• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

mechanical fan vs electric?? with proof?

M

mr42ndstblvd

New member
Joined
Nov 5, 2016
https://www.youtube.com/watch?v=ZXdLgaFXZzs


so these guys tested mechanical fans on a dyno engine mule.

and there worst fan stole about 30 hp

30 hp is crazy! considering a stock 240 only comes with 120 ish stock.

id honestly like to dyno a redblock with some different fans and see what the deal is.

i can safley say on my next car i will be running electric fans from a ford crown vic.

same fans my buddy uses on his 1500 hp foxbody. if it keeps that cool it will do wonders for my next redblock.


how do you guys feel about these dyno results??
 
Clutch fan ate 7 lb/ft of torque and 14 hp.

Hopefully I'll have my efan finished in a couple weeks and A cam installed. Between those two tweeks it will feel like completely different car!
 
If you go electric...
<iframe width="560" height="315" src="https://www.youtube.com/embed/rkpsp87z5is" frameborder="0" allowfullscreen></iframe>


The most common defense of clutch fans is that they are reliable and easy to service/replace on our Volvos. Just depends on what you want the car to do.
 
TurboDenny said:
They should have dyno'd with an electric fan drawing 30 amps just to be fair.
Click to expand...

30A @ 12V = .48HP. Say you're getting closer to 14V at the fan -- .56HP. You have some inefficiency in the fan motor and the alternator/belt drive --- but even in the worst case it doesn't take more than a HP or two even with larger electric fans. And, of course, that's only when they're running at full tilt. With variable speed controllers, you're often not even pulling that much when they're running --- I have a 'speed gauge' on mine and it rarely runs at more than 1/3 speed with the A/C off.

Moral of the story -- the switch to electric pretty much eliminates all of the parasitic losses associated with the mechanical fan. Losses from rotating the weight and aero losses that increase significantly with engine speed/air moved. There's a reason that most engines have had electric cooling fans for quite some time. VW broke the ground when they turned the engine sideways in the Rabbit/Golf back in 74/5. Eventually, even the longitudinal folk followed.
 
As we are pondering losses due to the fan....

Driving down the road even at 30 mph...

If the fan is Yelling it is time to increase the size of the radiator.

The fan should only be needed in traffic or at idle.

I use the thermostatic clutched fan in the rallycar with a 'Be Cool' aluminum radiator. Have heard the fan a few times on stages but temperature has never climbed.

Clutch fan is simple and reliable + it came from the factory with one.
 
I read a similar test a long time ago.
7hp was for an unlocked clutch fan. Way higher loss when that bi-metal spring heats up and locks the hub.
 
Don't forget that the alternator is only about 50% efficient, and that's before you factor in mechanical losses which are actually quite high for a V-belt. The electric fan is still probably more efficient than the mechanical fan but I doubt the difference is dramatic. Whether driven directly by the engine or electrically the energy to spin the fan still has to come from the engine.

I would love to see a dyno comparison though.
 
Also factor in that the electric fan doesn't run all the time. Only sometimes at idle and if you're cruising on the highway it probably never needs to come on.
 
I can check when I get this light blue 240 sorted out, but unless the clutch is locked up I wouldn't expect it to be more than a couple hp between spinning the fan or not spinning the fan (I'm not going to swap an e-fan on just to see, I'll just remove the fan and run it like that for a pull or two)
 
The mechanical fan doesn't run all the time either, it freewheels with the clutch disengaged. I have seen fan clutches bind up though, and I've seen them refuse to engage at all as well.
 
This thread is hilarious.

You really think that an efan is going to suck anywhere near 14hp and 7lb/ft of torque? Who is the supplier for what y'all are smokin'? :lol:
 
thismachine13 said:
This thread is hilarious.

You really think that an efan is going to suck anywhere near 14hp and 7lb/ft of torque? Who is the supplier for what y'all are smokin'? :lol:
Click to expand...

Who said it would?

I only suggested that the mechanical fan in a Volvo likely doesn't pull anywhere near 14HP, it's tiny compared to the mechanical fan in a lot of V6 and V8 domestic cars, and the energy required to spin the electric fan is not free. I have no data to compare but I doubt the difference is huge.

The noise thing has made me consider switching to an electric fan though. The mechanical fan really roars after sitting at a light in warm weather.
 
You must log in or register to reply here.
Back
Top