Naturally (or normally) aspirated 1.8 liter b series motor.
N/A = not turbocharged
b18b or b18a = non vtec bseries motor
b18c1 = gsr motor
b18c5 = type r motor
Thats the best I can do without going real in depth. You might want to check the FAQ at the top of this forum, has all the specs of the various engines availible in the Integra.