O I am trying to decide to go to an electric fan or stock fan on my 88 rx7. Is there any noticeable difference between the two cooling wise?

 

The Myth Of The Electric Fan

 

Too many variables to answer definitively, but in general, no.
Sufficient airflow is sufficient airflow, the radiator doesn't care how the air is provided.

That said, I much prefer electric fans, for a variety of reasons.

 

And what are those reasons?

 

I hate electric fans.
You lose the "tool tray" on the car.Otherwise known as the stock rad shroud.

For this solution you get a Electric fan with shroud(like a Merc Villager fan),a new alternator and a corsport front rad panel.

 

So I assume it doesn't matter what fan you put in there? I already have a new alternator on there with a double pulley too.

 

It's really personal preference. The biggest pro for an electric fan is a cleaner looking engine bay/easier access to the engine.

If going electric I believe it's said you want something that flows atleast 2800 cfm or better.

Do some research on it.

 

If you go electric,then try to simplify things and get a fan setup that will pretty well fit the Rad and you do not have to make any shrouding for it.
I opted for the Merc Villager fan and you just cut a small piece and Bob is your uncle.Installed with some L brackets.
A Fiero Fan(V6) is good and also the Taurus Efan or Lincoln I have heard is good too.

BUT there is nothing wrong with a Good Operational Stock Fan,so really it is your decision on what you do.
The Efan cleans up the engine bay a bit,that is about it.Makes things a little more visible.

 

I don't mind my stock fan, the only reason I would go electric is to free up some space.

I never priced a stock fan clutch, but maybe I would consider switching if it was a very pricey item

 

Free up space for what?
Switching to an efan left a giant gaping hole in front of my engine, space that I've filled with, ahh...well, nothing.

So far unmentioned, the best and most useful attribute of the electric fan is the ability to accurately control its operation.
The stock fan is a dumb, brute force solution to providing airflow, it has only the most general idea of what the coolant is actually doing.
A well set up fan control circuit will respond much more quickly and effectively to temp variation than the thermoclutch ever could.

After five years of efan operation I'm also prepared to say that you DO get a net horsepower gain using an efan...the whole "Increased draw on the alternator offsets the mechanical drag of the thermofan" argument is bullshit because it ignores the fact that the efan is hardly ever on.
There is always parasitic drag from the thermoclutch, it never disengages and free spins. The efan is only on for brief periods under normal circumstances.

Last summer I took a road trip and during the entire 3300 miles the fan came on twice, for a total of less than 15 minutes.
During the winter, as long as ambient is under @50°, even city driving doesn't trigger the fan. I check mine periodically just to make sure it still works because I don't think it has triggered on in months.
The FC is my only car and a daily driver, BTW.

I would ignore the "extra room" and "extra power" arguments as mere distractions, the real reason to use an efan is the more precise control it gives you over the cooling system, a critical component in the rotary package.

It is worth noting that even Aaron Cake, author of the cited "Myth" article, uses electric fans on his projects.
So there.

Mazdatrix lists it for $246, Rock Auto doesn't list it at all.

 

stock fan for stock car cant be beat, for modified car it cant be beat

control what? the thermostat controls the temperature the fan just keeps it in check

a properly operating stock set up is very hard to beat and keeps the car running very cool even on hot days , in traffic with the AC going I rarely seen 190 degrees

 

And how many people are spending $250 to ensure they have " a properly operating stock fan"?
How many 25 year old thermoclutches still work at spec?

What do you mean "control what"?
You control the amount of time the fan is on, obviously.

 

first off- If his fan is still working he should leave it alone

I dont see the need to control how long the fan is on, all the FCs I had with stock fans kept the car right in the 180-190 degree range keeping it simple is really nice sometimes

 

As owner of the nicest FC I know of your opinion must be respected, so I guess we'll just agree to disagree on this one.

I see no advantage to the stock fan other than it's already there.

 

if not operating- yes make a change, if its working keep it simple and dont touch it

sound good?

