Fordnatics List Archive

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Mail From: chucko (Chuck Fry)

I'm thinking about a similar electric fan setup to the one Robert King
proposed.

My plans call for two fans, perhaps one larger than the other, since
most of the electric fan catalogs do not recommend a single fan for
primary cooling. They would be wired to a pair of thermostatic
switches; the small fan would turn on at a lower temperature than the
large one. The two circuits would be completely independent from each
other all the way back to the fuse box, allowing some redundancy in the
event of a fuse, switch, or fan failure. The smaller fan would be wired
to a circuit that was always powered; the large one would be switched
with the ignition.

I would add a manual override to turn either or both fans on, but not to
disable them.

Any comments? Whose fans are the most reliable? The most efficient
(in terms of watts/cfm)?
-- Chuck

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Mail From: (email redacted) (Scott Griffith, Sun Microsystems Lumpyware)

On Sep 1, Chuck Fry wrote:

> My plans call for two fans, perhaps one larger than the other, since
> most of the electric fan catalogs do not recommend a single fan for
> primary cooling.

Well, you can get always get as elaborate in doing this as you want,
but anything over running a single big fan is probably not an
efficient use of _money_. The electric fan vendors make those
disclaimers so that they don't get sued if Joe Sixpack replaces his
ultra-reliable mechanical fan with an electric one, and blows his
motor because of a, unnoticed fan failure. The failure will probably
be caused by the fuse blowing (if one is used at all!), or because the
yoyo switched the motor's load current with the thermoswitch directly,
leading to fan failure. These are installation problems, not fan
problems, but the manufacturers want none of it anyway. That verbiage
is plain, simple ass-covering, and nothing more.

I run a single 16" Derale electric cooling fan in place of my old
mechanical fan. I do this primarily because it gets one heck of a lot
of cantilevered weight off of the nose bearing on the water pump. I
installed the fan inside the stock shroud, and have no problem with
street overheating.

Whatever fan you use, do yourself a _big_favor and bulletproof it
during installation. Disassemble the motor mounting hardware and
Loctite it, wire it with #10AWG even if the load only requires #14,
fuse it separately... You don't want a failure, and the fact is that
they are easy to avoid.

To install the thermostatic control that I use, I drilled out the
blanked-off port on the thermostat housing (that used to be used for
the Thermal Vacuum Switches in the pre-EFI days), tapped it 3/8" NPT,
and installed a Filko TFS-12 thermal switch. This switch grounds its
terminal at 109degC, and is a very good match for this application (I
thinks it's a Subaru cross reference, but there are lots of other
switches out there that will work as well). I then switch the load for
the fan motor with a nice heavy-duty Bosch continuous-duty 30A relay.
Do the wiring _right_, since it will be the only thing keeping your
motor alive in hot crawl-and-stall traffic. The thermal switch won't
live for long with the motor's 20A startup surges running through it.

You guys can do all sorts of other turd-polishing, with bypasses,
funky logic, redundancy, two-stage fans, and shutoffs and this and
that, but my personal take on something as critical as this is "keep
it simple, stupid!"....

I don't recommend using a fan setup that is always hot, allowing the
fan to run on after the ignition is switched off. This will certainly
lead to a flat battery sooner or later. This type setup works well for
Japanese cars that contain only a gallon of water, and use small
light-alloy blocks that cool by thermosiphon relatively quickly. With
your good old Ford heavyweight cast-iron block and heads, and the two
gallons of coolant all heated up to 195degF, you'll find that the fan
run-on times in the summer will get up to half an hour or so. I know
this, because I had mine set up this way originally... I got tired of
having to bump-start the car very quickly, and set it up to shut off
with the ignition. At the track, if I really want to cool it
gradually, I'll let the car idle for a short while.

-skod

- --
Scott Griffith, Sun Microsystems Lumpyware
expatriate SCCA New England Region Flagging/Communications worker
(and driver, of anything that turns both right and left,
and can pass tech...) Return Path : (email redacted)

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Mail From: (email redacted) (Brian Kelley)


Scott Griffith writes:

>I run a single 16" Derale electric cooling fan in place of my old
>mechanical fan. I do this primarily because it gets one heck of a lot
>of cantilevered weight off of the nose bearing on the water pump. I
>installed the fan inside the stock shroud, and have no problem with
>street overheating.

Looking at the Summit catalog, none of the electric fans are considered
appropriate for cars making more than 300 HP. As I recall, the high
end was 260 HP. I have considered an electric fan for the very
reasons that Scott mentions, but I don't think it will work for me.

