Detonation is VERY VERY BAD. Detonation is when fuel pre-ignites in the cylinder, causing stress on cylinders, valves etc. When intake temperatures rise or low octane fuel is present the threshold of the engine to resist detonation is lowered. For example, you raise the boost from 7 - 14psi on a standard turbo car, your intercooler is only capable of holding about 12psi. This is due to the turbo exceeding its efficiency range and also the size of the factory I/C. Once boost is wound up, the faster the turbo spins and hence the reason for excessive heat.
Hope this has been helpful. Anyone correct me if I'm wrong, I'm sure you will ya bastards. :finger:
Doc
(aka Ben)