Stock Radiator Fan Effeciency

[Dragonball]

Cant seem to locate this one anywhere

Anyone know what the effeciency in CFM is provided by the stock rad fan?

Checking out the pacet ones and looking to compare / improve etc etc

Cheers

Paul
:cool:

[Terminator]

AFAIK Paul, you will have a job to beat the efficiency of the stock fan. I am sure Chris Wilson will shed some light if he finds this thread.

[Dragonball]

Originally posted by Terminator
AFAIK Paul, you will have a job to beat the efficiency of the stock fan. I am sure Chris Wilson will shed some light if he finds this thread.

I know Chris likes the viscous fan - but I am interested in a total change to go with the new rad

The Pacets 2x12" HPC126 pull 3899 CFM

The flexalite 210 2x12" pull 2500 CFM

Just looking for a comparison

Cheers

Paul

[dude]

Originally posted by Paul E
I know Chris likes the viscous fan - but I am interested in a total change to go with the new rad

The Pacets 2x12" HPC126 pull 3899 CFM

The flexalite 210 2x12" pull 2500 CFM

Just looking for a comparison

Cheers

Paul

With or without the bag blocking the flow , the way you drive it makes no difference im still trying to get the stains off me seat you incontinent fool :p

John:flame Dev

[Alex]

Would have thought either www.mkiv.com of supraforums would know the answer....let us know when you do.

[Dragonball]

Ok - have used the search button ad nauseum :thumbs:

As I understand it there are the following options

Allair flows quoted by manufacturers under 'ideal' conditions

Stock fan and shroud

+ves -
Pulling more effecient than pushing
Moves a lot of air (2500CFM mentioned for a mkiii fan)
Good shroud - uses all of the rad surface
Thermostatically controlled
Good warm up time

-'ves
Uses 10 HP to run it
Takes up excess space
Ugly fecker !

Electric Fans

+ves -
Pulling more effecient than pushing
A double 12" combo can move a lot of air (3800 CFM mentioned)
Thermostatically controlled to come on at lower temps - faster warm-up
Easier access to engine
Prettier (!)

-'ves
Poor shrouding - therefore single 12" are not using radiator effeciently
Some singles 12"move a poor amount of air 1500 cfm
Uses more electrical power - can drain battery
Poor thermostat control from between the fins (needs to be water temp related)

Options

Keep stock and insert a secondary push fan between rad and FMIC (4400 cfm total)
Ditch stock in favour of 2 pacet elctrics jobbies (3900 CFM)
Ditch stock in favour of 15" pacet behind and 12 " pacet in front (4100 CFM)

Opinions please



:thumbs:

[Ian C]

How about - why do you feel you need more airflow through the rad...? :)

-Ian

[Terry S]

Ian Paul has flow problems ( no not his bag) with the Rad now he has a FMIC.

Paul knows this but FWIW I would NEVER give up a viscous now. The HP gains from electric fans are only gains when the fans are not running. When they are they probably take more horse power than a viscous. If it were me I would add a Push fan in front of the AC rad and use the existing sensor in the bottom left hand corner of the rad, this will bring the electric fan on at 97c.

[Chris Wilson]

There is no way at all any sensibly sized motor on an electric fan can move enough air to compare with the stock engine driven one. Toyota and all modern manufacturers go to IMMENSE trouble to duct and control rad and engine bay air flow, it is easy to bugger it up, very hard to improve it. You will be adding weight and restricting low speed air flow with electric fans, IMO forget all about them.

[Supraguy]

Dont meant to hijack this thread, but this discussion has me worried about some mods I have planned in the near future. One includes Hybrids and an 'R' spec FMIC. Will this intercooler block the intake to the radiator enough to worry about cooling problems?

I dont want to spend a ton of cash in mods only to be forced into cooling problems, and therfore more $$$ spending.

[Chris Wilson]

Originally posted by Supraguy
Dont meant to hijack this thread, but this discussion has me worried about some mods I have planned in the near future. One includes Hybrids and an 'R' spec FMIC. Will this intercooler block the intake to the radiator enough to worry about cooling problems?

I dont want to spend a ton of cash in mods only to be forced into cooling problems, and therfore more $$$ spending.

I have yet to see any commercially available FMIC kits that are done correctly. The ducting from the stock bumper mouth is removed in fitting all of them, which means air just takes the easy route, which is not THROUGH the I/C and rad cores. On autos with the auto box cooler in the N/S apaerture this has to go to get the I/C piping through. The FMICs all seem to block rad air flow enough to cause overheating on track days where the stock set up is fine. Removing the air con condenser rad helps, but not everyone wants to lose the A/C...

