HP Cooling Fans

In the first place, by mounting the fan on the front of the radiator, you lose the ability to shroud the blades. Why is this important? A pusher fan will push air through the radiator core in the area immediately beneath the outside diameter of the fan itself. A puller fan mounted on the inboard side of the radiator, installed within an appropriate shroud, will pull air through the entire radiator core. In general, fans work far better mounted away from the core, within a shroud. Think of the domestic kitchen sink. When you have a blockage, you use a plunger to suck the blockage free. The fan shroud works in a similar fashion.

The next problem that a pusher fan has is that it (at least partially) blocks ram air from flowing through the radiator. At cruising speeds air introduced to the front of the radiator core through the bonnet intake in the nose is deflected away from the core by any obstruction that you place in its path  -  in this case a fan. Some of the air will of course find its way through the fan, but certainly not all of it. There is also an argument that with the fan on, i.e. moving under the power of its motor, there will be turbulence created when the air from the bonnet intake meets the air being artificially moved by the pitch of the fan blades. That is why you will often hear about cars that will run COOLER at cruising speeds without
the fan on.

The next problem is that there is not really any room for a pushing fan of any size on the front side of an E Type radiator. The stone guard allows very little clearance between itself and the radiator core, when the bonnet is closed.

Finally, if you have a powerful pulling fan, there will be additional cooling benefits provided by the air the fan moves over the engine itself. A pushing fan has the flow of the air it generates dispersed by the radiator core long before it reaches the engine block.

When we are upgrading E Type cooling systems at CJ, we always install a high performance pulling fan.