It *might* be okay for road course stuff, where you get a cool down
lap and park it. But I don't think that it would cut it for Solo II's
where you might take 10 or 15 runs back to back. Bud Jasman runs a
big flex-a-light flexfan and it seems to work well. You'll cook inside
the car, but the engine will stay cool.

Thoughts? How do you cool a 400 or 500 HP car with an electric fan?

Brian


- --
(email redacted)

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Mail From: "Fontana Peter" <(email redacted)>

> Thoughts? How do you cool a 400 or 500 HP car with an electric fan?

The fan(s) is only needed for low-speed travel or idle, so driving along
passes some air, but I can see where autocrossing can keep you moving
fairly slowly while still taking the engine. If a single fan is
inadequate, then ensure you have a good shroud. Moving up, you can run t
fans side-by-side if the radiator permits (also requiring shrouding to
match), or run one fan as a pusher, and one as a puller.

Just thoughts - I have no experience here, but I can see electric fans in
my future.

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Mail From: "Wilson, Jon, INET ----" <(email redacted)>


> From: (email redacted) (Brian Kelley)
> Thoughts? How do you cool a 400 or 500 HP car with an electric fan?

The harder question would be "how do you increase engine
efficiency to the point that you are not creating huge amounts
of heat that cannot be dissipated by an electric fan?"


----------------------------------------------------------------------
Jon R. Wilson (email redacted)
Programmer/Analyst Team Ada (205) 416-5418 (fax:5654)
Computer Sciences Corporation Montgomery, AL

<<<<<<<<<<<<<< Every disclaimer I can think of applies. >>>>>>>>>>>>>>

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Mail From: (email redacted) (Brian Kelley)


That would definitely be the harder question. And I don't think that
it is really reasonable. Generally, you can get up to about 2.2
HP/cubic inch in a normally aspirated V8. Heat is just a fact of
life and very little can be done about it in a race engine. You're
selecting a cam based on power, not how much heat it makes..

Brian

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Mail From: (email redacted) (Scott Griffith, Sun Microsystems Lumpyware)

On Sep 6, Brian Kelley wrote:

> Looking at the Summit catalog, none of the electric fans are considered
> appropriate for cars making more than 300 HP. As I recall, the high
> end was 260 HP. I have considered an electric fan for the very
> reasons that Scott mentions, but I don't think it will work for me.

Whoopie. Look, the electric fan vendors are bending over backwards to
make sure that the hotrodders who buy from some catalog don't come
after them when their motors melt down due to an installation failure.
"Not for primary cooling, not for motors over 160hp, not actually
intended to be used at all, we were only fooling, please don't sue
us". A very good friend of mine is the president of a fairly major
aftermarket parts company, and damned near lost that company to some
pinhead who decided to sue when his car burned down after he installed
one of the company's composite fuel filters *in direct contact with
one of the primary tubes* on his headers. After all, the instructions
didn't say not to! They just said "The fuel filter casing is resistant
to underhood temperatures".

Duh. But try explaining that to a jury, eh?

I hate this kind of mealy-mouthed shit, but more vendors every day are
learning the hard way that any claims they make about their product
will be used against them in a court of law. And unfortunately, in
many case the wrong vendors are getting cleaned out. I refer to the
ones who make parts that _do_ something, as opposed to the ones who
make parts that don't, and then hype the shit out of them.

There are quite a few race cars out there that are using electric
fans, and aren't melting down into puddles after every run. That
electric fan of mine would work fine with a 400hp motor. It moves over
1000 CFM of air, and I'm happy with it. 1000CFM should be pretty
adequate, assuming decent fin area in the radiator, to cool you right
back down after a hard run.

> It *might* be okay for road course stuff, where you get a cool down
> lap and park it. But I don't think that it would cut it for Solo II's
> where you might take 10 or 15 runs back to back.
> Thoughts? How do you cool a 400 or 500 HP car with an electric fan?

You aren't going out back to back. You'll have a few minutes at idle
between runs, and at idle the heat production of even your mondo motor
is pretty trivial. I'd recommend that you size the rest of your
cooling system appropriately (have a tad bit of reserve capacity, and
a swirl pot), and then just let the damned thing idle until the temps
get back where you like them, assuming that they climb that high to
start with. A four-core aluminum race radiator will probably be
loafing with that kind of thermal load, and 1000CFM should be jes'
fine to keep things chilly.

