Thermo fan instead of clutch fan

[burnsie]

Hey has anyone replaced there motor driven fan with a large or even twin thermo fans do you get much more power or any other benifets

[Downunder35m]

No need.
The fan runs from the engine keeping the coolant at normal temp.
Electric fans use power from the system and unless you plan on big trips through the dessert I see no need.
Other thing that you will need proper mounts for the fns to cover the radiator, ther is no use of the fans if they just sit without it behing the radiator.
And for water crossings you need fans that can be turned off, pkus they must be fully submergeable - expensive

[Pauly Faulkner]

Going from a Viscous clutch fan to electric won't gain any performance from the engine. If the viscous clutch is stuffed then an electric setup is cheaper then buying a new viscous clutch but with side effects such as no aftermarket shrouds for electric fans(although a 15"-16" might strap to existing shroud with some effort) and most elec fans don't agree with being submerged in water.

[burnsie]

Awesome info thanks guys

[RedSector]

Hey has anyone replaced there motor driven fan with a large or even twin thermo fans do you get much more power or any other benifets

Going from a Viscous clutch fan to electric won't gain any performance from the engine...... and most elec fans don't agree with being submerged in water.

I have Thermo Fans for the last 2 years and they seem fine with water.... Granted mine turn off after hitting water within 1-2 sec and I have had the manual override running and they have run while wading through water near to bonnet height (yeap - my bad). Mine Thermo's still draw same amount of amp's they always do and never had any issue with them. They were not expensive either but are fully sealed type been under water / mud 32 or so times and copped sea salt spray.

In regards to run time - mine are set to turn on @ 82.5 and shut off 10 degress lower. They run if the air-con is on and cycle with it. They have manual override and I have a light inside that lets me know if they are turning (on). In practice they very rarely run with air-con off, basically if the car is moving @ 10-15km's hour and not reving the shit out of it.... they dont run. Worst case is a very hot day and stuck idle in traffic they are unable to lower the car below 80 and hold it there.... once you start moving not long and they shut down.

I just wonder if what you say paul in regards to thermo's is just popular myth of 4wd's rather than real fact ?

Also there would be very small HP Gain (there has to be) maybe in the range of 0.5 - 1 HP that under argument would be chewed equally in the electrical system when and if they thermo's are running. Whereas the Viscous clutch fan chews 0.5 - 1 HP all the time.

Hope this helps - I know, what I'm saying does not follow anything I've ever been told either, just saying to my knowledge they work fine I dont claim any more power can be felt but I will claim the engine has less vibration as it did with with viscous clutch fan.

[hootnah]

I have Thermo Fans for the last 2 years and they seem fine with water.... Granted mine turn off after hitting water within 1-2 sec and I have had the manual override running and they have run while wading through water near to bonnet height (yeap - my bad). Mine Thermo's still draw same amount of amp's they always do and never had any issue with them. They were not expensive either but are fully sealed type been under water / mud 32 or so times and copped sea salt spray.

In regards to run time - mine are set to turn on @ 82.5 and shut off 10 degress lower. They run if the air-con is on and cycle with it. They have manual override and I have a light inside that lets me know if they are turning (on). In practice they very rarely run with air-con off, basically if the car is moving @ 10-15km's hour and not reving the shit out of it.... they dont run. Worst case is a very hot day and stuck idle in traffic they are unable to lower the car below 80 and hold it there.... once you start moving not long and they shut down.

I just wonder if what you say paul in regards to thermo's is just popular myth of 4wd's rather than real fact ?

Also there would be very small HP Gain (there has to be) maybe in the range of 0.5 - 1 HP that under argument would be chewed equally in the electrical system when and if they thermo's are running. Whereas the Viscous clutch fan chews 0.5 - 1 HP all the time.

Hope this helps - I know, what I'm saying does not follow anything I've ever been told either, just saying to my knowledge they work fine I dont claim any more power can be felt but I will claim the engine has less vibration as it did with with viscous clutch fan.

Intelligent well stated response i reckon.
Cheers, Jim.

[Pauly Faulkner]

All good points Redsector
A viscous clutch drive fan would be lucky to even use around 0.2hp of mechanical energy under normal conditions, when overheating and viscous coupling fully engaged or stuck then maybe you might see upwards of around 0.5hp, if you're clutch fan packs it in or you go 4wding during summer alot with the air con running then electric is the way to go(i most likely will when mine gives in) but as a performance upgrade i can't see it being worth it for a mere <0.5hp.

