Alright gentlemen I have been pouring over the internet looking at electric fan options. Suppliers come at you from all angles....most claim one is better than the other. All with varied performance ratings, all with widely varied pricing...so for those running strictly electric fans what manufacturer have you all been pleased with for both cost and performance w/o breaking the bank? I would think above all CFM is out front with 1st choices. Again, in this case (2) 12" puller fans mounted to a shroud.
I don't run an electric fan, but the issue has been tossed around a lot on TheDieselStop forums for guys running the 7.3L PowerStroke. One of the guys there is a cooling system engineer and he says that the stock fan on a 7.3L draws 25 HP when the fan clutch is engaged. There's no way you can get an electric fan that will deliver as much air. Granted your engine doesn't need that much fan power, but it's still significant. I would go with the highest CFM you can get. They're probably rated with no resistance, but it's still a point for comparison.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
Electric cooling fans are a really dumb idea, when there's all that engine power sitting there 6 inches below the water pump. The factory designers weren't dummies. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I was getting at that, but leave it to Jerry to come right out and say it.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
My question is, what are you working on? I’ll agree with the other guys that there’s no way to replace a mechanical fan. On the other hand, in the case of engine swaps, it may not be possible to use a mechanical fan. Like what has been said already, the bigger, the better. On other forums I’ve seen a ton of swaps using 90’s Taurus fans, Volvo fans, and Tbird/Lincoln fans. I’m doing a non-traditional engine swap myself, I’m thinking the Volvo is going to be the best for my application being it has some better mounting options.
I am going to agree with Jerry, he says factory designers weren't dummies. The used the best technology available at the time. Just like today's factory designers are not dummies. Just about every car on the road today uses an electric fan. Even the ones with a north south engine. Why because it is more efferent at the job.The guy that says a fan on a power stroke is pulling 25HP is either not a cooling fan engineer or forgot to move a decimal place. If he is including the water pump the number is probably still not correct but closer.
Electric fans are more efficient because they can be driven at the ideal speed for the fan blade shape. A mechanical fan operates over a large rev range. Also on the open highway you often don't need a fan, there is a lot of air being forced over the radiator to cool. At low speed or stopped the engine is at or near idle an a mechanical fan is not pushing much air when it is needed most.
What I did on a recent car (Jaguar XJ6) was measure the radiator and go to the local wrecker (not sure what you guy's call them maybe auto dismantler). I found the radiator of a local built late model ar called a Ford Falcon in Australia was almost identical size and these have a 4 liter engine. For a very small sum of money I walked out with an electric fan that was designed by one of those clever factory engineer types that did a brilliant job of keeping a 4.2 liter Jaguar engine cool in stop start traffic in an Australian summer and freed up a couple of horsepower.
Also something to consider when it comes to puller and pusher fans, apart from aircon condenser fans I don't think I have ever seen a pusher fan on a factory designed car. Refer to the first sentence and make your own judgment.
Low speed function of a stock fan without a shroud is hideous, a good electric puller fan will walk all over it, Trucks with shrouds, what is the point, a mechanical fan will do just fine and really hard to beat in simplicity and function.
If that big diesel fan costs 25 hp to drive it, it will cost 25 horsepower to drive the alternator powering and equal electric fan as well, nothing is free in physics. The only way an electric fan is more efficient than a mechanical is when it is not running and/or low vehicle speed cooling ability. This one has been studied pretty good.
Last edited by sstock; 01/30/20191:44 PM.
1953 Chevrolet 3100 261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done In the DITY Gallery Video of the 261 running
1964 GMC 1000 305 Big Block V6, sm420, the next cab off restoration
Thanks fellows. I knew when I hit the send button on this subject it would bring your best. Yes, the parasitic loads about break even through an electrical draw or a straight mechanical one. In my case the much larger 3-row aluminum cross-flow rad already in place has allot of surface area 27" between the end caps to be exact. So, adapting some facsimile of a shroud that would be suitable using this aftermarket rad didn't seem plausible. Further, running this Camaro front clip targets the centerline of the water pump snout low on the rad. So yes, I'm going the long way around and spending more money choosing electric over mechanical.
Subject: '59 Apache Fleetside SWB, Camaro front clip, Camaro 10 bolt posi, 350, 350....lowered...no bags. no A/C, no htr
STILL WOULD LIKE TO GET THE ELECTRIC FAN GANG TO CHIME IN ON WHAT PREFERENCES THEY HAVE ON BRANDS, ETC.
