Quote:

Hi Tom
I would be really interested to see some actual, measurable data on this.
Please let me know the outcome.
Regards Matty

An 80 amp alternator typically has trouble with belt slip (with single old style v belt) on some apps. 80 amps x 12 volts = 960w . So even assuming a perfect energy conversion, the belts themselves have trouble with 1kw, let's say 50% conversion, the belts have trouble gripping with a 2kw load. SO I'd be tipping that that is about the most a mech fan can sap without the belt shredding in the first place. I know that's terribly backhanded (about as clean as I can make the original phrase) sort of reasoning, but it's worth noting.

I've always had the 'if it ain't broke' approach to most things, and a mech cooling fan is one of those things I think work well. I'd not swap to one if the car came with an electric fan mind you, but I'd be wary of their use otherwise. Playing devils advocate however - on highly modified minis cooling is an issue, the factory fans are so-so and the air has to go in from the front, and then out the side toward the passenger side wheel, which isn't where most of it wants to go at decent road speeds (meaning you don't get proper high speed airflow through the rad at high road speeds). On that application, a dc-31 fan happens to fit well in teh wheel well and transforms the otherwise borderline radiator physical dimensions into a workable proposition.

yes, many 1200s with cooling problems have been fixed by putting the stock mechanical fan back on.