Stock Radiator Fan or Electric Radiator Fans

[RJRENTON]

I drove my GTX from February of '68 through January of '73 and put over 100.000 miles on it and NEVER had any cooling system issues. Factory 29" radiator, (4 speed car) factory clutch fan, and factory fan shroud.

Everything's still on the car.

The B BODY GTXs never used a 29 inch radiator (unless previous owner changed core support and used a C body radiator). The biggest was a 26" max cool radiator (more tubes on closer centers) with a 7 blade fan, toque drive fan clutch, shroud, hood to core support seal, standard equipment with the A34 super track pack option, FPDB, 4.10 Dana 60 rear, PS pump oil cooler.......exactly the way my original 1970 GTX, RS23V0A****** was built.......
BOB RENTON

 

[dadsbee]

Everyone else caught the typo Bob...

 

[ynst]

Sorry for the fat fingers

 

[RJRENTON]

Sorry for the fat fingers

That's OK......I do it with great regularly.....or so I've been told.....join the club.....
BOB RENTON

 

[CHGRSE74]

Yes, install the shroud. Without it the air just swirls around the fan blades and nothing is drawn through the rad. These systems were engineered to work, and they did unless there was a maintenance issue such as restrictions to coolant flow. It also looks so much better the way they were designed.

 

[33 IMP]

I have NOT read this entire thread, so take my opinion for what it is, an opinion....
Factory fan, fan clutch, 26 (or more) radiator, (I'm using a high efficiency 28, from a big block cordoba) and a SHROUD.
Done.
Horsepower loss will be undetectable anywhere (except MAYBE a chassis dyno, and I doubt that).
I have two electrics on one of my cars, ONLY cause the radiator is at a 30° angle. (And no shroud is available for a dually radiator in a big block Opel GT)
The other has a mechanical fan for cooling, and an electric pusher, ONLY for between rounds cooling (usually unnecessary).

 

[WileE]

I drove my GTX from February of '68 through January of '73 and put over 100.000 miles on it and NEVER had any cooling system issues. Factory 29" radiator, (4 speed car) factory clutch fan, and factory fan shroud.

Everything's still on the car.

Yup... I would go to the beach on hot July days in my Mopar those days, never an issue with the OE setup. The only thing hot was the weather and my girlfriend.

 

[JARRETT LYNCH]

FOR THOSE THAT THINK THE FANS DONT SUCK THAT MUCH POWER- TAKE A GANDER

 

[RJRENTON]

FOR THOSE THAT THINK THE FANS DONT SUCK THAT MUCH POWER- TAKE A GANDER

Contrary to what this article says:
formulas are: CFM2/CFM1 = RPM2/RPM1, SP2/SP1 = (RPM2/RPM1)², and HP2/HP1 = (RPM2/RPM1)³. These formulas show that airflow is directly proportional to fan speed, static pressure varies with the square of the speed, and power varies with the cube of the speed.

Here are the formulas in detail:

1. Fan Law 1 (Airflow)
   • Formula: CFM₂/CFM₁ = RPM₂/RPM₁
     
     
   • Explanation: This law states that the volume of air a fan moves (CFM - cubic feet per minute) is directly proportional to the fan's speed (RPM - revolutions per minute).
     
     
   • Example: If you double the fan speed, the airflow will also double.
     
2. Fan Law 2 (Static Pressure)
   • Formula: SP₂/SP₁ = (RPM₂/RPM₁)²
     
     
   • Explanation: This law states that the total static pressure (SP) the fan generates changes with the square of the fan's speed.
     
     
   • Example: If you double the fan speed, the static pressure will increase by a factor of four (2²).
     
3. 
   
4. 
   
5. Fan Law 3 (Horsepower)
   • Formula: HP₂/HP₁ = (RPM₂/RPM₁ )³
     
     
   • Explanation: This law states that the fan's horsepower (HP) requirement changes with the cube of the fan's speed.
     
     
   • Example: If you double the fan speed, the power required to operate the fan will increase by a factor of eight (2³).
   These FAN LAWS APPLIES........especially the third law applies to horsepower requirements....... search fan laws for in depth information.....
   BOB RENTON
   

 

[dadsbee]

You can run the engine driven fan, or the electric off the alternator. Don't see either eating more hp than the other... let's move on!

