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Discussion Starter · #1 ·
Hey all.. I've been reading all about electric fans lately, and I noticed that they are all rated high, like 1,850 CFM and such. My electric fan is rated at 1,100 ACROSS THE RADIATOR but the "other" rating is almost 2,000 CFM.

Is this like gross vs. net horsepower ratings? Are most fans, like the August group buy SPAL fans, advertised with their across the radiator or straight flow numbers?

Just a random curiousity on my part.
 

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Could you explain that chart to us in English? :eek:

What is "Static Pressure in H.O."? I'd sure hate to be running it at 1.2 H.O. stuck in traffic! *LOL* (whatever that actually means).
 

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How's that fan been working for you, Anthony? It hasn't got a real test yet, I don't think since you put it in, as we've had some pretty darn nice weather for this time of year. Are you noticing your temps down any at all yet?
 

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I am curios if someone can explain this to me too? My zirgo 16" fan is rated at 2700CFM but it was noticably cheaper than the other ones that flowed less? Is this like the wet flow/dry flow testing where data variables are changed to make a product look better?
 

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Johnpro,

That's H2O (inches of water), not H.O. As air is drawn across the radiator it develops some resistance, which will create a differential pressure. All radiators are different. The more rows or fins the radiator has, the more resistant it will be to air flow and it will develop a higher differential pressure. Because it is so small it is measured in inches of water (in. H2O), which equates to the weight of a column of water. Just for a reference point, it takes about 27.7 inches of water to equal one pound. What you are reading shows as the resistance of the radiator core increases (larger H2O number) the fan will pull less air. The number the vendors normally display is with no resistance, so you will get the largest air flow, but that's not indicative of how the fan will operate in the real world. There are many factors that come into play (motor speed, blade diameter, blade design, etc.) that will determine how well the fan operates.

The bottom line is to compare the fan ratings using the different static pressures. Whether or not you can get all that info from the various vendors may be another story. The good ones, like Spal will display it. Hope this helps.

Lou
 

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I think about the best fan for the $ is Ford OEM units used on Police Mustangs, Mark IV and LTD's. Available new, used and they flow alot.....a very lot of air! an reasonably inexpensive!
 

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Discussion Starter · #8 ·
zHow's that fan been working for you, Anthony? It hasn't got a real test yet, I don't think since you put it in, as we've had some pretty darn nice weather for this time of year. Are you noticing your temps down any at all yet?
Well, if SOMEONE would allow me the use of their garage I might be able to actually put the mechnical gauge in to see exactly if my temps are down, empirically. My temp. gauge (stock) really sucks... So I dunno. BUT I did get to see on 80 East yesterday for 35 minutes at its hottest yesterday (91 degrees) without moving because of an accident. The car kept its cool, which is way more than the mechanical fan would have.

It's never had heat problems at speed, any speed, just idling and it seems that the electric fan resolved that. Guess I'll need 100 degrees to really see. :)
 
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