UA4C for Speeduino Seawolf Sea Fox

(5 customer reviews)


SKU: N/A Category:


Now In-stock! All shipped versions are vB2.

Version vB2 Sea Fox changes include:

-All SMD components including the sensors are now soldered on from the factory
-5 volt output is protected from overload
-Corrected parallel install issue
-Harness connector footprint improved to better hold the connector while soldering
-Further improved labeling
-Assembled in the USA

A new version of the UA4C (vB1 Sea Fox) is available
Changes include:

– Rearranging the serial headers for better fitment in the slim case
– Upgrading the low current outputs, they now support larger loads and are self-protecting
– Changed tachometer circuit to allow 5V, 12V, and high voltage tachometers
– Added indicator LED for 5V power, and improved labeling

The UA4C uses SMD technology to make a 4 ignition/4 injection channel board smaller, with more features, and cheaper. It is a bottom mounted Arduino MEGA shield. The MEGA is placed upside down on top of it.* This makes the total package thickness less than 20mm. All of the outputs (except for stepper idle) include an LED for quick troubleshooting during setup. An externally accessible jumper blocks resetting of the system when a USB cable is connected. Wire housings and 50 (four extra) terminals are included to connect your wiring to the PCB. Will fit in the slim or standard height Hammond case. If you include soldering service the sensors, connectors, etc will be soldered to the board. If you require special provisions you can leave a note on your order use the contact form on the help page.


– 4 ignition channels, logic 5V, 330mA max pulse
– 4 injector channels, ground switching
– 4 high current outputs (idle, idle2, boost, vvt) ground switching
– 8 low current outputs (fuel pump, tachometer, fan, fan2, aux1-4) ground switching
– Accepts DRV8825 module for stepper idle control


– 2 triggers (crank, cam, etc, logic level with socket for conditioner modules)
– MAP (250 or 400kPa) and separate barometer
– Voltage correction
– Throttle position
– Coolant and incoming air temperature
– Oxygen
– Flex fuel
– Launch
– Knock (future code update)
– 2 spare inputs


– Serial3 routed to external connector (optional CAN with future module)
– Bluetooth header with blocking diode to allow use of USB

Extra Stuff

NOTICE: This is an unofficial Speeduino board. Josh Stewart was very kind in adding a definition for this board to the Speeduino code. However, purchases of this board do not directly contribute to his upkeep and updates to the Speeduino software and website. PLEASE consider visiting Speeduino Forum and clicking Support Speeduino at the top.

*In order for the MEGA to fit the unused power jack must be removed. To do this use a pair of side cutters and cut the metal strap on the jack closest to the outside edge of the Arduino board. Then use a pair of slip-joint pliers to twist the jack back and forth while pulling it away from the PCB. It should come off fairly easily, but please take care when doing so. I will assume no responsibility for Arduino, bodily, or other harm. If you order an Arduino MEGA from me this will be done already.


These are the part numbers of official harness tools. While not eBay cheap, they are not as costly as you might think.
Hand Crimp: 10129483-001LF
Terminal Extractor: 10129274-030LF


vA3- No known.
vB1- The solder jumper on the bottom for parallel installation does not work as intended. Please contact me for additional steps if you wish to install in parallel with another ECU.

Additional information

Weight 2.5 oz
Dimensions 4 × 4 × 1 in
Include Harness Connections

Yes, No

MAP Sensor

250kPa, 400kPa

Through-hole Soldered

No, Yes

5 reviews for UA4C for Speeduino Seawolf Sea Fox

  1. DCwerx

    Without a doubt the best speeduino PCB to date. Super high quality and loaded with inputs and outputs.

  2. SMA Save Money Auto ltd (verified owner)

    Hi how are you,

    We purchase a UA4C board and cannot find no wiring diagram on Speeduino Wiki to support it can you kindly provide us with information on the wiring diagram we have a this is our second request thanks for your favorable response.

    • wmarkel

      As I have told you before, sorry if you do not receive my emails, there are no wiring diagrams specific to the UA4C. The Speeduino wiki and forum are full of diagrams on how to properly connect injectors, coils, sensors, etc to virtually any ECU. Descriptions of every pin on the UA4C including the circuit schematics can be found here:
      Thank you, Weaver

  3. yingste

    Great product, been running in my car for several months now. Slimmer and cheaper than the .4 and also includes a baro sensor. Almost definitely buying one again for the next project. Just wish you guys sold a premade loom/connectors with 8ft of wire since I’m bad at making nicely crimped connectors.

    • wmarkel

      Thanks so much. Sorry no harnesses here, but the nice guys over at SpeedyEFI do make them up.

  4. Blake Tchida (verified owner)

    Just purchased my second UA4C because the first project went so well and runs amazingly. Best speeduino based ecu out there with all the great features of a good standalone (4 ignition and injector channels, fuel pump and rad fan control, variable valve timing control, FLEX INPUT for E85, and much more!!!

    Thank you for providing such a great product at an incredible price for the performance!! Will definitely purchase another one as soon as I find a good excuse for another speeduino project lol

  5. Ryan S. (verified owner)

    Great Speeduino compatible board. I’m using it for a 1980 CB750 fuel injection swap and it has all I need to run full sequential injection. I do wish the board had a few extra inputs though, I’d like to run a few more sensors for logging. More than enough outputs for a motorcycle. Only issue I really have had was getting a vacuum line connected to the MAP inside the slim case from Hammond, I had to drill a hole through the top. The hose couldn’t make the sharp turn inside the case. Wish it was 90 degree/parallel to the board and more of a hose barb style sensor.

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