buckem85gslse

what fan wood you put in the car please help

Pele

iTrader: (28)

"Wood" like a tree is made of is not a good material for a fan. Breaks at high speeds and is heavy.

"Would" as in a interagotive sentance such as, "What fan would you put in an RX-7?" is what you're looking for.



Just messin' with ya.

Anywho... That all depends on what you're looking to spend and what you would like to do.

There are two types of fans in general. Clutch fans and electrical fans.

The stock fan is a clutch fan. It is driven off the water pump pulley and the speed is controlled by a thermostatic clutch. When the heat in the engine bay rises, the clutch gets mroe viscous and more force is put into the fan.

These fans are capable of some serious air flow and will cool the engine very well. But they rob the engine of a bit of power. Also the clutches sometimes fail and either lock up, causing the fan to spin at full speed all the time or freewheel and cause the fan to spin too slowly.

There are many types of blades that can be attached to the clutch. Flex fans with soft plastic, flexible blades that are curved to move more air, or standard types with striaght blades like the stock type.

New or junk yard is your choice. Personally, If I had to, I'd get the blades from the junk yard and get a new clutch.

The electrics also have many choices of blade type. The general drawbacks to the electric type are they can fail without warning, and place a high load ont he RX-7's already meidocre electrical system.

The advantage is that you don't use the engine's power as much and it also makes getting to the water pump and other front engine components a little bit easier.

A popular choice here is the Black Magic: Flex-a-lite fan. It is available from Summit racing, I believe at around $100-$150 USD. It moves a good deal of air and fits the stock radiator well.

Alternately, you can scavange an electric fan from a junk yard car. Be sure to choose one form a car with a V6 or V8 as the ones that cool four bangers aren't nearly good enough to cool a rotary.

Good luck on your fan choice dude.

Zalitore

what about the fan from a fiero or mr2? there mid engine so wouldnt they need a damn good fan? i think i read it on this fourm befor about a fiero electric fan is good, any input on this?

mar3

iTrader: (8)

Actually, the increased viscosity=more fluidity (by definition)=less resistance to input shaft from water pump=less force available to spin the fan blade. The fan blade is essentially as close to decoupled as a fluid transfer systems go so there is less HP lost at higher RPMs when everything is nice and hot underhood...

New clutches for the fan from any of the vendors (save for that surplus outlet mike p-28 found...) requires that you first take out a home equity loan to cover the purchase... I've been running my Derale on the street in a daily driver scenario for >4 years. That qualifies for OEM status, nicht war? You stated it best. "...That all depends on what you're looking to spend...". When it comes to fuel, cooling or ignition, SPEND the dime!! You get what you pay for. The only bargains are had at someone else's misfortune, ie. they fixed it up real nice and promptly had their rear-end torn off in an accident. Plenty of nice pickings up front for the vultures, though....

piston pounder

That was me that put the fiero v6 electric fan on my 7, and it works very well!. I havent had a problem drag racing or track racing. the car stays real cool!. By the way you dont need a fan above 30mph anyway.

V8kilr

well correct me if im wrong but i though his question was about electric fans???not to be cocky.what fans you buy depend on what yopur going for,and whether you like it or not the rotary is very hot,so you will need something good.here are some questions to ask yourself,will you be racing alot?will this be a daily driver?do you wish to be able to talk to someone in your car without yelling?do you have a "boomin" stereo?if you answered no to most of these questions then go with dual fans,one on each side of radiator,but this can only be acomplished by removing the stock ac core.or putting the fan in front of it?anyway dual fans might be a good idea,might not.im not for sure if running dual actually improves airflow over one fan,but you will have to get the same size,same rpm,same everthing,or one will slow the other down.i run dual on my car for mainly one reason,and that is if one fails i still have the other,one is hooked up on a switch,and i can hear the fan when it is on if i roll down the window and listen,if my heat starts to rise i flip the switch and problem solved.keep in mind im insane and although my car is for street use i have no sound system,and half my interior is gone,my car even though primarily a daily driver is also intended for street racing.which in my opinion can be just as if not more grueling then track racing when it comes to heat.sometimes you will be sitting in traffic on an 100 degree day and then start racing around but never actually pick up enough speed to cool off your engine through convential means.even though i find more slack to be takin up on a 12a oil cooling system then the water cooling system,if you dont have a 12a then you dont have that probelm.if you do then you should know what im talking about.

buckem85gslse

I will be drag racing the car mostly and I know a little about rx7. The car dose not have AC. All I want to know is what eletric fan I should used on the car and if it make a difference or not. thank you guys for the help. please take the time and help me out some more time and help me.


thank you

mike

FJ

Well, Pele mentioned a good new electric fan and piston pounder mentioned a good second-hand electric fan. As the fan will be shut off during drag racing either way I, for one, am not sure what difference you are referring to.

mar3

iTrader: (8)

Will it EVER see street duty? That is the information we need to answer this question correctly. If it's a straight drag car, then you need to go to an electric fan to free up some revving ability from the parasitic mechanical factory setup. Go as cheap as you want 'cuz it will only be needed for minutes at a time. The engine can be started and run without a fan for up to 8 minutes in 70 degree weather with no problems, so the only reason you need a fan at all is to bring coolant temps down right before a run and to cool the engine overall right after a run. If it will see street duty, then get the best aftermarket electric fan you can stomach putting on a credit card. Don't skimp...

