Electric fans?

[Stano]

Ok here is the results 332 mile round trip. I drilled quite a few 3/4 inch holes in a orderly fashion above and below my fans. I did notice a difference, not as much as I wanted to see but better none the less. At 65-70 mph it stayed in the 195 degree range during a heavy footed session it climbed to the 200 degree range but leveled off there. I am gonna put one of my new 160 degree thermostats in before long and we'll see what that gets me it will definately run cooler I think. I only had a 195 in it cause I had it and I was getting tired of messing with it and it was runnin that warm with the 160 and 180 thermostats in it. I think putting holes in the electric fan shrouds is beneficial to getting more airflow at highway speeds since the fans cannot freewheel that fast.

[Boog]

ok, well, just out of curiousity, I have just browsed Summit's catalog and there are over 900 listings in the cooling/heating section covering direct drive fans, fan clutches, blades, controllers, shrouds, sensors and electric fans and all that goes with them. Quite a number of offerings out there.
Back to where I mentioned earlier about some dual fan setups having vents made into them for increased air flow at highway speeds I found numerous ones listed so there is definately something to this. Most of them have a rectangular rubber flap over them that can open up under increased air flow through the radiator and remain closed at stop or slow speeds for more fan draw through the rad. The PermaCool setups do not cover their 12 holes at all.
I am listing the part # for several of these if anyone is interested in what I have found.
BeCool BCI 75007, 95007, 75037, 75044.
Flexalite FLX292, 295, 298, 278.
Permacool PRM19510, 19513,19514,19515, 19516, 19524.
Each one of these have vents made into the shrouds.

Intended as useful info when selecting a fan setup or diagnosing a cooling problem.
The top pic is a Permacool, then second one is a BeCool. Notice what look like black flaps on the BeCool unit.