fans on the intercooler?
08-25-2004, 09:32 PM
#1
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fans on the intercooler?
hey i was on the gallery page of this site and on page 3 i found this picture and saw these fans on the intercooler. does this add any hourse power of not and if it does are they just normal fans or are they speshul engin fans?
08-25-2004, 10:02 PM
#2
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i have not seen the specific picture that you are refering to. however, i have seen a few instances where people put computer fans on there intercoolers to help keep it cooler when not moving to prevent heat soak.
it is debatable on the forums here. seems like most people think it wouldn't help any and if anything, at highway speeds it would restrict airflow over the intercooler. however the people that have done it say they like it and it makes a positive difference while not moving and doesn't restrict airflow while moving.
personally i don't think it would be beneficial to have them on there. i lean towards the side that if anything it would restrict airflow. imo its more worthwhile to get a water sprayer or a nos/co2 sprayer kit. both of those have no negative drawbacks to them and yet have plenty of positives
it is debatable on the forums here. seems like most people think it wouldn't help any and if anything, at highway speeds it would restrict airflow over the intercooler. however the people that have done it say they like it and it makes a positive difference while not moving and doesn't restrict airflow while moving.
personally i don't think it would be beneficial to have them on there. i lean towards the side that if anything it would restrict airflow. imo its more worthwhile to get a water sprayer or a nos/co2 sprayer kit. both of those have no negative drawbacks to them and yet have plenty of positives
08-25-2004, 10:21 PM
#3
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Stick your hand out the window when your car is moving 30 MPH, and then stick your hand in front of a computer fan (blowing out). You'll see that even the most powerful computer fan is putting out a pathetic amount of air compared to what is actually entering the hood scoop when the car is in motion. Thus, the fans would be blocking airflow at speed, not accelerating it. While standing at a stoplight, they wouldn't be allowing the hot air to rise out of the hood scoop (where else would the hot air go -- the fans can't be forcing it through the intercooler and out through the engine compartment).
08-26-2004, 12:41 PM
#4
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this is true but if the fans are off while the car is in motion then wouldnt the air coming threw the hood scoup cause the fan blades to turn. and wouldnt this turning cause a sucking effect as the fan blads turn faster? which would bring more air in to the intercooler? i could be not making any sence or i could be making some sence but thats wut im thinking.
08-26-2004, 01:32 PM
#5
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If you turned the fans off while moving, they would just be obstructions. Even if the incoming air caused the blades to turn, it wouldn't help the fact that they were blocking the airflow.
08-26-2004, 11:59 PM
#6
I've seen data... don't remember where, of a small radiator fan bellow the IC. It made a very significant difference when the car was stopped... our IC's heatsoak really quickly without airflow. There was no good data while the car was in motion, but people have said that the WRX IC reaches max effeciency at ~20mph, so I seriously doubt that any obstruction the pull type fan would creat, would make a difference in the cooling efficiency of the IC at speed.
-- Ed
-- Ed
Last edited by MethodBuilt; 08-27-2004 at 12:02 AM.
08-27-2004, 09:08 AM
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hood vents with a TMIC are a VERY bad idea. it's been tried. it ends up increasing underhood pressure which causes a reduction in flow through the TMIC.
i get tired of these responses about fans "blocking airflow"--like it's a sheet of plastic over your IC core.
what planet are you people from? have you ever had a window fan, turned off, in a window that has a breeze flowing through it? what happens to the fan blades? what happens to the breeze through the window?
yes it's an obstruction, but there's also more to it than that.
there is also the fact that the spinning blades create turbulence and distribute to a very large extent a homogenous volume of air across the entire cross section of the fan. in other words, they act like a very effective "splitter" to ensure even airflow over the width and breadth of the IC core. splitters are commonly fit to increase the TMIC efficiency on imprezas. they also create an obstruction. does that mean they are universally bad?
comments like this make me shake my head in disbelief:
i don't even know where to begin.
a) you don't WANT hot air to "rise out of the hood scoop"--EVER! that is the whole point of this exercise...
b) how do you come to the conclusion that fans can't force air through the ic and out through the engine compartment? what makes the fans running while stopped any different from the ram air from the scoop while traveling at speed? answer: there is NO difference, and of COURSE they can force air into the hoodscoop and down through the IC core, even while sitting at a red light, stopped in traffic, or waiting at the staging lights on a 1/4 mile track.
