So I noticed that my 94 RS does not have a knock sensor.
I thought all Fuel Injected cars have them? I know the car only requires 87 octane
but can't you still have pre-ignition pinging and how does the car deal with it,
especially under hard load?

 

Detonation is actually more likely on 87 than on 91 octane. Unless it's happening at large throttle openings it's pretty easy to hear. The most likely time I think you'll hear it on a stock engine/ECU is high load, low RPM (e.g. lugging up a hill). If you hear it, reduce throttle or downshift. Most people with modded cars disable the knock sensor anyways and with a good tune it's not a concern.

 

no b18b1's come with knock sensors, only b18c1's do in integra's, the ECU does not have the provisions for it either.