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| [GMCnet] electric radiator fan [message #111783] |
Wed, 12 January 2011 17:37  |
Terry Skinner
Messages: 379
Registered: January 2004
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Well, I am still thinking about an electric fan. In fact I am thinking
about mounting the electric fan in back of the radiator and removing
the shroud, stock fan, and the fan clutch. That way a lot more air
would be free to move thru the engine compartment and the radiator.
Here comes the catch. I don't want the fan to be on all the time. Low
speed or stopped, all I can get. Above 35/40 MPH, not needed. So how
about some sort of a variable pulse power supply. Before you say no
that is how the new cars control the electric fan. All done with the
on-board computer, which I do not have. How do I come up with a
variable pulse power supply?? Can I tie it to the temperature and
speed of my GMC??...........Terry
--
Terry Skinner
253-686-2624
Roy. Washington
'76 GMC
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| Re: [GMCnet] electric radiator fan [message #111786 is a reply to message #111783] |
Wed, 12 January 2011 17:41  |
Steven Ferguson
Messages: 3447
Registered: May 2006
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Terry,
I set up my '57 Chevy so the ele fan was activated by relay via brake pedal
switch. Never had an issue and that was with the stock radiator.
On Wed, Jan 12, 2011 at 4:37 PM, Terry Skinner <gmcnut@gmail.com> wrote:
> Well, I am still thinking about an electric fan. In fact I am thinking
> about mounting the electric fan in back of the radiator and removing
> the shroud, stock fan, and the fan clutch. That way a lot more air
> would be free to move thru the engine compartment and the radiator.
> Here comes the catch. I don't want the fan to be on all the time. Low
> speed or stopped, all I can get. Above 35/40 MPH, not needed. So how
> about some sort of a variable pulse power supply. Before you say no
> that is how the new cars control the electric fan. All done with the
> on-board computer, which I do not have. How do I come up with a
> variable pulse power supply?? Can I tie it to the temperature and
> speed of my GMC??...........Terry
>
> --
> Terry Skinner
> 253-686-2624
> Roy. Washington
> '76 GMC
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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Steve Ferguson
Sierra Vista, AZ
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| Re: [GMCnet] electric radiator fan [message #111788 is a reply to message #111786] |
Wed, 12 January 2011 17:51 |
Terry Skinner
Messages: 379
Registered: January 2004
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Maybe you are on the right track. Between a temperature sensor and the
brake light switch it just might work..............Terry
On Wed, Jan 12, 2011 at 3:41 PM, Steven Ferguson <botiemad11@gmail.com> wrote:
> Terry,
> I set up my '57 Chevy so the ele fan was activated by relay via brake pedal
> switch. Never had an issue and that was with the stock radiator.
>
> On Wed, Jan 12, 2011 at 4:37 PM, Terry Skinner <gmcnut@gmail.com> wrote:
>
>> Well, I am still thinking about an electric fan. In fact I am thinking
>> about mounting the electric fan in back of the radiator and removing
>> the shroud, stock fan, and the fan clutch. That way a lot more air
>> would be free to move thru the engine compartment and the radiator.
>> Here comes the catch. I don't want the fan to be on all the time. Low
>> speed or stopped, all I can get. Above 35/40 MPH, not needed. So how
>> about some sort of a variable pulse power supply. Before you say no
>> that is how the new cars control the electric fan. All done with the
>> on-board computer, which I do not have. How do I come up with a
>> variable pulse power supply?? Can I tie it to the temperature and
>> speed of my GMC??...........Terry
>>
>> --
>> Terry Skinner
>> 253-686-2624
>> Roy. Washington
>> '76 GMC
>> _______________________________________________
>> GMCnet mailing list
>> List Information and Subscription Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>
>
>
> --
> Steve Ferguson
> Sierra Vista, AZ
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Terry Skinner
253-686-2624
Roy. Washington
'76 GMC
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| Re: [GMCnet] electric radiator fan [message #111803 is a reply to message #111783] |
Wed, 12 January 2011 19:39 |
Craig Lechowicz
Messages: 541
Registered: October 2006
Location: Waterford, MI
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Terry,
As far as I know, GM (and probably the other automakers) don't do variable speed controls of their electric fans, as the fans aren't very efficient at lower speeds, and it's easier to use the thermal mass of the coolant to level out the cooling needs from fan on to fan off. Some vehicles have used either 2 speed fans, or 2 fans switched separately. Usually this is done to run the low speed or a single fan of the 2 fan pair, when the a/c is on, but the coolant temperature isn't excessive in order to improve a/c performance. But, in any case, the computer is supplying either one or two on or off signals to a relay(s). What you call pulse is what is typically called pulse width modulated or PWM which is used for other motors or lights that want variable outputs, but not radiator cooling fans that don't need that level of precision. The newer cars switch this through the computer as it's essentially free, and saves them having to buy another temperature sensor.
