Thermo Fans

[R32 Zilla]

Before Summer hits Iam am very keen to upgrade my thermo fans so they actually work. A few years ago my clutch fan died and instead of paying the $400 plus to get a new one (wouldnt trust a 2nd hand one), I fitted 2 davies craig fans with no shroud. Of course this set up is just not up to the task and I know why.

I have searched and I understand the pros and cons of clutch fan v thermos. Iam really determined to make thermos work and Iam willing to spend the time and $$ to achieve this.

Id like to hear from those who have got good results from them and how you did it. Id like to keep temps at mid to high 80's on the dyno and in staging lanes ect on warm days.

I was going to buy some EL/EF ford thermos which come with a shroud and apparently have been used on skylines before. But after measuring it up it seems they are just too big to fit?

Thanks

Tim.

[TiTAN]

Have you upgraded the radiator?

[R32 Zilla]

No I have the standard radiator. I think it is up to the task with a decent fan set up. I dont really circuit race the car which by the way is a 32 GTR with about 310 rwkw. I do events like hill climbs and drags etc. If I was to upgrade the radiator there definitely would be room for a set up such as EL thermos. Iam open to suggestions though.

[TiTAN]

you can only push a standard radiator so far, considering that a replacement radiator is not that expensive its worth looking into.

[R32 Zilla]

yea I have considered it but what do I do then? Much less chance then of making a decent thermo fan setup fit due to the extra core thickness. Or does someone know of good thermos that will fit a 32 GTR on a thicker then standard radiator?

If all else fails i will just have to pay for a new clutch fan and i will upgrade the radiator then.

[Ceffy]

I upgraded to a 40mm triple core radiator and I rarely see temps above 85degrees on the street, only use the clutch fan with no shrud.

[blind_elk]

you can only push a standard radiator so far, considering that a replacement radiator is not that expensive its worth looking into.

The standard radiator is fine. I had a single 16" (unshrouded) on my 32, and it proved less than useless. 1 lap around Winton, and the engine would be boiling (despite the thermo working because it was over its set temp). After I put the standard fan back, I could do 4 laps at QR with only a minor increase in engine temps.

The problem with using thermos is getting the air to flow through the radiator. A factory fan, because it is always spinning and drawing air, achieves this. To get a set of thermos to work, you need to design the setup so that you direct all the air into the radiator, &/or create a low pressure region inside the engine bay so that air has to go through the radiator.

[JustinP]

Can I ask you a question - do you think it is worth taking off the clutch fan? Did it make much difference to the way the engine revs etc?

I changed my timing belt the other day and discvered my radiator was screwed (which will explain my high temps on hot days). So basically I am going to get a 40mm triple core radiator, and I wias thinking while I was at that I would like to get a thermo fan to replace the clutch fan.

I know a thermo fan is not match for the clutch fan, but I was thinking if i could somehow keep the shroud and made a thermo fan fit within it it just might cool the radiator sufficiently. Would be nice to get that reciprocating mass out of the loop

Before Summer hits Iam am very keen to upgrade my thermo fans so they actually work. A few years ago my clutch fan died and instead of paying the $400 plus to get a new one (wouldnt trust a 2nd hand one), I fitted 2 davies craig fans with no shroud. Of course this set up is just not up to the task and I know why.

I have searched and I understand the pros and cons of clutch fan v thermos. Iam really determined to make thermos work and Iam willing to spend the time and $$ to achieve this.

Id like to hear from those who have got good results from them and how you did it. Id like to keep temps at mid to high 80's on the dyno and in staging lanes ect on warm days.

I was going to buy some EL/EF ford thermos which come with a shroud and apparently have been used on skylines before. But after measuring it up it seems they are just too big to fit?

Thanks

Tim.

[R32 Zilla]

If your clutch fan works fine now id probably just stick to that. Its only that mine started locking on and making some bad noises that I tried thermo fans.

Like I have said a new clutch is very expensive and that is part of the reason why Iam am trying to make thermos work. The other reasons are the slightly better throttle response and accelerartion/power they give. I know some will say that it would hardly be noticable but I believe it is. They are also quieter overall and tidy up an engine bay.

I would think no single electric thermo fan would work good enough in the standard shroud. As blind elk said The problem with using thermos is getting the air to flow through the radiator. From what I have read and found out the best set up is a complete dual fan and factory shroud setup from another car such as an EL falcon. I just want to hear from someone who done this or seen it done with good results.

[Psymon]

I've noticed a company on eBay selling aluminium radiators that have aluminium shrounds and twin thermo fans on them already. Meant to be a complete bolt in setup. If anything it at least looks neat... couldn't really comment on performance though. I can't get a link atm because it's blocked at work but if no one else has found it by the time i get home i'll find one.

[juggernaut1]

Not directly on point but this is my SR setup using AU falcon fans with shroud and an A.R.E. radiator - I use low speed and high speed settings based on temps which are programmed into the ECU (Autronic). Temps generally around 82-84 degrees and up to 90 with aircon on in 40+ degree ambient air temps in traffic and using standard T-stat.

My brothers 509 rwhp Commodore also survives with its stock twin thermo fan setup, aircon and 150mm intercooler.

