Electric cooling fan requirements?

[PSB]

I need to get a cooling fan for my build. When I was researching fans, I read on the Flex-a-Lite website that a 4500 cfm fan is required to cool a V8 engine. There is no way I am going to be able to fit that big a fan into my engine compartment. How strong a fan do I really need?

My engine is a 408W with a Griffin 3-row aluminum radiator. I am also running the dual pusher fans in front of the radiator - mainly for looks as I suspect those are not going to provide near enough airflow to keep my enigne cool.


Thanks,
Pete

[Ron61]

Pete,

I don't remember just what the total cfm of my fans is, but I have been running a dual pusher set up since 1996 and I run it in our 118 degree Summer humid weather. The only time I have ever seen my temperature gauge climb past normal is after a long drive on the freeway and then having to stop and go in traffic and it has never gone high enough to worry about. Most days I keep the fans turned off as I wired them through a toggle switch and my motor needs to run warmer than the fan thermostat goes to in order to make maximum power. Most of the guys around here are runnning whatever fan they can get to fit on their radiators. That 4500 cfm for a V-8 sounds a little like advertisement to me. How many of your street cars with V-8 engines have that big of a fan? I have a 69 Torino Cobra that is bored out to 439 CI. and I use the stock fan that turns off the water pump on it.

Ron

[Tony Radford]

Pete, I recommend the SPAL 16" puller fan. I'm not sure what the CFM ratings is, but it works great. It's also micro thin so it fits a Unique with no modifications. I suggest installing a thermo-relay as well. They're only $10 or $15.

[cobra427mnsi]

Never use Flex-a-lite Blackmagic fans. I went through 2 of them before I ditched them for the dual Spal high speed fans. No problems now for 2 years.

The first Blackmagic fan fell apart. The permanent magnets in the body of the fan became unglued and attached to the armature. Obviously the fan didn't work after that. I called Flex-a-lite but they refused to do anything about it. I was forced to buy the second Blackmagic because the rad and mounting brackets were set up for it. I knew how much work it would be to change brands. So I hoped the second one would work better, but to no avail. I bite the bullet and changed my whole setup for the Spals. It was a lot of work ,but ,so far it was worth it.

Paul

[ENTDOC]

Pete,I used a fan from Southern Rods,it was a 16 inch with 2700 cfm if I recall and it fits our application very well.It seems to cool my 351c fine.It is also cheap.I did use a painless fan relay with thermostat.Ruble used a Summit Racing fan(aluminum) that also works well. chuck

[Aussie Mike]

On the recomendation from the guy that built my radiator I mounted a 16" thermo fan. This one is rated at 2700CFM like Chuck's. The radiator guy does lots of work for hot rods and custom stuff with hot motors and he says the 16" thermo fan is plenty to keep pretty much anything cool.

What's important is the shrouding. The flexalite fan may be able pull 4500 CFM of air but how much of it comes through the radiator? These 16" fans are well shrouded and pull almost all their air through the core.

I have one for the warm propane (LPG) powered 351C in my F100 and it keeps everything nice and cool (unless the fuse blows ). LPG makes the motor run a fair bit hotter than regular petrol too.



Cheers

[hog]

I connected my fan up with a Painless relay and temperature switch. I also wired the switch up so it can be turned on manually if you suspect temperature is going to get to warm or the temperature switch will turn it on automatically. Can do it with a single or double pole toggle switch.
hog

[PSB]

Thanks for the info guys! I think I'll go with the a 16" fan. If it'll keep a 427W cool, it should work for me.

Pete

[surfer44]

Check out Speedway Motors
http://www.speedwaymotors.com/xq/asp...qx/product.htm
$89.95 for a 16" Spal PULLER Curved Blade

[Rick Parker]

The Spal fans are on Ebay usually. They are available with a straight blade that is somewhat noisey (2300+ CFM), and a curved blade that I is a lot quietier (2070 CFM). With sidepipes and loud exhaust pick the straight blades. Your engine will thank you! Wire it through relays, as they pull a lot of current.

As of now 12/01/03 both types are currently available on Ebay.

Rick

[NMattison]

Hi pete i used a spal dual 11" puller fans it has 2780 cfm i have run the fans on my engine first start up. temp got up to 190 and i turned on the fans and dropped to 180 almost instantly so i think these will work well for my application. good luck Neil

[John Poling]

Mike Murphy,
What manufacturers' fan and model number are you using in the picture above? Also, Did you fab the mounting brakets or are they purchased from somewhere?

Thank you.
John

[jordanatkins305]

i have a 16" s-series flexalite on a very large 4 core in a 76 ford p/u. it is not enough alone, so i was forced to use the original water pump mounted fan with the electric mounted in the front. on a new 390 by the way.

[Aussie Mike]

Hi John,

I fabricated the mounting brackets from 1" aluminium angle and machined up the blocks that bolt to the side of them. They tie into the original mounting slots on the sides of the fan shroud.

I can't remember the brand and model number on the fan but I think I still have the box it came in so I'll check when I get home tonight.

Cheers

[werthie]

On the subject of fans, I'm using a pusher fan in front of the stock radiator. It's the SPAL 16" with straight blades, and, boy, is it loud!! I guess my exhaust isn't loud enough . . . . Will using the curved fan really reduce fan noise?
Also, since I mounted the fan in a hurry, it isn't flush against the radiator. There's about a three inch gap at the top. I assume this is a problem, particularly since there's no shrouding to keep the air going directly through the radiator.
Does anyone with a pusher SPAL have a picture of their mounting brackets?
Many thanks,
Alan in L.A.

[concobra]

Flex-a-lite's statement regarding the 4500 cfm is supported by: Permacool, Griffin Radiators, and others in the cooling business. To add to that the rule is better explained as you need 10 cfm for every cubic inch or hp made. Whichever is greater. Also the thicker the radiator the more need for air draw through it.

For what it is worth the only fan I found up to the CFM demands is sold by Vintage air and is called the Monster Fan. This was the only electric single fan that would pull the needed CFM. It works extremely well. My motor NEVER overheats and constantly runs between 160 - 180 degrees with the fan on. If fact last year I put in a 190 degree fan switch and even at over 100 degrees of air tempurature this fan cooled my motor down to 160 degrees in stop and go city traffic. I use it with a shroud offered by Vintage Air that best fits my radiator.

It's expensive but cheaper than warped heads.

I hope this helps.

[Aussie Mike]

Originally posted by John Poling


Mike Murphy,
What manufacturers' fan and model number are you using in the picture above? Also, Did you fab the mounting brakets or are they purchased from somewhere?

Thank you.
John

Hi John,

I found the box. The Company is ICE but it says on the packaging that the fan was made by a company called UniPoint.

The part number is 07-41612K

According to the graph on the packaging the fan pushes 2800CFM or if you flip the blade over and change the polarity it will pull 2500CFM. I've got mine set up in pull mode.

Cheers

[Dominik]

pete,
I use a 16" pusher fan from a BMW (I guess).
also a fan should never be needed once you travel faster than 30 mph.
if, your shrouding to the radiator is not good enough.

although I would stay away from shrouding ALL the air through the radiator.
I keep the upper side open to let some air flow directly into the engine compartmant.
that results in much cooler firewalls and interior.

dom, cape town