 

Sure it does.
To be fair though, that doesn't seem to be the approach you took with your car.

 

If your clutch fan can't be stopped by a single finger (wear thick gloves if testing this!) while the engine is running, the clutch is sticking. In which case yes, it is wasting a little power.

The clutch fan is only creating any significant load when the temperature dictates, just like the e-fan.

Weird. Every RX-7 car I've ever tuned will constantly toggle the e-fan during city and low speed driving. It's all datalogged.

Good bloody luck fitting large turbos, intercooler piping, air filter and associated upgrade parts with the stock mechanical fan.

Also note that I tried for a year to use a SPAL FAN-PWM to bring the gradual clutch-fan behavior to my on-off e-fan. Ultimately I gave up because the SPAL FAN-PWM sucks rancid donkey *****. But on my Cosmo, I used two smaller e-fans and have them programmed in stages to provide more linear temperature control vs. on-off. E-fans were used on the Cosmo due to space concerns and because A/C is installed.

 

I reject the "power consumption" argument as specious anyway, hardly significant either way except to note that the thermoclutch ALWAYS loads the engine because it never decouples.



Although I have an optimal setup for cooling- no AC and a NA engine- I'd credit my car's behavior more directly to the trigger temps of the fan.
My LOW speed (this is an 18" Lincoln fan, BTW) doesn't toggle on till 195° and I can sit for quite a while before hitting that point.


I never found more sophisticated control to be necessary.
Although my setup is hooked to the ECU and activates the BAC when the fan comes on, I usually can't tell if the fan is on till I see the VDO water temp gauge plummet. There isn't much noise or noticeable effect when it triggers.
I don't believe it has EVER gotten hot enough to switch to HIGH, which in my case is 210°.

 

Except that when the fan is idle, it's only spinning due to the slight friction of the bearings in the fan clutch. Romp the throttle and the engine speed increases while the fan freewheels unless the temperature is past the clutch engagement point. A properly working fan clutch is not a power drain in anything but a minuscule amount. Certainly well within a non-lab dyno's margin of error.

Though this is a wide assed guess, an idling air pump probably takes more engine power to turn than an idling clutch fan.

The way I see it, either fan will do the job just fine. Except that it's so easy for people to screw up an e-fan install that most are best served just keeping the stock clutch fan. I have had arguments with people installing e-fans because they say the fans I am recommending are "huge" and "bigger then ma' V8!". Then they come to me with overheating cars and I say "Yep, told you".

That's a pretty light load, and a higher trigger temp than I would be comfortable with in a modified turbo car, but I can see how in this case assuming a properly functioning rad, the fan doesn't trigger very often. It would annoy the hell out of me seeing the temp gauge wag up and down, and that's a much higher temp than Mazda runs the engine at.

More and more OEMs these days are PWM'ing their e-fans to act like clutch fans. More stable temperature control, and an electrical load that can be gradually increased and tailored to the cooling needs of the engine. All translates to better mileage and a smoother experience for the driver. People like to complain about OEMs but the fact is that they are now selling cars with 150K+ warranties, which are so refined that if the FC was produced today, it would be regarded as junk.

 

No, it isn't.
The FD for instance, doesn't trigger low speed fannage till 221°.

 

Everyone should remove the stock fan because it sucks. If you add an electric fan, you gain like 20HP. Also, ditch the thermowax because it adds heat to the intake, robbing you of at least 15HP! All stock equipment on this car is bad!

 

I love the smell of hyperbole in the morning.

 

Sadly, there are people who wouldn't quite understand that level of sarcasm and hyperbole.

 

SOLD

Thank you sir for the clarity and reason enough to purchase one. I always thought to myself, the stock one does JUST fine, can't argue that. BUT, E fan looks so CLEAN. I have only had one REAL concern about efans, that is the hint of it going out. With fan clutch I hear it, can spin it, and you can see it go out with the way the temp reads and car runs.

Your comment of consistancy makes total sense. Who doesn't want accuracy? And the benefit of much easier access to work on the car.

Thank you.

 

then pay me!