What is the difference between the MegaSquirt PCB 2.2 / PCB 3.0 / PCB 3.57?

They are all three able to use the MegaSquirt-I CPU as well as the MegaSquirt-II and MegaSquirt-III daughterboards, but they are based on different versions of the circuit board and as such there are different features .  You can click on any of the headings below to view an example of the product with pictures.


The v2.2 board dates back several years, it’s the least expensive of the currently available options, and the least developed.  It’s a great low budget solution that has served many people well (and continues to).



The v3.0 board has a lot of improvements made to it to reduce electrical noise and increase robustness (damage resistant), as well as make the board easier to expand.  All of the improvements with the V3.0 board are listed here.

The main high level differences are that the uprated flyback circuitry is included so you can run low or high impedance injectors, there are several improvements to make the board more robust and harder to damage in the event of a mis-wire or overload event. A prototyping area was adding to the PCB, and several changes were made to prepare the board for the MegaSquirt-II and MegaSquirt-III Daughterboards.



The v3.57 board’s major claim to fame is it’s ‘surface mount (SMT)’ design.   Otherwise it is almost identical to the v3.0 board and the above information on the v3.0 board fully applies.  The only other major differences are:

A) the addition of a PWM capable idle control transistor allowing control of a PWM idle valve or a standard on/off type FIDLE valve without need for modification.  This was a common modification applied to the v3.0 board and is no longer needed on the v3.57.

B) the addition of a DB15 connector next to the DB9.  By default this doesn’t do anything, but is there to allow for extra I/O for modifications.  It takes the place of the externally viewable LEDs, which are now internally surface mounted on the PCB.

C) Several signal pads have been added making common modifications easier.

D) The prototype area was sacrificed (removed) to make all of the above possible.


In general, if you’re looking for the cheapest option possible, the PCBv2.2 makes sense.  Chances are you’ll mate an MS1 processor with it in this case, such as with our MegaSquirt-I kits and assembled units.  Otherwise, if the small difference in price is worth it to you to go with a tougher and more featured board that was built with expansion in mind, the v3.0 or v3.57 boards make more sense.  We offer MegaSquirt I’s, II’s, and III’s using these two boards.  Some prefer the thru hole v3.0, and some prefer the v3.57.  See the above to decide your preference between the two.