Electric cooling fans

[itaracer]

I'm looking for an electric cooling fan. Getting one the right size doesn't seem to be a problem. My concern is how much air (CFM) do I need to keep a 12A cool with ambient air temps over 100 degrees F? Radiator is a stock 3 row 12 X 22 from an '82/83 with automatic transmission. Oil cooler is air type mounted under the radiator. The car has the overdrive pulleys, the bypass in the water pump has been blocked off and the thermostat is in place but gutted. The front airdam is a urethane type from British Victoria. The thermostat from the oil cooler has been removed and the bypass hole plugged.

1. What is the recommended CFM for a fan under these conditions?

2.Which works best a pusher or puller type fan?

3. Is through the core mounting OK or should I buy/fab brackets?

4. Straight or curved fans blades?

[SPiN Racing]

http://www.jegs.com/cgi-bin/ncommerce3/Pro...076&prmenbr=361 (http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1076&prmenbr=361)

Black Magic Fan... Works Excellent. 2800 CFM
Puller.. Comes with side mounts and a thermostat built in.
If you want you can get it without a thermostat for like 10-20 cheaper. (Just search for black magic at Jegs)

I have put that on Turbo street/Track 2nd gens with a stock radiator and it works real well. Also on Ported street/track N/A cars it works real well.

That is the highest CFM fan I have been able to find.. and yes it is pricey.. but it is a real nice fan.
I am sure it would be fine for a 12A.. unless there is a different issue causing high temperatures... (coolant leaks internally)

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Scott Neville
SPiN Racing
86 RX-7 EP
88 RX-7 20B SP

[AS-RACER]

You can also try alumrad.com. I have one of their Spal fans on my 2nd gen and it works great. Mine is a puller and it would suck the smile right off your face.


Sean S.
ITS RX7 #0
Rocky Mountain Division

[cpa7man]

I would just get a junk yard fan off a Ford Taurus or similar, Home Depot brackets with a switch in the car to turn it on. But than if you saw my car you could tell it came from Home Depot.lol

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Paul Pineider
ITA 05 (Soudiv)

[itaracer]

Paul, I've been using salvage fans and I'm still overheating. I measured the air flow through the radiator with my current fan. The anamometer indicated about 500cfm. I'm thinking this is just not enough. How much is enough? Or is there too much?

Scott, Thanks for the link. 2800cfm for the Black Magic. That's over 5 times what I have now. What are the temps on your cars in 100 degree weather?

Sean, Curved blades! Is ther any advantage over straight blades?

[bldn10]

I've always had the understanding that an electric fan will help you avoid overheating on the grid but is of no benefit at speed; and,in fact, may obstruct the natural airflow out of the radiator.

[C. Ludwig]

Originally posted by bldn10:
I've always had the understanding that an electric fan will help you avoid overheating on the grid but is of no benefit at speed; and,in fact, may obstruct the natural airflow out of the radiator.

BINGO! If the airflow at speed is not cooling the car you have other problems. Ducting, proper rad sizing, and the cooling system mods that Mazda recommends are the tickets.



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Chris Ludwig
08 ITS RX7 CenDiv

[mustanghammer]

Last year I had the same radiator/oil cooler setup that you are describing except that my radiator was a same size Griffin Aluminum dual pass Sirocco radiator and Spal fan. It didn't work.

On a hot day I had to run the fan just to stay under 225 water and 240+ oil. Without the fan the temps went even higher. I sold the radiator to a dude with....a Sirocco and went bigger.

This year I have 19x22" dual pass Ron Davis radiator and the oil cooler is in front of it. I mounted the Spal electric fan to the bottom of the radiator and use it after the race in impound and at Solo II events. During the race the fan is off and so far I haven't topped 180. I also have the Victoria British air dam and the radiator is completly sealed to the duct in the air dam.

Get a bigger radiator.

Scott

[itaracer]

Scott,

Thanks for the info. I'm looking into a Ron Davis Radiator now. I know that yo're going to be a HPT this weekend. Are you planning on making GIR later this month?

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Mark Jeffery
IT7 #92 '85 RX7
MiDiv - Arkansas Region

[Speed Raycer]

{Off Topic.....}

Hey Mark... check your email before sending your carb off!!!!

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Scott Rhea
It's not what you build...
it's how you build it
http://www.izzyscustomcages.com/images/IzysLgoSm.jpg (http://www.izzyscustomcages.com)
Izzy's Custom Cages (http://www.izzyscustomcages.com)

[mustanghammer]

*****

Thanks for the info. I'm looking into a Ron Davis Radiator now. I know that yo're going to be a HPT this weekend. Are you planning on making GIR later this month?

*****

Mark,

I'm not sure right now. I am planning on the MAM race in August but may have to cancel due to work commitments. If that happens I may do GIR.

The radiator I have came out of Monica Rollins ITS Mazda. David Long (82 EP) modified the top neck and added some mounting brackets for me. You might want to talk to Charlie Clark at GIR (or call him 816-257-7305) he has a source for dual pass radiators that might be cheaper that a new Ron Davis radiator.

Another source for reasonably priced radiators is AFCO. They have several that would fit for around $220-240.



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Scott Peterson
KC Region
IT7 #17

[ddewhurst]

Have you folks ever looked at the ISC Racing site for cooling products ? It gets HOT & HUMID in FL. iscracing.net

RX-7 stuff of alL sorts by racers.

Have Fun http://Forum.ImprovedTouring.com/it/wink.gif
David

[Karl Bocchieri]

Fluidyne will make you a custom double or triple pass radiator to your exact requirments. They do lots of custom stuff for nascar and drag racing. My custom built dual pass for a 2nd gen was $350. I have a Spal puller for the grid and sfter the race.