Thermal fan clutch

[sext7366]

hmmmmm I have heard of these before, but know little about them. I am assuming that at a certain temp they stop the fan from turning even though the belt is still turning the pulley.  This frees up some horsepower right? just because there is less drag on the system from the fan?  Is it worth 50 bucks to buy one of these or would it be better to stick with what I have? (the pulley is directly connected to the fan via a spacer.  This would be on a slightly high performance 383 engine driven on the street.

[Johnny SixPack]

Yep, go with the viscous clutch style fan.

I did see a difference in cooling at least, couldn't say the power increase was phenomenal. 

The MoPar Performance 5-blade clutch fan kit is what I used.

Just be aware that if you have an aftermarket radiator, you may run into space issues.

There is supposedly a holy grail of super-short spacers out there, but I don't have that info at hand.

Hope this helps.

[1970440RT]

The amount of hp you gain from changing out the fan may not be noticeable to you.  Another way to look at it is; with a direct drive fan, you know it is always on and working.  Although it will always be "dragging " on the motor.  If you search around the site about cooling, the fan you speak of is part of firefighter Ron's "bulletproof cooling package"

[Chryco Psycho]

some of the gain is on the highway where there is enough air flow without the fan + the fan can be blocking airflow at speed , it is a good upgrade