Ebay Fan Mod
 

I came into possession of two 10" ebay fans and figured I'd give them a go. It was apparent when I bench tested each (oem and ebay) that the ebay fans, even at only 10" in diameter, pulled more CFM due to design and rpms.

So then as I was overthinking all my options, I decided the best way to ensure it pulls air out of the rad was to shroud it, since it's much smaller than the face it needs to pull from. So, as usual, I came up with something brilliant. I decided to gut the stock fan shroud and put in place, my ebay guts.

It took me exactly 45mins from start to finish. this included walking up 3 flights of stairs a few times and waiting for a soldering iron to heat up, and playing with different combos of motors and blades.

Simply, unbolt the blades and motor. Then I had to make two holes and screw in the ebay and attached the blade. The end. Soldered the oem connector in place and presto.

It does looks silly being so small and all, but when I jump the fans, this little guy spins much faster and pulls tons more CFM. Eventually I'll grab a cheap 12" and throw those blades on it.

Attachment 211760

Attachment 211761

It's so tiny! So cute!!! AAwwwwww

sure is. ill get some 12" to replace it soon.

Nice work. Let us know if you see any difference in your CLT.
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well the only time i ever activate the fan is when im idling at a redlight, so ill be able to tell you if it drops the temps quicker before I start moving again ;)

Nice work, but methinks you mentally masturbate about things a lil' much. :jerkit:

I don't get it. Why change fans, do you have a problem with over heating while stationary?

It was free and i wanted to try it.

Fair enough. I just see a lot of people jumping on these slim fans and I wonder why. With the godspeed rad I was able to get the OE fans to fit with minor (needed) modification to the rad. I've got the big RB swaybar and there is still a (very) little bit of clearance.

Carry on.

I don't think people buy them for the size... at least I didn't. There is something re-assuring in the fact that your fans are blowing enough air to create a small hurricane under your car.

really, it's a lot easier to zip tie two $20 fans onto the new rad then to bother with the stock ones. The fact that you should never even need fans from the enormous size of the godspeed coupled with cheap ass high power fans, you can rest assure that your cooling system is more than "up-to-snuff"

I plan on tracking my car so heat management is a must for me. If a $20 fan works better than the oem one when i'm +130mph WOT on the front straight, surely I'm going to invest the $20.

I got these for free (plus shipping) and i wanted to try my idea out. I don't think the 10" fan in this shroud is ideal, but i like it better than being mounted directly onto the face of the rad. This give it room to pull from the entire shrouded area. Likewise, when I put a 12" blade on there it should work great. Like I said, I don't want to mount them directly onto the rad, there is plenty of surface area that would not get covered this way. And I dont want to use the plexi-glass sheet method as it blocks airflow from exiting the rad all together. and I dont think stepping it off an inch would help, or be as easy as this method.

I actually tried mounting the new motor with the stock blade, but the overall weight of the stock blades caused the motor to bog down and spin slower. I couldnt tell a difference with the ebay blades on the stock motor, so i used the ebay motor.

but with very little time/money invested, I know that I can go pick up a good 12" blade and have an easy functional shroud setup for it.

no shroud
path of least resistance
can you make a little shroud adapter?

Doesnt a good amount of effectiveness of the fans come from its fit inside the shroud? I would think your orginial thought of the ebay fan being too small would be correct and that putting inside a larger shroud would do nothing. Maybe even make it less effective. Its not going to pull air from the area between the ends of the blades and the shoud.

Do the fans have any effect on cooling at +130mph WOT? How many CFM are flowing through the rad at speed? More than what a couple of 12" fans can hope to achieve I'd guess. I'm sure they are the bomb in +30C stop and go traffic.

Do what you want, I just think you are fixing something that isn't broken. IMHO

The 10" fan itself is tiny as hell in relation to the rad surface area. the shroud attached to the fan, is more of a cage, preventing you from slicing off your finger tips.. thus is why I want a 12" blade.