-skod

- --
Scott Griffith, Sun Microsystems Lumpyware
expatriate SCCA New England Region Flagging/Communications worker
(and driver, of anything that turns both right and left,
and can pass tech...) Return Path : (email redacted)

This read-only message was archived from a public mail list.
Mail From: (email redacted) (Brian Kelley)


Scott Griffith writes:

>You aren't going out back to back. You'll have a few minutes at idle
>between runs, and at idle the heat production of even your mondo motor
>is pretty trivial.

Actually, we do go out back to back. That is the best way to get the
tires really hot. Some events are run heat style where you sit
between runs. Around here that often isn't the case. When you come
off course you have priority to pull right back up to the start.

During test days or fun runs after an event, we often get to run as
much as we want or _can_. The big question is if your car will take
the heat (and your tires - but I'm running road race tires, so it
behooves me to run back to back). We've taken 15 or 20 back to back
runs in Bud's car before, using a couple of drivers. The big question
with his well debugged setup is how long the driver can stand the
heat. And believe me - when you remove the interior and wrap your
headers, the heat that gets dumped under the driver and passed through
the firewall is truly oppressive on a hot day. I don't think the
hotbox in most prison movies is that bad!

As far as idle heat, you are correct. It isn't a big deal - IF you're just
dealing with idle heat. But I don't believe that is the case. In Solo II,
your run is over in a flash and a lot of the heat is still sitting in
the block, heads and coolant. It hasn't left the car despite the fact
that it has stopped moving.

Bud gave electric fans a really good try and has been running a 4 core
for years. He couldn't get the electric fans to work. He spoke to
Flex-a-lite (they make both high capacity electrics and the flex fans)
and they really didn't have any answers.

The GT1 car we ran last season was a former TA car. It had a hugely
thick aluminum radiator, excellent shrouding, two oil coolers on
either side of the radiator, etc. After the cooldown lap, the car
would come in and the coolant temps would immediately jump to 265. It
had a single electric fan. I'm surprised it didn't melt! It did not
do much to bring the temps down. It was tough getting the temps back
down for a co-driver race 35-40 minutes later.

>I'd recommend that you size the rest of your
>cooling system appropriately (have a tad bit of reserve capacity, and
>a swirl pot),

Can you recommend a good swirl pot setup? I've been looking.
Speedway is out of stock and Coleman and SCP don't list anything in
their catalogs that I have found.

> and then just let the damned thing idle until the temps
>get back where you like them, assuming that they climb that high to
>start with. A four-core aluminum race radiator will probably be
>loafing with that kind of thermal load, and 1000CFM should be jes'
>fine to keep things chilly.

I've got a four core now, but it isn't aluminum. I've seen a few AS
cars with 4 core aluminum radiators and cooling problems.. Though I'm
sure not all aluminum radiators are created equally..

But for the moment, I've got the flex fan and I'm fairly certain that
it will work fine. Once I establish a better baseline, I can
experiment with a good electric setup and have something definitive to
compare it with. But whenever I bring up electric fans with Bud he
shakes his head and immediately starts doomsaying. And I've got to
respect anyone who's been flogging a '79 5.0 that hard since '79.

Brian


- ---
(email redacted)

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Mail From: (email redacted) (Scott Griffith, Sun Microsystems Lumpyware)

On Sep 7, Brian Kelley wrote:

> Actually, we do go out back to back...
> During test days or fun runs after an event, we often get to run as
> much as we want or _can_. We've taken 15 or 20 back to back
> runs in Bud's car before, using a couple of drivers.

Well, at this point I have to bail out. I have no experience with
events like that. This particular application is nothing like anything
I've ever tried, and it may well be that there is no way to set up a
cooling system for enough reserve capacity to allow a smaller-volume
fan to do the job. It's almost like a fixed-installation problem (like
a generator powerplant, or something similar) where you run at full
power with no ram air at all. You're out of my league.

The sad thing is that if you optimize the cooling system for this
particular end of the spectrum, you could start to run into airflow
problems when you get to speed, as you will on a real road course. You
definitely have a problem there, sir, and it may well be that a
mechanical fan is the only thing that'll save you.

That's the first time I ever heard of an autocross style event where
you could just keep going. Shoot, if there were more of them like
that, I might try it. I got burned on the "run for 30 seconds, sit for
2 hours" style of event, I guess.

> Can you recommend a good swirl pot setup? I've been looking.
> Speedway is out of stock and Coleman and SCP don't list anything in
> their catalogs that I have found.

