Only in the sense that you do a lot of double talking.

"Power robbing high output alternator"? Is that like a gas mileage increasing perforated fuel tank? Come on Ray, I thought you were a scientist!?

Mazda engineers, blah blah, keep it stock, blah blah. Same old, same old. I don't have an efan btw, I was only stating facts of their advantages. I am not sure why you debate in these threads about increasing horsepower, since you are "essentially" or "normally" never putting yourself in a position to take advantage of it anyway.

Park your best car right now and don't drive it. Mine will still be in better shape 5 years from now.

 

Some info of this never ending debate..
http://howto.globalvicinity.com/gv_w...=149&co=1&vi=1

In my GMC pickup, the fluid leaked out of the clutch while driving causing the clutch to full engage and spin at what ever rpm the engine was spining at. Quite loud I must say. I don't know if this is the same for our clutches though, I got rid of mine years ago.

 

Take a look at his engine bay, then talk

 

"causing the clutch to full engage and spin at what ever rpm the engine was spining at. Quite loud I must say."

Yeah I had this happen to a fan clutch in my brown 85 GSL, sounded like a friggin' turboprop at the airport and you could feel the wind ten feet away. I wouldn't stick my finger in that one.

 

There are numerous posts here with dyno results showing that additonal hp is gained with an efan. Why is this thread still around?

Huh? Where? I missed it.

So Mar3, are you going to do some dyno testing on this subject or did I misunderstand you?

Well OK, it depends on conditions. So Mar3 will have to tell us exactly what's being dyno'd and how.

Here's my last post in the relevant thread, a new board in the Rotary Performance section...someone else is doing the back-to-back, same day, same car chassis dyno run, not me this time around. This will get you to just my post that has new relevant information, but there's a spot to click at the top right corner if you want to read the whole 5 page slug-out....

CatDaddy Speaks Up....


A little whiny and condescending, yes......the Mazda engineers also had to save MONEY per unit, Ray, and electric fans weren't the norm yet, way back when, or they most assuredly would have been standard equipment...and my Derale is running a switch that varies fan speed to temperatures I set....it comes on around 175*F at low speed and goes to high speed around 180*F and stays there until it sees 175*F again....right now that crazy radiator won't let the coolant temps get past 170*F, so it hasn't been on at all this winter except fot the 60*F days we occassionally get inbetween the 34*F days......no toggle switches here, it was installed right...and I'm running the '89 TII alternator, another fine Mazda factory piece...you should be proud of my upgrades.



If you check out Ray's video, you can see that there's no real force behind the spinning blade. I don't think there's any realistic drag on the motor at that point.

That fan is spinning pretty fast, but it isn't moving much air.

In my experience a fan clutch that is as easy to stop and turn backwards as the one in the video is worn out and has lost most if not all the fluid in it.

When the clutch is cold it is supposed to do that.

Also when hot.


LOL....OK, somebody's got to be wrong here...if it free spins when hot and cold, how can it even do anything at all? Why bother?

 

Clutch fans are a bit confusing, aren't they.

When you fire up a cold engine, the clutch fan will usually spin up for a few seconds to a minute and then relax until it is needed. Once relaxed it is easy to stop with a finger. It takes fractional horsepower to spin it at this point. You would not see this on a dyno.

Once the engine warms up and requires some cooling, the clutch fan will start to increase drag as it pulls just enough air to maintain temps at the Mazda preset for the internal oil and/or bimetalic strip (180-190).

As the engine cools down after a hard run or what have you, the clutch fan will loosen its 'grip' and begin to relax again, pulling hardly any air and not enough power to be noticed.

As for the main question everybody is asking ie how much HP does a clutch fan steal? I think the answer has to do with running conditions. It can vary from not enough power consumed to show on a dyno (within the margin of error) to probably upwards of 15HP, as one dyno test apparently proved a few years ago, but don't quote me on it.

My own personal experience in cars with clutch fans assures me that they don't suck up enough power to be noticed. Infact the only time when it pulls hard (right after start up, which only lasts for a brief period) is when I pay attention to them, and you want to know a little secret? I haven't felt a difference from when it 'grips' to when it 'slips'. I guess maybe if my engine had like way less power, the tiny amount the clutch fan uses right before it goes into 'relaxation mode' would be more noticeable. In other words, the clutch fan's drag would work out to be a higher percentage of my total engine output and therefore easier to tell when it is pulling max CFM and when it isn't. But since idle speeds have enough power see the clutch fan through its wake up procedure, I only notice it because I can hear it; that mini cyclone under the hood.

