What is MegaSquirt?

Megasquirt is a range of standalone engine management systems.

megasquirt ADE Tuning
With Megasquirt you get the opportunity to learn how engine management works and gain full tune ability of your engine.

Megasquirt-3 with MS3X

This is the present top of the range ECU in the ‘traditional’ Megasquirt range. It has 8 fuel and 8 logic spark outputs offering full sequential fuel and spark for hi-z injectors and logic level coil-on-plug coils (or high-current coils with suitable external ignition module.) This supports full-sequential on a V8 or semi-sequential with wasted spark on a V12. Spark and fuel are fully trim-able per channel and injector timing is mappable for optimum power (~1% gain available) Six relay or solenoid outputs for nitrous, boost, fan control, shift light, tachometer outputs etc. Switch inputs for launch, idle-up, nitrous-in etc. and additional sensor inputs for external MAP sensors or measuring pre/post intercooler etc. On-board SD-card data logging allows fast data logging without the need for a laptop while logging. Built-in USB-serial adapter eases connection to modern laptops.

CAN communication ability to interface with extender boards for more inputs and outputs on the more complex installs – e.g. multiple EGT, multiple wide bands, speed sensors etc. Calibration to adapt to OEM temperature sensors is straightforward and numerous wideband calibrations are supported.

Initial setup is aided by test modes for the fuel and spark and by built-in tooth loggers to help diagnose incoming tach signals.

The MS3 software includes many ‘race’ type features, two stages of progressive nitrous, water injection, closed loop boost control etc. Vehicle speed sensing, logging of EGT (with external hardware.)

In most configurations, the MS3 + MS3X +V357 can be used by setting a few configuration jumpers inside the box. It requires little or no DIY effort inside. (Other Megasquirt options are far more DIY intensive.)

Megasquirt-3 without MS3X

This gives all the software features of the full Megasquirt-3 but does not include the driver board to support 8 channel fuel and spark, relay outputs or switch or analogue inputs. Included is batch-fire fuel, SD card logging and USB-serial.

This option may be of use to the more DIY orientated user who wants to add their own options or as an upgrade from Megasquirt-1 or Megasquirt-2.


Megasquirt-2 gives many options, but most will require DIY customisation by the end user (or builder.) Up to 4 cylinder sequential fuel and 6 cylinder coil-on-plug are supported, various race features and CAN communications. Much of the tuning interface is very similar to the Megasquirt-3. No SD-card logging and communication are serial only as standard.

Megasquirt-2 uses the same calibrations, test modes and diagnostic loggers as Megasquirt-3.


Microsquirt offers similar features to Megasquirt-2 but comes pre-assembled in a case and is half the size. It offers two fuel outputs, four ignition outputs and two crank/cam tach inputs as standard. However, it requires an external add-on to support 4 wire stepper idle.

Microsquirt module

The Microsquirt-module comes as a bare PCB and is most often used to form the core of a packaged ECU. For example, the DIY-PnP range from DIYAutotune use the Microsquirt module at the heart. The module is specifically intended to form part of your product with licensed B&G hardware and firmware of your choice. It is not intended for novice end-users.


Megasquirt-1 offers a cost effective entry level to the aftermarket ECU market. Coupled with an EDIS module, the Megasquirt-1 V2.2 was cheap but gave mappable spark and fuel. For direct coil control (non-EDIS) the Megasquirt-1 V3.0 is still a cheap and simple ECU. As expected Megasquirt-1 lacks many of the features of the newer ECUs. Few OEM wheel patterns are supported, temperature sensor and wideband calibration is more tricky and there are fewer diagnostics. All features require DIY modifications to the circuit board.

The processor used within the Megasquirt-1 is now obsolete and will become unavailable once supplies are exhausted.
It is strongly recommended that you consider Megasquirt-2, Microsquirt or Megasquirt-3 products instead.