I guess you are thinking of an ECU upgrade and heard of the detonation problem. Well, detonation or pinging is when the engine (air/gas mixture) missfires at the wrong time for various reasons. This is a serious prblem and will kill the engine if you let this happen for a while.<p>Few examples that will cause detonation are: use of lower octane gas than what is recommended, too high of a compression of the air/gas mixture, hot sopt in the engine cylinders and etc. All these can cause the mixture to ignite while the cylinder is still moving up in the chamber. Of course the ignitin will force the cylinder to go downward and this will cause a mechanical stress on the engine (becuase it is still trying to move up).<p>Basically if you hear a weird, high pitched, metalic, "ping" sound from your engine when you step on the gas, then most likely it is due to detonation. if so, let go of gas and stop or slow down.<p>I am sure someone else can explain this better to you.<p>

Detonation is not the premature ignition of the fuel/air mixture. That is called preignition and is often caused by the mixture being ignited on the compression like a diesel engine. The definition of detonation is an uncontrolled, explosive ignition of the fuel/air mixture within the cylinders combustion chamber. Normal combustion allows a smooth buildup of temperature and pressure and ensure that the expanding gases deliver the maximum force to the piston at exactly the right time in the power stroke. Preignition and detonation often take place simultaneously, and one may cause the other. The driver has no way of telling which is taking place. The only security from these is to run the proper grade of fuel. Detonation preignition will sound like someone put marbles in you valve covers.

Detonation in IC engines happens when the spark initiated flame front progresses at transonic velocities. The pressure wave will cause autoignition at other areas, causing the pinging much like preignition. <p>Carbon buildup can cause this as it serves as a hot spot promoter. Burned valves are another source.<p>Detonation is keyed on transonic velocities.