Outer Limits 4x4 Board

i have a hilux that im building up and im putting the radiator in the rear which is out of a 100s landcruiser should i run twin or a big single thermo to keep it cool any advise would be great

cheers justin

IMHO the rule of thumb is, you should use the biggest fan you can physically fit. And then if there is still room for a second, fit a second.

Basically one 16-inch fan will move about the same amount of air as two 14-inch fans. The only thing is that in your case, with the rad in the rear, you are completely stuck if your fan dies, because you can't rely on air flow from driving at highway speeds to keep your engine cool.

Here's some info to compare air flow from different sizes: http://www.daviescraig.com.au/documents ... _specs.pdf

But then some fans are claiming heaps more; this one is a high-rpm 16" claiming 3600cfm, nearly double what Davies-Craig claim for their 16" model. It would have to be very noisy but at least there are options for better cooling if the fan you choose turns out to be a bit too weak.

I think with a rear-mounted one you'd want a well designed shroud and to space the fan(s) away from the radiator a bit, not have them mounted hard against it.

Thinking about this more, I think maybe for a rear-mounted rad it would be good to run a dual-temperature fan switch and run the fan(s) at low speed and high speed depending on how hot the engine is getting, just so the fans have a longer lifespan.

i have two 16 inch fans on mine i think there 16 never gets hot i have sd33t

stokedapollo wrote:i have two 16 inch fans on mine i think there 16 never gets hot i have sd33t

Two 16" fans would be pretty huge! I doubt you would ever have to worry about overheating.

You can't go past the AU-BA-BF twin thermo setup..
Available new for as little as $100 if you look around.

Here's a set on Ebay for $165.

http://cgi.ebay.com.au/Ford-AU-Falcon-F ... 240%3A1318

Jas.

yeah not 100% sure they are 16's
but think they are
could be 14's
but yeah i have no probs at all
i used to live in the hills etcand drove it hard and never gothot
i havenever had it go past the half way mark really
even hot day stuck in traffic

sorry but i also forgot to say that its a commodore v6

Be very careful of the way the fans you are proposing are rated and how your shroud is constructed.

Factories do lots and lots of engineering work, and masses of testing both on the dyno and in the outback/death valley etc to ensure there is adequate performance from a cooling system.

I've seen lots of cars with thermo fans fail to deliver under challenging circumstances, including hiluxes with commodore conversions.

Having seen the way that davies craig rate some of their products, I am suspsicious that they aren't always going to deliver what it looks like they can. (see note below) SPAL, I m aware, offer very good data on their fans' performance.
Personally, I wouldn't use davies craig unless I had a massively overengineered cooling system and could get away with poor fan performance.
That's not going to be the case with a V6 in a hilux though - that engine bay gets full and they have a small frontal area.

You need to shroud the fan so the whole radiator is being utilised, and bear in mind that trying to match the flow of a mechanical fan at high engine speed with an electric fan is very hard.

You may need to look at 2 stage fan control - stage one from 85-90 deg maybe, and second stage from 90deg up - with a 16" puller for normal use and a 16" pusher for "boost" Running both all the time might make for unsustainable current draw and mind-numbing noise - I've certainly heard a SPAL 16" inch puller in operation and it was LOUD.

That AU setup is the business - but on an AU radiator, where it fits the way ford intended and pulls the whole radiator. Also, sure, the ebay item will work for a while or help someone fix up their $1500 junker ex taxi, but will it perform after being full of mud, or after a hit with the pressure washer? I dunno...

Note re davies craig - (did you know their electric water pumps have a quite short rated life - 1500hrs from memory - that's only a couple of years for the average car... now bear in mind the consequences of electric water pump failure - tha's not a leak, that's a total loss of flow without warning. Odds are that's going to result in engine destruction - electric water pumps are cool - I'm running them in my 660 cc engined suzuki, but I'm not running Davies Craig.... I'm just not sure they are up to Original Equipment quality.)


Just some thoughts to bear in mind.

Steve.

Im running a commo v6 in a suzuki truggy and have had great success with a magna 2.6 radiator which is mountd in the rear also.I run the standard electric fans and the temp has never gone above 90 deggrees c.

want33s wrote:You can't go past the AU-BA-BF twin thermo setup..
Available new for as little as $100 if you look around.

Here's a set on Ebay for $165.

http://cgi.ebay.com.au/Ford-AU-Falcon-F ... 240%3A1318

Jas.

I like these too. I would be tempted to grab the matching radiator as well, because it would have to be easier to mount them to it.

But going back to what I was saying before, remember that for any given manufacturer, their 16" fan is going to be approximately as effective as two of their 14" fans.

Do you happen to know the dimensions of the AU fans... I mean the whole shroud etc?

I had a set of these and a matching radiator in an EB2 XR8. Definately worth grabbing a matching rad as it has the mounting points cast into the plastic and the fans and shroud slid into place on it.

EL-AU were single speed fans, EF were dual speed. 3 wires per fan instead of 2. Have long sold the car so don't have any dimensions sorry Chimpy. Were reasonably shallow though and made the car much easier to work on. Do have some pics at home of the fans out of the car.

Side issue, as I posted in the Auto Elec section, it isn't hard to make the one-speed fans into two-speed fans if you need to, it just involves a very cheap and easy trip to a local Pick-a-Part sort of wrecker.

Funny the earlier falcons had dual speed fans when later ones didn't...

There is also a few kits going around for PWM control of electric motors including engine fans, so you could have fine adjustment from slow to max speed using a simple pot.

chimpboy wrote:

want33s wrote:You can't go past the AU-BA-BF twin thermo setup..
Available new for as little as $100 if you look around.

Here's a set on Ebay for $165.

http://cgi.ebay.com.au/Ford-AU-Falcon-F ... 240%3A1318

Jas.

I like these too. I would be tempted to grab the matching radiator as well, because it would have to be easier to mount them to it.

But going back to what I was saying before, remember that for any given manufacturer, their 16" fan is going to be approximately as effective as two of their 14" fans.

Do you happen to know the dimensions of the AU fans... I mean the whole shroud etc?

How thick are these? Will they fit between the rad and a 4.2 petrol?

Dave

CruiserPatrol wrote:

chimpboy wrote:

want33s wrote:You can't go past the AU-BA-BF twin thermo setup..
Available new for as little as $100 if you look around.

Here's a set on Ebay for $165.

http://cgi.ebay.com.au/Ford-AU-Falcon-F ... 240%3A1318

Jas.

I like these too. I would be tempted to grab the matching radiator as well, because it would have to be easier to mount them to it.

But going back to what I was saying before, remember that for any given manufacturer, their 16" fan is going to be approximately as effective as two of their 14" fans.

Do you happen to know the dimensions of the AU fans... I mean the whole shroud etc?

How thick are these? Will they fit between the rad and a 4.2 petrol?

Dave

approx (ignoring brackets) 680w x 450h x 95 thick