As Power Rises So Does The Challenge Put To The Cooling System

Keeping your eye on the ball is a good thing, but it is also prudent to stand back and look at the big picture. All too often, enthusiasts become so focused on turning up the boost and/or unleashing a barrage of high power mods to their car they fail to consider the byproduct of their actions. It is wise to remember that as you make substantially more power than stock, you do so by burning substantially more fuel. Where there's fire, there's heat. With more fuel burning, there is an accompanying increase in heat.

Depending on the car in question, you may go a long way before taxing the cooling system, but beware: heat kills. A Honda has a cooling capacity designed for commuter duty. Turbocharging the engine and upgrading the injectors to the point of making 450 whp can easily overwhelm the OE cooling system. Also, remember as the ambient temperature rises, the cooling system's ability to fend off heat can lessen. A car that is borderline in the fall will be hurting in the heat of the summer.

An automotive engine cooling system consists of a water pump, radiator, cooling fan and an oil cooler. We like to throw in transmission cooling as well because the concept and benefits are very similar to engine cooling. Oil and tranny coolers are not part of cooling systems on all cars, but they should be.

The efficiency of the stock system and the intensity of the mods made to the engine will dictate which method of cooling system fortification is needed. For some, a fan upgrade will do the trick. An upgraded fan increases the radiator's efficiency by flowing more air through it, which is especially useful in stop-and-go traffic where the fan system earns its pay.

When things get really out of hand, as in the case of our 450-whp Honda, it's time to step up to a custom radiator. These units feature more rows of cooling passages and, in some cases, more effective fin designs. Don't get carried away with having too many rows because this is a decreasing dividend proposition.

As the cool air moves through the radiator it exchanges heat and as a result becomes warm. So by the time it gets to the last row the air's higher temperature means it has less cooling power in it than when it first contacted the radiator. The best solution is a larger surface area but space limitations in street cars make this option more difficult. A four-row radiator of a decent surface area should handle most cooling tasks.

The water pump is usually not an issue because the water flow rate is not really a problem. In fact, the longer the water is in the radiator, the more it is cooled-a win-win situation. In racing applications, an electric water pump may be employed, but this is done to eliminate the parasitic drag of the stock-style pulley driven pump.

Oil coolers are an often overlooked, yet extremely beneficial modification. It's all about longevity, and cooler oil will lubricate better, longer. This addition is more of a service life issue rather than a cooling issue. The resulting reduction in oil temperature will only reduce engine heat nominally.

Ditto transmission coolers on automatic transmissions. However, heat is the leading cause of death for automatics and an ounce of prevention will add miles to the life of your slush box.

There is a car that represents a "convergence of cooling" with all the correct ingredients but a rather poor execution. The Buick Grand National has a decently sized radiator, an electric cooling fan, and oil and transmission coolers in stock trim. The twist? The oil and tranny coolers are incorporated into the radiator.

In stock trim, the Buick runs an air-to-air intercooler mounted behind the radiator that cleverly uses a conventional clutch-driven fan to pull air through it. The stock GN cooling system is adequate but it can be saturated when the car is driven hard in the summer heat.