Cooling Question

[39 Chevy]

What do think dose the best job electric or mechanical fan?

[cffisher]

I think(on occasion) that both server a purpose and both work well depending on the need

[Itoldyouso]

Yep. No one single answer to this one. Same with mechanical vs electric fuel pumps.............you will find both get the gas to the engine, and which is better depends on a lot of factors.

Don

[HWORRELL]

Mechanical set up with the proper fan shroud works just as good as electric. Only difference that I can see would be room for the mechanical & shroud. The mechanical may use a couple more horsepower over the electrical and the electric will still rob some horses from the load on the alternator.

[robot]

Everyone so far has given a good answer so I will throw mine in too....it's a question that will be argued for quite some time to come. When you ask "best", there is an answer.....whichever one does the best job for your situation. A car that idles for hours in heavy traffic at the rod run sometimes takes a different solution than does a car that is primarily driven at high speed on the highway. Similarly, a car driven in Tucson, AZ may take a different setup than would a car driven in Calgary, AB. Air flow over the radiator is the goal. The radiator doesnt care how that happens, it just cares that it happens. An engine-driven fan runs at an rpm proportional to the engine....at engine idle, the mechanical fan is at its lowest speed....if that is sufficient to keep the engine at the desired temperature, so be it. IF the fan were electric, at idle, the fan is turning at its maximium (and constant) speed so it theoretically pulls more air than the mechanical fan (at idle) and therefore, the electric fan is "Better".

At higher speed, either fan needs to shut off and let the natural air flow over the radiator to occur.....that flow is greater than the fan can pull so having NO fan is better at high speed. That's why clutch fans disengage/engage, if the clutch sees low temp air flow that is sufficient to cool the clutch, the clutch releases. When the temp of the air crossing the clutch rises, the clutch engages.....most OEM electric fan systems turn the fan off when the cooling is not needed.

New cars have electric fans for three reasons, cost, control, and packaging. The electric fan is easier to package when the engine is turned sideways or the engine has a bunch of junk hanging on the front. Since everything is sensor driven, the electric fan is easy to start/stop as needed.

Of course, the fan is only a part of the system. Without the proper shrouding, coolant capacity, thermostat, coolant, and system health, the best fan is still a failure.

[sunsetdart]

Biggest difference between electric and belt driven is flow capability. An electric pump will only push as many gallons per minute as rated by the manufacturer. Mezerie advertises their high volume pump will push 55 GPM. That means it will flow 55 GPM at idle and the same at 60 MPH. Problem is when the motor is at speed,60MPH it is also making more heat, but still only getting 55 GPM. Electric pumps work fine for racing, but for street, not so well.
Belt driven pumps on the other hand can be overdriven ,taht is, a smaller pump pulley and larger crank pulley. In that situation, the pump can push 45-50 GPM at idle and 90-120 GPM at speed.

[cffisher]

Biggest difference between electric and belt driven is flow capability. An electric pump will only push as many gallons per minute as rated by the manufacturer. Mezerie advertises their high volume pump will push 55 GPM. That means it will flow 55 GPM at idle and the same at 60 MPH. Problem is when the motor is at speed,60MPH it is also making more heat, but still only getting 55 GPM. Electric pumps work fine for racing, but for street, not so well.
Belt driven pumps on the other hand can be overdriven ,taht is, a smaller pump pulley and larger crank pulley. In that situation, the pump can push 45-50 GPM at idle and 90-120 GPM at speed.

Fan not pump was the question

[1gary]

Going to use my favorite set up.The 14" Ford Crown Vic fan hands down flows more air than most out there.The down side is they need relays because they draw so much power,and they are very loud because the amount of air they move.You can hook them up to a thermostat to turn on and off.The rest of the system as stated has to be up to par and anytime you are looking to cure a over heat condition you have to consider if the coolant is moving to fast threw the rad.There is a balance you need to obtain.If the car doesn't need antifreeze,we know that water is a better coolant because once antifreeze gets hot,it stays hot longer than water.

My $1.00 opinion discounted to .02 for my home base site.

[Itoldyouso]

What year Crown Vics do you use?


Don

[39 Chevy]

I was just diging to see what everybody had to say. I've got a 383 stroker 460 hp everything under the hood is brand new. It runs 195 down the road 210 in traffic. I was just wandering if the temp coming from right on top of the motor is the gage giving a true reading. 2750 cfm fan.

[robot]

Just for comparison, I have a 350 roller cam engine with the GM HOT cam, MEFI injection, 9.5 to 1 running 106 unleaded in a 4500 lb 4wd. Griffin aluminum radiator, tight fan shroud, stock GM Vortec truck serpentine fan (belt driven) and no tranny cooler in radiator. In 110F outside temp, engine never goes over 200F when pulling long hills and it can idle for over an hour with zero temp increase. Running Zerex coolant additive (like the NASCAR guys use) and no antifreeze. I'd probably have to tape over the grille to get the thing hot.....my take on the success is the fan shroud with no leaks and tight clearance around the blade tips. The fan blade fits inside the shroud by about 1/2". Remember, if it sucks, you've done it right.

mike in tucson

[1gary]

Don-I can't seem to put my hand on those notes right now.Been awhile since we did one.From what I remember they started in the late 1980's on up.Plenty of them at your local pick and pull yards.Make sure you get the harness for the relays too.Bottom line guys is I do remember that fan's cfm is huge.

Here is a quick search of a aftermarket one:

http://www.autopartsdeal.com/catalog...e+Radiator+Fan

1500+ cfm is alot.

[Mike P]

I think Robot hit it pretty much on the head, a lot of it depends on the build, location and type of driving.

My own experience is nothing moves more air than an OE 7 blade fixed fan with the most pitch you can find, HD fan clutch and shroud. The down side is they they take a fair amount of room due in part to the thickness of the clutch, require a lot of belt wrap or 2 belts and make a fair amount of noise due to the amount of air they move. They also take the most HP to turn when the clutch locks up.....but if the engine starts to heat up do you really care?