Many of our customers are unsure which MegaSquirt hardware version is right for their project. We've written this guide with the hope of helping to stem some of that confusion, and potentially help you save some money.

You need the v3 PCB if:

• You plan to drive a coil without any external modules (MSD 6A, Bosch ICM, etc)
• You plan to drive more than one coil, or run wasted spark
• Your engine has a VR sensor that you plan to use for RPM Input
• You plan to run low impedance injectors
• You plan to add any additional output circuits (fan control, nitrous, water injection, etc)

Some additional features of the v3 board:

• Higher quality PCB means means less chance for onboard component failures
• Onboard current limiting helps keep power surges from damaging the ECU
• Output drivers have an onboard heatsink to minimize component failure even during the worst conditions
• Seperate power and ground planes on the PCB help to eliminate internal noise
• Capable of driving up to 4 coils (4 cylinder coil on plug, or 8 cylinder wasted spark)
• Onboard support for 20psi boost
• Upgradable to 45psi boost sensor with realtime barometric pressure compensation

The v2.2 PCB is ideal if:

• You aren't planning on controlling spark
• Your vehicle has a hall sensor, which can be used to provide the RPM input
• You plan to control spark, but will drive a single coil from an external device (MSD 6A, Bosch ICM, etc)
• You aren't planning on adding any additional output circuits, such as nitrous control, water injection, etc
• You will only be using high impedance injectors
• You're looking for a simple, cheap, reliable option to control fuel and spark without any major plans of upgrading the ECU once the car is running

If it sounds like the v2.2 board is right for you after understanding the differences and limitations, we would be happy to configure one for you. Both units are equally as capable of running the MegaSquirtnSpark extra (MSnS-e) code, so it is generally a matter of the engine hardware, budget, and scope of the project that help to make the final decision.

For most new installations, we typically recommend the v3 board, as it provides all of the required area for future circuit upgrades, as we find most people normally want to continue expanding their project. It also allows for easier troubleshooting if something does go wrong. As we've found lately, more and more people are begining to use the MegaSquirt to run wasted spark configurations with a factory trigger wheel and VR sensor, both of which lend themselves well to starting off with a v3 board.

For more information on the differences and features of each board version, we encourage you to visit www.megasquirt.info. There you'll find a wealth of knowledge from the creators of MegaSquirt, as well a more specific details on each version of boards.