Flex Fans

[TomoHawk]

Higuys,

I've been looking into the flex fans, specifically the Flex-A Lite fans, and the variety of fan types is confusing.  You can get 6-blade fans, 5-blade fans, fans with "wide blades and narrow ones:

   

The first photo is a reverse-rotation fan (I think) and the other two are normal-rotation fans.

I think I would select the 6-blade fan with the narrow 'paddles' although I'm not too sure what the difference would be between the narrow and wide ones would be, besides the amount of air flow.  Any advice would be appreciated.  I think it's a normal rotation fan.

I'm not in a hurry;  this would be a winter project.  It'll take that long to figure out hot to get the top half of the shroud off

The blue colour seems to be close to the colour of the engine, but can you get other colours?  I like the clean look of aluminum or stainless, and I have some "chrome" or aluminium coloured paint...

 

Edited September 27, 2016 by TomoHawk

[Namerow]

Don't overlook the possibility that the 'reverse-rotation' fan may be just a flipped photo image.  Does this look better?...

What's your goal in changing to this style of fan?  More CFM?  Less noise?  Weight reduction?  Hi-tech look?

[TomoHawk]

I think that less weight and drag would be the reasons to switch.

Edited September 27, 2016 by TomoHawk

[psdenno]

I used a flex fan for decades after my original fan took out my radiator when the water pump broke.  The style I used was more like the wide vane five blade unit in your pictures.  It was a little loud, but threw a lot of air.  I changed back to a stock plastic fan with clutch a few years ago when I upgraded my AC and added electric fans.

Dennis

Edited September 27, 2016 by psdenno

[Mark Maras]

 I ran a flex fan on mine for many years too. It was the style in the second pic with the big flaps. My theory was, lighter is better (it replaced the original heavy steel fan and clutch), it would pull more air at an idle, at low RPMs and at low speed than the skinny ones. Any faster than 10-15 mph, no fan is needed IMO. The big flaps flatten out at high RPMs reducing drag (HP loss). It functioned as expected and was a great mod on my first Z.

[TomoHawk]

I read a number of discussions elsewhere, and the common  opinion was that  the clutched- fan was MUCH better than the non-clutched fans, for cooling and less power loss.  Then if you add a flex fan, you decrease the drag some more. NO one commented about noise, except in regards to an electric cooling fan.  The white plastic fan is not easy to clean and people complain that the 'race car has a street-fan on it.' The former reason is probably why I'd like a 'prettier' fan.   IMO, as long as the clutch is working (and you can hear it engaging while you idle with the bonnet open)  It will be fine, unless someone has a very significant reason (like up to a 45 HP gain) to take off the clutch.

[Mark Maras]

 Keep in mind reduced drag means the fan is pulling less air. Especially when the car is not moving, which is when it's needed the most. 

 Most of the road racers "back in the day" didn't use a fan. No need for one if the car is always moving. Take the fan off when the car goes on the track and just turn off the engine when the car isn't moving. 

[TomoHawk]

I suppose I will have to order one and try it...

I suppose the exhaust manifold-header discussion should be avoided too?  "Everybody knows" a header gives better performance....

[gundee]

11 hours ago, Mark Maras said:

 

 Most of the road racers "back in the day" didn't use a fan. No need for one if the car is always moving. Take the fan off when the car goes on the track and just turn off the engine when the car isn't moving. 

I usually removed my fan. No heat issues with the tripple core radiator on mine.