Thermo Fan

[toylica]

Hey Guys.

I have recently been thinking - after being prompted by someone whose name escapes me at the moment.

I have heard that - the viscous fan assembly and fan itself is somewhat 'inefficient'?

My question is - is it possible to remove the engine driven fan and replace it with electric equivalent thermo fans? AND will it bring any reward in the power category?

Thanks



Dave

[79GT]

the viscous fan puts load on the engine
the electric fan puts load on your alternator.

if your changing it for the power increase dont bother.
- that being said it may increase your cooling ability if your having any over heating or need the extra room in front of your engine. leave it how it is.

[lexsmaz]

I know of many people over the years who swear by sticking with the original fan assembly, ( they draw more air & work better ) as you said it is a viscous coupling so doesnt really rob much power until needed ( temp related ) but make sure it is runing the cowling too ..

The only reason i have run thermo's in the past is due to space restriction ..

[PlacentaJuan]

yes the stock hyro fan is usually more betterer / efficient (maybe because the shroud is a perfect fit??)

only reason 2j\z people do it is because the hydraulics is run by the water pump, and a hydro/water pump is 10x the price of a water only pump, so you can save some $$$$ by switching to thermos.

[Mos]

Are you talking about a hydro fan or a viscous coupling fan?

The hydros have an amazing amount of torque that can be applied to the blades, so consequently the amount of air they draw exceed any electric fan you can get.

The viscous coupled fans, however, have some slip on the coupling, so while being as large as a hydro fan, they don't appear to have the same amount of propulsion. Over time, from my experience anyway, the coupling looses tension and doesn't apply as much torque to the blades. I have never replaced one, but my impression is that it's not a lifetime part (like a block).

My preference is usually for hydro, but otherwise electric, unless you know your viscous fan is 100%.

Mos.

[Alan 4Runner]

I have an old 3Y (petrol 2L) 4 Runner and have just put a thermo in for the same reason you are thinking about.. Lots of people told me there would be little or no benefit to doing the swap..

In my case specifically, the thermo only needs to run if i'm stopped in traffic or 4x4 crawling

So, 98% of my driving is done without the thermo running and I have noticed a slight gain because there is less draw on the engine and now get an extra 15 km from each tank of juice..

It would depend on what type of driving your vehicle will encounter most and how efficient your cooling system is as to whether this swap is beneficial to your needs

Hope this is some help to you!

[frostyadonis]

your going the wrong way about it.
1st you slide the 1ggte+supra box combo in
then goes the alloy radiator
then the thermo fan, last...

[Jonny Rochester]

I have a RWD Toyota with original style viscous clutch fan.
I am wondering if anyone has any more figures/ reasons for going to electric fan in place of the viscous clutch?
Also, does anyone know of a factory race car that uses/used the viscous clutch?

Any other ideas on how it would effect dyno result or real driving acceleration?

[Jonny Rochester]

After more thought and holding these items,
I think the clutch fan is fairly heavy and a modern electric fan is fairly light and slim. So there maybe just a static weight difference. (Of interest if building a small "race" car, not an issue with bigger cars).

Also when the clutch fan is "free" there is still a fair bit of resistance with the one I have. Some that are well worn in (worn out?) may freewheel a bit better.

[river]

Hi,

I used an electric thermo fan on my set-up because of space limitations. I have another car with same engine and using the viscous fan. The viscous coupling needed a refill a few years ago, as the engine was getting hotter as the fan was slipping. Once it was refilled it was perfect again, and still is.

I don't think there's any massive performance gains by employing an electric fan over a viscous one. Maybe save a kilo here and there, maybe get an extra 300watts of power (depending upon the thermo fan you select when compared to the load of the viscous unit) and a smattering of kms per full tank.

As I said, I went electric for space, not for better performance.

seeyuzz
river