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Does anyone truley know what the AMP/CFM ratios are? I've looked quite a bit and see all kinds of claims by companies.
Example- How many amps drawn to produce 1500CFM's.
I'm going to go with 2 10" fans and would like not get hoodwinked and buy a pair of duds.
Every fan has specs for amp draw. As long as you are buying them from a respectable manufacturer.
let me rephrase this. ....Is there an average, like 6-10 amps will usally produce roughly 1250 CFM's? Say there are 5 reputable companies selling fans that claim to produce 1250 cfm but the amp draw is scatterd between these companies from 6 to 15 amps.How do you know which is closest to the truth.
You plan for the worst. Heat and speed will add current to a fan. Two decent fans require to good relays period. 30 amp per fan is what I would recommend.
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Fan amperage does vary by fan (Lincoln Mark VIII fans spike around 70 amps at startup for example). One note, 2 10" fans may not be enough cooling for your car. Check with fan suppliers for how much cooling you will need. I have one 16" 3000 cfm fan and keeps the car cool, although in hot weather it creeps up a bit sitting still in traffic. It doesn't get too hot, maybe 215, but I still worry a little. I may add a second fan in front if I can get it to fit (oil cooler in the way).
Be carefull which fans you buy. Forget the amerage draw, just put a pait of 30 Amp relays on it and forget it. But 10s basically suck , or should I say DON'T suck! Unless you get high performance fans which are very tall. The low profile 10" fans will only pull about 500CFM, I don't care what the claims are. I would really suggest trying to at least move up to 11s, and get the Spahl high Performance units that are about 2 1/2" deep, assuming you can clear those.
Thanks guys for the input. Frank I've been running a stock copper rad. and clutch fan with no problems. here in Buffalo there is no bumper to bumper and I have had zero problems with over heating.
If I go with a stock SIZE aluminum rad. I can only fit 10" fans but If I go with a little wider like 24" or 26" rad. I will be able to fit 12" fans in there.
Go for a "Big block" size radiator. And go with the bigest fans you can. the 10s really pull very little. Been there, done that, got a tee shirt, lit the tee shirt on fire!
I've been doing some research on electric fans lately and just bought a new setup for my car. The rule of thumb I found was that for every 1000cfm of air flow the fans should pull 10amps.
So a true 2000cfm fan should be pulling around 20 amps.
It makes for comparing electric fans a little easier and weeding out the false cfm ratings. I've seen quite a few 10" fans stating the flow 2000-2500cfm but if you look at their amp draw, its usually less than 10amps.
Derale dual fan setup I just bought has two 13" fans rated to pull 4000cfm for the pair and they have a 50amp draw.
Thanks Adrew and guys thats the info I needed. Now go take a look at my new post about fan shrouds....
Topless, a Taurus 3.8l fan with shrould would be a near perfect setup for the stock size rad in your car-its also a 2 speed setup and they move quite of bit of air and can be had for cheap-about 25$ at your pick-n-pull or 50$ off Fleabay and it includes a shroud all youw ould need is to fab some mounts up and wire it.Quote:
Originally Posted by Topless69