Megasquirt Product Comparison



This table shows the maximum features available for each option.

Feature / Version

Megasquirt 1

Megasquirt 2

Microsquirt

Microsquirt module

Sequencer

Megasquirt 3

Product Picture

(without case)

Summary

Single board, with plugin CPU, can be DIY assembly.

Lowest cost entry level. Limited features.

Single board, with plugin CPU card, can be DIY assembly.

Better tunability, driveability and diagnostics than Megasquirt-1.

Single pre-assembled board, no DIY.

Similar to Megasquirt-2. Two ignition outputs.

Pre-assembled module forms core of an ECU.

Same technology as Microsquirt, but more outputs accessible.

Single pre-assembled board, no DIY.

Microsquirt technology extended to sequential

Main board, can be DIY assembly, plugin CPU card, plugin extension card.

All MS2 plus, 8cyl sequential, more I/O, SDcard logging.

Connectors

Standard D-type

Standard D-type

AMPseal

pin header

AMPseal

Standard D-type

Built in Hardware






(Assumes MS3+MS3X)


2x fuel channels hi-z, low-z with PWM limiting

2x fuel channels hi-z, low-z with PWM limiting

-

-

-

2x fuel channels hi-z, low-z with PWM limiting


-

-

2x fuel channels without PWM

2x fuel channels without PWM

8x fuel channels without PWM

8x fuel channels without PWM


2 wire PWM idle

(mod needed on V3.0)

2 wire PWM idle

(mod needed on V3.0)

-

-

2 wire PWM idle

2 wire PWM idle


-

4 wire stepper idle

-

-

4 wire stepper idle

4 wire stepper idle


Fuel pump relay control

Fuel pump relay control

Fuel pump relay control

Fuel pump relay control

Fuel pump relay control

Fuel pump relay control


CLT, MAT, TPS inputs

CLT, MAT, TPS inputs

CLT, MAT, TPS inputs

CLT, MAT, TPS inputs

CLT, MAT, TPS inputs

CLT, MAT, TPS inputs


2.5 bar MAP sensor

2.5 bar MAP sensor

-

-

-

2.5 bar MAP sensor


Magnetic (VR) , hall, optical, points tach input

(No VR on V2.2 board)

Magnetic (VR) , hall, optical, points tach input

(No VR on V2.2 board)

2 x Magnetic (VR) , hall, optical, points tach input

2 x Magnetic (VR) , hall, optical, points tach input

2x Magnetic (VR) , hall, optical, points tach input

2x Magnetic (VR) , hall, optical, points tach input

(No VR on V2.2 board)


1x high current coil driver

1x high current coil driver

2x high current coil driver

-

-

-


-

-

OR 2x logic level coil

2x logic level coil

8x logic level spark

8x logic level spark


-

-

2x medium current outputs

2x medium current outputs

4x medium current outputs

6x medium current outputs (e.g. nitrous, boost, VVT, fan, etc.)


-


1x spare analogue inputs

2x spare analogue inputs

2x spare analogue inputs

3x spare analogue inputs


-

-

1x switch input (flex)

2x logic input

1x switch input (flex)

4x switch inputs


-

-

1x low current output

1x low current output

-

3x low current output


-

-

-

3x logic output

-

2x logic output


-

-

-

-

-

2x logic input


-

-

-

-

-

2x raw analogue inputs


-

-

-

-

-

SDcard slot for datalogging


RS232 serial tuning

RS232 serial tuning

RS232 serial tuning

RS232 serial tuning

RS232 serial tuning

RS232 serial tuning


-

CAN communications

CAN communications

CAN communications

CAN communications

CAN communications


-

-

-

-

-

USB serial tuning

Optional hardware (DIY)








