There is a chance it will work but it is a very bad idea for several reasons:

1. This connects power and ground of the Twinsync (and receiver) to the iginition system and battery (interference is possible)
2. The hall sensor included with the twinsync is more than just a hall sensor (other circuitry in it)
3. The voltages may not be compatible (Twin sync hall sensor is power by 5V but outputs 0-3.3 volts

The right way to do it is with an optically isolated input from the hall sensor or read the rpm from the iginition with an optically isolated circuit. (I actually have prototype that do this but have not productized them.