V8kilr

yes it does make a diference,you get what you pay for etc.but if you go dual el'cheapos i think you will be quite alright,like i said there's more slack to be taken up in the oil cooling system then the air cooling system.try to squeze on 2 14",yea i know there gonna be big,but if you look around most auto parts places have the 14" for around $10 more then the 10",the 12" is usally $5 more,

going with a bigger fan refers to computer technology where people opt for a bigger 80mm fan over a 60mm fan because a 60mm has to spin at alot higher revoloutions to make up for the cfm rating.same applies here,so if you want high cfm with a decent sounding fan go cheap,the more expensive fans push more cfm thus being alot louder.

any fan is going to make a decent amount of noise though becuase your not only hearing the fan but also the air being moved,but id rather hear a wooosh noise then a high pitched scream coming from my engine bay,unless of course its a camden supercharger

jimmyv13

SEARCH SEARCH SEARCH!!!!!!!!!!!!!!


for all your answers, upper right corner of the page. You'll get more than enough information.

FJ

Actually, increased viscosity=less fluidity, by definition. High viscosity =more force to spin the blade, yes, but in a fan clutch it is the opposite of what you want.
More coupling when cold is not ideal for a fan clutch.

If, as Pele mentioned, the oil in the clutch was to get more viscous with heat, it would be a neat trick as all fluids that I know of, from water to honey, get less viscous as the temperature increases. (Viscosity is inversely proportional to temperature.) I just checked How Stuff Works, however, and they agree with Pele saying the fluid in the clutch gets thicker as it warms up. I don't buy it.

As far as I know, most fan clutches use bimetallic strips to control the fan speed, not oil viscosity. By controlling the silicone oil available for coupling, or using an expanding bimetallic coil to lock the fan when hot, using oil as a lubricant.

Anybody know of a fluid that thickens as it gets hot?

-John.

crazy dog

Anybody know of a fluid that thickens as it gets hot?



BBQ sauce!!

FJ

True.

mar3

iTrader: (8)

Err, uhh...


Ouch, I can't believe I posted that...I stand red-faced and corrected...I got caught working off Pele's statement...
Obviously, most fluids don't act that way...on an interesting note, a viscosity equation I dug up in my college physics book to determine the force necessary to transfer fluids through a tube does not mention heat as one of the characteristics even needed to determine the answer...I think I'm going to let this sleeping dog lie but I do know that a thermostatic fan decouples at higher speeds and temperatures because your car speed is all that's necessary to get the correct airflow through your radiator...you need the fan at lower car speeds when this ain't happening...

FJ

Agreed.

-John.

Pele

iTrader: (28)

I said the clutch gets more viscous, but what I meant to say is that it engages and transfers more force.. I was researching the center differentials for Subaru AWD (Outback Sport/Impreza Wagon) and it was in my mind... (Yes, I know theres a clutch type in the Automatic version and the viscuous link in the manual version... But as far as I'm concerned, the clutch type doesn't exist... I don't drive cars with only two pedals. )

I assumed it was a spring inside that was similar to the thermostat spring metal. Expands and makes contact and spins the fan faster...

Fluid? How does it work? I'll have to break one open and see.

Rallyon

If you go electric, you want a fan that moves a minimum of 1600 cfm. 2000 cfm is preferable. Also look at the amprege consumpution . Some of the high output fans consume 15 to 20 amps. With such a fan combined with a high output sound system just turning on your head lights could cause you to exceed the capacity of your alternator (50 amps on most 1st gens). That means you're running on your battery at that point.

JoseReyes

I just recently installed a 16" Derale Electric Fan in my 82 GSL is a killer. It has 2100 + CFM's and with the 16" blades it goes past below into the oil cooler, so it cools the oil too. Clearance was very minimal (even though the fan specs said 3.90" required) it was a very tight call. Works great, it does pull around 25 amps, so I had to upgrad my alternator. I have pics on my webiste: http://www.rotaryrx7.com
under my rx7 page....

I am real happy with the fan, it pulls some serous air when it come on and is not as noise as other people had led me to be... you can still hear it when it comes on but not as loud....

mar3

iTrader: (8)

Excellent, Jose! I knew you wouldn't be disappointed! Now there's two of us on planet Earth running the Derale fan in a rex!! Now all ya gotta do is replace your fuel pump or ditch the Carter if you have one and run a Mallory to leave the masses behind!

And at that point, he'll be ready for this gem...
how to stick an 80 amp alt into a 1stgen RX-7

Enjoy the power!