A new electrical project to tackle

[QWK SVT]

So, you've just finished a run down the 1/4, and the engine is well into "normal operating temperature" range, or beyond. Most of us do the same thing, we park the car, pop the hood and walk away, to let it cool down.

There's an electrical fan in the engine bay, just asking to be flipped on. Anyone installed a switch? There's got to be a way to get the fan going, with the ignition off. Most aftermarket e-fans allow this - just a matter of wiring it up right, I would think.

Anyone been down this road, yet? :help:

[FordNut]

So, you've just finished a run down the 1/4, and the engine is well into "normal operating temperature" range, or beyond. Most of us do the same thing, we park the car, pop the hood and walk away, to let it cool down.

There's an electrical fan in the engine bay, just asking to be flipped on. Anyone installed a switch? There's got to be a way to get the fan going, with the ignition off. Most aftermarket e-fans allow this - just a matter of wiring it up right, I would think.

Anyone been down this road, yet? :help:
Difficult with the MM fan. It is controlled by the PCM, not a simple on/off function.

[MarauderMark]

Difficult with the MM fan. It is controlled by the PCM, not a simple on/off function.


How about adding in another type of fan and mounting where though?

[Wires]

We'd need more information about the cooling fan motor. The wiring diagram shows battery power going directly to the motor, and a control input from the ECU.

It seems logical that with proper current steering diodes, a switch could be placed to also activate this input, but without knowing more details about the fan motor, I can't say for sure. Is it just a relay added on? Is it a semiconductor type relay added? Something else?

I was surprised to see this - most cars have the ECU switching a discrete relay. In that case, it's easy to add a switch to energize the coil.

Anyone have any info on this motor? Anyone have a junk CV or GM motor to test the theory?

[Rider90]

Through the Predator you can adjust at what temp the fan kicks in and at which of the 1 of 2 speeds. I would think any tuner would offer this ability...

[martyo]

It's all about relays......ask me how I know! :D

Another "first" for LK.

[LCSO34]

And in with an electric water pump you can throughly cool to your hearts delight. Marty did L/K go this route also?:D

[DEFYANT]

Yet another good idea. I had thought of this when I was into the 4X4 scene. Electic water pump and fan keep everything noce and cool when your 4wheelin.

Can you hook a switch to the PCM to activate the fan? Sorta like the performance tune switches some of us have?

[QWK SVT]

It's all about relays......ask me how I know! :D

Another "first" for LK.OK. I'll ask - How do you know? :poke: Care to share? ;)

I would think 10 - 15 minutes with the fan goin should really help cooldown the engine between runs, without drawing all the juice out of the battery. It works for Lightnings who swap mechanical for electrical fan, why not here...

[DirtyDog]

I have an "On" switch under the hood for my electric water pump. I put a red light in the circuit so you know when it's on, you can't hear the pump running.

[David Morton]

In my opinion this is worse than a waste of effort. This is techno-bling and can hurt more than help.

First off, I've done a lot of running down at the BMP and never had mine run hot. I've also never noticed it run any better "cool". It runs better cold as in just cranked it up in the morning but I doubt anybody's gonna get one that cold at the track in 30 minutes no matter what you do.

Second and more importantly, cold metal wears faster, that's why there's a thermostat. 195-210 degrees is best for wear. 160 degrees and you are wearing out the cylinder walls ten times faster. I've seen the wear charts.

My car is cooling adequately and that's enough for me.

[SergntMac]

I experimented with add-on fans two summers ago. I attached two 7" Deraile fans to my intercooler heat exchanger, and one to my second tranny cooler. Both fans lasted the summer, and died in the fall. When considering if they should be replaced, or, just retired, I concluded that the fans helped keep things cooler while stopped at idle or stuck in slow moving traffic. However, at highway cruise speed they blocked more free flowing air than they produced, and that's not good. I removed them.

I agree with David Morton's comments too, at the track I'm running 180 to 185 degrees engine water temp, and I concentrate on my water-to-air coolant temps for the lowest possible reading. I have found no difference in performance at normal operating temp, vs. cooler temps, and the only thing I try to stay away from, is hot lapping. You should give the car a breather between runs, or you will heat soak oil and coolants.

[MikesMerc]

the only thing I try to stay away from, is hot lapping. You should give the car a breather between runs, or you will heat soak oil and coolants.

Good advice indeed!