Up to 6 high current coil drivers

Up to 6 high current coil drivers

-


-

Up to 6 high current coil drivers


2x spare analogue inputs

2x spare analogue inputs

-

-

-

Raw analogue inputs can be conditioned


Launch/nitrous/ tableswitching inputs

Launch/nitrous/ tableswitching inputs

-

-

-

Logic inputs can be used for switches


Relay drivers for nitrous

Relay drivers for nitrous

-

-

-

Logic outputs can power drivers


Boost output

Boost output

-

-

-

-


Fan control output

Fan control output

-

-

-

-


Tacho output

Tacho output

-

-

-

-


MAP sensor upgrade to 3 bar, 4 bar

MAP sensor upgrade to 3 bar, 4 bar

External MAP sensor


External MAP sensor

MAP sensor upgrade to 3 bar, 4 bar

Firmware features







Fuel table size

12x12

12x12 or 16x16

12x12

12x12

12x12

16x16

Fuel table resolution

1%

1%

1%

1%

1%

0.1%

rpm resolution

100 rpm

1 rpm

1 rpm

1 rpm

1 rpm

1 rpm

Accel enrichment

TPS, MAP, RPM

Simple (TPS,MAP), Enhanced (wall-wetting)

Simple (TPS,MAP), Enhanced (wall-wetting)

Simple (TPS,MAP), Enhanced (wall-wetting)

Simple (TPS,MAP), Enhanced (wall-wetting)

Simple (TPS,MAP), Enhanced (wall-wetting)

Spark table size

12x12

12x12

12x12

12x12

12x12

16x16

Advance resolution

0.3 deg

0.1 deg

0.1 deg

0.1 deg

0.1 deg

0.1 deg

Injector phasing

Bank/batch fire, pseudo random, crank based.

Bank/batch fire

Semi sequential for 4-cyl

(Experimental code available for 4cyl sequential)

Bank/batch fire

Semi sequential (4cyl)

Bank/batch fire

Semi sequential (4cyl)

Fully sequential (up to 8cyl)

Fully sequential (up to 8cyl)

Injector timing

Not adjustable

Timed within crank pulses

Timed within crank pulses

Timed within crank pulses

Timed within crank pulses, to specific angle

Timed for start, middle, end of injection pulse

Injector trim

Not adjustable

Not adjustable

Not adjustable

Not adjustable

Trim% per cylinder

Mapped trim table per cylinder

Spark trim

Not adjustable

Not adjustable

Not adjustable

Not adjustable

Time degrees per cylinder

Mapped trim table per cylinder

EDIS

Y

Y

Y

Y

N

Y

Distributor spark

Y

Y

Y

Y

Y

Y

Trigger return dizzy

Y

Y

Y

Y

Y

Y

Simple wheel decoding

Y

Y

Y

Y

Y

Y

Every tooth wheel decoding

N

Y*

Y*

Y*

N

Y*

Wasted spark

Y

Y

Y

Y

Y

Y

Coil on plug

Y

Y

Y

Y

Y

Y

Dual dizzy

Y

Y

Y

Y

N

Y

Cam / 2nd tach input

Y

Y

Y

Y

Y

Y

Number of spark outputs

6

6

2

2

8

8

Rotary trailing

Y

Y

Y

Y

N

Y

HEI7, GMDIS

Y (with bypass control)

Y (with bypass control)

Y (with bypass control)

Y (with bypass control)

Y

Y (with bypass control)

TFI

Y

Y

Y

Y

Y

Y

Oddfire wheel decoder

Y

Y

Y

Y

N

Y

Oddfire dizzy

N

Y

Y

Y

N

Y

Neon/420A

Y

Y

Y

Y

N

Y

36-1+1

N

Y

Y

Y

N

Y

36-2-2-2

N

Y

Y

Y

N

Y

Subaru 6/7

N

Y

Y

Y

N

Y

IAW Weber-Marelli

N

Y

Y

Y

N

Y

Mitsubushi 6g72

N

Y

Y

Y

N

Y

4/1 CAS

Y

Y

Y

Y

Y

Y

4G63 (Miata)

Y

Y

Y

Y

Y

Y

99-00 Miata

N

Y

Y

Y

N

Y

Renix 44-2-2

Y

Y

Y

Y

N

Y

Twin trigger (aka. dual spark)

N

Y

Y

Y

N

Y

Suzuki Swift

Not with std code

Y

Y

Y

N

Y

Suzuki Vitara

N

Y (Untested!)