if you can't tell by now, i'm just flabbergasted at the comments...
computer fans are NOT the correct fans for this application. this certainly does not mean that the idea is completely without merit (or maybe it does to some, but not those who have a modicum of intelligence). where is the scientific method in all of this?
have fun
ken
i get tired of these responses about fans "blocking airflow"--like it's a sheet of plastic over your IC core.
what planet are you people from? have you ever had a window fan, turned off, in a window that has a breeze flowing through it? what happens to the fan blades? what happens to the breeze through the window?
yes it's an obstruction, but there's also more to it than that.
there is also the fact that the spinning blades create turbulence and distribute to a very large extent a homogenous volume of air across the entire cross section of the fan. in other words, they act like a very effective "splitter" to ensure even airflow over the width and breadth of the IC core. splitters are commonly fit to increase the TMIC efficiency on imprezas. they also create an obstruction. does that mean they are universally bad?
comments like this make me shake my head in disbelief:
While standing at a stoplight, they wouldn't be allowing the hot air to rise out of the hood scoop (where else would the hot air go -- the fans can't be forcing it through the intercooler and out through the engine compartment).
a) you don't WANT hot air to "rise out of the hood scoop"--EVER! that is the whole point of this exercise...
b) how do you come to the conclusion that fans can't force air through the ic and out through the engine compartment? what makes the fans running while stopped any different from the ram air from the scoop while traveling at speed? answer: there is NO difference, and of COURSE they can force air into the hoodscoop and down through the IC core, even while sitting at a red light, stopped in traffic, or waiting at the staging lights on a 1/4 mile track.
if you can't tell by now, i'm just flabbergasted at the comments...
computer fans are NOT the correct fans for this application. this certainly does not mean that the idea is completely without merit (or maybe it does to some, but not those who have a modicum of intelligence). where is the scientific method in all of this?
have fun
ken
08-27-2004, 02:25 PM
#10
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Originally Posted by ride5000
hood vents with a TMIC are a VERY bad idea. it's been tried. it ends up increasing underhood pressure which causes a reduction in flow through the TMIC.
i get tired of these responses about fans "blocking airflow"--like it's a sheet of plastic over your IC core.
what planet are you people from? have you ever had a window fan, turned off, in a window that has a breeze flowing through it? what happens to the fan blades? what happens to the breeze through the window?
yes it's an obstruction, but there's also more to it than that.
there is also the fact that the spinning blades create turbulence and distribute to a very large extent a homogenous volume of air across the entire cross section of the fan. in other words, they act like a very effective "splitter" to ensure even airflow over the width and breadth of the IC core. splitters are commonly fit to increase the TMIC efficiency on imprezas. they also create an obstruction. does that mean they are universally bad?
comments like this make me shake my head in disbelief:
i don't even know where to begin.
a) you don't WANT hot air to "rise out of the hood scoop"--EVER! that is the whole point of this exercise...
b) how do you come to the conclusion that fans can't force air through the ic and out through the engine compartment? what makes the fans running while stopped any different from the ram air from the scoop while traveling at speed? answer: there is NO difference, and of COURSE they can force air into the hoodscoop and down through the IC core, even while sitting at a red light, stopped in traffic, or waiting at the staging lights on a 1/4 mile track.
if you can't tell by now, i'm just flabbergasted at the comments...
computer fans are NOT the correct fans for this application. this certainly does not mean that the idea is completely without merit (or maybe it does to some, but not those who have a modicum of intelligence). where is the scientific method in all of this?
have fun
ken
i get tired of these responses about fans "blocking airflow"--like it's a sheet of plastic over your IC core.
what planet are you people from? have you ever had a window fan, turned off, in a window that has a breeze flowing through it? what happens to the fan blades? what happens to the breeze through the window?
yes it's an obstruction, but there's also more to it than that.
there is also the fact that the spinning blades create turbulence and distribute to a very large extent a homogenous volume of air across the entire cross section of the fan. in other words, they act like a very effective "splitter" to ensure even airflow over the width and breadth of the IC core. splitters are commonly fit to increase the TMIC efficiency on imprezas. they also create an obstruction. does that mean they are universally bad?
comments like this make me shake my head in disbelief:
i don't even know where to begin.
a) you don't WANT hot air to "rise out of the hood scoop"--EVER! that is the whole point of this exercise...
