Your thoughts on Elec. Fans.....
 

My car gets a little warm on the freeway, dont know why. but I thought I would get an electric fan for the hell of it. What are your thoughts on elec. fans, how well do they cool with the a/c on in 95+ degree weather (to Las Vegas in the desert type shit).
I was looking into the black magic 150.....

i think most people get the electrical fan to have one less belt and free up a couple horses, but i think some of the nicer ones, like the black magic, cool better than the stock fan, but i might be wrong, i don't know about the AC though

go the electric fan if u have to, eg FMIC piping in way....
if its warm on the highway, that's another prob. no fan is going to push air through the rad like 100km/h down the highway is going to. having a electric fan switched on while doing highway speeds is just going to be a restriction. the standard fan is speed controlled meaning it keeps the engine at its efficient temperature. with the electric fan, the temp will fluctuate more, even when controlled by computer. but if u do go the electric, get the biggest one that will fit, eg 16inch.

Electric fan's are a HOT debate topic among rx7 perf. mechanics.

Some say not enough volume, even with the correct shrowd.

Thats assuming your just using it as a replacement and not suplemental.

I tend to agree because I keep seeing the "up to 95degrees Farenheight."

For supplemental it would work, but since you want it to suck and not blow I'm not sure how you'd do it.

I have some actual data on a couple of electric fans, and how they work in both N/A and TII setup's.

I initially used a Permacool fan on my 91 vert to free up some HP and get a quicker rev due to less drag on the motor. The Permacool worked fine, even in the AZ heat of summer with the A/C on. Then the fan died after 2 years or so. I then just picked up a cheapie fan at the local parts store. It was the same size, but didn't have the CFM rating that the Permacool did. The difference at idle was about 10-15F hotter with the new one. The thing I found funny, was that most people say "freeway speeds make the fan useless" That is not true. With the Permacool, the temp was 160F radiator outlet temp. Right after changing to the cheapo fan, the temps went up to 175-180F outlet temp. So that saying is not true, at least not in all situations.

Now with the TII setup. I used a similar fan as the cheapo one in my 86 TII with a Griffin 22X19" AL radiator. under stock conditions like boost etc...that one worked fine due to the larger AL radiator. With a T04 hybrid and more boost, the temps went up pretty high. I recently switched to a Black Magic 150, and it is UNREAL. The front of the Griffin is actually COLD after driving due to the ammount of air going through the radiator. I don't have A/C in it to compare A/C temps on the motor, but I don't think you will have any problems with the BM and the A/C running. Hope that helps!

The stock fan does a great job. The viscous clutch slips when cold & bites when hot. It also max’s out at 4000rpm so it draws no more power at 8k than it does at 4k. They seem to wear out every 160000 miles, so at that point, black magic 150 will give you more room.

perma cool finger chopper 16 in. my temps went down about an 1/8 in. from half way on the guage, never tested the temps, but them damn mazda guages are never wrong....... didn't really notice a power gain but the extra room almost makes you want to work in the engine bay.

well, I am not sure. All I know my engine bay gets HOT !! like a 16 y.o. girl in heat, I am still using the stock fan.

Black Magic
 

I had a Black magic fan kit a while back and the damn onboard thermostat would never work right. Then I realized that the damn thing was mounted upside down. i want to use the same fan again. but find a diferent way to cut it on and off. Any suggestions??

My experience is this:

There is NO electric fan that works as well as the factory setup.

If you don't have a/c, don't drive in the city traffic or, don't drive during the day, then you don't experience the same things as me.

I will NOT go back to the factory fan even with the way I feel about the e-fan.

Mike

http://brfoundation.com/RX-7/Images/fluidyne10.jpg

what controlls when your fan comes on / goes of. Thats the BM150 right and it does have a built in thermo unit.... Did you use that how did you hook it up. Also how is the rad. You like it was the install easy?

I'm still using the built-in thermo-thing. I plan to hook this wire (photo below) from the Haltech to do the control.

http://brfoundation.com/RX-7/Images/e-fan_wire_1.jpg

As far as I know, it's the 400-150. Yes, I'm using the built-in and, the built-in thermo thing is working just fine for me.

The mechanical part of the radiator install was not easy. I had to spend money at the welding shop and, the bolt holes had to be modified to allow the install.

Overall, I WILL keep the e-fan.

Mike

If the perma-cool is the hand chopper one with the aluminum blades that maybe at highway speeds the fan gave less restriction to the air coming through the rad.than the one you replaced it with and that was why the temps were lower with the perma-cool.Just a thoughtI have noticed my fan doesn't seem to be running when I come to a stop but will start not long after I stop on a warm day.

My friend had an '86 base. He purchased a Black Magic "Flex-a-lite" fan for super cheap, and installed it. His engine temp. was always slightly more than it was with the clutch fan. We didn't dyno his car, but he had a G-tech, and we should a 0HP increase. So, that's why I've never wasted my money on one.

The only thing that's good about it, is it will cool down your block even when the car is off.

SureShot, I ate through 4 fan clutches in 25k miles. i don't think they can take the high revs of the 7 (at least not mine :D). I bought the cheapo fan at discount auto and it's fine to me. keeps that temp gauge way down there. the room does make you want to work inside your engine bay.

MikeL, are you arguing for or against the electric fan? I couldn't tell...

I'm arguing against the e-fan.

I have had two. The last is the Black Magic. I think it's about the best but, it doesn't cool as well as the factory setup, for me.

I like the extra room. I won't go back to the stock fan.

Mike

"We didn't dyno his car, but he had a G-tech, and we should a 0HP increase."

The e-fan does not increase HP, but it does allow the engine to rev faster due to less drag from the stock fan. Were his 0-60 times faster? 1/4 mile times? That is where the improvement will show, not HP.

And as far as the temps go with the different fans, that is a good possibility that the permacool had less restriction behind the radiator than the el-cheapo one. That is what I attributed it to, combined with the fact that the cheapo one pulled only like 1200CFM and the permacool pulled like 2950CFM.

Either way, an AL radiator with an e-fan will do better overall for performance and security than the stock one, IMHO. Others like the stock one. I think it is purely a matter of choice on which to go with.

It's true that the engine itself puts out no more GROSS power when you remove parasitic devices. However, the g-tech calculates HP based off 1/4 mile and 0-60 runs. This is more like the NET power, which COULD be affected by removing any parasitic devices such as the fan...

However... an e-fan still needs power to move, and that power has to come from somewhere--the alternator now. So, it's possible that any freedom gained from removing the e-fan is lost thru making the alternator harder to turn.... But....the e-fan isn't on ALL the time...

Plus, I imagine it's lighter. :)

-Tesla

From what I understand, I'm going to have to disagree with that. The G-tech was measuring RWHP I thought, and if having the e-fan frees up AVAILABLE power, not increases it, the RWHP value should have changed and it didn't. Furthermore, we ran some 3rd gear 1500-7000RPM runs, 3 with the e-fan, 3 without, and the times averaged out to the EXACT same value. 0% increase in all aspects.