Focus Fanatics Forum banner

1 - 20 of 50 Posts

·
Registered
Joined
·
3,365 Posts
Discussion Starter #1
As I mentioned in another thread. I am working on a new 'winter' project for my 07 which I call the "The under-hood hood-scoop project". I would like to gather some of your thoughts as I proceed. this thread will keep them all together.
The goal of this project is to reduce the engine bay temps without resorting to body work (a traditional working hood scoop) and do so with minimal current use (it also has an automated controller circuit but I will show that later). This project is an extension of a mod 1st posted by Bluefont.

I built a frame to hold 3, 120mm fans. The fans are comair rotron muffin XL rated 12v, .5A, 6w, 110CFM (free air), 50dba, Max pressure of .278 in H2O. Weight = 21.52 oz. Total weight of the assembly is 4 pounds, most of which is the fan housing as they are metal.
I temporarily placed the fans in the engine compartment, over the exhaust heat shield and connected them to the battery. Performance was very good, able to pull a 'smoke trail' horizontally from the radiator.
Complaints:
Noise. These units are rated 60dba at 12v. Prob go up to 65dba at 14v.
Weight: At over a pound (each) there heavy (these are metal frame fans).

Proposal: Use a similarly rated fan with a plastic body, such as the "Silverstone FM121.
( http://www.silverstonetek.com/products/p_spec.php?pno=fm121&area=usa).

Question: As engine bay temps can exceed 170F, do you think that the plastic frame fan would survive mounted over the exhaust manifold without deforming?

Question: Do you think the constant air flow (300+ CFM) is going to create an issue for the unprotected downstream components (02 sensors, steering rack, exhaust flex pipe. If so please try to elaborate your concern.

Question: Do you think this is a solution in search of a problem.


Thanks. [:)]

Here is a lousy pic of the frame with muffin fans mounted, and another of the Silverstone FM121
 

Attachments

·
C2H5OH
Joined
·
11,867 Posts
Very neat project indeed, but ...


Header wrap is much simpler and proven, and is something that everyone can do. Plus it helps with exhaust scavenging by keeping the heat in the manifold (less pressure drop over distance).


The Silverstones are not quiet either IMO. I have a FM91 and FM81 mounted in my computer tower. I can hear both in the next room with ease when on full blast. I'd imagine that through walls could compare to through the firewall (though engine noise may drown it out some). They do move a lot of air though and the noise vs flow is worth the trade off.

As far as heat goes, it's hard to say. If it where pulling cold air and forcing hot air away I could see them lasting awhile. But if they are just moving hot air around I can't see them lasting as long. So unless you are planning on taking cooler dry air through some kind of duct to the fan to move the hot air, I would say they won't hold up too well (lack of cool air flow to cool the motor = motor drawn more amperage and eventually burns out the windings).


I would honestly say that header wrap and making the hood air tight would benefit more.
Make the hood air tight to create a lower pressure in the engine bay and let the moving air under the car "suck" the hot air out. Probably not the easiest to do either.
 

·
Registered
Joined
·
16 Posts
i dont know if the trade off of added wight and extra power fron the cars electric system is going to be offset by the cooler temps, plus what kinda of air movment happens under the hood at higher speeds the fans may become usless under higher speeds, meaning that the air moving threw the fornt of the car is greater than the air being pushed by the fans.

iminhell had a good idea, seal the hood to the car and let the air moving into the front of the car stay there.
 

·
Registered
Joined
·
3,487 Posts
Wow...you actually got three fans crammed in there, with the hood closed? I temporarily set a two-fan unit in there and I think it would barely fit. Three fans?



As far as the plastic frames melting.....unknown. That three-fan setup would completely cover the top of the exhaust manifold, and would be taking the brunt of the heat soak. Those Silverstone fans suck IMHO. There are better fans around.

But there's no sense speculating with this setup.....you'll just have to give it a go. My setup with the aluminum fans has been going great. I can't hear them at all with the engine running.
 

·
Registered
Joined
·
3,487 Posts
Well....on the contrary, I sealed my hood even more than the factory, since I don't want water getting in there. That was one reason for my little fan mod.
 

·
C2H5OH
Joined
·
11,867 Posts
I am thoroughly impressed now.
 

·
Registered
Joined
·
16 Posts
so have you put a temp gauge under the fans to see if it make any differance at all? with no fresh air gettin into the engine bay i would think all your doing is blowing warm air onto the exshat manifold and around the engine.

also have either of you put the fans on got under the car and see if the air is blowing out from the top? if its not than how much good is it doing. i know that if the hot air is being blown down that far the flow of air under the car will pull it out

im not trying to put down your guyes work just wonder how much benifet is there
 

·
Registered
Joined
·
3,487 Posts
norcal....those fans over the exhaust manifold blow downward. The air goes outward through the exhaust tunnel. And while it does so, it pulls fresh (cool) air into the engine bay, through the radiator and other places. My setup has a second fan about where the std Duratec air filter box was located....before my Steeda install. That fan blows cool air into the engine bay....a sort-of flow-through ventilation.

And yes....I did plenty of temperature testing with mine. I run about 25F cooler around town with my two fans going, but not as much gain on the highway.
 

·
Registered
Joined
·
3,365 Posts
Discussion Starter #11
I was shopping and got the mount hardware (the rest of it). I designed a semi-floating mount so that the engine vibes/movement do not affect the fans.

Responses: iminhell >> You cannot apply header wrap to the stock 2.0l mani to my knowledge. But the stock mani does have an excellent heat shield. And even if you could. I am not sure we should wrap a cat. I am afriad we would burn it out. At ~$1400 replacement I don't want to experiment.

