Most pilots subscribe to the adage, "Fuel is cheaper than engines". Certainly, using more fuel to cool the engine is cheaper than burning a piston or a valve due to a hot lean mixture. Of course, lean mixtures can lead to detonation which exists when the super-hot compressed fuel/air mixture prematurely explodes, instead of burning with a smooth flame front across the piston dome. Adding more fuel to the mixture can discourage the tendency to detonate.
Another, more effective, method to prevent detonation is to provide cool compressed air to the mixture. Cool compressed air provides the same effect on detonation protection as a rich fuel mixture, and provides an extra margin of engine operational safety. It is typical of modern aircraft engines and the trends shown are substantiated by independent technical information previously published by the Society of Automotive Engineers.

Cool charge air can allow an engine to be operated at best economy fuel flows, with equal or better detonation margins as when operating with hot charge air, richer mixtures and much higher fuel consumption. By simply cooling the charge air temperature to 100°F, and keeping all other parameters constant, the maximum allowable I.M.E.P. increased to 210 PSI, a 40% improvement in allowable pressure for the same fuel mixture.

With intercooling, the pilot can run leaner mixtures and still obtain equal to or better detonation margins.. Now back to the old adage, "Fuel is cheaper than engines." With intercooled engines, even conservative leaning can result in 2 gph per engine. With the high price of fuel, you could save up to $7,000 for single and $14,000 for twin engine over a 1600 hr. TBO. The point here is that fuel isn’t exactly cheap either. If you can reduce fuel consumption and maintain good detonation margins with a quality intercooling system it’s certainly worth considering.

Recently, Mr. Peter Garrison of Flying Magazine investigated, and stated, "Fuel is expensive, but turbochargers and cylinders are too; I feel that the best way to go easy on an engine is to operate at moderate power settings.. Intercooling makes it easier to do this, and so my inclination is to regard any well designed intercooling system as a benefit." Regarding the effects of hot and cold induction air and engine life, he said, "To the extent that you can harm your engine, you’re much more likely to do it with heat than with cold".

He further explains that "with efficient intercooling, you can use mixture settings closer to peak or even at peak and get much lower fuel flows, so long as turbocharger inlet temperatures stay below limits (normally 1650°F) and cylinder head temperatures are below 400°F.