Even so, put your hand between the fan blade edge and the shroud and tell me it's no pulling air through there as well. Maybe not as well as if a 12" blade, but it still has a "sealed" area to create a vacuum for. Once mounted, as is, this fan is creating a small windstorm inside the engine bay. the stock fan; a light breeze. I'm positive it's doing a better job than simply flush mounted to the surface.

With that said, expect to see a 12" blade on there fairly soon.

possibly yes. Does it hurt anything to have a more efficient cooling fan? no. My a/c will work better and the temps will drop quicker if said fan turns on.

My stock fans have work fine for me for 13 years. I never really had plans to upgrade, however I've had overheating issues on the track at 120mph before. If I had simply strapped the fan to the face of the rad and posted, hey "I got a new fan" would you have bothered posting?

I thought I came up with a creative method of mounting the fan while retaining some sort of shrouding and thought I'd share.

Don't be cranky.

You are absolutely correct, having a more efficient fan is better. I just don't think that your overheating problem at 120mph will be fixed with a new fan.

I'll agree, your method of mounting is a good one, I'm surprise no one thought of it before. :)

Would I have posted if you had said "I got a new fan" absolutely. This isn't the first time I've asked someone to justify changing out a perfectly good OE fan for a $20 ebay unit.

Ironically a couple of years ago I bought an a/c fan from you ;) Installed, but still not wired! :)

This thread is pretty informative.

I am also debating weather or not to buy new fans for my mishi rad.

With my stock rad, and the car stationary, the fans cannot drop the temps of the coolant. I hope that with the larger rad + stock fans this wont be a problem anymore.

I used to think this way too until I saw this:
http://www.vidilife.com/video_play_9...ta_P_demo_.htm


http://www.vidilife.com/video_play_9...lta_P_demo.htm

It's not super scientific but you get the idea. Bottom line, you want shroud with fans unless your radiator is the first heat exchanger and the bumper is not blocking the airflow.

what i dont like about that shroud is that it's only stepped out 1/2" from the face of the rad. utilizing the stock one, tapers the air from the edges inward...should work better (with a 12" blade :)

but like his video shows....having an IC, A/C, and Rad....airflow is next to none without fans....that's why I stated my 130mph statement, Jay.

Werd. Plus it's stock so you don't have to dick around making an unneeded part.

Gotta say, his little video was enlightening to see. I knew the flow would be low but that was WAY low.

What's that say about the potential affectiveness of an extractor? If there's so little flow behind the rad, then how much air can we really be extracting? I mean, an extractor would need to create a very low pressure to have notable impact, right? It would seem to be more usefull to just get fans with bigger balls and call it done.

Has anyone taken pressure readings from various locations underhood, with and without an extractor? Before and after temp readings under controlled conditions? I'd like to know before I cut a big hole in hood.

Is that a function of the shrouding or the additional CFM the fans add? My argument isn't about the fact there is a fan present, my arguement is about upgrading over the stock fan.

I know at speed I rarely if ever get above 97* that the fans come on at. So I guess I'm sayin' good enough.

The second video wasn't launching for me, I'll watch them again and maybe I'll get some sort of Revelation.

Okay watched the video. I still stand by what I've said. MY experience in real life with out a leaf blower indicate that the coolant temps don't get high enough to start the fans. Maybe I don't drive hard enough or something. But running a under high load at lower speeds like autocross is going to stress the cooling system as much if not more than running high load at high speeds.

Or I'm talking out of my ass.

don't bother. there's very little flow behind rad. that's all you'd need to know

In my case it was due to the over-the-top IC piping configuration and the resulting tilt of the top of the radiator rearward to clear the piping. It would not have worked without slim fans.

