17 replies to this topic

[Punchy]

Guys, I'm starting to get to the fun part of my build, ( apologies for not posting more about it..) however I'm curious about engine fans. I've seen some talk about Ford AU electric fans being fitted up but haven't found a lot on the installation and success of the fitment.

 

Are these fans a viable fit up and will they keep angry 308's cool?

 

Does much stuffing around have to be done to fit them.?

 

 

Cheers

 

(Yea ill put some picks up shortly as well.)

Edited by Punchy, 30 July 2015 - 10:40 AM.

[Redslur]

Ford Mondeo ones are a better and easier fit.  And kept my angry 355 cool.  You can buy them off Ebag for about $180 delivered.

[GMH-01X]

G'day Scott
Check out this thread on the AU thermo fans, there is some pics of how they are fitted

http://www.gmh-toran...you-mount-them/

[yel327]

I noticed Ingram/Ashdown sell the whole setup new cheap.

[TerrA LX]

Got links?

[yel327]

It was actually www.speedyairspares.com.au not Ingrams.

 

I can't post anything here including links for some reason, but go to THERMO FANS, on pages 2 and 3. Cheap as.

[Punchy]

Thanks for the info guys. Twin Au fans Incoming!

[Punchy]

Done. Sweet as!

[76lxhatch]

Motor vehicles have used alternators rather than generators for many decades now.

You don't "hope" that your fans are on or off, you run an appropriate thermostat. If fan cooling is needed there is no way around that regardless of what type of fan you're using - although you could install an override switch on electric fans.

Any component in the vehicle can fail or cause adverse side effects if not correctly installed, electrics are no different. You could make a similar list of reasons why your brakes might fail, but they don't because you (hopefully!) keep them in good order.

The most efficient engine driven fans are generally the large clutch type, these move a lot of air (when hot) but the major drawback is not the parasitic power loss, its that they are not suitable for quick acceleration or high RPM - when you have one fold up into the radiator you'll start thinking about alternatives.

[Bigfella237]

Any fan, be it engine-driven or otherwise, is useless when the vehicle is moving more than a slow crawl anyway. If you want to do the math, let's say a 14" fan moves 600 cubic feet of air per minute (note that this rating is subject to a few variables like supply voltage and air density).

 

14" diameter is roughly 1 square foot in area, so 600 feet of air passes through the fan per minute, which equals 6.82 mph or roughly 11 km/h.

 

If the vehicle is moving through the air any faster than that then the fan starts to become a liability as it (and its shroud) now impedes air flow through the radiator. That's why decent quality fan setups will include trapdoors in the shroud, which allow extra air through the radiator when the vehicle is at speed but are sucked close by the fan(s) when stationary.

 

 

But the statement...

 

“Under-hood temperatures are affected by your choice of fan type and switching from a mechanical to an electric fan raises the temperature all around the engine bay as the cooling is only working when the water temperature is high.”

 

...is a load of crap anyway, assuming everything else is working as designed, it's the engine's thermostat that controls the operating temperature, not the fans.

[TerrA LX]

Just when you thin k you haven't seen it all, FMD the best working radiator is un shrouded.
As some have mentioned, a fan is only needed at idle and low speed such as traffic crawl.

[ls2lxhatch]

But the statement...

“Under-hood temperatures are affected by your choice of fan type and switching from a mechanical to an electric fan raises the temperature all around the engine bay as the cooling is only working when the water temperature is high.”
 
Do you know if its true?
 
anyone?

 
...is a load of crap anyway, assuming everything else is working as designed, it's the engine's thermostat that controls the operating temperature, not the fans.

 

 

The statement is talking about under-hood temperature not engine temperature. 

 

When the car is stationary and the electric fan has switched off the engine temperature will be stable however the under-hood temperature will rise as there is no air circulation. A mechanical fan will always be circulating some air though the engine bay so the under-hood temperature when the car is stationary will be lower.

 

An electric fan with a speed controller linked to the coolant temperature can typically be configured to kick in at low speed soon after the car stops which will minimise the difference if you are concerned about under-hood temperatures.

 

 

[Bigfella237]

I did miss the distinction but I doubt it makes much difference.

 

At idle an engine-driven fan is doing bugger all unless you're sitting there with the motor revving (which in itself introduces new problems such as raised exhaust manifold temps etc.), that's why air conditioned cars run the thermo fan whenever the a/c is on, regardless of whether the car has a mechanical fan or not, because the mechanical fan isn't doing anything at idle.

 

Even less so for a fluid-clutch fan which is basically freewheeling most of the time, the only time they actually drive is under the same conditions that an electric/hydraulic fan would be running anyway.

 

The whole thing is a moot point anyway, if you're that worried about under-bonnet temps then fit a cold air intake, problem solved!

[76lxhatch]

As above the engine bay temperature can be affected by how the fans are used/controlled, doesn't really have anything to do with the type of fan. I would suggest that exhaust would be the first thing to address if the engine bay temperatures are too high (but there is no issue with coolant temp).

Generators and alternators are different things, not interchangeable colloquial terms for the same.

[Bigfella237]

Just watched an interesting YouTube video where they did an engine dyno comparison of some popular types of engine-driven fans...

 

 

[spoiler alert below]

 

The best fan they tested took 14 horsepower to drive and the worst took 30 horses! That was only spinning the engine to around 5500 RPM, they reckoned you would see a much larger number at higher revs but also reckoned this power draw would likely remain constant no matter what engine it was fitted to?

 

They also tested without a fan shroud and it was several horsepower less draw than with the shroud, but I suppose it would be drawing air around the radiator instead of through it too so less actual cooling efficiency?

 

So, how much does an electric fan draw?

 

According to google, 746 watts = 1 horsepower, at say 14 volts (with the engine running) that's just over 53 amps... most cooling fans don't draw that much (even allowing for motor inefficiencies of 10-20%).

 

So even if you're running 10 electric fans they would still draw less power than 1 of the best engine-driven fan tested!