I'll say it once more for any who missed it. I'll use a clutch fan whenever I can. I'll only use electric if I have to, such as in a project car where a clutch fan would not work out. You guys spending big bucks on large radiators and expensive electric fans better be making enough power to justify it. I'd rather spend my monies on lighter flywheels to free up psychological HP.

 

Still waiting on dyno results...got a question....would anybody try doing Ray's video but with a little twist? Wait until the engine is warmed up and then have a friend spin the engine to 7200 rpm and hold it there....NOW put your finger in there...will we have the same results?

 

Listen to Jeff, he has some common sense.

As for me, when the debate switches from the debate to the debater, you know you've won the debate. I'll be keeping my clutch fans.

But I wish you efan guys all the best, really I do! (Drives down the price of clutch fans).

Ray

 

The fan will never rev up to 7200 rpm since there is not enough HP transfered to the fan to and the air resistance will limit the rpm the fan will spin at. On that note, if you rev the engine up to 7200 rpm and the clutch is at the same disengagment, then yes the same will happen.

 

Theory is nice, now prove it with a video where we can see from the inside what the engine is spinning at and then your highly hesitant face as you prove your theory...

Now lemme go check the other thread to see if they did anything or posted anything...most shops will be closed by now. It was a customer car, not any of the owners or tech's...




edit: nada as of 1713 hrs CST....

 

Have you never looked at the operation of a mechanical fan while its freewheeling and while you rev the engine? I have. The fan spins no faster when you get the engine up to 7500 rpm. It may over time spin a LITTLE faster and as the engine heats up gradually the clutch may provide less and less slip but the fan will NEVER hit 7500 rpm.

I would never stick my hand in a running fan, just common sence, but if Ray held that fan and reved up the engine, that fan would not move untill the engine heats up more or untill the radiant heat warms up the clutch to spin the fan a little faster since there would be no airflow while holding the fan still, radiant heat is the only other source of heat to effect the clutch.

so what do you want to prove? Wait for the engine to heat up AT 7500 rpm and stick your finger in the fan? Proving the fan wont spin up to 7500 rpm? You can't hold the fan still when you rev it to 7500 rpm?

The power consumption of the clutch fan will vary depending on the outside temp, engine temp and what location you are at in the united States. For us in New Hampshire where temps may not reach 100*F and usually will be in the 80s to 90s, you think a good operating clutch fan will on a DD or slightly modded engine will rob 10hp from an engine? I don't think so. Down in texas where the temp can get near 120*F or higher from what I have seen anyways on the weather channel, I don't live down there, I can believe the clutch fan would rob even more power especially with high HP engines producing A LOT of heat!

Don't go around saying you will gain 10hp be removing the clutch fan and switching to an e-fan. You will gain what YOU, YOU loose from a good operating clutch fan.

Either way, what are you trying to prove here? Its simple, the fan WILL NOT rev to 7500 rpm. At max engagement it will be around 80% of the engines rpm. That means the fan would potentially spin at 6000 rpm if it was at max engagment which it wont be when the car is warmed up at idle nor will it be when the engines temp has increased due to you holding the rpms at 7500.

 

Maybe the real questions we should be asking are:

1. Which method is more efficient?
2. Which is going to have more of an effect on performance at a time when performance is required (racing, honda at a stoplight, etc.)?

We already know that an efan removes a lot of clutter and obstructions from the engine bay. Is there any weight difference that's worth mentioning?

How about dependability? In the case of the MR2 fans, if one fan goes out you still have one running. But then again, if the clutch fan goes out, it fails in a locked position, right? I'm not quite sure about that one, because I had a Toyota pickup that overheated due to a failed clutch assembly. Are Mazda clutches built differently?

I think it's safe to assume that each version is capable of cooling the engine under any conditions, so maybe it all comes down to aesthetics?

I've already noted the fact that the car seems to have a bit more "zip" in the lower gears with an efan. And when the efan does run, it is drawing off the reserve of power stored in the battery, which can be "made up" over a longer period of time. Whereas the stock fan draws power immediately, every time that it engages. This may (and in my opinion does) have an impact on autocross racing, and probably streetlight racing too.