b) how do you come to the conclusion that fans can't force air through the ic and out through the engine compartment? what makes the fans running while stopped any different from the ram air from the scoop while traveling at speed? answer: there is NO difference, and of COURSE they can force air into the hoodscoop and down through the IC core, even while sitting at a red light, stopped in traffic, or waiting at the staging lights on a 1/4 mile track.
if you can't tell by now, i'm just flabbergasted at the comments...
computer fans are NOT the correct fans for this application. this certainly does not mean that the idea is completely without merit (or maybe it does to some, but not those who have a modicum of intelligence). where is the scientific method in all of this?
have fun
ken
good argument... im leaning on your side
08-27-2004, 02:32 PM
#11
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take off your hood it will prevent heat soak
maybe some battery sprayers to keep the battery cool
maybe some battery sprayers to keep the battery cool
08-27-2004, 02:55 PM
#12
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Gee, thanks for the tech SnoHumper.
ride5000, you are absolutely correct- the application doesn't really work, but not for the reasons mentioned here. Personally I would much prefer a good water spray to the duct-and-fan method. Although I'd REALLY like to figure out how to setup a top-front mount like the WRC car without blowing $10k...
ride5000, you are absolutely correct- the application doesn't really work, but not for the reasons mentioned here. Personally I would much prefer a good water spray to the duct-and-fan method. Although I'd REALLY like to figure out how to setup a top-front mount like the WRC car without blowing $10k...
08-27-2004, 03:58 PM
#13
I honestly don't understand why people like water sprayers so much... You need to carry around and re-fill a good sized water reserviour, and even with all that, the sprayer really isn't all that effective. I put together a DIY sprayer, and although it did help out while staging at the rallyx, it used up the water way too quickly and didn't work THAT quickly. A nice fan setup won't require maintanance or even attention and should keep heatsoak at bay better than a water sprayer.
What I'm really appauled at is that our WRX's come with this TMIC configuration that is ridiculously prone to heatsoak, and yet Subaru didn't even give us a water sprayer, not to mention a fan!
-- Ed
What I'm really appauled at is that our WRX's come with this TMIC configuration that is ridiculously prone to heatsoak, and yet Subaru didn't even give us a water sprayer, not to mention a fan!
-- Ed
08-27-2004, 04:18 PM
#14
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Brushing aside "Ken's" ill-advised attempts at personal insults, it is actually quite easy to see why adding fans to the top of a stock intercooler would interfere rather than help. Anyone who has ever blown up a balloon will observe a simple principle of physics -- air, by its very nature, always attempts to evenly distribute and equalize its own pressure. It is this principle which causes balloons to be round, and which (indirectly) causes airplane wings to generate lift. Thus, while the car enters the hood scoop and is pressurized by the push of air behind it, the air will distribute that pressure over the maximum surface area possible -- like in a balloon -- and there's no need for useless bling like splitters. The fact that a splitter, a simple piece of die-cut metal, costs $125 from ZeroSports puts it handily in the "bling" category; if anyone has a dyno graph or timeslip to share that demonstrates the usefulness of a splitter, I'd be happy to see it.
All fans have a maximum flow rate (measured in CFM, cubic feet per minute). If you take a fan past its max flow rate, you will either 1) burn out the pin bearings, 2) cause it to spin backwards (I've observed this with window fans during a thunderstorm) or 3) just plain break it. I'm willing to bet cold, hard cash that normal highway speeds would exceed the max flow rate of any fan small enough to actually fit under the hood scoop. Furthermore, you have air that was previously striking the intercooler at an acute direct angle now hitting the intercooler at oblique angles.
As for sitting at a stoplight, which is the only time a fan arrangement might be useful, again I don't think any fan small enough to fit on top of the intercooler would be able to generate enough airflow to actually force that hot air (which of course rises by its nature) back down again. The intercooler is not a screen door, it is a dense network of screens and tubes, and it requires a bunch of pressure (I read on SPD Tuning's site that the intercooler begins to function at 15 mph and above) to actually cool intake/precharge air. You're facing a battle of diminishing returns -- it will take a bigger fan to move more air to cool the intercooler, but the bigger the fan the bigger obstacle it becomes. This problem can then be solved by moving the fans to the bottom of the intercooler, and trying to pull air through it -- but this is clearly much less efficient, because you lose the "seal" that the top of the intercooler has with the hood scoop itself.
