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Bob-omb

Electric Fans that Actually Cool?

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Bob-omb    11

Can anyone recommend a good set of electric fans for desert temps?

 

I've got the Champion Radiator 3-row with shroud and dual 12" electric fans ("550hp rating" says Champion) on my mostly stock '77 280Z.  I gotta say, this combo is hot garbage on 100° days here in Las Vegas.

 

http://www.championradiators.com/Datsun-240z-radiator-shroud-1970-1973 

 

With the stock brass 3-row rad and clutch fan, my temp gauge would very slowly creep higher while idling in stop and go traffic -- manageable with no danger of overheating.  Same goes for the Champion aluminum 3-row rad with stock clutch fan and no shroud.  

 

However, when equipped with the electric fan/shroud combo (yes, they're spinning in the right direction), the needle climbs up to 3/4 of the gauge sweep within 15 minutes of stop and go traffic and steadily keeps climbing.  It only cools at highway speeds when the fans aren't doing any of the cooling.

 

Any suggestions?

 

Cheers,

Bob

 

 

 

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Chickenman    4

For where you live... where it's over 100 F fairly often I'd say go back to the stock clutch driven fan with a shroud. I encountered the same problem when trying to run electric fans on my 1971 Camaro.

 

One trick that does work is to use Redline Water Wetter. I've used this product for many, many years on my Hill climb cars and it pulls overall temps down by at least 10 degrees. Most of my competitors also use it or a similar product. It works amazingly well.

 

We even used it on some British Double Decker Buses when I was in the Tourism business. They had up-rated Radiators, up-rated transmission and oil coolers, but still boiled over when they had to climb a particular long grade, fully loaded. The Redline Water Wetter dropped the temps just enough to stop the Boil Over when they stopped at a View point at the top of the hill. It is designed to be used with antifreeze.

 

Now, if your set on using electric fans. Get a single BIG Arse fan... with a shroud. I've heard that Ford Taurus fan (from a 1990-1995 with 3.8L engine) works well. But I don't know if Vegas might be too much for them.

 

Guys from the SR20 DE Turbo forums also like the Altima Twin fans with shrouds. Nissan Altima Fans are very large twin fans. The Spal 16" diameter fans may do the trick as well.. but $$$

 

Here's a thread on the Altima fans.

 

http://www.sr20forum.com/240sx-s13-s14-rwd/169960-altima-fans-vs-taurus-fan-comparison.html

 

Altima Twin Fans:

 

P9080010.JPG

 

Ford Taurus fan on a Champion Radiator. :

 

taurusfan.jpg

Edited by Chickenman

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ritrebor    0

I have a Champiom 3 row aluminum radiator and replaced the fans that came with it with a pair of Spal 12" curved puller fans and it made a difference in cooling my blown Chevy.

 

http://www.ebay.com/itm/Spal-USA-30101522-12-Medium-Profile-Fan-Pull-Curved-/131104426051?hash=item1e866ec843:g:MWgAAMXQrhdTSB5i&vxp=mtr

 

It stays around 180 degrees in stop and go traffic.

I have a 280z, so when I bought the radiator they didn't have a shroud for it. So I made my own.

The Spal fans holes needed to be relocated and the fans were a little wider then the champion ones.

 

ritrebor

Edited by ritrebor

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Chickenman    4

If you choose Spal  check out their home site carefully to get specs. The 30101522 Spal is a 12" Medium duty fan. It only pulls 1,328CFM. That may not cut it in Vegas with AC on.

 

The IX-30102049 pulls 2,048 CFM in comparison. Note the curved " S " blades. Most High Performance fans use " S " blades to increase surface area and allow more CFM to be pulled or pushed.  Following is link to Summit... but you may find them cheaper on E-Bay;

 

http://www.summitracing.com/int/parts/spu-ix-30102049/overview/

 

cir-ix-30100291_xl.jpg?rep=True

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Chickenman    4

One thing to remember about mechanical fans. There is a reason why they can cost you 5 HP or so at High RPM. They are moving a S**T load of air.

 

Mechanical fans can be much larger and have more aggressive profiles than electric fans, and in general will pull a LOT more CFM than an equivalent sized electric fan. Pitch on mechanical fan blades can be steeper and  blades can be wider because they are driven by the engine. This equals more airflow, at the cost of a bit of power and MPG. Stock 280Z fan blades are eight blades and thye have a very steep pitch and are wide. They are also noisy when the thermo-clutch kicks in.... but they do move a Ton of air.