Either of these kits from Summit would probably accomplish what you are trying to do. I'll also stay out of the debate over electric fans in general.
<http://www.summitracing.com/parts/FLX-31147/>
<http://www.summitracing.com/parts/SUM-890015/>
Craig Lechowicz
'77 Kingsley, Waterford, MI
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| Re: [GMCnet] electric radiator fan [message #111816 is a reply to message #111783] |
Wed, 12 January 2011 20:51 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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| Terry Skinner wrote on Wed, 12 January 2011 15:37 |
Well, I am still thinking about an electric fan. In fact I am thinking
about mounting the electric fan in back of the radiator and removing
the shroud, stock fan, and the fan clutch. That way a lot more air
would be free to move thru the engine compartment and the radiator.
Here comes the catch.
--
Terry Skinner
253-686-2624
Roy. Washington
'76 GMC
|
Terry,
Sean (Duce Apocalypse) did quite an involved installation and test this summer. It was most interesting. There were parts I, II and III. Here is a link to part of his work:
http://gmc.mybirdfeeder.net/GMCforum/index.php?t=msg&goto=92627&rid=0
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: [GMCnet] electric radiator fan [message #111850 is a reply to message #111783] |
Thu, 13 January 2011 06:04 |
g.winger
Messages: 792
Registered: February 2008
Location: Warrenton,Missouri
Karma: 0
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The problem with most elec. fans is they are to small for a 12000+ vehicle. If you look in the Jegs or Summit catalog they have fans for 12k +. Listed for 2500HD or 1ton Duramax Diesel PU. They weigh 6600+ and tow 15 to 20k(new ones rated to tow 22000 for a total of 28000+). But they run in excess of 500 bucks. Ford super coupe fans are suposed to be very strong. I've read this on other boards. But they draw more current than most of the fan controlers(most fan controlers are made for 1 fan and a max of about 50 amps). Up to as much as 40 amps EACH,,,,,and you need TWO!!!!! Look at the past posts on this forum. Alt upgrade AND bigger wire/isolator,,,,ETC. would help. I think a well thought out plan and shroud/system would work. This is all my opionion of course,,,,,,GL,,,,keep us posted,,,,,,PL
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| Re: [GMCnet] electric radiator fan [message #112001 is a reply to message #111850] |
Fri, 14 January 2011 11:51 |
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Well, I must say I forgot to update my progress, my 2supercoupefans are still getting the job done, and recently performed well on a nearly 1000 mile trip which involved pulling many grades, including the Grapevine and Tehachipi(sp?).
The only problem I have had was with the controller, I used the flex-a-lite controler from their ford superduty fans, the problem is the 2 supercoupe fans draw a combine 60 amps when at full blast, that exceeds the 45 amp rated current for the flexalite controller. so Ihad to put one of the fans on an accessory relay which is triggered when the controller activates the other fan. Iam thinking about switching to a Dakota Digital controller which can handle 70 amps and 2 fans and using the flexalite for one of my Mustangs.
The Supercoupe fans draw about 4300 CFM so the pair will pull 8600 CFM a full speed, and these fans do cool! I actually disconnected one of the supercoupe fans to see if one would do the job, and even one managed to cool the engine and shut off, but 2 fans dispatch the heat much faster and the fan on time is usually about a minute before shutting off. if there is enough ramair on a mild day they dont come on at all. in the summer they may come on only when under high load. when I tested them in 105 degree heat going up and down a grade it held tems around 205-210 degrees. my fans are set to come on a little after 210, and shutdown below 200. so far so good! I would like to custom desing a fan and shroud to maximize their effectiveness, the GMC can be cooled electrically, I think I proved that pretty well.