In the end, it's your car. Nobody can tell you what's right for your own car, so the choice is yours...

 

Depends on the application to which you are questioning.
High hp application will benefit from the e-fan where as stock or slightly modded daily drivers wont see much of anything for a gain when switching.

The electric fan can move more air with less power consumption form the motor but the clutch fan has the potential of moving more air than the electric fan. This is covered in the link I provided.

Electric Fan. Why the hell would you be racing a honda on the street from a stop light anyways?

Another question you could ask, which is more dependable and more ecconomic?
My answers, clutch fan. How long have the original clutches lasted on our cars? 19, 20, 26 years? If you need to replace one, get an OEM clutch not a rebuild from the auto store.

Also, switching to an electric fan requires a bigger alternator since the stock alternator would be able to keep up very well.

The electric fan is usually installed incorrectly with the wrong terminals, wrong sized wire, wrong or no fuse or relay, bad crimps, etc. The electric fan has a much GREATER possibility to be far more unreliable than the clutch fan.

Another question. How much "racing" do you do which requires additional cooling from a proper selected electric fan compaired to the amount of daily driving you do where the clutch fan can be a little more effective?

Overloading your alternator is not good practice. This could damage the alternator. When switching to an e-fan, you shuld upgrade your alternator so you have a proper functioning charging system. Besides, a fan will move more air while the systems volts are at 13.5 than 11-12v.

The clutch fan on the 1st gens act a little different than those on the FC. The FC clutches have a wider temperature / engagment range where as the FB has a very short range and consumes more power at a lower temp.

Can a FC clutch fit on a FB water pump shaft?

 

I've seen it and it looks very nice, especially considering all those miles on it. I'm not sure Mazda engineers deigned everything under there to have armor all on it though, but to each his own. Looks are nice, my car has them too and she makes 50% more power than stock to boot. When it comes to cars I'd rather go for a sexy ***** who gives me what I paid for over a cute chick who won't put out on prom night, but hey whatever pulls your wagon. Speaking of pulling, that's exactly what my fully "molested" FB was doing to all the n/a FC's at our meet this past Saturday. Since the FC is a newer model with a bigger engine, I guess I out-engineered Mazda on that one.

Ray you flipped from "maybe I'll try an efan" to "therefore there is no horsepower gained from switching to an efan, stock is better" within just a few posts. If that's not like a politician then I don't know what is.

Its not about you or me Ray, its about cars. A forum member took some pics this weekend at our meet so when he posts them you can judge mine for yourself. But out of generosity I should allow that everyone can't have a low mileage FB that looks and performs great like mine does. No "red, green and everything between" interior on mine, been there done that with two before. Black is the way to go!

 

DJ old buddy, I thought you'd given up on us! Good to see you're back!

Like Ken says, it really comes down to aesthetics, and here we probably do disagree. For example, I'd much prefer the cute chick who won't put out on prom night, makes a better, safer lover and a more reliable wife. To each his own, I say.

About the engine, that's not Armor All, just a light coat of engine oil I use to protect the finishes after a clean up, which I do every month or two (which is the answer to "how does he keep that thing so clean"). Also, use Lexol, a preservative, on your interior plastic and leather, instead of Armor All. Lexol does a much better job than Armor All, which is just a polymer coat.

I was kidding about the "maybe I'll try an efan" stuff, a joke about Ken's argument that you should put an efan in because the cool kids do it. That's a good reason of course, but since an efan offers no advantages, doesn't cool as well and invites a variety of problems, as outlined by others in this post, I'd never switch to one. As for aesthetics, I think the stock clutch fan wins hands down over even a nicely installed efan.

But of course this is all a matter of taste. You like black, I like white. I think red leather interiors are to die for, you'd dye yours black. And I like Hillary. Let me guess, you like Obama? He sure kicked butt in your state!

The good news is that we are both happy and I'm sure I'd like your low mileage 7 too. I never met a 7, or a 7 owner, I didn't like.

Post us some pics, or the link that you mention.

Here's a few of The White One:





And a couple showing the fan clutch and 2GDF installation:

 

A clutch fan and an 8 pound flywheel are more enjoyable than an e-fan and a stock flywheel.