 

 

One reason why manufacturers went to electric fans was to increase fuel mileage. CAFE numbers are really, really important when you sell millions of vehicles a year.  The other reason was Transverse engines in FWD cars. Just my .02c...

Edited by Chickenman

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Bob-omb    11

Thanks for the feedback guys.

 

 

I have a Champiom 3 row aluminum radiator and replaced the fans that came with it with a pair of Spal 12" curved puller fans and it made a difference in cooling my blown Chevy.

 

http://www.ebay.com/itm/Spal-USA-30101522-12-Medium-Profile-Fan-Pull-Curved-/131104426051?hash=item1e866ec843:g:MWgAAMXQrhdTSB5i&vxp=mtr

 

It stays around 180 degrees in stop and go traffic.

I have a 280z, so when I bought the radiator they didn't have a shroud for it. So I made my own.

The Spal fans holes needed to be relocated and the fans were a little wider then the champion ones.

 

ritrebor

 

Exactly the info I was looking for.  Spal 30101522 12" (x2) were what I was leaning towards, but wasn't sure if they'd fit.

 

 

If you choose Spal  check out their home site carefully to get specs. The 30101522 Spal is a 12" Medium duty fan. It only pulls 1,328CFM. That may not cut it in Vegas with AC on.

 

The IX-30102049 pulls 2,048 CFM in comparison. Note the curved " S " blades. Most High Performance fans use " S " blades to increase surface area and allow more CFM to be pulled or pushed.  Following is link to Summit... but you may find them cheaper on E-Bay;

 

One of Tony D's posts about fans on Zcar mentions something around 2200-2500 CFM being the magic number.  The Spal 12" (x2) would be 2656 CFM total.  The 12" fans that came with the Champion kit are supposedly 1000 CFM each.

 

 

What Thermostat are you running? You could try to edge some more flow out of it by drilling a few holes in it. 

 

160* thermostat in the summer. 30/70 glycol/water with 1 bottle of Water Wetter.  Air flow is the issue, given that the stock mechanical fan is adequate but not great at cooling. 

Edited by Bob-omb

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Chickenman    4

A picture of the Bob's fan setup would be nice. One thing that is very important is to use a full coverage fan shroud, just like the stock setup. The full back face of the radiator should be enclosed in a shroud. The idea is to pull air through all of the radiator fins.

 

In the Desert you can never have too much Airflow. Especially if you have AC.  IMHO I'd go for the highest CFM combo that you can afford. The Taurus fans are reputedly around 2,700 CFM on low speed and 3,800 CFM on high speed.

 

Another very good option is Volvo 2 speed fans.

 

https://www.youtube.com/watch?v=-954_wpRWsQ

 

Interesting thing about Electric Fans. General rule of thumb is that they pull approx 10 amps per 1,000 CFM ( Source Spal ) . So a Taurus fan on Hi Speed pulls a good 38 amps continuous. A stock 60 Amp alternator ain't gonna cut the Mustard with the Electric fans and AC on at idle. 

 

Hot Rod actually had a very good article addressing the issues of running Electric fans on Vintage cars. Good info from Spal on current draws of fans, CFM ratings and how they vary, use of Full shrouds and why a 60 or 70 Amp alternator may not be enough.

 

Full article at:

 

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

Edited by Chickenman

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Chickenman    4

Excerpt from the article above. This is some very good info IMHO:

 

 

The Electric Side of Cool

What most car crafters rarely consider is that the early '60s and '70s vintage alternators rated at 60 to 70 amps were not designed to crank out maximum amperage at idle. Late-model alternators or high-performance alternators rewired by companies such as Powermaster are designed to generate greater amperage at idle. These more efficient alternators are capable of delivering the 40 amps or more required of dual fans running at full boogie along with a big electric fuel pump, lights, and maybe a thumpin' stereo. Add the draw from a pair of headlights and perhaps a defroster or A/C fan, and a load of 50 to 60 amps from the alternator at idle is not unusual. This will also require large 8- or 10-gauge wiring from the alternator to the underhood power source for your fans and multiple solid-ground circuits between the engine and the chassis. A good ground also means the ground wires should be of equal size as the power leads. The biggest electric fan won't run at anywhere near peak efficiency if the ground circuit suffers from resistance. A simple voltage drop test will tell you if the wiring circuit is the culprit.