There will indeed be some efficiency loss due to flow around the tips of the blades if they are not close to a shroud. It is the same kind of tip loss seen on turbines and airplane wings. But, this loss is relatively less critical for high aspect wings or blades. And if the small fan works well enough, well then it works well enough. Empirical data is hard to argue with.

thinking out loud here... the fan is a resistance to air flow when the car is moving. in that case, perhaps the smaller diameter fan will increase the car's ability to flow air through the rad and out the extraction vent while driving. if the previous is true, then it would be true that the smaller fan is in all ways better. :dunno:

Roar believes it to be true...
http://img172.imageshack.us/img172/5562/pict0007uu0.jpg

When you get the shroud/fan matched together so the fan is pulling air through the radiator instead of circulating air behind it, your motor will thank you at the first red flag you experience on the track. Flag was seen way too often on Road Atlanta last weekend and that is not good when one has to stop car from full blast without any cool down time.


hrk

Damn, this thread is making me wish I never threw my old fans away. Even though they didnt work. Off to the U pull it........
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Care to post a couple pics of your new set up please?

Perhaps this is the latest and greatest front in DIY miata mods.
I'd like to see 2 main fan shrouds installed side by side... rather than one main and one AC fan.

I don't think a 12" will fit in the AC housing... but it sure looks like it will fit in the main housing.

$42 shipped
http://cgi.ebay.com/ebaymotors/x2-12...mZ160271774883

12" will fit for sure in the main housing. later this afternoon/eving ill do the cooling one and see...I know it's a touch smaller.

It looks good, maybe ill do this.

I also agree with Ben, it seems if you have HIGHER cfms with a SMALLER fan, cooling would be increased all around (high an low speeds).

I would assume the fans spin freely as airflow passes through...i dont really see them disrupting flow whatsoever.

Fan seems to be generating a lot more heat at my feet than I've ever remembered on a cool summer day. hell, on a hot summer day for that matter. Makes me think a lot more air is passing through at idle.

Here is links to photos, sorry for not embedding them in thread because of their size.
Front
http://russmarshall.com/d/19637-1/P3130007.JPG

Intercooler side
http://russmarshall.com/v/cars/cmc7/...geViewsIndex=1


Oilcooler side
http://russmarshall.com/v/cars/cmc7/...geViewsIndex=1

Spal fan
http://russmarshall.com/d/19602-1/P1161345.JPG

So far it has worked great, water has not exceeded 215 deg F under run, and fan should have enough cfm to keep thing cool in case of sudden stop from full song and car kept on idle. This setup has not been tested like this yet, luckily.
Previously temps went 230 and beyond on a 100 degree ambient day during 30 minute session, then I had to start feathering throttle.

I saw one Hoosier DOT track tire suffer damage after red flag last weekend. Tire had bulges on about 270 degree area on the inside sidewall. While we were watching it at the paddock it suddenly bursted without further provocation than sun heating. It was removed and unloaded at the time, driver had pulled in because the car felt wierd after second red flag in one race. Tore 4" long rip on bulged area. Scary stuff.

hrk

Attachment 211747

Attachment 211748


A/C fan done.


Here's some actual real magnehelic gauge testing data I found:

Both fans raise the atmosphere .25 ~h2o when running. Both drop it .25 just in front of blades, obviously.

I was able to have the a/c fan drop it .50 inches of water in a certain sweet spot, but alas I couldn't find a spot on the other side where it would increase that much.

I do need the 12" to fully utilize the shrouding...toward the outside edge of the cooling fan, it tends not to raise the pressure as much, obviously due to the size in the shroud. the a/c side raises it evenly across the entire opening.


Now I need to test the same with stock fans mounted.

So in someone wanted to use this as an example, buy a 12" for the cooling fan and 10" for the a/c.

you can also see in my picture with a 2" radiator, i don't have much wiggle room with a 7/8" solid bar.

I just got my Mishimoto radiator so figured I would put new fans on there...I bought two 12" fans from this seller and got them in a few days (and they don't screw you on shipping like most of the ebay sellers...1/2 price shipping on the 2nd fan so $15 total shipping for 2...$55 for two fans shipped: http://cgi.ebay.com/ebaymotors/12-EL...mZ250282592683
...they seem to be of pretty good quality, although I haven't hooked them up yet...I'll be getting a piece of Lexan from Home Depot and fabbing up a shroud and adding that and the fans to the radiator, then installing that and my ebay intercooler!!:bigtu:

Im curious, did you have to cut out the new fans from their factory shrouds or can they be easily separated?

they unscrew. new ones are screwed into the plastic, with new holes.