[RedSector]

All good points Redsector
A viscous clutch drive fan would be lucky to even use around 0.2hp of mechanical energy under normal conditions, when overheating and viscous coupling fully engaged or stuck then maybe you might see upwards of around 0.5hp, if you're clutch fan packs it in or you go 4wding during summer alot with the air con running then electric is the way to go(i most likely will when mine gives in) but as a performance upgrade i can't see it being worth it for a mere <0.5hp.

Where do you get your figures <0.5hp = 377 watts ... nope as mechanical engineer unless proved wrong by another one I stick to what I gave as the figures for my engine 6g74 DOHC (0.5 to 1 hp). lol wonder why they lighten flywheels and cam sprockets for 0.5hp (I think my figures were well and truely conservative estimates of power loss, yours are too low)

Anyway this isnt the reason to do it.... vibration is. I rather have 7900 rpm without a viscous clutch fan than with one .... what a mess they make when they fly off. ooooh ouch!

[Stevie-Ray]

There's a couple of advantages of thermo-fans (disregarding the Hp/Kw loss/gain debate which imho is in favour of thermos), if you can find or build a controller, you can tailor the on/off temps as well as isolating them for fording. Also while the viscosity drops at lower temps, there is still some drag & the viscose-fans still place a small load on the engine (if you don't think there's any in freezing weather, I dare you to stop fan-blades with your hand!), plus as they take a while to cool down, the blades can flex enough to reach the radiator when suddenly dipped in a river!
Always helps if you obtain the fan/s & controller cheap 2nd-hand!

Steve

[RedSector]

Also you can deal with heat soak with thermo's

[JayRome]

speaking from experience, yes there is a slight noticeable difference with having a clutch fan vs thermo's (with a temp controller)

yes there is a slight increase of response while driving (manual Paj though, auto wont see any difference)..

engine comes up to operating temp faster in cold weather..

A/C on a very hot day seems to work a lot better (40+ deg Melb heat)..

they drop radiator temps faster then clutch fan..

a S*&T load easier to change belts on the side of the road in an emergency..

they may take a lot more load from the electronics of the car, but only at idle speeds. once rpm rises the Alternator comes to full efficiency and replaces the loss. thermo's are almost never running while at cruising speeds unless ambient temps are high..

my actual set up:

[Stevie-Ray]

speaking from experience, yes there is a slight noticeable difference with having a clutch fan vs thermo's (with a temp controller)

yes there is a slight increase of response while driving (manual Paj though, auto wont see any difference)..

engine comes up to operating temp faster in cold weather..

A/C on a very hot day seems to work a lot better (40+ deg Melb heat)..

they drop radiator temps faster then clutch fan..

a S*&T load easier to change belts on the side of the road in an emergency..

they may take a lot more load from the electronics of the car, but only at idle speeds. once rpm rises the Alternator comes to full efficiency and replaces the loss. thermo's are almost never running while at cruising speeds unless ambient temps are high..

my actual set up:

Was hoping you'd respond to this thread to hear your feedback, as I'm planning to do something similar with a single 16" fan (ebayer had bought it but had abandoned project), & the Pivot twin-fan controller I bought from seller who just listed it as a temp-gauge, but after a bit of research!
Also will make a cowling with sloped-ends & a bit of space between blade-ring & radiator-fins to reduce noise & improve air-flow. Another thing that can help are bonnet-vents, so I've just picked up some Ford Sierra-Cosworth style vents (will also help with extractor-heat).

Steve

[RedSector]

Was hoping you'd respond to this thread to hear your feedback, as I'm planning to do something similar with a single 16" fan...
Steve

Can I say you might want to go with two fans rather than one.... that way if doing some swimming and you are unlucky enough to blow one... well still have one to go and some time to replace it .... just a thought.

[Stevie-Ray]

Can I say you might want to go with(2) fans rather than one.... that way if doing some swimming and you are unlucky enough to blow one... well still have one to go and some time to replace it .... just a thought.

The motor like most thermo-fans, is brush-less(?) & sealed to be water-resistant, but I might do a little bit tank-testing to be certain.
As for fitting twin fans, the 16" fan's blade-ring is about the same diameter as the std engine fan, so squeezing in a pair is out of the question!



Steve

[JayRome]

Can I say you might want to go with two fans rather than one.... that way if doing some swimming and you are unlucky enough to blow one... well still have one to go and some time to replace it .... just a thought.

Agreed...

i have had one fail on my Galant (after 5 years of daily use though) with the same set up as my Pajero, with the same fans, and the single unit still had enough flow to handle the large 3core racing rad and keep my temps normal..

i would never trust a single electric rad fan on our cars.. but if you are going that way, id suggest having a back up switch for the A/C fan or installing a space front fan next to the A/C fan as a back up...