Y (Untested!)

Y (Untested!)

N

Y (Untested!)

Daihatsu 3 cyl

N

Y (Unproven)

Y (Unproven)

Y (Unproven)

N

Y (Unproven)

Daihatsu 4cyl

N

Y (Untested!)

Y (Untested!)

Y (Untested!)

N

Y (Untested!)

Rover K Series 36-1-1

N

Y

Y

Y

N

Y

Rover K Series 36-1-1-1-1

N

Y

Y

Y

N

Y

Rover K Series 36-2-2

N

Y (Untested!)

Y (Untested!)

Y (Untested!)

N

Y (Untested!)

Honda VTR1000 12-3

N

Y

Y

Y

N

Y

Chrysler 2.2/2.5

N

Y

Y

Y

N

Y

GM 7X native

N

Y

Y

Y

N

Y

Nissan 360 tooth CAS

N

under test

under test

under test

N

Planned

Load methods

SD, AN, MAF

SD, AN, map/baro (load%)

SD, AN, map/baro (load%)

SD, AN, map/baro (load%)

SD, AN, map/baro (load%), MAF

SD, AN, map/baro (load%), MAF

Load blending

Y?

Y

Y

Y

Y

Y

Load tables

1

2

2

2

1

2

Staged injection

Y

Y

Y

Y

N

Y

Over-run fuel cut

Y

Y

Y

Y

N

Y

Tachometer output

Y

Y

Y

Y

Y

Y

Launch Control/flat shift

Y

Y

Y

Y

N

Y

Spark cut rev limit

Y

Y

Y

Y

N

Y

Dwell duty%

Y

Y

Y

Y

N

Y

Dwell battery correction

built-in

table of %ages

table of %ages

table of %ages

table of millseconds

table of %ages

Cranking pulsewidth

table of pulsewidths

table of %ages

table of %ages

table of %ages

table of pulsewidths

table of %ages

Alternate cranking injection

N

Y

Y

Y

N

Y

Specific cranking advance, dwell

Y

Y

Y

Y

N

Y

Fixed timing for setup

Y

Y

Y

Y

N

Y

Test mode

N

Pump, Inj, Coils, Idle

Pump, Inj, Coils, Idle

Pump, Inj, Coils, Idle

Injectors?

Pump, Inj, Coils, Idle

Closed loop idle control

Experimental

Y

Y

Y

N

Y

Boost control

Open loop

Y (open or closed loop with PID control)

Y (open or closed loop with PID control)

Y (open or closed loop with PID control)

N

Y (open or closed loop with PID control)

Nitrous control

Y

Y (2 stage)

Y (2 stage)

Y (2 stage)

Fuel addition, spark retard

Y (2 stage)

Knock sensor (software)

Y

Y

Y

Y

Y

Y

Realtime barometric correction

Y

Y

Y

Y

Y

Y

Water Injection

Y

N

N

N

N

N

Table Switching

Y

Y

Y

Y

Y

Y

Configurable outputs

Y

Y

Y

Y

Y

Y

AFR target tables

Y

Y

Y

Y

Y

Y

Dual fuel tables (per bank)

Y

Y

Y

Y

Y

Y

Synchronous sensor sampling

N

Y

Y

Y

Y

Y

CAN communications

N

Y

Y

Y

Y

Y

Built in tooth/trigger loggers

Y (tooth and trigger)

Y (tooth, trigger, composite)

Y (tooth, trigger, composite)

Y (tooth, trigger, composite)

N

Y (tooth, trigger, composite)


* = see notes below

Find out more

Megasquirt 1 - B&G firmware - MS1/Extra firmware

Megasquirt 2 - B&G firmware - MS2/Extra firmware

Microsquirt - B&G firmware - MS2/Extra firmware

Microsquirt module - B&G firmware - MS2/Extra firmware

Sequencer

Megasquirt 3



Notes on boards

The Megasquirt 1, 2 and 3 may use a V2.2, V3.0 or V3.57 mainboard. The V2.2 and V3.0 are available in DIY kit form. If you wish to DIY, the V3.0 is recommended as it has an inbuilt magnetic input (VR) circuit and better support for low-z injectors. The V2.2 is the simplest and cheapest option. The V3.57 is a pre-assembled version of the V3.0.