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Bob-omb    11

Yeah, I have a Powermaster alt and bigger fans on my '56 Buick.  I was hoping I wouldn't have to go that route, which is why I avoided the ever-popular amp-hungry Taurus fan.

 

The shroud completely covers the core.  Here's a pic from their website:

 

 

CC110shroud_1970-1973_240Z_Radiator.jpg

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HuD 91gt    2

Speaking of shrouds like the one above. It's hard to see from the pictures, but is there any space between the rad and the shrouds in that kind of setup?  If the sheet metal is mounted flat against the rad does that not decrease the efficiency of the rad drastically?  Or are the pictures just deceiving and there is in fact a small spacing?

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Tony D    143

Remember that those Fans are rated at more than CFM...that rating they give is at a specific static pressure. If they pump into someplace that doesn't let the air out easily then their rating goes  DOWN. Also in stop and go, if you don't run the splash pan underneath to prevent the hot backside air from simply recirculating....goes without saying it will steadily heat up.

 

If the car does not overheat at 30mph in 5th gear diving steadily (go find a flat open road in the desert and put your hazards on) then the issue is not in  your cooling system, and you can assume the 2 sq ft of radiator air, being pushed at half a mile a minute (2,640 fpm---so by simple calculation: 5,280 Cfm) will cool your car. WHATEVER temperature  the engine  achieves in this status that's where you should have your fans kick on and off 5 to 10 degrees F Below... They should cycle in traffic like that. mine do and it's  twin 10" units. My old Suzuki Fans worked similarly.

 

In idle situations  there is less heat added, but if it follows a run on the freeway that temp spike can cause issues of runaway that are hard to fix... Put a 24# Radiator Cap on the thing (no less than 16#) and  see how it fares.

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jap tin    5

I have the Champion 4 row Z radiator in my Z.  The fans that come with them suck, but not in a good way. I switched to a pair Spal pullers 30102054 which were better but still didn't cut it. I went back to a 6 blade mechanical fan, 15" with aluminum blades and that helped but still wasn't there even with a high flow waterpump being overdriven. Now I put a pair of Spal pushers, 30102806 on it along with the mechanical fan and it is fixed. Driving in town in 105 degree heat today it worked fantastic.The only problem is that the fans pull a lot of amps but the alt I put on can handle it. The fans run off a pair of 50 amp relays and switch on at 185 and off at 175. When they come on they run for under a minute and then switch right off.

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calZ    1

I have the Champion 4 row Z radiator in my Z.  The fans that come with them suck, but not in a good way. I switched to a pair Spal pullers 30102054 which were better but still didn't cut it. I went back to a 6 blade mechanical fan, 15" with aluminum blades and that helped but still wasn't there even with a high flow waterpump being overdriven. Now I put a pair of Spal pushers, 30102806 on it along with the mechanical fan and it is fixed. Driving in town in 105 degree heat today it worked fantastic.The only problem is that the fans pull a lot of amps but the alt I put on can handle it. The fans run off a pair of 50 amp relays and switch on at 185 and off at 175. When they come on they run for under a minute and then switch right off.

 

Did you have a shroud on when you used the puller fan setups?

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Chickenman    4

I have a Copper three core rad ( freshly boiled out ) and the stock 280Z 8 blade fan with a new Thermo-clutch assembly. Stock 280Z fan shroud. New factory Nissan W/Pump, Zerex Anti-freeze and a bottle of Redline Water Wetter.

 

Car has factory air and runs right in the middle of temperature gauge, with AC on and ambient temps of 90 - 95 F. Usually sits right on the " E " of the word " Temp " on the factory gauge. Stop and go traffic, and needle creeps up a bit, but only to the first leg of the " M ".  As soon as you start moving Temp guage needle drops right down to the " E" mark again. Ambient temp has to be really hot to Pretty happy with that. Factory 280Z fan moves a TON of air.... just saying.

 

Edit: Oh yeah... and Factory Nissan Thermostat ( 180 F ) . I always use OEM thermostats on all cars now, since I found Stant Thermostat quality took a nose dive about 10 years ago. Even the premium Stants ( and other makes ) vary all over the place. The factory stats are dead nuts accurate.

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