[Gagfish]

Just run an A/B switch with A set at the 12v+ from the PCM and B as a 12v+ constant. Should take all of 10 minutes to install.

[FordNut]

Why not just program the PCM to run the fan at 170 degrees, turn on the key in the staging lanes or between rounds and the electric water pump will run along with the fan until the water cools down. Only problem is you can't forget about it for hours on end or the electric water pump will leave the battery dead. Ask me how I know...

[martyo]

Why not just program the PCM to run the fan at 170 degrees, turn on the key in the staging lanes or between rounds and the electric water pump will run along with the fan until the water cools down. Only problem is you can't forget about it for hours on end or the electric water pump will leave the battery dead. Ask me how I know...

That will also keep the fuel pump running.

[FordNut]

That will also keep the fuel pump running.
Not on a returnless system like the Marauder is equipped with from the factory. The signal from the PCM turns the pump on & off to regulate fuel pressure, so once the pressure is up, the pump quits running.

[Lidio]

Not to trying to talk any one out of this, cause I'm all for it on 1/4 mile cars, but....


The electric fan on a MM is a variable speed. It’s not as simple as an on/off thing. The computer actually varies the speed based on the engine temp and A/C inputs. It’s possible you'd get lucky and find the PCMs trigger wire for it and simply fully ground it or send a full 12V to it, and the fan might go to full speed but I'm not sure. Try it at your own risk I guess. I haven’t.

Or just tap into the main 12V large wire right at the fan for full speed. For the fan to run while the engine is off, its best to also have an electric water pump too to circulate the water for a good cool down while the engine isn’t running as you already know or would guess. But once the thermostat closes it’s all done any way. On race cars this works good because with electric water pumps you traditionally don’t use a thermostat ( you use the fan to dictate water temp). You just run the pump and fan till its as cooled off as you want it. I raced my MM a lot last year in some pretty hot Michigan weather and it was particularly hot at FFW at Norwalk….Engine temps that get a little high don’t bother me as much as the way the rest of the under hood temps tend to get and the way the rest of all of the components tend to get hot soaked on warm days while the engine runs with the hood closed. A warmed over or hot EFI intake manifold with long runners will hurt you more then hot water temps.

In these conditions I like to open the hood (like most probably do anyway) facing away from the sun or in the shade if there is any time between runs for as long as possible. This to me makes a big diffenrce on a lot of cars. As we all know heat rises. I cant stand a hot soaked EFI intake, there’s a lot of metal there that can put heat into the incoming air to some extent.

[TooManyFords]

Marty, you mentioned you have done something like this...

My thinking on this and with what Lidio has added is that to make this really work we need to remove the thermostat, have an electric water pump and insert some relays into the fan motor circuit. [long sentence alert!]

My questions are:

1. Has anyone actually done the thermostat delete yet?

2. If so, what is the average engine temp when warmed up?

3. Is it less than 188?

4. How long does it take for the 4.6 to reach operating temperature if you remove the thermostat? (I've always been taught that the engine is ready to go as soon as it is started, but to not stress it till it warms up to insure rings and bearings expand and seal correctly. YMMV)

I guess I need to look up the 4.6 cooling path to see how this would/could all come together and make our cars do "double duty".

Cheers!

John

[FordNut]

The electric fan on a MM is a variable speed. It’s not as simple as an on/off thing. The computer actually varies the speed based on the engine temp and A/C inputs. This is what I thought. It is one reason that Dennis' S/C kit uses a Mustang fan shroud (for fit) but you have to take the Marauder fan out of its shroud and remount it in the new one (for function). The 'stang fan is not controlled as a variable speed like the MM is.

Marty's car has many electrical mods which are unlike any other MM. Fan, Alternator, Fuel system, etc...

Or just tap into the main 12V large wire right at the fan for full speed./QUOTE]That should work, but I would be sure and have the switch or relay disconnect the PCM wires from the fan while it is bypassed. I don't know what kind of circuit is in the PCM to control the fan, but it is possible that back-feeding voltage into the output signal connection could fry something.
[QUOTE=Lidio]For the fan to run while the engine is off, its best to also have an electric water pump too to circulate the water for a good cool down while the engine isn’t running as you already know or would guess. But once the thermostat closes it’s all done any way. .
When the thermostat is closed, the cooling from the fan/radiator doesn't do anything to help cool the engine. But circulating the water in the engine with the electric water pump does help to cool it down a little faster than just letting it sit.

