Yeah fabrik8r; and don't forget the list of purchasers you already have when you begin to market that great invention....

 

In theory, your description of the "convection effect" and the "cycle runs away...", ultimately resulting in engine overheating seems logical at first glance and I wouldn't argue against it without evidence to the contrary. But the testing I did about a year ago doesn't validate your theory. I have the "parachute" air cleaner you've described installed on the bike I tested and the phenomenon you describe does not exist to any detrimental extent. I can idle the bike indefinitely and it never approaches "overheating" temperatures. I'll agree that it may exist to some extent but that it is inconsequential to the overall cooling effects of the fan.

As for wiring the fan to rotate backwards and draw the air from right to left, here's my theory. In doing that the amount of air across the engine's fins will be reduced significantly, to the point that the cooling effect will be severley compromised. This is only my theory. I don't have any test data to back it up. But the fan works so effectively in its intended configuration that I don't see the point of altering that. And this is not theory. I have extensive testing and data to substantiate that claim.

To the OP. Yes these types of fans work to prevent the situation you described. And they work very well. As far as which brand. I only have experience with one so I can't say which works the best or is the most reliable, but I highly recommend a fan of some nature.

 

Ran across this on eBay, this is the web site...know nothing about them, just FYI...
Anyone using this?

http://bigskyfan.tripod.com/id11.html

 

Also almost all fans are designed to run in a certain direction, and when you reverse them you can cut down the amount of air moved by as much as 50%....air reduction is not only in cfm's but air pressure is reduced also...so a fan rated at 50 cfm at 3 inches hg when reversed may only move 25cfm at 1 inch hg....on top of all that now you are putting that hot air drawn from the engine over the motor in the fan causing it to run in even less than ideal conditions than it was designed (although, by running it backwards it will probably draw less current and thus run cooler)...Now if you could flip the whole fan/motor assy. around 180d then you would have something that might work reasonably well...but why bother it works the way it was designed to when installed correctly...

 

Wow, that harley fan kit is just over 500 bucks! Any less expensive alternatives?

 

You need to shop around. Lookie here:

http://www.lshd1.com/servlet/Detail?no=790188

 

So how about putting it right on the oil cooler instead. Somene did a thread on adding your own aftermarket DC fan that looked real promosing I was going to put some serious consideration time in on?

 

Your best bet for that project would be a 4" SPAL ATV puller fan, try Absolute Radiators website, part way down the fan page, not real expensive. It will definately take the abuse, I've been running a SPAL for over three years.

 

LeNale fan $199. It just plain works! 210 CFM @130 MPH

 

Tucci,

The Engine Cooling Fan (parade fan) addresses engine temperatures by controlling the cylinder head temperatures [(CHT) the hottest part of the engine] and in doing so keeps oil temperatures lower. Less heat in the engine to transfer to the oil results in lower oil temps.

On the other hand, a fan on the oil cooler only attempts to control the oil temperature, which has less of an effect on the CHT than vice versa.

Oil temperatures change relatively slowly when compared to CHTs. Therefore controlling CHTs with an Engine Cooling Fan has a more immediate benefit than simply trying to control oil temperatures with an Oil Cooler Fan.

Either methodology works to a point, but my experience has shown the Engine Cooling Fan to be the most effective way to control temperatures in congested traffic conditions where prolonged idling and/or very low vehicle speeds exist.

When I did the bulk of my testing on this subject about a year ago, I wrote a 21 page white paper with my findings. If you or anyone else is interested in seeing it, send me a PM with an email address and I can send you a copy.