The Rpi would serve dual purposes:
1. Convert from RS232 (which is what the radio uses) to TTL serial (which is what the rusefi board uses) by means of connecting a converter that
@ already has connected to the RPis USB port. This could certainly also be accomplished by means of a TTL-RS232 converter.
2. More importantly: Buffer the data. Maybe even compress it. The radio only has a 256 byte buffer. We anticipate communication breaking down on the track for periods of time that require a larger buffer, so we need to insert something to take care of that.
Granted the RPi is immensely overpowered for the task at hand. But considering that it comes at a $10 pricetag and I already have one in my parts bin which isn't used, I say "So what?"
And of course there's other neat things you can do with it now that it's getting data from rusefi- like a display connected to the native HDMI port.