[Supraguy]

Well, my Veilside nose cone looks to have good ducting to force air into the FMIC / Radiator. Leon @ JPS should be doing the work, so going from other's feedback about them I have some confidence it should be ok. I'd just rather hear it from someone with a big FMIC like the 'R' spec and their experiences.

And no.. I dont want to lose my AC! :D

[Alex]

Fitting an FMIC will show up any problems you have with your radiator.

Best to replace you radiator and create ducting for both.

Supraguy - if your nose cose duct is flush to the FMIC then yes it may well duct ok, but its not the size of the hole that matters. Its more to do with being air tight and angled in the right way.

[Branners]

FMICs tend to cause problems with airflow to the rad on track days where the car is really pushed. I drove a Supra at Rockingham with an s-type IC and on the fast banked left hander and then on to the straight the water temperature rose sharply, through the rest of the lap it was fine, it was only when flat out on the baking that the temp rose. I didnt want to push it too far as it wasnt my car but I would suggest the FMIC was blocking the rad enough to present a problem eventually.

JB

[Terry S]

Chris whilst I agree, the fan pushing through the air con rad is a definite help.

I have an R type intercooler and have never had a cooling problem on the move with the stock viscous fan. If parked up on a hot day though my temperatures will rocket ( easily 100+ c at idle). Once moving again they drop nicely. You should ask Leon to wire the small ac fan so that it comes on at 97c whether the AC is on or not. You may find that this is enough for you. There is a wiring mod for this on MKIV.com

[Rob]

Further Hijack.

Is the stock fan really "viscous"?

When I took mine off, I was having a good look, and it has a spiral wrapped metal band that grips the shaft. It seemed to me that if it heated up it would expand and grip the shaft tightly, thus spinning the fan faster.
Couldn't see any other mechanism that that.

[Terminator]

Originally posted by Rob


Is the stock fan really "viscous"?



Yes AFAIK

[Chris Wilson]

Originally posted by Rob
Further Hijack.

Is the stock fan really "viscous"?

When I took mine off, I was having a good look, and it has a spiral wrapped metal band that grips the shaft. It seemed to me that if it heated up it would expand and grip the shaft tightly, thus spinning the fan faster.
Couldn't see any other mechanism that that.

Yes it is, `onest `injun :conf:

[Dragonball]

OK decided that I am going to keep the stock viscous and have our rad design amended so that the stock shroud etc works with it

I can always change at a later date to electrics

However I am also going to put a 'pusher' fan between the rad and I/C with a water temp thermostat (not fin temp) that will come on at higher temps

Also a refridgerator in the boot with a couple bottles champers with blue neons





:p :thumbs:

[Chris Wilson]

Not trying to be funny or clever Dick, but you need to read up on air flow through intercoolers, a fan in front and one pulling too is not good, the electric one will play hell with on the move air flow, the rad should only need a fan at all at low speeds if it's correctly sized and ducted. A puller fan is far better as it doesn't mask frontal area as an electric one in front will do. Most additional in front ones are to add air flow in traffic for the A/C condenser.

[Dragonball]

Well today I flushed the existing rad (burned my hand quite succesfully in the process I might add, village that I am...)

and topped up with good coolant and....

Still gets very hot when on a higher speed run for over 10 mins

OK around town though - so presume that the rad 'heat-sink' capabilities are gone

So def up for the new rad:(

We are going to modify the designs on these so that both the stock fan shroud and pacet electric shrouds will fit (to keep everyone happy!)

:thumbs:

Point taken Chris on the set-up any other inputs from anyone welcome

[Dragonball]

Just an update on this

Fitted our new 'Miiami-rice' radiator to mine today and re-fitted the engine under tray

Have amended the radiator design so that it works with the viscous fan and shroud

OR

With two 12" Pacet Fans (we are working with Pacet on this)

Whichever you prefer!

Fitting excellent - slightly wider than stock and has a lovely flat black top - ready for a nice bit of bling!

Result!

Temps are now 'normal' and the air conditionoiing works a treat

Also about to fit our 13 and 19 row oil coolers to the oil and tranny oil respectively -


:thumbs:

[SimonB]

Just a thought, is it possible to have 2 SMICs, with the other one on the passenger side ? Dunno how much room there is down there, but I don't remember there being much there (apart from the coolant expansion tank maybe). I guess there must be a reason why nobody does this ?