ra28 aluminium radiator & elect fan questions

[Omegaman]

Hi guys.
Just bought myself a new after market 3 core radiator for my celica ra28 build.
i hope someone out there can answer some questions regarding the setup.

here is the radiator in question and core dimensions.



Question 1. as its a 3 core is a pull through elect fan best (or push). if so what power fan and cfm eg(80w or more & 1300-1600cfm or more)???

2. flat blade fan for better flow or S shape fan for less noise.???

3. Now heres the tricky part. should i go with 2 x 10 inch fans or 1x 12 inch...14inch is too big.
these will hopefully have some sort of shroud.

this will be wired up with relay and switched with haltech ps500.

If i can get the most efficient set up done in my garage, that will be great.

fyi.. i also asked these Q's in my build thread.

[Omegaman]

well after some searching today. i ended up answering my own questions, hope u agree.

Answer 1. i bought a push/ pull universal type fan. It is a 80w/1730 cfm. But i will have it as a pull setup.

Answer 2. i bought S shape blades, 10 blades as opposed to most being 6 blades.

Answer 3. i went with 2x 10 inch fans, as i believe they will cover more surface area of the core.

so from my calculations the 2 x 10 inch fans will cover 54% of the core & the 12 " will only cover 39% of the core.

agree?????

[Bazooka]

Where did you find a 10" fan that flows 1730cfm?
I'd definitely look at fitting a single 14" fan. Although it might cover the top and bottom tank a little it will give much better flow than two smaller fans.
Look at it this way. The SPAL (best in the business) 10" flows 708cfm so you have this over the 54% coverage of your radiator. However the 14" version flows 1864cfm over what would still cover 52% of your core. This works out to be over twice the flow of the two smaller fans.
I've always used the rule to use the largest single fan you can possibly fit. This will always give the best flow.
And a pull fan will always be better than a push type.

[allencr]

AC have/need one always on?
1, 2 & 3, are hard to go very noticeably wrong.
ECU control would have a long delay compared to a sensor on the radiator outlet when the airflow through it would need a fan assist.

[allencr]

...54%......39%...

also, except at stand still speed, that's near a 54 vs 39 restriction in airflow when it just freewheels.

[Omegaman]

Where did you find a 10" fan that flows 1730cfm?
I'd definitely look at fitting a single 14" fan. Although it might cover the top and bottom tank a little it will give much better flow than two smaller fans.
Look at it this way. The SPAL (best in the business) 10" flows 708cfm so you have this over the 54% coverage of your radiator. However the 14" version flows 1864cfm over what would still cover 52% of your core. This works out to be over twice the flow of the two smaller fans.
I've always used the rule to use the largest single fan you can possibly fit. This will always give the best flow.
And a pull fan will always be better than a push type.

hi, well the fan i bought rated at 1730cfm says at "maximum speed" so who really knows. But other 10' quoted 800cfm or so but varied in blade type and amount of blades.
i couldn't get an answer whether one fan will cope well with the 3 core radiator, so i went for the 2 fans to get a bigger surface coverage.
i watched a few youtube vids and mostly a shroud was required for single fan, but even then, the edges of the radiator did not get enough suction.
One of the main reasons i went for the 2x10' is it does cover most of the vertical tubes across the face as opposed to a 12 or 14 covering the centre only.
As this is a vertical drop radiator, cooling on most tubes seemed logical.

The 14 inch fans were to big and would overlap, but i wasnt prepared to play with the fitment. Air escaping or entering through the overlap may cause a reduced effect.
As its not a race car, the whole set up will be better than std.

Great, Pull it is...

[Omegaman]

AC have/need one always on?
1, 2 & 3, are hard to go very noticeably wrong.
ECU control would have a long delay compared to a sensor on the radiator outlet when the airflow through it would need a fan assist.

Yep, im sure the set up of 1,2,3 will be fine.
As for the ECU controlling the on/off, i dont know what could be a down fall here. As the car will be a daily, city/burbs driving, i'll probably use the ECU to switch the fan on at 70-75deg & hold it steady at 80.

[Omegaman]

also, except at stand still speed, that's near a 54 vs 39 restriction in airflow when it just freewheels.

allencer, what do you mean by that. I'm trying to picture the scenario...& effects.

[BoostBoost]

Pull through as Bazooka has mentioned. If you mounted the single 14" on a shroud which went to every corner of the radiator this would be the best setup imo. That way it draws air through most parts of the radiator. mounting it flush on the radiator will only draw air parts the area of the fan. More blades = less noise.

[Omegaman]

I see your point, but 14" seemed to big, i would then have to look at the clearance of my ATI balance and trigger system. which would then come into account.

[Omegaman]

Well since u all feel 14 " would be better. I just bought one rated at 120w as opposed to 80w, with S blades., for 35 bucks delivered. I'lol compare them when I get them early next week.
Thanks guys for yr thoughts on this. Very helpful.
If I don't show any more pics here, there will be on my build thread.

Cheers

[allencr]

Planning for the worst case scenario: like this is the cooling system for a Cop/Meter Maid vehicle. Are you?
It's just a blockage to the free airflow when you're driving, @anything over 20MPH or kilometers. They'll freewheel so the restriction will be somewhat less then your calced 59 or 34 percent. IDK by how much but it's still there, then again its still more then just the blade's area from the bracket stuff. Do not shroud them unless you really want to block the non-standstill flow.
//
DOES it or does it not have AC? They seem to like more consistency and have a dedicated cond. fan.
//

...ECU to switch the fan on at 70-75deg & hold it steady at 80.

WHERE is the sensor/sending unit for action that located?
It'll turn'em on just when the thermostat opens. At 100kph @10C during Winter they'll be running if the sensor is on the engine.

[Omegaman]

Well the end result was i fitted the 2 x 10inch fans. As these were easier and looked better, but also covered all the vertical water rails.
The paper test showed that they pulling sufficient air right across the face of the radiator.

Test fit of 14", overlaped the core, not by much, but was pretty close to the crank trigger pulley.


and the 10" fans


and the test video.
http://vid1381.photobucket.com/album...pscumbbfdx.mp4

thanks for the advise guys.

[Hen]

I really can't remember the source now, but I was led to believe that pull type fans are a little more efficient that push type. Something to do with more of the airflow produced actually going through the radiator, but I'm afraid the details are lost in the mists of time.

[Omegaman]

Im not sure what the actual solution is.
As it seems there are many variables. ie core thickness. cfm of fan, blades, regular driving conditions, shrouds. etc.
As my car never overheated with std radiator, the new one should be at least 20% better cooling on it own.
The fans can be relocated to the front if required to push type.
So i will look at it once roadworthy.
As for me, all the water tubes will be getting air pulled through them...SOOoooo who knows.

Its hard to know if push is better than pull. when the car is speeding up, more outside air is being forced in naturally.
Would this free flowing air overtake the speed & push the fans make, at some stage??? Hence now becoming a hindrance to natural air flow.??? just a thought!!!
So at least with pull type, the natural air at speeds, has already gone through the core.. Hmmm