So clearly thermo fans have the ability to regulate temps of highish hp cars....I believe the trick is to ensure you have shrouded thermos and try to seal the shroud to the radiator with sponge rubber or similar so that it draws the air through the rad.....just like the manufacturers do.

A vented bonnet would also increase the efficiency of any cooling system by creating a low pressure zone behind the rad just like all factory Evo's.

Edited September 28, 2009 by juggernaut1

[R32 Zilla]

Looks great juggernaut1. I wish I had the room that you do. Could you tell me the dimensions of the shroud and fan? especially the depth/thinkness as that is where iam most short on space.

Thanks

Tim.

[juggernaut1]

Looks great juggernaut1. I wish I had the room that you do. Could you tell me the dimensions of the shroud and fan? especially the depth/thinkness as that is where iam most short on space.

Thanks

Tim.

Have to get back to you on the dimensions of the shroud. Fans are 2 x 12 inches.

[tridentt150v]

I had a CD thermo fan on a hilux with a supercharged v6 commodore motor, it worked really well. I made up my own shroud and mounted the fan on it, but found that complete cover and no cover was not as good as a half cover, don't know why, but the temps liked it better, especially on long uphills in low range 4wd where the motor was revving and pulling at low speeds for a while.

I thought they worked fine as long as you set them up right.

[TiTAN]

i have a single 16" thermo hanging off the back of a 50mm radiator no heat issues so far and the fan only ever comes on if you are sitting ilde for a while. (ecu temp controled)

[Simonster]

Its an interesting topic. I didn't realise people were having drama's with thermo's.

I run an RB25 in an S13. I had A.R.E make a dual pass,cross flow 42mm radiator that sat under the radiator support due to the room restriction of the RB.

Initially i ran a Davies craig 16inch thermo (~1900cfm) with no shroud, it couldn't pull the heat out of it while stationary- very frustrating. I then ducted the radiator to force all the air through it. Better, but still high 90's. Fitted a 16inch SPAL (3000cfm) fan & pulled out the aircon and BAM no heating issues. It sits on 79C on the highway (Autronic) I can do 5 flat out laps of QR and it sits solidly on 90, on the cool down lap i'll enter turn 2 and the temps will be back at 80!!

i also have a vented bonnet.

Whats my point? Give the radiator the best chance to cool, it has a hard time as the inlet charge has to go through your intercooler which takes a lot of speed and temp out of it, then the aircon core, slowing and heating it fruther still then finally it gets to your radiator. Ducting will force the air through the core as air will take the easiest route and go anywhere BUT through your core. Otherwise on a street car, if you still have temp issues i'd say you have bigger issues.

I have the thermo set to come on at 85 and off at 82. It's never on while driving around the streets.

Hope that helps

[mad082]

other factory thermo setups you could look at trying would be those off a later model v6 magna, or those off a smaller car such as a pulsar or lancer.

[R32 Zilla]

Some good stuff on here:

http://www.a1electric.com/spal/faninfo.htm

http://www.a1electric.com/catalog/cat_spal.htm

I wonder if the big 3000 cfm 16 inch fan would do the trick on my standard radiator. It would cover 3/4 of it. I then also have the option of leaving one of my davies craig 10inch fans in the space that is left. I would have to keep the standard readialtor though for it to fit and even then it would be tight.

Ultimately I would get this but its a bit too big i think.

http://www.a1electric.com/Merchant2/mercha...de=30102130-KIT

[R32 Zilla]

If I got the dual 12inch kit i would need to cut about 3 cm's out of the bottom of the shroud then seal it up again so no air escapes. I supose that isnt impossible.

Edited September 30, 2009 by R32 Zilla

[discopotato03]

Where everyone seems to fail dismally is that they attemp to control ENGINE temperature with electric fan/s rather than radiator temperature . The water thermostat is there to regulate engine water jacket temperature so provided the radiator contains a reserve of cooler water the system will work .

If you don't want to have a ridiculous tail chase situation then the rad temp ideally should be lower than the water thermostats opening temp .

Provided the water thermostat works properly the rad water temp could be 30 degrees and the the engine water jacket temp should be whatever the water thermostat regulates it to be . If you don't believe me drive your car around in near zero ambient temps with a mechanical fan and see what the gauge shows .

If you were going to track your car then I don't see any reason why you wouldn't run the coolong fans flat out for the hard and cool down laps .

Some of the rally people I knew had their factory fans (east west engine) run flat out any time the ignition was turned on , these did few road miles and never wore their fans out .

The factory mechanical fan works because it pulls a considerable volume of air through the core all the time . IMO the value in elec fans is that they don't have to operate when there is sufficient airflow through the radiator to keep its temp low .

In warm climates and round the burbs situations the elec fans probably have to work as well as the mechanical one to achieve the same thing .

I think the simplest situation is to use the std viscous hub and maybe a higher capacity radiator but don't overkill on the core .

Imo the single row core with the longest single tubes gives the best heat transfer for the thickness of the core . Multiple rows of tubes are a joke because each successive one cops the pre heated air from the one in front of it so the more rows the less heat transfer available . Also where there are gaps between rows there is no heat transfer from tubes to gills/fins so wasted space .

Another 2c , cheers A .