Cooling fan shootout - Engine Masters

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dannobee
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Re: Cooling fan shootout - Engine Masters

Post by dannobee »

Tuner wrote: Fri May 07, 2021 7:59 pm Come on people, look at the 5 HP electric motor on your shop air compressor, do you see two 5/8" belts? A 3/8" V belt is not going to deliver anywhere close to 30 HP and last 50,000 miles.
It's not eating up 30hp the whole time, only when at slower than freeway speeds, or when you drop down a gear and buzz the engine up. If your engine is loafing along at 1700rpm at 75mph in OD, the wind is probably pushing the fan faster than the engine is, resulting in no power loss.

Go look at the Horton clutch fans on big trucks, three or four v-belts and a bigazz compressed air controlled clutch. If you turn on the fan switch at idle, the fan will literally move enough air to sweep the shop floor.
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Re: Cooling fan shootout - Engine Masters

Post by lc-gtr-1969 »

Tuner wrote: Fri May 07, 2021 7:59 pm
CastIron wrote: Fri May 07, 2021 7:34 pm
Tuner wrote: Thu May 06, 2021 7:44 pm You really think 30 HP + the water pump through a 3/8" V belt? #-o
A V belt powers the mowing deck on my 27hp garden tractor, so yeah.
That belt is 1/2 or 5/8 inch wide. How much power goes to propelling the mower vs. turning the blades?

Come on people, look at the 5 HP electric motor on your shop air compressor, do you see two 5/8" belts? A 3/8" V belt is not going to deliver anywhere close to 30 HP and last 50,000 miles.
If you do not believe the data, an if you have access to a dyno- why don't you spend 30 minutes to run up a car and remove the mech. fan and post before and after data? I am sure plenty would be interested.
Fumbling around in the shed...
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Re: Cooling fan shootout - Engine Masters

Post by Tuner »

lc-gtr-1969 wrote: Sat May 08, 2021 1:44 am
Tuner wrote: Fri May 07, 2021 7:59 pm
CastIron wrote: Fri May 07, 2021 7:34 pm

A V belt powers the mowing deck on my 27hp garden tractor, so yeah.
That belt is 1/2 or 5/8 inch wide. How much power goes to propelling the mower vs. turning the blades?

Come on people, look at the 5 HP electric motor on your shop air compressor, do you see two 5/8" belts? A 3/8" V belt is not going to deliver anywhere close to 30 HP and last 50,000 miles.
If you do not believe the data, an if you have access to a dyno- why don't you spend 30 minutes to run up a car and remove the mech. fan and post before and after data? I am sure plenty would be interested.
See, this is what happens when you don't read the whole thread and just jump right in with a kneejerk reaction instead of applying you maff skilzz. 1 HP = 746 Watts. 30 HP = 22371 Watts / 12 V = 1,864.25 Amps. A large electric fan assembly listed in Summit which has two fans/motors is rated at 50 amps. 50A x 12V = 600 Watts 1 HP = 746 Watts. It is ridiculous to think a fan driven by a single 3/8" belt is absorbing 30 HP.
Tuner wrote: Thu May 06, 2021 5:58 pm
blackford wrote: Thu May 06, 2021 12:49 pm I'm sorry, but am I the only one who thinks that 30 HP to turn a fan is absurd? So, I would need to take a very powerful 30 HP electric motor that spins the fan up to speed (either directly or by gearing it up) to move the same amount of air as the same fan being spun by an engine? Does that seem reasonable to anyone?
Not reasonable at all, 30 HP is just nuts, yellow journalism. 30 HP = 22371 Watts / 12 V = 1,864.25 Amps. Who wants to try again?

Once upon a time on a chassis dyno on a hot summer day with a 355 SBC short-track car that had no fan at all it started getting warmer than ideal with just a 110V squirrel cage fan blowing at it so we put one of those molded black plastic fans on it about 12"-14" diameter and it did not change the RWHP at all but it did cool the engine just fine so we left it on and made a shroud out of one of the shop's Rubbermaid trash cans that serendipitously was the perfect size, length and diameter, when cut short and attached with tranny cooler zip ties through the heater core and the lip of the trash can.
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Re: Cooling fan shootout - Engine Masters

Post by 6.50camaro »

Is it reasonable to assume it would take 22 ft/lbs of torque to turn a 6 blade 14" fan 7000 rpm ? If it is , than the lose of that torque at 7k rpm would account for about 30 hp @ 7k .
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Re: Cooling fan shootout - Engine Masters

Post by F-BIRD'88 »

The power problem is not in turning the fan or water pump, or power steering pump, its turning these @7000 rpm thats the problem.
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Re: Cooling fan shootout - Engine Masters