A warmed over or hot EFI intake manifold with long runners will hurt you more then hot water temps.
Precisely the reason I had mine painted with thermal dispersant coating! I don't know if it will help but there is potential.

[QWK SVT]

In my opinion this is worse than a waste of effort. This is techno-bling and can hurt more than help.

First off, I've done a lot of running down at the BMP and never had mine run hot. I've also never noticed it run any better "cool". It runs better cold as in just cranked it up in the morning but I doubt anybody's gonna get one that cold at the track in 30 minutes no matter what you do.

Second and more importantly, cold metal wears faster, that's why there's a thermostat. 195-210 degrees is best for wear. 160 degrees and you are wearing out the cylinder walls ten times faster. I've seen the wear charts.

My car is cooling adequately and that's enough for me.

I'm not saying there's power to be had by doing this, I don't see how there could be any. Consistency, maybe. But, with an efan sitting right there, it seems like a logical move. Helping speed up the cooldown is a good thing, in my books. If I can get a 30-minute cooldown, in a 20-minute timeframe, That's an extra run (and extra smile) per hour :D

I'm curious how hot the Eaton supercharger gets, on top of the 4.6L. Maybe someone can chime in with some details, here. I know the intercooler does wonders, but I suspect that an Eaton that hasn't cooled down is really hampering performance, the way it does in other applications.

In my Lightning with a ported Eaton being spun 4lbs over, I see 16psi on a good cool day. The blower get quite hot, quickly (particularly being spun faster than stock), and performance is adversely affected. Hot lapping is definitely a no-no. Even after a 30 minute period, hood open, 50* with a breeze blowing into the engine bay, it's still quite warm to the touch, without additional cooling mods.

[Gagfish]

As said prior, you need not only the fan running but the ELECTRIC water pump running and the t-stat open to acheive what you want to do. One way you could do this is add in a temp sensor with a relay that will send electrical signal if the water temp is above a specified degree (same as the t-stat temp). This way you can wire up the fan and water pump so the relay will send power to them while the t-stat is open. This way you'll get cooling above a specified temp with the car on or not and they will automatically shut off again when the t-stat closes.

And like you said, it's not a power adder but will help in cool down times.

[Wires]

The electric fan on a MM is a variable speed. It’s not as simple as an on/off thing. The computer actually varies the speed based on the engine temp and A/C inputs. It’s possible you'd get lucky and find the PCMs trigger wire for it and simply fully ground it or send a full 12V to it, and the fan might go to full speed but I'm not sure. Try it at your own risk I guess. I haven’t.

Or just tap into the main 12V large wire right at the fan for full speed.
Not to enter the debate as to whether or not this is a good idea or not, but purely as an acedemic question:

The wiring diagram looks like whatever control module is used is built into the motor - not separate. The power wire is connected to constant 12V, and the "signal" wire from the ECU is what turns the fan on and off, or, as I learned from Lidio , controls the speed depending on temp.

If it's a separate module, then the power wire can be switched directly to the fan with a relay. If it's integrated, then we'd have to know what that signal looks like. I'll borrow the scope from work and see for myself - might be good info to have in case something ever goes wrong.

It might be a PWM signal, and 12 V might turn it on full, or it could fry the module if "full on" is only a 50 percent duty cycle.

I said I wouldn't get into it, but I just now wondered - even with no water flowing (no electric pump) would cooling the radiator have ANY benifit just due to convection currents? (thermostat would be on untill engine cooled.)

[dansenander]

Has anyone ever found a solution to this yet?
Seems to get kicked around, but I have not seen any 'real' posts yet?

Its 96 degrees today and I just hate to let her sit in the garage sweating.

My 94 LT1 Caprice did this stock. Seems to me all cars should.

DS

[Wires]

Well, I'm down here in the garage, using my "garage computer," so, since the Marauder is right here, I took a look. (required a mirror.)

Seems the module IS separate, but it's very close to the motor, and it's all nicely integrated into the motor bracket. (fan assembly? However you want to say it.)

Looks like if one wanted to, it's possible to install an additional relay and control the motor directly - connected so the module feed is disconnected during "normal" operation, and power is fed to the fan during "override" operation.

I still need to take the scope home and look at the signal on the green wire - just to satify my curiosity.