I've seen several. It's not too hard to make them, and the one I'm
contemplating will probably be very simple. Moroso makes a header
tank that is adaptable to being a swirl pot of sorts, and the
aluminum housing is easy to tap and install bleed lines and the like.
By the time mine is done, I'll be running 3AN hard lines from each
head, the waterpump housing, and the radiator tank to the pot, and
splicing it into the heater outlet/pump inlet.

"Swirl" is less important than providing a good artificial high point
in the system for bubbles to be trapped and bled off, but sure as heck
won't hurt... If you feel like fabricating something, and like welding
aluminum, you could easily make your own by welding a water inlet
tangentially up high on a 3" tube about 6" long, and blocking off the
bottom and top and installing a radiator cap neck on top and a water
outlet on the bottom. Smallbore bleed lines don't have to be
tangential- the flow of water from the large-bore heater line will set
up the swirl.

The goal is just to get the water to swish around a couple of times on
the sides of the pot so that bubbles can collect, before it runs on
out the bottom and on to the pump. That way, bubbles check in, but not
out, and the pot can be set up to be the lowest-pressure point in the
system, so that gas bubbles will migrate in and be trapped above the
liquid surface. Set it up with a standard check-valve style pressure
cap and run a coolant recovery tank on the vent line, and you'll have
a very nice self-bleeding system. Trick as hell.

-skod

- --
Scott Griffith, Sun Microsystems Lumpyware
expatriate SCCA New England Region Flagging/Communications worker
(and driver, of anything that turns both right and left,
and can pass tech...) Return Path : (email redacted)

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Mail From: (email redacted) (Dave Williams)


-> My plans call for two fans, perhaps one larger than the other, since
-> most of the electric fan catalogs do not recommend a single fan for
-> primary cooling.

Bah. The Corvettes are rated at 300hp and don't puke their coolant on
nice 115F autocrosses or track events, and they have no engine driven
fans. They use two electric fans, 5 blade, 11.77" dia, 2200 RPM. I
forget what the current draw is offhand.


------------------------------

year. TRW, Speed Pro,
Hastings, and others all agreed: no synthetics on initial startup, even
with moly or ceramic rings. No exceptions. These are the people who
make the damned things, anyway, and we're talking about a lousy $6 of
dino juice for the fire-up oil, which ain't gonna be in there long
anyway.

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Mail From: Dan Malek <(email redacted)>



[...this got lost in our mail hub during a power failure,
so I am sending it again. Sorry for the delay...]

> Date: Tue, 6 Sep 1994 12:11:34 -0400
> From: Brian Kelley <(email redacted)>
>
>

>Looking at the Summit catalog, none of the electric fans are considered
>appropriate for cars making more than 300 HP. As I recall, the high
>end was 260 HP. I have considered an electric fan for the very
>reasons that Scott mentions, but I don't think it will work for me.

Ummm, why would an electric fan be rated on the HP output of an
engine?

>It *might* be okay for road course stuff, where you get a cool down
>lap and park it. But I don't think that it would cut it for Solo II's
>where you might take 10 or 15 runs back to back. Bud Jasman runs a
>big flex-a-light flexfan and it seems to work well. You'll cook inside
>the car, but the engine will stay cool.

>Thoughts? How do you cool a 400 or 500 HP car with an electric fan?

Well, NASCAR requires you run an electric fan. They don't like any
of that spinning metal (or worse, fiberglass) on the front of an
engine. Our GN cars are around 500 HP, and the unrestricted Winston Cup
is over 700 HP, so I don't see much of a problem on any other car.
There is nothing trick about these fans either, I think ours came from
the Motorsport catalog.

The one we use is fairly small, and crude. It covers, maybe, one half
of the radiator at most, and we just bolted it right to the radiator.
Literally, just bolts through the fins with big washers on the front.
Any kind of bracket would have just added weight, without providing
any benefit, so quick and dirty does the job again :-). We "pull
through" the radiator, that is the fan is between the engine and the
radiator. Others use a "push through" where the fan is on the front
of the radiator. Both work, just use whatever is convenient.

We don't have any kind of temperature switch, just a toggle switch
on the dash. If it starts getting too hot, just flip it on. One wire,
one less place for a water leak (no temperature sensor).

Of course, if you don't have sufficient air flow to cool the water,
it won't matter what kind of fan you use. Our GN T-Bird will "cool itself"
if it is not in traffic and we are at racing speeds. At any other time,
like caution laps, in the pit, or in traffic, the fan is usually running.

Keep your cool!


-- Dan