Post by Ken_Parkman »

The explanation that makes sense is there if you use your math skills. Take that self same fan and spin it many times outside of its design point at a power cubed factor and see how the math works out. Yes 30 hp is absurd - that is the point. I also find it also absurd that people will kill themselves for an extra point of compression worth ~ 2% yet run a giant eggbeater fan and a tiny paper air filter. And hey guess what - some fan belts slip because the power draw is so absurd.
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Re: Cooling fan shootout - Engine Masters

Post by blackford »

6.50camaro wrote: Sat May 08, 2021 2:55 pm Is it reasonable to assume it would take 22 ft/lbs of torque to turn a 6 blade 14" fan 7000 rpm ? If it is , than the lose of that torque at 7k rpm would account for about 30 hp @ 7k .
Yea, I agree. That's essentially what I said in a previous post but I used 25 ft-lbs and 6000 rpm which resulted in about 28 HP of loss. This analysis makes sense and is believable. Really no good reason to run a fan at such a high rpm is there. My flex fan flattens out when I rev the engine so maybe the loss is only 20 HP...yea!
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Re: Cooling fan shootout - Engine Masters

Post by ClassAct »

lc-gtr-1969 wrote: Sat May 08, 2021 1:44 am
Tuner wrote: Fri May 07, 2021 7:59 pm
CastIron wrote: Fri May 07, 2021 7:34 pm

A V belt powers the mowing deck on my 27hp garden tractor, so yeah.
That belt is 1/2 or 5/8 inch wide. How much power goes to propelling the mower vs. turning the blades?

Come on people, look at the 5 HP electric motor on your shop air compressor, do you see two 5/8" belts? A 3/8" V belt is not going to deliver anywhere close to 30 HP and last 50,000 miles.
If you do not believe the data, an if you have access to a dyno- why don't you spend 30 minutes to run up a car and remove the mech. fan and post before and after data? I am sure plenty would be interested.
When my dyno is up and running Tuner has a standing invitation to come over and test anything he wants to test.
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Re: Cooling fan shootout - Engine Masters

Post by Rick! »

Tuner wrote: Sat May 08, 2021 2:33 pm
lc-gtr-1969 wrote: Sat May 08, 2021 1:44 am
Tuner wrote: Fri May 07, 2021 7:59 pm
That belt is 1/2 or 5/8 inch wide. How much power goes to propelling the mower vs. turning the blades?

Come on people, look at the 5 HP electric motor on your shop air compressor, do you see two 5/8" belts? A 3/8" V belt is not going to deliver anywhere close to 30 HP and last 50,000 miles.
If you do not believe the data, an if you have access to a dyno- why don't you spend 30 minutes to run up a car and remove the mech. fan and post before and after data? I am sure plenty would be interested.
See, this is what happens when you don't read the whole thread and just jump right in with a kneejerk reaction instead of applying you maff skilzz. 1 HP = 746 Watts. 30 HP = 22371 Watts / 12 V = 1,864.25 Amps. A large electric fan assembly listed in Summit which has two fans/motors is rated at 50 amps. 50A x 12V = 600 Watts 1 HP = 746 Watts. It is ridiculous to think a fan driven by a single 3/8" belt is absorbing 30 HP.
Tuner wrote: Thu May 06, 2021 5:58 pm
blackford wrote: Thu May 06, 2021 12:49 pm I'm sorry, but am I the only one who thinks that 30 HP to turn a fan is absurd? So, I would need to take a very powerful 30 HP electric motor that spins the fan up to speed (either directly or by gearing it up) to move the same amount of air as the same fan being spun by an engine? Does that seem reasonable to anyone?
Not reasonable at all, 30 HP is just nuts, yellow journalism. 30 HP = 22371 Watts / 12 V = 1,864.25 Amps. Who wants to try again?

Once upon a time on a chassis dyno on a hot summer day with a 355 SBC short-track car that had no fan at all it started getting warmer than ideal with just a 110V squirrel cage fan blowing at it so we put one of those molded black plastic fans on it about 12"-14" diameter and it did not change the RWHP at all but it did cool the engine just fine so we left it on and made a shroud out of one of the shop's Rubbermaid trash cans that serendipitously was the perfect size, length and diameter, when cut short and attached with tranny cooler zip ties through the heater core and the lip of the trash can.
You too, can become a belt application engineer with Design IQ and DF-Pro.
Now when Horton renews my subscription, I'll post up a graph of fan performance.
https://www.gates.com/us/en/knowledge-c ... tware.html

Relating the power back to 12V amps may not be the proper approach. But, if you raise the volts to 415 or so, then the current becomes manageable, or believable. I can assure you that a fan takes more than a few HP to create a deltaP and the subsequent volume flow. This could be why Teslas use a 600v motor to transmit "Ludicrous" torque? :)
Using Power = torque x omega (rad/sec), it is easy to see how fan hp (kW) numbers are "fathomable."
Also, trying to determine fan power backwards from aero and drag forces using some relative velocity is best left to the CFD types. I'm not sure how one could grab a velocity, bulk or otherwise, and demonstrate fan power is proportional to v^3. Now that I've stated it, though, someone will come up with a version of an explanation.

