Cooling Fan/System Ideas?

[Dodge68charger]

Running a Sbc With a 3core Aluminum Radiator. Around 375 Hp..

Would You Go Electric Fan, Flex Fan, or Clutch Fan?

Any Other Suggestions on To Keep It Cool. Thanks
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[rpmerf]

My thoughts on this. Search around, there's a handful of electric fan threads.

I would avoid flex fans. I've heard of them exploding.

Thermo clutch fans are decent and simple. I put this on my truck. The blades say not to spin them past 4000 RPM. I never actually mathed it out, but I think the blades spin about 80% through the clutch. Be aware of the ratio though the pulleys also. Basically dead simple, bolts right up, and cheap.

Electric seems to be best. 0 load on the engine. There are different ways you can go. I've heard of people using fans from 90's Fords, like Windstars. You can get new ones also. The important part is how well it covers the radiator. You will need to install a temperature controller - sensor, controller, and relay. This tells the fan when to turn on and off. Usually turns off 10* or so below when it turns on so it isn't switching on and off a lot. Electric fans do draw a bit of power, so this may be a consideration if you will have a generator. If you have a 90 amp alternator, you should be fine.

I've heard debated of whether or not electric can maintain the airflow necessary. A clutch fan is directly spinning the fan. An electric fan uses the engine to spin the alternator to convert kinetic energy to electric, then send that electricity to the fan motor where it is converted back to kinetic. Overall, it is lossy, but it is worth it if you don't use your fan a lot. I guess it really depends on where you live and what the temperature is like. If you are in someplace further south with temperatures 90+ and running the AC all summer, you might be better with a clutch fan.


Another consideration is how much work you want to do. Clutch fan will bolt right up in a couple minutes. Electric may take some fabrication to get it installed and functioning correctly.

Clutch fans tend to be cheaper. Could even pull some parts from the yard. Use your factory shroud, clutch from rock auto for ~$20-$25, 18" blades from summit for ~$50. You might be able to setup an electric setup for cheap using junkyard fans and a cheaper controller for $30-$40

[Mike C]

I prefer a 7 blade clutch type fan on a truck. But nothing wrong with a GOOD, name brand electric setup with the appropriate shroud.

But just say no when it comes to flex fans.

[Andy4639]

I agree with the no statement 100% on flex fan's.

My truck runs electric now that I have the LS in it. They work great and yes they have enough air speed to handle my 6.0 with factory AC. It's wired just like my 64 Impala only difference is it's 2 electric fans.

My 64 SS Impala has the electric fan and the clutch fan for cooling. I have the electric up inside the shroud and you can't see it but when it's on you can feel it ! I have it wired off one relay for 2 speeds. It's main job is keeping the AC temp good and cold so it moves a bunch of air across the coils up front when sitting still. I have the low speed set for temperature on/off setting with adjustable thermostat. Then the high speed is turned on anytime the ac is on which cuts power to the low speed. I also run a micro switch out in the grille area hooked into the high speed wire to cut the fan off at high way speed. I used a golf cart micro switch for this since they are good for over 50 amps. I made a paddle for the micro switch arm so that when the car is at speed the air pushes it and cut's the power off to the fans, the low speed can't kick on because the relay has the switched power to it so then the motor fan takes care of it. This setup has worked very well for the past 2 years and my Impala can sit running and I have never seen it get above 200* no matter what the outside temp is. Even with it idling and AC on. Oh and with the AC on it runs 38* inside the car on 85/90* days.

Last but not least. Make sure there are no escape routs for the air to go around the radiator. Seal off all area's that will allow the air to not go through the radiator itself. This is a great advantage when going down the road forcing the cooler air through.

[Stocker]

All good advice. Yes, avoid flex fans. Besides the possibility of coming apart, they don't cool well at all. Years ago I ran a flex fan for a short time and the truck ran hotter than normal.

I prefer a Heavy Duty clutch with an 18" 7-blade fan, and of course a shroud.

There are three types of thermal fan clutches -- standard duty, heavy duty, and severe duty. Good explanations / illustrations here: http://www.haydenauto.com/featured%2...s/content.aspx

Standard Duty turns fan at 60-70% of shaft speed when engaged; Heavy Duty turns fan at 70-90% of shaft speed when engaged; Severe Duty turns fan at 80-90% of shaft speed when engaged

My K20 had a factory heavy duty unit, but most listings are for standard duty, and a very few are severe duty. Went to my local NAPA and another customer overheard us and suggested looking up the part for a slightly newer K30. Bingo! NAPA p/n 271303, Hayden fan clutch #2747. Made by Four Seasons in Lewisville, Texas. I installed it in 2016 and it's been working perfectly.

[davepl]

If it were up to me, I'd do exactly what I did when it WAS up to me:

- Stock 4-core rad
- Stock shroud
- Stock clutch fan with good tight clutch

PLUS

- Dual 12" SPAL electric pushers in front of rad on thermal switch

You shouldn't really need the electrics that often but when you do, they work great. I'm not a converted SPAL fan fan!

[garyd1961]

I'll never run anything other than a clutch fan on my truck. It's simple and it works.

[LockDoc]

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I don't know how the aluminum radiator compares to the stock one but I used the dual fan setup off of a 2002 Toyota Camry on my '67 Chevy Panel Truck and it fit really good. Just a small amount of trimming on the plastic frame, made two small "Z" brackets for the top, and drill one hole in the bottom for one of the mounting bolts. One of the bottom mounting holes in the fan lined up with an existing hole in the radiator frame..... I have them wired for progressive operation, the second fan doesn't come on until 220º. Other years may also work.

LockDoc

[Steve Cole]

How about this?? This thing is a beast.

https://derale.com/product-footer/el...753-764-detail

I bought one but I may not be able to use it due to a LS swap.

[Big Kev-O]

I used a sever duty clutch fan and my truck sound like a semi for the first 10 minutes the car is on. I switched to a heavy duty and its a bit more quiet but still sound like a damn mac truck until the clutch releases. That said, the truck stays cool on 105* days. I will be switching to electric. I wonder how many CFM those Camry fans blow. the whole assembly is available around $90.

[Stocker]

Originally Posted by Big Kev-O

I used a sever duty clutch fan and my truck sound like a semi for the first 10 minutes the car is on. I switched to a heavy duty and its a bit more quiet but still sound like a damn mac truck until the clutch releases.

Interesting..... I wonder if there's a difference in clutch units from one brand to another, maybe a difference in the fan blades too. I have a HD Hayden clutch and a factory 7-blade fan, and you can hear it when it's engaged but it's just enough to notice, definitely not loud.

[Minkota]

The guys at Roadkill (Engine Masters) did a comparison, maybe it will help...

https://www.motortrendondemand.com/d...ut/0_olymz420/

[rpmerf]

I assume that is the how accessories kill episode, showing that fans can kill like 30 hp (I forget the exact number). The thing to note there, is that clutch fans only pull that much power when the clutch is engaged. When the clutch is disengaged, they are somewhat free spinning.