 

[33 IMP]

I'm running the exact plastic flex fan in that test that sucks up a bunch of power. BUT! It's in a primarily bracket car (sees some street use) and it does a fine job of keeping the engine cool. Considering an extra 20hp might make my car one tenth faster, it's inconsequential compared to running cool in my opinion.
(My faster car has an electric fan, and electric water pump, and a controller for both. It also has the biggest radiator that will fit between the frame rails, and has a notch in one tank to clear a frame rail. Still marginal for street use)

 

[33 IMP]

....and I thought the amount of air a fan moves had something to do with blade pitch, diameter, number of blades, among other things
Oops, guess I was wrong. I guess volume of air only has something to do with rpm, proportionally.

 

[33 IMP]

You can run the engine driven fan, or the electric off the alternator. Don't see either eating more hp than the other... let's move on!

I think EM did that test too. Extra load on the alternator to run the electric fan (could have been a couple fans) amounted to so little it was hard to measure on the dyno. Bunches less power than a bad engine driven fan.
(Don't care, gonna keep my engine driven fan, thanks!).

 

[RJRENTON]

....and I thought the amount of air a fan moves had something to do with blade pitch, diameter, number of blades, among other things
Oops, guess I was wrong. I guess volume of air only has something to do with rpm, proportionally.

Suggest that you review the fan laws......remember, that the temperature of the air being moved will affect its density......hot air requires less hp to move a given volume (ie, pounds of air/CFM/degree F)...in addition to RPM of the fan. This applies to ALL fan types.....propeller, centrifugal (forward inclined and backward inclined). FYI.......google search fan laws......it's not a simple straightforward relationship........
BOB RENTON

 

[33 IMP]

Suggest that you review the fan laws......remember, that the temperature of the air being moved will affect its density......hot air requires less hp to move a given volume (ie, pounds of air/CFM/degree F)...in addition to RPM of the fan. This applies to ALL fan types.....propeller, centrifugal (forward inclined and backward inclined). FYI.......google search fan laws......it's not a simple straightforward relationship........
BOB RENTON

I suggest that a bigass fan will move more air than an Itty bitty one at the same rpm. Is that hard to understand?

 

[Crash520]

I’ve run both, if your looking for a great two speed non PDM control electric fan, grab one from a chev cruze, the single fan unit really draws some air and fits perfectly on the smaller Mopar radiator, I have this one on a 408 half grouted block, W2 iron heads and works fantastic

 

[dfrazz]

Don't forget radiator, fan, clutch and shroud are only part of the cooling system. You need a good water pump and the right thermostat for your car to run at the proper temp.

 

[68-500]

I couldn’t find the Engine Masters electric fan test. And at the risk of starting some **** I’m going to question some things.
1. Not such thing as free energy. So if an electric fan requires X amps to produce X cfm. That can be equated hp=VA/745.6. So if an alternator needs to make a that amount of amperage if is going to use a the same amount of hp.
2. The only way an electric fan can use less hp than a mechanical fan is to move less cfm, or visa-versa.
3. You can level the spike of load on the alternator with the battery, but in the end energy used
has to be = energy created.
4. Thus the only way an electric fan can use less hp than a mechanical fan is to move less air or the fan blade design be more efficient. I have a hard time believing one fan design for a car can use 10-20 less hp than a different design.
What say you?

 

[JARRETT LYNCH]

You can run the engine driven fan, or the electric off the alternator. Don't see either eating more hp than the other... let's move on!

Wrong, the alternator doesnt' draw 30 hp from the engine when the fans are on and also you can set your electric fans to only run at a certain temperature so when your engine is cool they are not on and when your on the hwy or fwy they are not on. With a fixed fan you are robbing horsepower 24/7. There is a reason every new car today is using electric fans.

 

[33 IMP]

I couldn’t find the Engine Masters electric fan test. And at the risk of starting some **** I’m going to question some things.
1. Not such thing as free energy. So if an electric fan requires X amps to produce X cfm. That can be equated hp=VA/745.6. So if an alternator needs to make a that amount of amperage if is going to use a the same amount of hp.
2. The only way an electric fan can use less hp than a mechanical fan is to move less cfm, or visa-versa.
3. You can level the spike of load on the alternator with the battery, but in the end energy used
has to be = energy created.
4. Thus the only way an electric fan can use less hp than a mechanical fan is to move less air or the fan blade design be more efficient. I have a hard time believing one fan design for a car can use 10-20 less hp than a different design.
What say you?

The test referred to is one of horsepower killing.
I think it tested how much power was drained by fans, alternators, water pumps, and air conditioning compressors.
I may be wrong about some of those.
I have over 50 em vids on my dvr....but not that one.