Detonation, or engine knock, occurs simply when fuel pre-ignites before the piston reaches scheduled spark ignition. This means that a powerful explosion is trying to expand a cylinder chamber that is shrinking in size, attempting to reverse the direction of the piston and the engine. When detonation occurs, the internal pneumatic forces can actually exceed 10x the normal forces acting upon a properly operating high performance engine. Detonation is generally caused by excessive heat, excessive cylinder pressure, improper ignition timing, inadequate fuel octane or a combination of these. Of the previous, excessive heat is usually the culprit. As an engine is modified to generate more power, additional heat is produced. Today's pump gas will only tolerate a finite amount of heat before it pre-ignites and causes detonation. Although forced induction engines usually produce far less heat than comparable naturally aspirated high compression engines, the cylinder temperatures in intercooled engines are radically cooler yet. It is rarely boost that causes detonation, just unnecessary heat. An intercooler is such a natural solution for forced induction, that in almost every sophisticated application, intercooling is part of the package. For engines that are experiencing detonation problems, the primary options are the use of ignition/timing retard systems, higher octane fuel, or intercooling. While ignition retard systems can be helpful in certain situations, they can also greatly reduce the horsepower output of an engine, as any reduction in timing will reduce horsepower. And while a reduction in timing can save a motor from detonation, the excessive heat which was causing the detonation is still present. Intercooling, on the other hand, actually removes the heat which causes detonation, and allows higher boost levels to be safely run with full timing on pump gas. This produces the maximum benefit in terms of both horsepower gains and engine protection, without any additional maintenance or hassle.