Speedhut Speedo Gauge and Fueltech FT450

Hello guys im trying to connect the speedo gauge from speed hut it comes with 2 wires signal and ground. i have the FT450 ecu receiving speed signal from the transmission speed sensor from the sr20 engine. how can i hookup the speed hut gauge, Do i just splice the signal wire from the sensor with the ECU wire and the speedhut gauge and leave the ground disconnected or do i need to use a resistor with the signal wire, like a pull up

What do you know about the speed signal from the transmission sensor used with the SR20? Is it a hall-effect sensor, or a VR (variable reluctance)? One clue would be how many wires does it have? Do you know the pinout of the connector for the sensor? I would figure these things out first -- consult a workshop manual, internet forums, or knowledgeable local shops.

Once you have that info, perhaps we can help. Most likely, you will be able to just connect the signal to the original speed signal, and the ground to the original sensor ground.

What is the specific model of gauge you're trying to use, and what does its installation guide say?

There is also a very high probability it will need to be calibrated for your specific application, which should also be in the guide.