The features chart is based on using a V3.57. The only real difference when using the V3.0 is that a small modification is required to adequately support PWM idle. If you are considering adding circuits then the V3.0 is likely a better choice as it has a prototype area provided for the purpose.

When using the MS3, the MS3X expander board already contains many input and output options and the MS3, MS3X, V3.57 is a recommended package.



Notes on firmware features

For Megasquirt 1, the features listed are those from MS1/Extra code 029y4

For Megasquirt 2, Microsquirt and Microsquirt Module, the features listed are those from MS2/Extra code 2.1.0

Sequencer and Megasquirt3 are using their own latest firmwares.



Explanation of the terms in the table

Fuel Table Size: The number of cells in the fuel tuning table. Note that because the rpm and load values are adjustable a good tuner is unlikely to need more than 12x12.

PW resolution: The step size of increments of fuel pulsewidth. In theory the smaller the step, the finer the control available. Whether this translates into better engine performance is largely impacted by how well the engine is tuned and operating factors. MS1/Extra hi-res allows better injector resolution by using a timer for injector control but loses injector PWM control in the process. Note that the fuel calcs will often have a lot of inbuilt fuzziness, so the 0.67us hardware precision may not be useful.

RPM resolution: The MS1 codes only use rpm in steps of 100 internally, so this means you can only tune in 100rpm steps. Not a big deal.

Accel enrichment: There are various methods of responding to acceleration transients for best engine driveability.

Advance table size: All present Megasquirt versions with spark control use a 12x12 table for setting the advance at different loads and rpms. Megasquirt 3 extends this to 16x16

EDIS: Ford's standalone ignition control system

Distributor spark: Simple spark control using a single coil and typically a distributor mounted pickup, crank mounted pickups can also be used.

Trigger return dizzy: Some distributors with hall effect sensors have a shutter wheel that provides “cranking” and “running” signals on each edge. This can give improved starting ability and also better running precision.

Simple wheel decoding: The MS1/Extra wheel decoder can decode regular wheel patterns (36-1, 24/2, 60-2, 24/1) but gains no timing improvement from the additional teeth. The early MS2 wheel decoder worked in a similar way.

Every tooth wheel decoding: The MS2/Extra code samples the time between each tooth for speed data and sets the advance/dwell as a tooth number plus a time offset. Unsure what MS2 base does.

Wasted spark: i.e. multiple spark outputs. Without modifications to the MS2 card, MS2 base code can only do single spark output. The modifications also remove the ability to control low-Z injectors using PWM - resistor packs would be required.

Coil on plug: As above, but additional code is required to decode the trigger wheel.

Dual Dizzy: For engines like the Lexus V8 where a trigger wheel and two coils and distributors are used.

Cam / 2nd tach input: For any coil on plug install a phase sensor is required. Any engine with a non-missing tooth main wheel also requires a 2nd tach input. MS2 can do this with modifications to the card. Microsquirt has it as standard.

Number of spark outputs: This determines how many coils you can drive.

Rotary trailing: Specific code to drive the trailing coils with programable split angles.

HEI7/GMDIS: An ignition system from GM. The bypass output controls inbuilt timing or controlled timing. A dedicated output alleviates the need for an external relay.

TFI: An ignition system from Ford.

Oddfire wheel decoder: Using a regular trigger wheel to drive coils on an oddfire engine that requires an angular offset between the outputs.

Oddfire dizzy: Some engines such as GM V6 use an oddfire pattern and a distributor. This code detects and works with the uneven pattern.

Neon/420A, 36-1+1, 36-2-2-2, Subaru 6/7, IAW Weber-Marelli, Mitsubushi 6G72, 99-00 Miata, Suzuki Swift, Suzuki Vitara, Daihatsu 3cyl, Daihatsu 4cyl: These are all special wheel decoders for these specific engine and trigger wheel patterns. See the main page for links to pages about these wheels.

