CFM flow for intercooler fans

Bacondoggy

Registered User
I found this fan here:
http://cgi.ebay.com/ebaymotors/New-8-Automotive-Radiator-Cooling-Fan_W0QQitemZ150279245112QQcmdZViewItem?hash=item150279245112&_trkparms=39%3A1%7C65%3A1&_trksid=p4506.c0.m245.l1318

my question is it says approx. 300 CFM. Is this enough? I know the perma cool fans draw 4.5 AMPS and produce 800 CFM. They are also more expensive.

Also, How do most people have the fans setup, to "push" or "pull"? I assume you would want to mount the fan between the intercooler and engine, and "pull" the air through...
 
pull usually always wins.. seems kind of small.. for comparison my stock radiator fans pull around 2500cfm. but thats also pushing a lot more energy out. anything is better than nothing though but if its calculated.. 300cfm with a 8"D that runs it about approx 10mph across the localized area of the fan. at those speeds i would think it would need a little more speed for the air to go turbulent which increases the heat exchanged a lot.
 
I just found an 1100 CFM 7" puller (reversible) that draws 3 amps @ Silicone Intakes for $25 +shipping.

The fit is nice as the frame/guard is straight on two sides and tucks in nicely between the side flanges on the IC, allowing a flush fit against the core.
 
I'm purchasing the one's on siliconeintakes, the numbers are probably a bit exaggerated but the curve radiator fans seems to produce a lot more, like the SHO's and I think SC's.

a quick search, say a lot of the stang guys go with this one

http://www.teamrdr.com/store.php/products/mishimoto-10-electric-fan-12v-universal

http://www.americanmuscle.com/mishimoto-slim-radiator-fan.html

http://www.modacar.com/products//All/MISHIMOTOEF/Mishimoto+10"+and+12".html

I think those numbers are more realistic, given around 2000 rpm, use abour 1"=100CFM. my .02
 
This is the 7" IC fan from SiliconeIntakes after installation...fairly quiet. I recommend removal of the IC when installing the fan unless you have time, patience and small enough hands to deal with things otherwise.

Naturally, the weather turned cooler once this little project was done, so I haven't had a chance to 'field' test it yet. On the advice of others, here at the Temple, I wired it with a switch/relay and let it run constantly when the engine is on. A quick check w/the temp gun showed a 15 deg. ~ 20 deg. drop at the ctr. of the IC core when the fan was running.
 

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Your getting only 50% effectiveness out of that fan. Your getting flow inversion because the air that is coming out of the fan around 25% of its edge is getting sucked back to the front of the fan because of the negative pressure. You need to put a plate in to cover the IC and cut a hole out the size of the fan to get maximum benefit.

I learned about this with fans when I was working down in a mine and we where flow testing stand alone ventilation fans that had no ducting. Measuring the CFM of the fan 5 feet away showed a value approaching half of what the fan was rated for. We then for a joke decided to measure air flow beside the fan against the housing and found the other half of the air flow. We realized that the air was flowing back to the front of the fan which lessoned its effectiveness to draw away explosive gases etc. We then installed 20 foot conduits on the fans and got back almost the full flow rating and had zero flow back to the front.

Just something to think about, and explains why Ken's DIC's are so effective with the fan shroud in place.

Frit
 
>Your getting only 50% effectiveness out of that fan. Your getting flow inversion because the air that is coming out of the fan around 25% of its edge is getting sucked back to the front of the fan because of the negative pressure. You need to put a plate in to cover the IC and cut a hole out the size of the fan to get maximum benefit.

I guess I'm expecting at least minimum flow from even the slowest forward motion of the car, to work in tandem with forced flow off the fan, to help negate inversion. And then I'd be concerned about restricting flow when the car was at speed. Also, I'd think the built-in shroud, combined with the 3" thickness of the channeled core would prohibit any reverse flow back into the fan...has to be 100% effective.

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I wonder what stock flow rate in CFM is, thru the core, versus vehicle speed..?

I think I've seen flaps used in conjunction with plating....they swing open when the vehicle is at speed & the core is forced thru the air, and then close at rest to direct all (fan forced) air flow thru the fan shroud and fight inversion.

Might find time to run tests to confirm - thanks for the info :)
 
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are the perma-cool fans thinner? It looks good on your IC, but will this fan fit on Ken's DIC's??? I just ordered the last one from him with a shroud (thanks Ken), and I need a fan, but would hate to order this, and find it doesn't fit...
 
>are the perma-cool fans thinner?

Which p-c fan are you thinking of using? The 8" @ spinningwheels is spec'd at 2 1/4" deep. The 7" SI fan measures 2 1/2" deep.

>I need a fan, but would hate to order this, and find it doesn't fit...

What is the dia. of the opening in the DIC shroud?

Keep in mind the 7" from SI has a built-in shroud and would have to sit 'on top' of any shroud that comes as part of a DIC. The p-c 8" looks similar. How much free space is there once the DIC is installed?

AFAIK, in a stock configuration (example: 1990 SC), there is 3.5" clearance between the pwr. steering pulley and the rear of the IC core.
 
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well the DIC I got has a shroud already, and it has threaded inserts for an 8" fan, so I guess the spinning wheels should be the way to go for me. Yay - no more detonation!
 
Sounds cool! (ouch - sorry)

Photos when together would be great. Good luck w/your DIC project.
 
The shroud inserts are spaced to accept the 8" perma cool fan and the spacing of the shroud allows clearance between the DIC, with fan installed and the power steering pulley. It is a snug fit and I know at least one guy had to install the IC and than the fan but most have had no problems just slipping it into place. You will need 1/4" X 3/4"course thread bolts to bolt the fan on. I think you will like it;)


Ken
 
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