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77gp
Tribal Scout

14 Posts

Posted - 11 Mar 2015 :  06:32:15 AM  Show Profile  Reply with Quote
I have a question about electric fans, do they need a shroud or not? The car is a street rod and it tends to overheat in traffic. It was built in a "hot rod shop" by one of those "master builders". He put a cheap flex fan on without a fan shroud. I was going to build a shroud for it but there is very little room, 2 7/8" from the water pump pulley to the radiator. So now I want to use electric fans on the front of the radiator and am not sure if I need to build a shroud. I know these cars aren't typical for this board but I've noticed you guys seem to actually know what you're doing versus many other people on the internet. Thanks in advance

67drake
Sitting Duck

Azerbaijan
1501 Posts

Posted - 11 Mar 2015 :  09:12:22 AM  Show Profile  Reply with Quote
I don't think a shroud will do as good for a fan that mounts directly to the radiator. I have seen them though,very thin shrouds.


71' GTO Original 400 M20 3.23 posi
13.95@102.1 MPH on street tires

Edited by - 67drake on 11 Mar 2015 09:13:47 AM
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Steve C.
Crazy Horse

1674 Posts

Posted - 11 Mar 2015 :  09:51:13 AM  Show Profile  Reply with Quote
Good related article...

http://www.hotrod.com/how-to/engine/ccrp-0707-high-performance-cooling-system/

I would try and fabricate a fan shroud to the rear of the radiator. Note comments regarding a fan shroud:

Airflow through a radiator can be maximized only if the entire core is covered by a shroud. This Flex-a-lite Black Magic fan uses an integral shroud and rubber seal to cover all but the corners of this Flex-a-fit aluminum radiator. If the fan generates sufficient airflow through the radiator core, it will enhance cooling even when stuck in slow-moving traffic.
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Chicagogoat
Cochise

USA
823 Posts

Posted - 11 Mar 2015 :  8:50:15 PM  Show Profile  Visit Chicagogoat's Homepage  Reply with Quote
The Black Magic fan that Steve C mentions is a good all around choice because it goes for about $300 flat and has a 16" fan built in a lightweight nylon shroud that will cover most of the radiator core. I'm running one since '08 with a universal Griffin 1 1/4" dual core rad with 31" X 16" core. So the fan covers 80% of the core or better but cools my 455 just fine for a number of years already. My temps range from 175-190.

77GP posted that he only has less than 3" between the rad and pump pulley? I'm not sure what fan assembly you can fit in there that tight. The before mentioned Black Magic fan assembly is roughly 4 1/2" thick.



Pure Pontiac: learn it, live it, love it!
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77gp
Tribal Scout

14 Posts

Posted - 11 Mar 2015 :  8:57:50 PM  Show Profile  Reply with Quote
Because of the 3" clearance I was going to mount them to the front of the radiator and use them as pushers instead of pulling air. That's alot of the reason I was curious about a shroud, it seems it would be blocking much of the radiator core as opposed to fans pulling air using a shroud that force all the air through the fan. It's not an ideal setup but with minimal room it's the best I can think of.
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Chicagogoat
Cochise

USA
823 Posts

Posted - 11 Mar 2015 :  9:16:51 PM  Show Profile  Visit Chicagogoat's Homepage  Reply with Quote
Oh BTW, the Black Magic fan is similar to the one on a lot of fox body mustangs, same fan assembly no shroud. The Black Magic X-treme is the one designed with the shroud that I have.http://www.jegs.com/i/Flex-a-lite/400/180/10002/-1

Pure Pontiac: learn it, live it, love it!
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Chicagogoat
Cochise

USA
823 Posts

Posted - 11 Mar 2015 :  9:21:39 PM  Show Profile  Visit Chicagogoat's Homepage  Reply with Quote
I just saw your post 77GP. Unfortunately with the tight quarters on your GP I see why your guy opted for the flex fan setup. The pusher setup is pretty inefficient especially at high speed.

Pure Pontiac: learn it, live it, love it!
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77gp
Tribal Scout

14 Posts

Posted - 12 Mar 2015 :  1:43:16 PM  Show Profile  Reply with Quote
Chicagogoat, this isn't for my GP. This is a street rod that belongs to a friend of mine. And it only overheats in traffic, at speed it's fine. That's why I think it needs a shroud. I will check with Black Magic and see what they have.
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Steve C.
Crazy Horse

1674 Posts

Posted - 12 Mar 2015 :  3:08:45 PM  Show Profile  Reply with Quote
Using a electric fan. They always work better pulling air thru a radiator rather than pushing air. Hundreds of good tech articles published on this subject. Many opt to design and fabricate their own custom made fan shroud.
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Steve C.
Crazy Horse

1674 Posts

Posted - 12 Mar 2015 :  8:04:29 PM  Show Profile  Reply with Quote
chicagogoat- WOW, outstanding looking engine bay ! Love the 'one color' engine scheme.

Here is my fan shroud in picture #17
http://www.hotrod.com/cars/featured/0712phr-1970-pontiac-trans-am/

Again, do what we can to fabricate or buy a fan shroud. Put the fan blades 3/4 way inside the shroud opening. Those here that have factory looking street cars are lucky, order from a catalog and adapt them.




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Chicagogoat
Cochise

USA
823 Posts

Posted - 12 Mar 2015 :  11:09:26 PM  Show Profile  Visit Chicagogoat's Homepage  Reply with Quote
That's a nice looking setup as well Steve. It appears you guys fabbed up a shroud to house dual 15" fans? I use the famous DCcontrols module to automatically control the fan and water pump together for a few years now. It was recommended by another member here from Texas named Lee. It was advice well taken, It's very reliable and easy to install and adjust.

Pure Pontiac: learn it, live it, love it!
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