9krpmrx8's Boost Build Thread
#2553
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![TX](https://www.rx8club.com/images/icons/tx.jpg)
The measurements of the factory fan shroud assembly is about 26.5"W, 15.5"H, and a depth of 4.2 inches. The fans them selves are 12" units, and Fan #1 draws 11.4 amps, and fan #2 about 7 amps at full tilt. My Mizu's are 11" and I just learned they push about 1850CFM but there is no amperage info available.
So, I was looking through the Jegs catalog and found this winner
The dimensions are perfect just like the Flex-a-lite setup and they flow 2600CFM while pulling 12.4 amps per fan.
http://www.jegs.com/i/JEGS+Performan...2116/10002/-1#
So, I was looking through the Jegs catalog and found this winner
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
http://www.jegs.com/i/JEGS+Performan...2116/10002/-1#
![](http://www.jegs.com/images/photos/500/555/555-52116.jpg)
#2555
SARX Legend
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iTrader: (46)
It's only about a 7 amp increase over stock, I hope adding these fans doesn't cause too many problems. I am already thinking of going with the high amp Alternator Canary is running.
#2557
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![TX](https://www.rx8club.com/images/icons/tx.jpg)
Here's what I run.....16" single fan 3630CFM 10 amp draw......
http://www.summitracing.com/parts/HFM-ZFU16S/
http://www.summitracing.com/parts/HFM-ZFU16S/
Damn, 3650CFM.............. Did you make a shroud or do you just run it on the rad as is?
#2558
Modulated Moderator
iTrader: (3)
In reality the shroud makes things worse at speed...and the fan is only on when the car is going slow......and with that much flow and that big it isn't a concern
The thing I like about this fan is it's low current draw.....It draws less than the OEM fans and helps give me a bit of leeway for all the other electric crap I run
#2560
Registered
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Yes there is. You have to remember Dans car is a purpose built car and he lives in a cooler climate. He doesnt spend much time idling/at low speed/ or with the a/c on ---lol. I dont think he even has a/c......
Still its a great find for a fan!
But the weakness of a single fan set up is the area of coverage. he only has 16 inches of coverage while two 11 inch fans for example has 22 inches of coverage. You want to cover as much of the radiator as possible with air flow--the bigger the fan coverage the better. yes to can place a good shroud on there to help with that but then the stroud would restict airflow when the car is at high speed. A 2 fan set up is better for a street car with air conditioning.
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
Still its a great find for a fan!
But the weakness of a single fan set up is the area of coverage. he only has 16 inches of coverage while two 11 inch fans for example has 22 inches of coverage. You want to cover as much of the radiator as possible with air flow--the bigger the fan coverage the better. yes to can place a good shroud on there to help with that but then the stroud would restict airflow when the car is at high speed. A 2 fan set up is better for a street car with air conditioning.
#2561
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![TX](https://www.rx8club.com/images/icons/tx.jpg)
I run it mounted like it is.
In reality the shroud makes things worse at speed...and the fan is only on when the car is going slow......and with that much flow and that big it isn't a concern
The thing I like about this fan is it's low current draw.....It draws less than the OEM fans and helps give me a bit of leeway for all the other electric crap I run
In reality the shroud makes things worse at speed...and the fan is only on when the car is going slow......and with that much flow and that big it isn't a concern
The thing I like about this fan is it's low current draw.....It draws less than the OEM fans and helps give me a bit of leeway for all the other electric crap I run
#2563
SARX Legend
Thread Starter
iTrader: (46)
To single fan or dual, that is the question...............................
I do believe the shroud is restrictive at speed, my GF's Mazda3 S has little flapper doors in the shroud that open up at speed so I am guessing Mazda knows this as well.
I do believe the shroud is restrictive at speed, my GF's Mazda3 S has little flapper doors in the shroud that open up at speed so I am guessing Mazda knows this as well.
#2569
Registered
iTrader: (3)
guys--come on--think a bit.
Why have a shroud in the first place? What does it do?
Why is high speed cooling parameters different than low speed parameters? How are both addressed?
How does air flow "work" through a radiator? What makes the air go from one side of the rad to the other?
What restrictions are there or could exist that impedes radiator air flow?
To be fair cooling systems are complex and there is much more to how they work than just air flow through the radiator. But for the sake of what we are speaking about now lets just focus on that part.
The correct summations after all those questions are answered will tell you why a dual fan shrouded radiator is the best for a street car with airconditioning.
Why have a shroud in the first place? What does it do?
Why is high speed cooling parameters different than low speed parameters? How are both addressed?
How does air flow "work" through a radiator? What makes the air go from one side of the rad to the other?
What restrictions are there or could exist that impedes radiator air flow?
To be fair cooling systems are complex and there is much more to how they work than just air flow through the radiator. But for the sake of what we are speaking about now lets just focus on that part.
The correct summations after all those questions are answered will tell you why a dual fan shrouded radiator is the best for a street car with airconditioning.
#2570
what was I thinking
iTrader: (8)
so let’s think outside the box for a min and help me understand....please ![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
if you have a 12 inch fan without shroud then the fan is pulling air through only a % of the surface area where as a shroud allows you to pull air through 100% of the surface area....right so far?
so if you take 2 shrouded fans that move, let’s say, 1000cfm each through 100% of the area. why couldn’t you have a double win..... lose the shroud, up the CFM and it will work out that the volume of air contacting the rad just over say 80% but you will gain more flow at speed (which in my case I spend most of the daily driver time...50mph and up)
now I can understand that you could see a very small drop in efficiency due to the % of surface area in contact with cool air but hell if you can up the CFM by 30%....well you get the idea.
Please correct me as this is just theory in my head
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
if you have a 12 inch fan without shroud then the fan is pulling air through only a % of the surface area where as a shroud allows you to pull air through 100% of the surface area....right so far?
so if you take 2 shrouded fans that move, let’s say, 1000cfm each through 100% of the area. why couldn’t you have a double win..... lose the shroud, up the CFM and it will work out that the volume of air contacting the rad just over say 80% but you will gain more flow at speed (which in my case I spend most of the daily driver time...50mph and up)
now I can understand that you could see a very small drop in efficiency due to the % of surface area in contact with cool air but hell if you can up the CFM by 30%....well you get the idea.
Please correct me as this is just theory in my head
![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
Last edited by houstonrx8er; 05-31-2012 at 01:01 PM.