asfor the alt, I am using a CS144 of a 95 Caddy, this is an upgrade you should do even if you dont want to run electric fans, simply because it will keep the battery charged and headlights bright. I got mine from a mens mall for $30 and the 6ga charge cable for free. cant beat that 
| g.winger wrote on Thu, 13 January 2011 06:04 |
The problem with most elec. fans is they are to small for a 12000+ vehicle. If you look in the Jegs or Summit catalog they have fans for 12k +. Listed for 2500HD or 1ton Duramax Diesel PU. They weigh 6600+ and tow 15 to 20k(new ones rated to tow 22000 for a total of 28000+). But they run in excess of 500 bucks. Ford super coupe fans are suposed to be very strong. I've read this on other boards. But they draw more current than most of the fan controlers(most fan controlers are made for 1 fan and a max of about 50 amps). Up to as much as 40 amps EACH,,,,,and you need TWO!!!!! Look at the past posts on this forum. Alt upgrade AND bigger wire/isolator,,,,ETC. would help. I think a well thought out plan and shroud/system would work. This is all my opionion of course,,,,,,GL,,,,keep us posted,,,,,,PL
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73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
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| Re: [GMCnet] electric radiator fan [message #112005 is a reply to message #112001] |
Fri, 14 January 2011 12:43 |
Terry Skinner
Messages: 379
Registered: January 2004
Karma: 0
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Senior Member |
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Have you considered using two of the flex-a-lite controllers?? That
way you could program the first to come on at 200 and the second to
come on at 210. You might find that one fan is all that is required
most of the time.
Where are the fans? Front or behind the radiator?? How close to the
radiator?? Have you tried all this without a shroud?? If you are using
a shroud do you use flap valves ala VW Rabit??
OK we will quit with this first group of questions. Don't want to
scare you off.<VBG>..........Terry
On Fri, Jan 14, 2011 at 9:51 AM, Shan Rose <defconfx@gmail.com> wrote:
>
>
> Well, I must say I forgot to update my progress, my 2supercoupefans are still getting the job done, and recently performed well on a nearly 1000 mile trip which involved pulling many grades, including the Grapevine and Tehachipi(sp?).
>
> The only problem I have had was with the controller, I used the flex-a-lite controler from their ford superduty fans, the problem is the 2 supercoupe fans draw a combine 60 amps when at full blast, that exceeds the 45 amp rated current for the flexalite controller. so Ihad to put one of the fans on an accessory relay which is triggered when the controller activates the other fan. Iam thinking about switching to a Dakota Digital controller which can handle 70 amps and 2 fans and using the flexalite for one of my Mustangs.
>
> The Supercoupe fans draw about 4300 CFM so the pair will pull 8600 CFM a full speed, and these fans do cool! I actually disconnected one of the supercoupe fans to see if one would do the job, and even one managed to cool the engine and shut off, but 2 fans dispatch the heat much faster and the fan on time is usually about a minute before shutting off. if there is enough ramair on a mild day they dont come on at all. in the summer they may come on only when under high load. when I tested them in 105 degree heat going up and down a grade it held tems around 205-210 degrees. my fans are set to come on a little after 210, and shutdown below 200. so far so good! I would like to custom desing a fan and shroud to maximize their effectiveness, the GMC can be cooled electrically, I think I proved that pretty well.
>
> asfor the alt, I am using a CS144 of a 95 Caddy, this is an upgrade you should do even if you dont want to run electric fans, simply because it will keep the battery charged and headlights bright. I got mine from a mens mall for $30 and the 6ga charge cable for free. cant beat that :)
>
>
> g.winger wrote on Thu, 13 January 2011 06:04
>> The problem with most elec. fans is they are to small for a 12000+ vehicle. If you look in the Jegs or Summit catalog they have fans for 12k +. Listed for 2500HD or 1ton Duramax Diesel PU. They weigh 6600+ and tow 15 to 20k(new ones rated to tow 22000 for a total of 28000+). But they run in excess of 500 bucks. Ford super coupe fans are suposed to be very strong. I've read this on other boards. But they draw more current than most of the fan controlers(most fan controlers are made for 1 fan and a max of about 50 amps). Up to as much as 40 amps EACH,,,,,and you need TWO!!!!! Look at the past posts on this forum. Alt upgrade AND bigger wire/isolator,,,,ETC. would help. I think a well thought out plan and shroud/system would work. This is all my opionion of course,,,,,,GL,,,,keep us posted,,,,,,PL
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Terry Skinner
253-686-2624
Roy. Washington
'76 GMC
_______________________________________________
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List Information and Subscription Options:
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| Re: [GMCnet] electric radiator fan [message #112011 is a reply to message #112001] |
Fri, 14 January 2011 15:19 |
 |
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Shan,
Sorry for not remembering but do you have a standard or aluminum radiator?