CAS 4/1: This is handled as part of the wheel decoder.

Twin trigger / Dual spark: This is often used on 4 cylinder bike engines. A single lobe is mounted on the crank shaft and two pickup coils detect it passing. MS2 and MS2/Extra support this with different code implementations.

Load methods: SD = speed density, standard MAP sensor input. AN = alpha-N - TPS and RPM. MAF = using a Mass Air Flow sensor. Map/baro = a variant on speed density that better allows for altitude changes.

Load blending: Combining multiple load methods for smoother transition from idle to full load.

Load tables: How many load tables operate at one time.

Staged injection: Inspired by RX7 and similar. For use where two banks of dissimilar injectors are used. e.g. you can have a bank of small injectors for idling and low load and a second bank of large injectors for full load operation. The code automatically enables the second bank as and when required. This can greatly improve the fuel regulation under low load.

Over-run fuel cut: A standard feature in most fuel injection systems since the 1980s. Fuel can be cut off totally under heavy deceleration conditions to conserve fuel.

Tachometer output: When using a complex trigger wheel or wasted spark a special output is often required to drive the tachometer.

Launch control/flat shift: A “two step” rev limiter primarily used for racing.

Spark cut rev limiter: A method of limiting revs. It is far harsher than a simple engine-preserving fuel cut, but works very well for launch/flat shift.

Dwell duty%: For some ignition systems like TFI or MSD a percentage dwell output is required instead of a coil charge dwell. This allows various percentages to be set in software.

Dwell battery correction: As the supply voltage varies, the required dwell time also changes. Different methods for achieving this.

Cranking pulsewidth: How the fuel injected during cranking is controlled. A percentage table is supposed to allow first time setup as the number is scaled based on the injector size. The latest MS2 codes also take X-Tau, air density and flex fuel into account.

Alternate cranking injection: The standard scheme is to inject fuel once per ignition event. On large cylinder counts this can result in low precision and difficult start. This option allows the number of injections to be halved to allow better control.

Specific cranking advance, dwell: A specific setting for the cranking advance and dwell instead of a table lookup.

Fixed timing: A setting to lock the timing for easier first time setup and confirmation that the ignition system is working correctly.

Test mode: Various modes for testing system components without running the engine.

Idle valve control: Options for different types of fast idle valve.

Boost control: Mode to control the wastegate on a turbo to vary boost levels.

Nitrous control: Control system to only allow nitrous when certain conditions are met, add more fuel, retard the timing etc. also delay nitrous after launch.

Knock sensor: Take feedback from a knock sensor and retard the timing

Realtime baro: Input from a second map (pressure) sensor for continual barometric adjustment. Useful in mountainous regions. Not much use in the Netherlands.

Water injection: Specific system to control water injection solenoids and pumps.

Table Switching: An external switch input swaps the fuel or spark tables being used. Note - this is not for “economy vs race” - that is a common misunderstanding of fuel injection systems and that is what your right foot is for. Valid examples are nitrous or swapped fuel.

Configurable outputs: Various on/off outputs for fans and warning lights etc.

AFR target tables: Using your wideband to target different mixtures and different rpm/loads.

Automatic Mixture Control: The ECU responds to the wideband input and adjusts the fuel VE table automatically. As an alternative use “Auto Tune” in Megatune.

Dual Fuel tables (per bank): Another name is Dual table. Originally written for mapped water injection. Can also be used on V engines for different tuning on each bank. Do not confuse with staged injection.

Synchronous sensor sampling: The sensors are sampled at a particular crank angle. This gives far more repeatable response on the MAP sensor signal on most engines.

CAN communications: The MS2 and Microsquirt have CAN communications built in which allow communications with addon boards. ( See also here. )

Crank based injection points: MS2/Extra 2.0 can do a semi-sequential which has improved the idle on 4G63 engines for sure. Sequencer and MS3 can do fully sequential.



Last Updated: 20 July2009 19:19:04

(C) James Murray 2009