 

Ray, actually I generally vote Republican, but it may be time for a "change". BTW is that not the most overused political buzzword in this whole affair?! Actually after watching the debate the other night I was thinking that an Obama/Clinton or Clinton/Obama ticket would probably be unstoppable.

I like the pics, very sharp. Spark will be one of the next mods I do. I'll have to research it more to see if I do the 2GDF or the DLIDFIS (whatever the hell that acronym is). Also I want to get a 2G fuse block and get rid of the links. Thanks for the tip on the Lexor, I will check it out.

Rotarybeat1287 (Allen) hasn't posted the pics from the meet yet, when he does I'll let you guys know.

 

Hey DJ, you coming down for the OGTA meeting in Suwanee GA tomorrow evening at Crit's house? We can do the 2GDF in the driveway, I think I have a spare. It takes about 20 minutes. I'm looking forward to seeing those pictures of your meet, I'm not sure which one it is, there's so many in the south east these days. Post 'em up!

 

I'd like to do that but its about 4.5 hrs drive away from me. Are you going to DGRR at Fontana in April? Thanks for the offer on the 2GDF, what have you noticed since you installed it? I know the stock ignition peters out in the upper RPMs.

Allen hasn't posted any pics yet but another guy did of us all on the road.
https://www.rx7club.com/showthread.p...9&goto=newpost

 

That's a long drive, although we've had people from Tennessee and the Carolina's drop in before.

You've got a lot of 7's in those photos, looks like fun. A lot of those new fangled FCs and FDs. OGTA is pretty much old school, although we get a few of the newer models.

The 2GDF is pretty much what you'd hope for from an ignition system that sends the spark directly from the coils to the leading plugs, by passing the distributor and rotor and all the spark gaps created in there.

Real smooth idle, better than anything I could get with the stock ignition, smoother acceleration and another mile or two in gas mileage.

Here's a movie:

http://youtube.com/watch?v=n3Va3xwWzVQ

And another one where I forgot to put the distributor cap back on before starting it up:

http://youtube.com/watch?v=kwKlbX0DSRk

There's a write up on it somewhere, you don't need to change the wiring around in the 2GDF coil, basically just hook it up + to + and - to -.

 

well back to topic ... the results are in from the other guy that was doing a dyno of Clutch fan VS Electric fan .... I'll let the graph speak for itself.

 

Very interesting.

On a high horsepower engine the difference would be even larger.

 

No advantages? I think the graph shown here blows that theory out of the water and the only time it will cause any problems is if it's not installed correctly. As for aesthetics, I think my electric looks far cleaner than it did with the clutch fan.

 

Nice installation! We should have a beauty contest:



I'll have to get some better photos!

Is that graph for the volkswagon or the FC? Not sure which is clutch fan or efan? Is there any data for an FB? Especially one that has not been heavily modified, which is what most of us drive?

 

Ray,

The solid curves at the bottom of the graph are for the VW GTI. The top two curves are for the 2nd gen NA. Green curve is the horsepower, blue is the torque. The dashed lines show the stock 2nd gen clutch fan (both HP and torque). The solid lines just above those dashed lines would be the gain from the electric fan switch. The yellow vertical line is a graphical representation of the numbers that are shown on the right. It is a snapshot of one point on the HP/Torque curves for each configuration.

If I'm not mistaken, the FC that was tested is pretty much stock. I think that it would be pretty accurate to just ratio the gains and make an educated guess for the 12A that way. Albeit, it's not perfect, but it would give you a rough idea.

The FC went from 124.3 HP to 135.9 HP. Torque was increased from 97.5 ft-lbs to 106.6 ft-lbs. A 9.33% HP increase, and a 9.33% torque increase.

The FC I believe is rated at 146 bhp, so figure about a 14.9% loss through the drivetrain to get your stock number of 124.3 hp. This seems fairly accurate. An FB is rated at 100 bhp so to the wheels we would expect to see about 85 hp. (Keep in mind we are applying the FC drivetrain losses to the FB, so this may be a little conservative even.)

So, we have determined that a stock FB has somewhere in the neighborhood of 85 whp. A 9.33% increase on that stock setup would give you about 93 whp, or a gain of about 8 horsepower to the wheels.

Jamie