"The Silverstones are not quiet either IMO" >> Ya! But there only half as loud as these Muffin XL's I got. [:)] (These things are loud). I was more concerned when the car is turned off. Still considerable heat coming off the mani and engine and the fans would not be turning. I know the muffins can handle this. But there just so friggin heavy.

Per yours and blufronts comment about sealing the bay. I did some measurements. When moving forward the bay is flushed with incoming air and temp moves close to ambient. But when you stop for a traffic light, the temps rise quickly (160+F). Water + heat = rust. You cannot keep the water out, at least not in MO in the summer. That is why we don't use 'car bras' here. Condensation is a real problem.

norcalfocus01 >> 3 fans create an 'air curtain' that does not permit air recirculation. It all goes one way. Effect can be futher enhanced with a little top level baffling but I don't think its needed. It could be added however for purely visual enhancement.

bluefront >> Ya! I did. [eek]
P.S. Pass me the info on your fans again plz. Make/Model would be wunerful!

Got a question for you all regarding the controller. Would you prefer one that is more expensive but incredibly simple to build, understand, and is naturally weather resistant(~$30), or one that is much cheaper but requires you to know a bit about electronics and requires more effort (~$10). Note: The ~$10 can be made to be more flexible (for extra $) with settable temp points, startup sleep mode, timed cool down etc. but the complexity goes up as well.

I will post the mount soon as I have it built. That will take a few hours as I am going to attempt to make it somewhat pretty. (Well, at least my version of pretty) [unsure]
 

·
Registered
Joined
·
16 Posts
3 fans create an 'air curtain' that does not permit air recirculation.

okay that makes a lot more sence of what your trying to do

i would go with the 30 controller if its easier and better what 20 bucks? go to the moives with the wife and our out 20 bucks to just get in
 

·
Registered
Joined
·
3,487 Posts
I'd personally like to see a fan controller that was temperature controlled, and turned off by itself when the under-hood temps were lower (like in the winter). My two fans run all the time when the ignition is on.....and have to be turned off manually.

My manual after-cooler timer also is working great......long as I remember to set the thing. Perhaps you could incorporate an automatic one in your controller?

I'm hoping you go through with the project.....maybe we can start a trend. [:D]
 

·
Registered
Joined
·
3,365 Posts
Discussion Starter #14
I'd personally like to see a fan controller that was temperature controlled, and turned off by itself when the under-hood temps were lower (like in the winter). My two fans run all the time when the ignition is on.....and have to be turned off manually.

My manual after-cooler timer also is working great......long as I remember to set the thing. Perhaps you could incorporate an automatic one in your controller?

I'm hoping you go through with the project.....maybe we can start a trend. [:D]
Even the more simple expensive one won't activate if the air is to cold (unless the bay gets above threshold). You can also use an 'always on' connection and they will run until the temps go below threshold (Note: Current draw at low speed is like 1 amp). And even then they will turn off pretty rapidly if its cold out (nature makes for a very large heatsink).
What device? >> Digikey. Cantherm bi-metal thermal cutouts. Otherwise known as a thermal relay. Note they can handle up to 6A inductive. Can measure air temp. Weather resistant. Case is voltage neutral. Made for this application. :)

I also drew up a schematic with all the bells and whistles. It uses 2 temp sensors and works in differential mode. Very Neat. But it also almost mandates a circuit board and is far more complex. But it is fully adjustable. Circuit boards can get very expensive if your doing small quantity (min $25). plus the components, connectors etc. This one would prob run min $75.
 

·
Registered
Joined
·
3,365 Posts
Discussion Starter #15
Update. > teaser
OK. I did not wait for winter. I like to tinker and it just kinda got done.
Its delayed because the temp sensors 'switch on' temp (round things at the top on the backside pics) are low by ~20f, but consistently. So either I am not interpreting the specs correctly or they sent me the wrong parts. Anyway, waiting for the replacements. If you have a genuine interest in building this, now would be a good time to let me know if you need measurements.
Front pic. 'bullet' fans, controller 'front' with manual switch and 3 LED (From top, Power Good, Thermal Fault, Fan Power). The Blue/Red thing in the middle is the thermal fuse. It must be exposed to the engine bay.
Backside Pic. Show the controller and overall wiring.
Controller Pic. Closeup of the controller. Note: NO solder joints, with exception of the LED's which are glued to the plate to prevent flexing. The power resistor wires are of course soldered, but there made with very stiff legs and will not flex or bend.
I think I should paint the the front black so it 'disappears' in the engine bay. what do you think?
Note: It has not been 'weatherized' (sealed) as yet. That is the last step.
Note2: Fading memory cell tells me 'someone' wanted to know about how to make solid connections using fastons, butt connectors etc. Was that on FF? If so let me know and I will start a thread.
 

Attachments

·
Registered
Joined
·
3,487 Posts
Wow....you went all the way. How you got three fans stuffed in there is beyond me. I'm waiting for the final photos with the assembly installed in the bay. Paint it black for sure.....otherwise you'll get comments like "it doesn't match", or something like that. [paranoid]
 

·
Registered
Joined
·
3,365 Posts
Discussion Starter #17
I said I was going to build it! [wiggle]
Ya! Agree! I will paint it soon as I get the new temp switches (there riveted so might as well wait). But its going to 'disappear' in the engine bay once I do that. Black on black. So good pics are going to be rough to get. Maybe will take a few before I paint?
You like the bullets on the fans? There chain-link post tops. I like them anyway! ~2-3 weeks for final installation, then it will stay installed all winter and next summer for longevity testing. If it survives all that time with no maintenance then it will be 'blessed' as a permanent mod. I already have an idea how well they will work as I have done a few 'smoke' tests. But never with the fully hood closed.
 

·
Focused Focus
Joined
·
6,403 Posts

·
Registered
Joined
·
3,365 Posts
Discussion Starter #19
1 - 20 of 50 Posts
Top