Electric vs viscous fan

[Shane]

I've googled this topic and opinions seem to vary quite a bit.

There doesn't seem to be any definate consensus.

I'm busy dropping a D4D into my SFA Hilux.

I have the opportunity to go both ways ( wrt the topic Manny).

I'm not worried about power gains.

Which is best for low down 4x4, keeping water crossings etc in mind?

Looking forward to some solid opinions.

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[grips]

If you can, stick to the viscous. No nonsense low maintenance option.

Have found in all our V8 conversations that only state of the art electric fans like Syclone deliver effective cooling.

My son bought a SFA Hilux with a Davies Craig electric fan from Hot4cold. Had numerous overheating problems.
Hilux had a 2.8 Supra engine.

Bought a Syclone from the V8 Shoppe problem solved

https://www.flex-a-lite.com/16-inch-syc ... c-fan.html


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[Shane]

Thanks Grips.

Was kind of leaning towards the viscous (KISS principle), but wanted to hear some opinions in case I was missing something.

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[Wave]

I would stick with the viscous fan, seems to be reliable and simple

[Mad Manny]

Shane, did you not buy a complete D-4D motor?

[BushWacker]

I guess one must ask why Toyota' s design didn't provide for an electric fan in the first place ... as opposed to the
viscous fan option ?

On the Landys, Ive had to replace the viscous units on both the Range Rover and TD5 though when they went it wasn't show-stopping crisis stuff.

Normally removing viscous drive is motivated on power & economic grounds as its seen as a continuous if varying engine load ... Electric fan however spins after 2 energy transfers ... Mechanical - Electrical , then Electrical- Mechanical ...

I would keep the viscous but perhaps/maybe carry a 2nd hand electric as a spare on long trips ... but I do have a lot of space down in the basement of my canopy ...
(I also keep a used alternator etc etc there ! )

[Anthony Forgey]

The viscous fan is the better option.

Unless you go for 2 X 12" Spal electric fans
Or a ford falcon fan and shroud.

But electric fans use a lot of current and require additional wiring and fuses so my 5c is go with the viscous

[BushWacker]

Intuitively I’m inclined to stay with Viscous ... alternators are only about 65% efficient on energy conversion and then
electric fans ? maybe , at a guess, 70% ... giving about a net 50% energy loss.

The attached article however ... argues the opposite !
One argument implied below is that, at slow hot slog speeds (river trips ?!),
mechanical fans are a disproportionately big load call on the motor at the worst time...

https://wasteadvantagemag.com/studies-p ... ling-tech/

[BushWacker]

... intuitively I’m, as said, also inclined to stay with Viscous ... alternators are only about 65% efficient on energy conversion and then electric fans maybe , at a guess, 70% ... giving about a net 50% energy loss.

The attached article however ... argues for mechanical fans !
One argument implied below is that, at slow, hot, slog speeds (river trips, Kalahari sand etc ?!), mechanical fans are a disproportionately big load call on the motor at the worst time...

https://wasteadvantagemag.com/studies-p ... ling-tech/

[grips]

I have installed Toyota alternators on all my v8 Conversions as they are very compact and pushes 90A.
Only once had a problem with an electric fan and that were on the 347 V8 Yank Ranger at Donkerpoort when a hot connection on a relay prevented it to come on.

Have towed a 3 ton lathe in 40deg conditions from Upington to Kathu in mid summer. The 347 stayed put at normal.
Also done numerous dune trips in these conditions. I will not use any other fan than Syclone if there is no space to fit a viscous fan.
This is my experience with cooling engines in the Kalahari.

[Shane]

Shane, did you not buy a complete D-4D motor?

I did, but while I'm busy I considered the two options.

Have decided to stay with the viscous.

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[Shane]

Thanks for all the input guys.

Viscous it is!

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[Mad Manny]

I guess one must ask why Toyota' s design didn't provide for an electric fan in the first place ... as opposed to the
viscous fan option ?

On the Landys, Ive had to replace the viscous units on both the Range Rover and TD5 though when they went it wasn't show-stopping crisis stuff.

Normally removing viscous drive is motivated on power & economic grounds as its seen as a continuous if varying engine load ... Electric fan however spins after 2 energy transfers ... Mechanical - Electrical , then Electrical- Mechanical ...

I would keep the viscous but perhaps/maybe carry a 2nd hand electric as a spare on long trips ... but I do have a lot of space down in the basement of my canopy ...
(I also keep a used alternator etc etc there ! )

My understanding is Viscous is an 'On Demand' system, it spins faster & pumps more air when required.
Much better for that stop & stand 4x4 driving.
Removing the Viscous, in my opinion is not " motivated on power & economic grounds" but rather because the viscous clutch packs up...

[BushWacker]

Viscous unit costs less than 1 tank of petrol
and ...
in my case, lasts between 150k-300k km.

* smalltype : 'excl. labour '. ...