I wonder how well pusher style fans in front of the radiator would work. I remember seeing the newer Mercedes SUVs (ML) w/ fans mounted pusher style.

When I upgraded my radiator in my Integra, my AC really suffered b/c of the thicker core. There was constant cycling. I ended up getting a slim fan placed in front of the condensor and no more cycling. Although the slim fan was now directly next to the condensor, instead of having to pull air through the radiator first, it seems that pusher fans still can help an overheating car if space permits.

I was going to wire up a relay so I could get 2 AC fans running at once, w/ my main fan. I don't know if Miatas have enough room in front of the condensor to mount a fan though.

how did you get the stock shroud to mount so shallow? I have the "coolradiator.com" aluminum rad, and hopefully mine will fit between the sway bar brace.

I bought my fans on ebay from these guys. Shipped it out the next day. Best price I saw for 2 fans shipped. I paid $54.17 including 2 fans and shipping.
Might be better out there but it seemed pretty good and they got it out in less than 24 hours.

http://stores.ebay.com/abad71camaro

The fan is resistance possibly the way that car is set up with air directly channeled to the radiator. With most cars I have to agree with the video about the shroud for the 2/3 cobra on the 1st page. Most of our cars have the IC in front. Those with AC have the IC and AC in front of the rad. Even at high speeds air isn't moving very fast or smoothly by the time it reaches the radiator. Add in any back pressure in the engine bay and I don't think enough air is being forced through the rad for the fan to be a source of resistance.

has anyone thought about putting little flapper door thingies on the shroud like VW does to let air pass through the shroud, then shut when the fans come on? Its going to be nice to put these theories to bed when I start working on my cooling disaster.

you could always straighten the air going into the head exchangers:
http://i35.tinypic.com/300t9bd.jpg

?? bolted right up i dunno...the motor doesnt stick out really far is all now.

sway bar distance.

i have a coolraditor.com rad, as you can see no issues...it was the 2" one, not the 3"

Why not 2 12" fans?
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^A 12" fan will not fit in the factory AC fan-shroud.

I posted earlier that a very clean and functional upgrade to the stock fan system would be to source a second main-fan housing from salvage and run 2x12's in side-by-side stock main-housings. It would be completely stealth and provde XX% more airflow (exact number still pending). I am catalogging little stuff like this... may be a super-cheap solution to a common hi-power Miata problem.

Guys like me who disdain the stock black plastic nose-funneler and undertray would love this mod if it's enough of a jump in efficiency.

Gotcha.
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Is fitment theoretical or proven fact?

second main housing would not fit...that's why there is a 12" and 10" from the factory.

that's what I assumed, just checking

Really? Is the AC that much smaller? I assumed the housings themselves were the same size just with a smaller fan/shroud in the middle of the AC.

My bad for assuming. 2x12's would appear to be the ticket though for fitment using the plexi-method.

Are the NA/NB stock fan assemblies and mounting tabs the same? Anybody?

did you not see my pictures?


A/C Fan Shroud with 10" ebay fan:

Attachment 211732


Cooling Fan Shroud with 10" ebay fan:

Attachment 211733


from tip to tip the stock fans measure in at 12.5" and 11"

Or just mounted directly to the radiator. Cjernigan is running a 2x12" setup on his oversized radiator, Godspeed I think. I am running 2x11" Spals on the stock radiator and it works fine. No overheating, daily driven, South Texas heat. In other words, you may not need to bother with the lexan shroud.

^But plexi is baller... unless it's mounted to your rollbar and houses Pioneer 6x9's.

someone should just trade me a 12" fan for my 10" fan and be done with it ;)

you know you want to.

this shit is bananas