dual electric fans with shroud fit/size?
 

I have a champion aluminum radiator

the core measures 27 1/2" x 17" do I need this exact same measurement for the fan shroud I get?

the car is a 72 firebird, what is the best direct fit for this radiator?

first time electric fan effort here, hoping to get it right the first time with some input. what little I know I seem to like the derale brand with built in controller.

I have plenty of room to the water pump pulley but I noticed down at the steering box to radiator is only 1 3/4" clearance.

Plenty of options that will work, but I really like my Lincoln/Taurus fan, as they move a ton of air. Regardless of which option you go with, spend the money on a good controller. I bought one from Auto Cool Guy, which operates the fan as true variable speed, not just 2 speeds.

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contemplating a single fan. seem to find a better fit with one fan.

I did not have a cooling issue. my block is partially filled keeping coolant up higher where the heat is, and the march serpentine system spins the water pump slower cooling better. car usually stayed at 185 and rarely 195 in extreme heat.

hows the durability with a good quality electric fan?

best quality
 

Seeing quite a few bad reviews on derale controllers and fans. anyone with real world experience have some input on that?

Here's a few things I learned trying to cool my '67 bird.

1 large fan (if you have the room) cools better than 2 smaller fans. If you have go with 2 fans, get as big as will fit.

Puller fans are more efficient than pusher fans.

SPAL heavy duty fans FTW!

The shroud should cover all of the core.

Fan controllers aren't needed. I use a heavy gauge, fused at the battery to a relay that can carry the amp load of the fan. Bosch type relays are ok, but for about the same price, you can get an 80 amp, continuous duty, 12v relay that looks like a Ford starter relay that will last forever.
A thermostatic switch plumbed into the coolant can ground the relay to come on at a preset temp. I think I used one from a BMW that comes on at 185*

In my case the Cold Case radiator (worked excellent) with the stock shroud and clutch fan. The electric fans did not keep it cool.

Good information here, as well as another link embedded in the thread from speargun that is helpful.
https://r.tapatalk.com/shareLink/top...ink_source=app


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"Fan controllers aren't needed"

True statement, but I like the fact my fan controller allows the fan to operate at variable speed, automatically increasing fan speed as temps require. In addition, i added an override switch so fan goes to high speed when desired, such as in between drag runs. Also, very handy to tweak the off/on temps with the turn of a dial.

My old 66 had loud dual fans installed that only kicked in at full speed. Neighbors were not sure if a car or a jet engine was coming around the corner!

It did add $200 to the install but I like it :)

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Couple things. First, the wizz-bang cheap fans/shrouds are usually not very good, the shrouds/fans are too close to the radiator, and only draw the circumference of the fan(s).

Good example is in that link that states the 'Cold Case fans outcool the Champion', the wizz-bang shroud used with the Champion is junk, and not a fair comparison.

As long as the shroud is properly designed, and covers as much of the core as possible, you will get max cooling/flow/cfm from the fan(s) installed. Compare combined fan cfms, and pick the most/biggest, especially for a performance application.

Also don't agree with the statement that Derale fans and controllers have a bad wrap. I use them religiously and have never had a problem. They make a wide variety of sizes and shapes, and the new PWM controller works great.

I say definitely run a controller, for a number of reasons. Electrical load 'shock', alts last longer, fans last longer, and cooling is efficient. I say only run PWM type controllers for the same reasons.

The Derale PWM Powerpack fans are great, have the controller built in, and makes for a very clean package. For your core size, it's a little tricky, since you need to look at the top and bottom to figure out if you can use the one large size of 27 x 18. It's ok if the shroud contacts the top & bottom (1/2" top/bottom) frame of the radiator as long as you can get it to seal right. That's what I plan to use on my 'bird, but if you're concerned, you can drop back to the 26 3/8" x 16" setup.

https://derale.com/product-footer/el...709-753-detail

Thing about 2 fans compared to a single fan. Real estate up there gets tight, and with a single fan, centered, the fan at it's thickest part, usually the fan motor, is lined right up with the water pump. With two fans, there is more room there.

I mounted my shroud on my A-body using tread-serts into the top & bottom frame of the radiator, with brackets, worked great. Plan on doing the same with the 'bird.


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The Derale setup I have on the 442 has been on there over 5 years, and 35k miles, still works great, so durability is great. That car with A/C runs like 3-5 degrees over t-stat rating, in all conditions.


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Best controller on the market we've seen is Dakota Digital PAC 2750 and the newer PAC 2800 w/blue tooth. A lot of features, very reliable and reasonable price.

The problem with the Dakota Digital/PAC controllers:

" Mounting is recommended inside the cab of the vehicle or an alternate dry environment."


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what keeps the fans from running once the car is shut off and the thermostat switch is heat soaking? do you also run a manual off on switch?

No, there's a key-on feed to the controller. You can add a start delay too, so when it's hot, and you get in to fire it up, the fans won't run while you're trying to start it.



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For any street vehicle used more than on a sunny Saturday afternoon, you should definitely invest in a good controller for all the reasons mentioned in this thread. Or, just stay with a factory style clutch fan with proper shroud if someone is trying to get by with minimal $$$.

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That's what I did, the duel electric fans didn't work for me so I went back to the stock shroud and clutch fan, I only go to the track a couple times a year.

Refresh my memory on how the electric fans didn't work for you again? I vaguely recall there were cooling issues, the cause slips my mind tho…

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I bought the cold case set up, radiator, alum shroud dual 12" fans. The radiator is great but the shroud in my case blocked off to much area, it would run 190+. I had a 4 core in it for years in Cincinnati but moving to Arizona is a little warmer. On long stretch of highway it would heat up but normal short trips was fine. So now with the alum radiator stock shroud and clutch fan it keeps the 571 real cool.

?
 

These things are not cheap, that would really chap me if I run hotter than did with the mechanical fan.

gonna follow thru and see if it works for me. would definitely want the delay fan at start up. always wanna hear the engine first.

so what's the biggest benefit of running one anyway? I thought there was no question of better cooling.

can you run them without the engine running to cool down without draining the battery?

I am by no means an expert, but if you cannot cool your car with a proper radiator and mechanical fan setup, i think you will be "chapped" with the results of an electric setup. A factory style mechanical fan moves a buttload of air!

I ran the factory setup with great results in my 73 gto, even with a number of trips to drag strip spinning up to 6k. When putting the same motor in my 68, I was starting fresh with no fan, shroud, clutch etc. Since I was starting fresh and this car is setup for regular visits to the strip, I decided to invest in a good electric fan and controller.

Same good cooling results with the Mark8 fan, but now I can have more control, save a couple horse power, cool down between runs, etc. Yes, anytime the fan is running you will be putting a good load on your battery and/or alternator.

If only running a 40amp alt, you will likely want to upgrade that to ~100amp as well.

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