12" electric fan won't work properly, but a 16" does for me.......
The 350 SBC mounted too low in my 49 GMC to center a mechanical fan to the radiator so I went electric and I won't go back LOL.....
The radiator on a GMC is made a little differently than a same year AD Chevy in that it mounts a little further forward. This additional inch or so allowed me to make up a shroud and mount a 16" 2700 CFM electric fan to it. I use a fan sender mounted in the water jacket of the intake manifold that turns on at 200 degrees and turns off at 185 degrees The fan hardly ever comes on when cruising below 60 MPH, avg'ing 190-195 degrees by being cooled by air flow through the radiator. It comes on when idling or when driving in heavy bumper to bumper traffic and the fan maintains the temps from 195 to 205. It's never gotten above 210 on 90 degree days.......
I saw a similar electric fan/shroud setup to this linked one on a Chevy AD at a car show.. It had just enough clearance and the owner said he had no cooling problems: Link
For what it’s worth, Silverados since about 2007 and Ford’s since about 2010 have used dual electric fans and no belt driven fans. My wife’s 5.4 powered Expedition weighs around 6000lbs and has a 10,000 lb tow rating. So electric fans do have merit.
Anyhow, I was thumbing through a Derale catalog, they have numerous sizes of fan and shroud combos. Most are around $200. I’m sure you can find one that fits good.
I’ve read a lot of posts about the Volvo fan relay setup. They have a high/low fan switch which goes through the relay module. Looks like a clean setup.
I'm using a Spal 16" fan on my 235 along with an aluminum shroud from Old Air Products. It is either 2070 or 2700 cfm and that along with the thermostat they sell with the package is a great combination. It sits right smack in the center of the radiator and has flaps at the corners that open to allow incoming air to pass through when needed. The noise/vibration reduction alone was worth the price of it and if you live in a metro area with high summer temperatures and sluggish stop/go traffic there is no way a mechanical fan can do as well as an electric one.
When the mechanical fan was removed it was interesting to note how much smoother and quieter my engine instantly became. Some of these old fan blades are comically out of balance. I wouldn't be surprised if I cover the cost of the electric fan in added water pump life.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
I really appreciate the input/output you fellows provided. Volfandt> I can see where a single vs. double is more suitable in your '49. Narrow at the nose...whereas my '59 has larger opening...plus I will need (2) fans to split the difference around the water pump. Whitedog> thanks for the lead with the Volvo relay and Derale products...I will investigate that further as well.
Its all preference old school/new technology...both have there place.
The guy that says a fan on a power stroke is pulling 25HP is either not a cooling fan engineer or forgot to move a decimal place. If he is including the water pump the number is probably still not correct but closer.
I am not a cooling system engineer, but am a Professional Mechanical Engineer and understand thermodynamics as well as pump and fan systems. I was reporting what I read from a person who worked in the automotive industry as a cooling system engineer. The PowerStroke fan is a multi-blade affair about 18 inches in diameter and I have no doubt that it would draw 25 HP (note there's no decimal point there purposely) at highway speeds with the fan clutch engaged. The water pump load is minuscule in comparison. The fan would be running in excess of 2000 RPM. I have specified electric fans running at 1800 RPM with 25 HP electric motors and they're pretty big, and definitely wouldn't fit between the radiator and engine on a SuperDuty truck or any other similar or smaller vehicle.
Originally Posted by sstock
If that big diesel fan costs 25 hp to drive it, it will cost 25 horsepower to drive the alternator powering and equal electric fan as well, nothing is free in physics.
Very true. There's no such thing as a free lunch.
That's not to say that an electric fan wouldn't work, but it depends on your application. Many modern cars have electric fans (with shroud) A 3.8L Buick I had used an electric fan (it had two fans, IIRC). I also know a guy who ran an electric fan on his PowerStroke that was highly modified (He ran 15's in the 1/4 mile) and was his daily driver. Of course, up here we rarely see 75 F, so he didn't have any cooling issues. If he did that in Barstow, CA it might be a different story.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
Spal puller fans selected, along with their dual relay and thermostat wiring kit. Shroud from Champion. Set in place to check for any interference issues. Close quarters but should be fine. Still deciding the wire layout. Anxious to wrap this up and get to the next phase of actual testing overall performance.
