled V3.0, and they run the same firmware.

  16. 0 votes

    Yes, these ones use a fairly straightforward distributor, and you can use the "G" sensor to get sequential injection with the stock ignition. Or swap to a later cam angle sensor from a DLI motor if you want more precise triggering.

  17. 0 votes

    This one has two 37 pin connectors, each needing their own harness. These links will take you to the harnesses needed in 10' length.

    Main board harness

    MS3X harness

  18. 0 votes
  19. 0 votes

    Yes. This works the same was as the Nippondenso CAS settings in the manual although it has a 12 tooth wheel at crank speed rather than a 24 tooth at cam speed.

  20. 0 votes

    It includes a set of solder cup connectors for making your own harness. We sell flying lead harnesses separately in 10' or 2' lengths depending on whether you want to wire the engine from scratch or make a patch harness. You will need separate harnesses for the main board and MS3X if you go that route.

  21. 0 votes

    The MS3 has VVT control as well.

    We plan to release an MS3 based MSPNP for these cars soon.

  22. 0 votes

    This replaces the entire stock ECU. Although it can be tuned to produce good tailpipe readings, it does not make any attempt to keep the factory smog equipment working and is not CARB approved. Consequently, it's sold for unregulated race cars only. Sorry.

  23. 0 votes

    You'd just need to add our wiring harnesses (both the main board and MS3X), as long as you are using coils with built in ignition modules. A wideband O2 sensor will also be helpful for tuning. The website will calculate shipping once you check out, before you send payment.

Send me a notification for each new answer.