I Want To Lose Power vs It's That Yr's OEM

[Rodger]

Hola All

Last Saturday I had a very good time when I went to FireStone, Colo and saw all the other Dodge Trucks there ( ... viewtopic.php?f=3&t=17105 ).

I made my way to most of the trucks asking the driver to please open open the hood.

As I have been thinking of the trucks this past week I realize that I only saw one flex fan. Remember that I did not look at all trucks and this is an week later of " Oh Yeah".

Now to my learned thoughts:

The worse item for not doing a very good all usage "Cooling Job" is the electric fan. These fans are OK if they are on an front wheel drive with the engine sitting side-ways or an vehicle at the races and runs the fan when sitting at the pits. Regular street users mostly say the battery of their vehicle never gets fully charged once they changed to the electric fan and the cooling is never at the same level as the factory's Cooling Fan. The added cycles of electrical needs also eats at the life of the alternator and battery.

The worst HP power robbing is the Flex fan and the direct bolted OEM Seven/Six Blade units. The dyno says they take away as much as 15 HP at Hwy Speeds. But in 1946 to the late seventies when the truck was new, many did not even have an Fan Shroud. This was the mind-set of the times, so to have an Cooling Fan in an truck that does not eat HP was not fully thought of by the common driver.

In yester-year before the electric fan was on the common market, the sales/marketing people pushed the flex fan as an improvement to the un-knowing. These are the ones that you may have heard about coming apart and an blade going through the hood.

The common four blade Cooling Fan is just that. It will cool the water temp of the radiator as it is designed to do. Do not ask for an higher level of cooling or whatever.

Since all Cooling Fans take the power from the moment of the engine's started and increase the draw of HP in relation to RPM, until the engine is aqain at an idle ( or shut off ), what can a driver do to lessen this robbing of HP. The answer is the Silicone Clutch Fan Unit. In 1962 the Imperial Division and the New Yorker's of the Chrysler Div started using the Clutch fan. In time the lessor car division's also started using the clutch fan with A/C vehicles. In the arrivial of the HP wars, the silicone unit was up-graded to take the torque from the brutes. The improved version was the "Thermo Silicone" clutch units. The need for cooling was still needed so all of these units had seven blades.

The Imperial Division diam was 18 1/2 inches standard. For cars if they had the Hi-Perf, Towing, Police and the other like needs, the diam was always 18 inches on the V8's. Then in 1974 all MoPar's went to 20 inches as the diam. When MoPar did the new 20" diam they bragged the new Cooling Fan drew more air than older versions, made less "fan noise" than older versions and used less power than older version's. The older four blade direct drive Cooling Fan was being phased out and the silicone clutch with a twenty inch diam and five blades was now being phased in as the entry level unit. A new designed seven blade unit with 18 an inch diam with the Thermo Silicone Unit was the "super cooler".

If you want to follow the pack and have some more usable Hwy HP and MPG you may get the better Thermo Clutch Unit from NAPA under their roof if you say #271303. This unit will bolt directly to an Slant Six or any of the eights. Go to the local pick & pull with less than a twenty and you can find the seven blade Cooling Fan or just the five blade version.

If you have the Slant Six the max diam of 17 inches is better for you.

Hmmmmmn, now what.

Rodger & Gabby
COS