It would be a good idea to put some holes in the shroud with flaps on the engine side to allow road air out of the radiator when moving(see VW Rabbit, etc.)
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires. '47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle. '54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed. '55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
"I really appreciate the input/output you fellows provided. Volfandt> I can see where a single vs. double is more suitable in your '49. Narrow at the nose...whereas my '59 has larger opening...plus I will need (2) fans to split the difference around the water pump. Whitedog> thanks for the lead with the Volvo relay and Derale products...I will investigate that further as well.
Its all preference old school/new technology...both have there place."
Apache 1,
This discussion is an example of the value of taking information from a variety of sources to benefit from the combined experience of forum members. As others have pointed out new vehicles have electric fans, not mechanical fans even where a mechanical fan could be attached to a forward pointing water pump snout. An example is our front engine, rear wheel drive V8 powered 2017 Chevy Tahoe. It has 2 electric fans mounted on a shroud and if mechanical fans were superior that's what would have been used. My wife and I have had a variety of cars with electric fans over the decades and none has ever malfunctioned in any way.
Another electric fan advantage is they can be mounted anywhere they fit independent of engine position.
On my '32 Ford roadster street rod I implemented Ed's idea of flaps in the shroud corners and it noticeably improved highway speed cooling compared to the prior condition (photo) of no corner flaps The flaps stay closed when not moving or inching forward in gridlocked traffic or in left turn pockets. That matters because this roadster is driven regularly in a variety of conditions. On the roadster the fan is controlled by a thermal switch. By trial and error I discovered that I could vary the turn on/off temperature using the same thermal switch by installing it at different locations on the engine which, it turns out, run at different temperatures.
...It has 2 electric fans mounted on a shroud and if mechanical fans were superior that's what would have been used....
It could also be that the bean counters over-ruled the engineers. But, hey, that's never happened before. Adequate versus best weighs in to that decision.
Originally Posted by yar
Another electric fan advantage is they can be mounted anywhere they fit independent of engine position.
Yep, a transverse mounted radiator along with transverse mounted engine fan wouldn't work very well. Couldn't take advantage of "road air" unless you were drifting in the right direction.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
"yar. do you have a picture you could share showing the addition of the flap/s?"
I actually just took a couple for someone else who asked. They are pulled tight against the cookie sheet fan shroud by the fan when the roadster is standing still and they definitely improved highway cooling.
"Yep, a transverse mounted radiator along with transverse mounted engine fan wouldn't work very well. Couldn't take advantage of "road air" unless you were drifting in the right direction."
Hey Kevin, you might be joking but the hoodlums over in nearby Oakland have outlaw car events called "Sideshows" where if your car isn't going sideways you get NO respect. To each his own, huh?
"Originally Posted by yar ...It has 2 electric fans mounted on a shroud and if mechanical fans were superior that's what would have been used....
It could also be that the bean counters over-ruled the engineers. But, hey, that's never happened before. Adequate versus best weighs in to that decision."
It seem like the bean counters would like the mechanical fan because a simple stamped sheet metal fan would cost way less than 2 electric fans and all the stuff to control them. But what do we know? We're just grease under the nails gear heads.
"They are pulled tight against the cookie sheet fan shroud by the fan when the roadster is standing still"
Explain how the flaps are pulled tight...it seems they just hang w/o any positive sealing effect and the fan would be trying to pull preheated from the engine back thru the shroud. Just an observation.
yar> I stand corrected. Yes with right material the fan would attempt to pull the flap closed. So did you simply use a hole saw to create your holes? Maybe some aluminum flat bar stock, button head screws and some ultra fine rubber gasket material for your flaps. Does this all sound about right?
"yar> I stand corrected. Yes with right material the fan would attempt to pull the flap closed. So did you simply use a hole saw to create your holes? Maybe some aluminum flat bar stock, button head screws and some ultra fine rubber gasket material for your flaps. Does this all sound about right?"
Yes, that's exactly what worked out well for me. Good eye!
I'm really glad to be able to offer some information that's potentially useful to you.
If electric fans were really not effective as some suggest they would not have found their way onto countless millions of cars and trucks. If "Expert" opinions were always accepted without question there would be no innovation. There are a lot of members on this forum and the more adventuresome ones have tried a lot of things, some of which worked and some of which didn't.