I searched the photo site for "fan" but nothing came up.
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Shan Rose
Sent: Saturday, January 15, 2011 4:52 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] electric radiator fan
Well, I must say I forgot to update my progress, my 2supercoupefans are
still getting the job done, and recently performed well on a nearly 1000
mile trip which involved pulling many grades, including the Grapevine and
Tehachipi(sp?).
_______________________________________________
GMCnet mailing list
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] electric radiator fan [message #112022 is a reply to message #112011] |
Fri, 14 January 2011 21:17 |
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@Robert,
I still gotta get the pix of my install up, I actually made video which I shot in full HD, so I have to run it though some software and grab stills as well as actually edit and post the videos online. I need to get pix of the install on my GMC page since a picture is worth a thousand words after all. And yes, I still am running the stock radiator. cant afford the aluminum job yet, though I suspect that would even do better with my fan setup. I must say not having to hear the stock fan during warm up and while driving is the biggest advantage to going electric.
@Terry,
No questions are to many when doing this kind of a project, from what I gather from all the previous posts I seem to be one of the only people to successfully cool a GMC with electric fans, and it has been a bit of trial and error during this process, as one can imagine. as for my setup the fans are behind the radiator in the traditional position, the stock fan, shroud, horse collar and clutch are deleted, and 2 super coupe fans now occupy about half that space since they are only about 4-5 inches thick. the SC fans come molded with their own shroud, so I adapted them for use with the GMC. they are oriented at 45 degrees or about 2 o'clock and 235 degrees or approx 7 o'clock positions if you are in the coach facing front. This was the easiest way to mount them which doesn't interfere with the radiator coolant lines. The only lines which had to be moved were the oil cooler lines, which required 90* elbows be added to keep them from interfering with the mounting of the upper fan. I then drilled the mounting holes in the radiator frame with a right angle drill, this is the only way to get them in such a tight spot, and then used metal screws though the shroud to secure the fans. on the lower fan I fashioned 2 brackets secured from home depot for about a dollar and some change, this allowed a lower mounting point for the lower fan since the 2 17.25 inch fans are a little larger then the radiator frame, as a result the lower fan hangs over about an inch, but this is acceptable since these fans were never designed for this application and such a small gap will not cost too much cooling efficiency. the fans themselves spin only a couple inches from the radiator, and the Central area there is a gap of an inch or so. I think using some pipe insulation I may be able to seal the shrouds to the core, thus creating 2 ducted cooling areas. I would estimate about 75% of the total surface area of the radiator is covered by the fans. I really need to get some pictures up...
As for fan controllers, the flexalite cost $100, the Dakota digital about $130, I was interested in getting the fans in for the least amount of money possible, in retrospect as you suggest a second flexalite controller would offer the ability to tune the second fan to come on at a higher temp and thus providing extra cooling, the wiring would not be much more complicated than what I finally wound up doing. the only weak link in the flexalite system is the temperature probe which needs to be as close to the radiator inlet as possible to ensure that it provides consistent results. the wires were too short so I had to lengthen them. the Dakota Digital controller IIRC uses a temperature sender actually mounted in the coolant stream itself rather than a probe wedged in the fins of the radiator. I suppose some thermal transfer sealant like what is used on computer chips to heat sinks would improve the felxalite system to the point where the difference between the two would be negligible.
if you have any other questions, fire away...
| Robert Mueller wrote on Fri, 14 January 2011 15:19 |
Shan,
Sorry for not remembering but do you have a standard or aluminum radiator?
I searched the photo site for "fan" but nothing came up.
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Shan Rose
Sent: Saturday, January 15, 2011 4:52 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] electric radiator fan
Well, I must say I forgot to update my progress, my 2supercoupefans are
still getting the job done, and recently performed well on a nearly 1000
mile trip which involved pulling many grades, including the Grapevine and
Tehachipi(sp?).
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
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