WHY USE A ELECTRIC FAN AND WHY A FAN SHROUD ?

Grib’s Note * This is not the answer to all cooling problems, in fact there are numerous problems that face racers and especially Street Rodders. But I think this is the first step.

Receive the Benefits of Improved Fan Efficiency

In most all cases, when your are traveling down the road or racing on the track, air is forced through the radiator because of the pressure of the car moving. Again, in most all cases, that’s enough to keep the water flowing through the radiator cool. So.. you usually don’t need much of a fan or shroud when you are at speed.

It’s when you are stopped or crusin or sitting at a light that you don’t have any air moving across the radiator. You then need a fan to move the air. Fans move air through the radiator, which helps in cooling the engine.

A fan without a shroud is better than no fan. But consider this: at idle or cruising speeds, you need your entire cooling system working at its optimum. An unshrouded fan is moving air through only that portion of the radiator equal to the surface area of the fan, not the entire radiator.

For example, on a normal ’32 Ford radiator, the area of a 15.50" fan is approximately 189 sq. in.; the core of the radiator is approximately 371 sq. in. This means that almost 49% of the unshrouded radiator is not receiving any benefits of the fan.

Shrouding your radiator permits the fan to pull air through the entire core (every square inch) of the radiator. A pull type fan will create a suction or negative pressure inside the shroud.