I put an RB20 in place of a Ka24E, but unfortunately I didn't document the wiring. However I pretty much followed a guide someone else had posted here before for RB20 -> 89/90 S13. I still have one wiring gremlin (hard starting...it feels the same as when I don't connect the ignition signal wire from the S13 dash harness to the ECU when doing SR swaps).
However if you get stuck on a particular wire and I'm in a good mood I'd be willing to take a peek at my wiring and try to help you out
Edit: Here's a link to the wiring guide I used.
http://www.nissaninfiniticlub....iring