Classic MegaSquirt 3 MS3X Expansion Card & Connector Kit

Unlock the full capabilities of your MegaSquirt-3 ECU with the MS3X Expansion Card & Connector Kit. This plug-and-play expansion board installs directly inside your MS3 case — no soldering required — and connects via the included ribbon cables to your existing MS3 daughter card. Whether you’re looking to run full sequential injection, staged nitrous, or multiple ignition outputs, the MS3X makes it simple with pre-configured circuits and a seamless TunerStudio setup experience. Key Features – Adds the Following I/O to Your MS3 ECU: 8 Sequential Fuel Injection Outputs Drives high-impedance injectors Unused outputs can be reassigned for auxiliary control 8 Logic-Level 5V Ignition Outputs Compatible with LSx coils, IGN-1A coils, and other smart ignition systems Requires coils with internal ignitors or external ignition modules 6 Medium-Current Outputs Ideal for: Boost control 2-stage progressive nitrous Tach output 2- or 3-wire PWM idle control General-purpose relay or PWM control 3 Analog Inputs Perfect for logging: External MAP sensor Secondary O2 sensor Fuel pressure Accelerometer Other custom sensors 4 Digital Switch Inputs Use for: Launch control Data logging trigger Nitrous arming Table switching VSS input (with external signal conditioning) 1 Cam Sensor Input Compatible with VR, Hall, or optical sensors Installation & Compatibility: No soldering required – connects via included ribbon cables Designed for use only with the MegaSquirt-3 daughter card Fully supported by TunerStudio for easy configuration Compact form factor fits cleanly inside the MS3 ECU case What’s Included: 1 × MS3X Expansion Board Ribbon cables for plug-in installation Header connectors