Rob is still looking for his fan solution to have an edge on his LS street competition and we haven't been able to convince him that a thermostatic clutch fan is the smart way to go. At the very least the discussion is entertaining.
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Re: Cooling fan shootout - Engine Masters

Post by n2omike »

Only questions that need asked...
Do you trust the Engine Masters crew to do a valid test and be honest with their findings?
I say YES. If you follow their channel, you will see that Jim Brule is one of the most experienced dyno guys out there, and is using some of the best equipment. Highly reputable, and has some good clients he isn't going to risk his reputation over a fan test.

Once you trust the results, the only question is 'how' does a fan absorb 30hp?
Fans are designed to move ample airflow at around 1000 rpm. Start spinning them 5k+ and they absorb a TON of power.
How hard is it to wade through a swimming pool... Now, how hard is it to run?

There is a reason ZERO cars come with an engine driven fan anymore.
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Re: Cooling fan shootout - Engine Masters

Post by ClassicRob »

[/quote]
Rob is still looking for his fan solution to have an edge on his LS street competition and we haven't been able to convince him that a thermostatic clutch fan is the smart way to go. At the very least the discussion is entertaining.
[/quote]

Whoa! LS? I don’t think so! If I was an LS guy, I’d just buy the “Stage 2” cooling fan. 🙄🤦‍♂️
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Re: Cooling fan shootout - Engine Masters

Post by Circlotron »

Another thing to consider is that the radiator dissipation capacity is very nonlinear with airflow. A small initial flow of air makes a big difference but more and more air makes less and less difference. There's got to be some point past which it just isn't worth it.

Illustration of the performance of a finned aluminium heatsink with forced air
Image
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Re: Cooling fan shootout - Engine Masters

Post by Steve K »

On a stock engine, sure run a fan because it'll rarely see 4000 rpm which is what stock fans are designed for. Run that up to 6500 rpm or better and that is just plain nuts and dangerous. OEM's use electric fans for a reason. I've run electric fans for years with no issues, rarely see more that 180 -190 deg on a 90 deg day. Why spend money an building a performance engine and then muzzle it with a horsepower draw like a mechanical fan. To each his own but to me, unless it's a stock restoration, it doesn't make sense.
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Re: Cooling fan shootout - Engine Masters

Post by bobmc »

my 1994 S10 commuter vehicle developed a fan to shroud conflict in some bumpy situations, rather than figure out what needed fixing I had a flex fan that was 2 or 3" smaller in diameter, it increased the tip to shroud distance at least an inch and moved the fan toward the pump an inch or so, the cooling did not change that I could determine in Georgia summertime stop and go surface street travel, the fuel mileage did not change at all, 20mpg on my particular commute
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Re: Cooling fan shootout - Engine Masters

Post by jeff swisher »

306" Ford 6000 lb race weight 18.2 ET 2 times in a row.
I pulled my battery and gave it to my buddy for his dragster which had a dead battery.
I put his dead battery in my Ford and ran another pass, my amp gauge was pegged all the way over and you could hear that 63 amp
alternator buzzing.
I ran 21.5 second ET and it felt like I was pulling an anchor.
Battery acid all over the engine compartment after the pass.

His battery was junk.
Found out he always charged it quick start.

Electrical system can pull down an engine.

I ran a flex fan and a clutch fan for some testing on a SBC 350 of my own and the clutch fan was the big power robber and starting at 3000 rpm the single V belt would squeal something terrible.
My flex fan would also slip the single V belt but not as much.

My Flex fan is a factory Ford Flex fan. Pretty flexible spring steel blades.

I have had many clutch fans go bad and one took out the radiator when it fell apart.
I have replaced many cracked heads from failed electric fans so I have little faith in those.

A Ford Flex fan gives me peace of mind.
I used to drive 70,000 miles a year as did the wife in another vehicle and you will see failures when you rack up a ton of miles.

If you drive 10-20 K a year you may never see failures on the scale that we did.
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