I think the fact that there is only one commercial WRX product based on this, sold only in Japan (for $600.00, cooincidentally from splitter-maker ZeroSports) for a limited time, proves that it isn't a useful line of inquiry. I found an interesting article written by a very capable chap who recorded a temperature difference of -10 degrees C at stoplights, which was offset by a 3 to 4 degree loss in cooling while driving at speed (ahem.) With intercoolers running into the hundreds of degrees while idling at a stoplight, I don't think a 10-degree difference is going to produce a measurable result. Here's the article for reference: http://www.netcomuk.co.uk/~gavinp/airwater.htm
In any case, plenty to think about. Certainly a water- or CO2-spray kit is going to be more effective, in light of these facts.
All fans have a maximum flow rate (measured in CFM, cubic feet per minute). If you take a fan past its max flow rate, you will either 1) burn out the pin bearings, 2) cause it to spin backwards (I've observed this with window fans during a thunderstorm) or 3) just plain break it. I'm willing to bet cold, hard cash that normal highway speeds would exceed the max flow rate of any fan small enough to actually fit under the hood scoop. Furthermore, you have air that was previously striking the intercooler at an acute direct angle now hitting the intercooler at oblique angles.
As for sitting at a stoplight, which is the only time a fan arrangement might be useful, again I don't think any fan small enough to fit on top of the intercooler would be able to generate enough airflow to actually force that hot air (which of course rises by its nature) back down again. The intercooler is not a screen door, it is a dense network of screens and tubes, and it requires a bunch of pressure (I read on SPD Tuning's site that the intercooler begins to function at 15 mph and above) to actually cool intake/precharge air. You're facing a battle of diminishing returns -- it will take a bigger fan to move more air to cool the intercooler, but the bigger the fan the bigger obstacle it becomes. This problem can then be solved by moving the fans to the bottom of the intercooler, and trying to pull air through it -- but this is clearly much less efficient, because you lose the "seal" that the top of the intercooler has with the hood scoop itself.
I think the fact that there is only one commercial WRX product based on this, sold only in Japan (for $600.00, cooincidentally from splitter-maker ZeroSports) for a limited time, proves that it isn't a useful line of inquiry. I found an interesting article written by a very capable chap who recorded a temperature difference of -10 degrees C at stoplights, which was offset by a 3 to 4 degree loss in cooling while driving at speed (ahem.) With intercoolers running into the hundreds of degrees while idling at a stoplight, I don't think a 10-degree difference is going to produce a measurable result. Here's the article for reference: http://www.netcomuk.co.uk/~gavinp/airwater.htm
In any case, plenty to think about. Certainly a water- or CO2-spray kit is going to be more effective, in light of these facts.
08-27-2004, 05:24 PM
#15
meilers,
the key to your post is that you keep saying "I think this, I think that." Do a search for this on nasioc and you will see that people have actual data showing that even a push type fan on top of the IC, makes absolutely no difference in post-IC temps, be it on, off, or removed from the car. There is also data that shows the fan doing extremely well to combat heatsoak while the car is standing still.
The fans used in the article you referenced are tiny computer-like fans. This is simply not enough to make a significant difference. The fan I'm talking about flows 300+CFM.
Also, your thoughts on breaking the fan while at speed are kinda ridiculous if you're actually using a propper fan for the job. I'll be using one of these 6.5" SPAL pull type fans under the IC and the fan is made for automtive use and can easily withstand highway speeds and above. The only challenge will be actually mounting the damn thing under the IC... not much space there.
-- Ed
the key to your post is that you keep saying "I think this, I think that." Do a search for this on nasioc and you will see that people have actual data showing that even a push type fan on top of the IC, makes absolutely no difference in post-IC temps, be it on, off, or removed from the car. There is also data that shows the fan doing extremely well to combat heatsoak while the car is standing still.
The fans used in the article you referenced are tiny computer-like fans. This is simply not enough to make a significant difference. The fan I'm talking about flows 300+CFM.
Also, your thoughts on breaking the fan while at speed are kinda ridiculous if you're actually using a propper fan for the job. I'll be using one of these 6.5" SPAL pull type fans under the IC and the fan is made for automtive use and can easily withstand highway speeds and above. The only challenge will be actually mounting the damn thing under the IC... not much space there.
-- Ed