There are a few types of detonation. If it occurs in an ejector seat, you feel yourself forcibly thrown upwards and you need some clean underwear. If it occurs in a nuclear bomb, you won't feel much. In our normal daily lives however, it feels like the timing is off - lack of power and pinging from the engine under accelleration. You will also have a rough idle.
In cases of light detonation, small black or gray spots will be noticed on the core nose of the spark plug. In cases of severe detonation, insulators may be cracked and/or chipped. The same high pressure waves created during detonation can break spark plugs, damage intake valves and break pistons. Make sure that the correct octane fuel is being used, assure proper operation of emission and computer systems, and assure the correct heat range of spark plug is being used.
BTW, I wouldn't reccommend fiting an ejector seat in your Z. And try not to carry too many nuclear bombs!! One is more than enough!!!!!
believe it or not my insurence lady asked me that... she had a bunch of questions to ask me and one of them was are you going to carry any radio active material in the vehicle... I looked at her and asked if she new what a Z was... she just sadi that she had to ask all the questions