Home » Public Forums » GMCnet » Radiator Electric Fans
| Radiator Electric Fans [message #92370] |
Sun, 18 July 2010 10:47  |
bryant374
Messages: 563
Registered: May 2004
Location: Pleasant Valley, NY 12569
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There has been considerable discussion here to find an electric fan replacement for the original fan/fan clutch. As I understand it, a good electric fan possibility has been found, although a high current draw requires a new alternator, new wiring, additional brackets, controller, relays, etc.
Here is where I am aparently missing something. I have traveled over 260thousand GMC miles under all weather conditions, without problems in maintaining normal operating conditions, with OEM equipment. Don't get me wrong, I support upgrades & improvements that provide better performance in needed areas. Here is where I am aparently missing something, replacement of a simple well performing system, with a system that requires a number of additional parts (which likely means lower reliability) in an unproven application for questionable gain, brings me back to my question, what am I missing?
I'm sure someone out there will set me right :^)
Thanks
Bill Bryant
PO 1976~PB (owned 34 years)
1914 Ford (owned 70 years)
1965 Corvette (owned 39 years)
GMC Motorhome History
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 Re: Radiator Electric Fans [message #92375 is a reply to message #92370] |
Sun, 18 July 2010 11:03  |
GeorgeRud
Messages: 1380
Registered: February 2007
Location: Chicago, IL
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I don't think you're missing anything! It does seem that there are some folks that are always looking for a "better" way, and the GMClist provides an outlet for their ideas. In the long run, some things work, and others don't.
As technology improves, there are some gains to be made. However, as you pointed out so well, there is the old adage of "if it ain't broke, don't fix it". I personally enjoy hearing of people's ideas, though I certainly don't apply all of them.
George (who's still looking for that 20 mpg magic bullet!)
George Rudawsky
Chicago, IL
75 Palm Beach
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| Re: Radiator Electric Fans [message #92378 is a reply to message #92370] |
Sun, 18 July 2010 11:32 |
g.winger
Messages: 792
Registered: February 2008
Location: Warrenton,Missouri
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Bill, I'm still a rookie. Only 5% of the GMC distance that you"ve driven. With that in mind, I would like to have a little better performance when stopped out of my AC. It seems performance is poor when stopped and the fan clutch is disengaged. If I have the clutch that Steve tested (4949) and ran 357rpm's at an engine speed of 1320, I would like more air flow. As soon as I get moving the AC seems colder. Also, I would like to clool the radiator and engine with a timer(like Arch??) when stoped,,resturants, campgrounds, etc. I mounted a 140amp when I built the supentine setup when switching to the Caddy. So thets one less item to swap. I respect your opinion, and envy the distance/time youve had with your GMC. I do like the KISS theory though. It appears my F. clutch is inop so thats next. Best regards, due respect,,,,,PL
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| Re: Radiator Electric Fans [message #92389 is a reply to message #92378] |
Sun, 18 July 2010 12:46 |
bryant374
Messages: 563
Registered: May 2004
Location: Pleasant Valley, NY 12569
Karma: 1
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snip...
With that in mind, I would like to have a little better performance when stopped out of my AC. It seems performance is poor when stopped and the fan clutch is disengaged. If I have the clutch that Steve tested (4949) and ran 357rpm's at an engine speed of 1320, I would like more air flow. As soon as I get moving the AC seems colder.
>
>
>
I'm not sure we can get any better performance from our AC compressor when the engine is at a low speed or idle. I notice performance of an AC will improve at RPMs above idle even on modern cars. Any connection between a fan clutch and AC performance is likely coincidental.
Just my opinion.
Bill Bryant
PO 1976~PB (owned 34 years)
1914 Ford (owned 70 years)
1965 Corvette (owned 39 years)
GMC Motorhome History
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| Re: Radiator Electric Fans [message #92394 is a reply to message #92370] |
Sun, 18 July 2010 13:10 |
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There is no doubt that a huge fan right behind the condenser will improve AC performance. One of the 2 fans I have installed sits right behind the portion of the radiator where the condenser is, and will toggle to full power when the AC is activated.
As for those who seem to poopoo the idea of an Electric fan being a worthy update, because "the stock system is sufficient" to that I say why bother updating the GMC at all, since when it rolled off the assembly line everything on it was functional and "sufficient" with that attitude we would never have had all the snazzy updates that we have now like the reaction arm brakes, 4 bag systems, updated front ends and so on.
I for one got tired of the racket and drag the old fan put on the motor, when it came on I could feel the engine loose power. while there is significant drag on the alternator when the electric fans engage, it feels like much less of a drag on the motor and it is on for a much shorter time period. since I had to do my water pump it made sense for me to do this experiment since I had to remove all the old fan stuff anyway. I might add that with the fans, controller, and wiring and even the CS alt I'm only into this project for about $200-$250 and once I know what works that cost to repeat will go down dramatically.
I might also add that I have not upgraded the alternator as of yet, and no new brackets are needed, just slight mods to the alternator and existing brackets and it will function just fine. basically I think the alternator is a system on our coach which should be updated to a CS alt anyway, its a worthy update and will give you superior charging. the alt update is just one that you should do even if you do not run an electric fan IMHO.
73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
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| Re: [GMCnet] Radiator Electric Fans [message #92396 is a reply to message #92370] |
Sun, 18 July 2010 13:11 |
tmaki
Messages: 200
Registered: September 2005
Karma: 0
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On 7/18/2010 8:47 AM, Bill Bryant wrote:
>
> There has been considerable discussion here to find an
> electric fan replacement for the original fan/fan clutch.
> Here is where I am aparently missing something.
> replacement of a simple
> well performing system, with a system that requires a
> number of additional parts (which likely means lower
> reliability) in an unproven application for questionable
> gain, brings me back to my question, what am I missing?
I'm kind of with you on this, Bill.
I've been studying the cooling system with respect to some
of the ideas presented, and of course that study includes
understanding the original design and its components.
There have been several ideas for improvement as we know.
But nowhere in any of the discussions of the topic that I've
seen over the last 11 years has there been any discussion of
the fan shroud and what has lovingly been called the"horse
collar" -- except to get rid of it, and then only to make
changing belts, etc. easier.
That "horse collar" is an integral part of the cooling
system, and GM clearly makes a case that the rubber seal
should be intact all around. The more important part of the
assembly is that that several pounds of steel is a venturi
ring and has a designed purpose, which I am convinced was
not to use up surplus steel that GM picked up over in the
foundry yard on Montcalm St.
I'd like to know more about why it has been found beneficial
to remove this part, how removing it might contribute to
degrading cooling system performance, and how aftermarket
fan shroud assemblies have addressed the design function of
the venturi ring.
I understand the venturi principles involved. My study of
this part and its function has taken me to several other
disciplines, and I'm not convinced that removing it
contributes to better cooling system performance.
I have no cooling issues with my GMC at this point and it
has the original radiator, and a replacement AC/Delco fan
clutch with intact fan shroud, venturi ring and surrounding
seal. And it gets driven in the kind of heat that seems to
put others on the side of the road.
I'd like to know more.
Toby Maki
'73 Glacier 230
Riverside, CA
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| Re: [GMCnet] Radiator Electric Fans [message #92402 is a reply to message #92396] |
Sun, 18 July 2010 13:26 |
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I understand the concept of the venturi ring, it was to maximize efficiency of the stock fan by creating a ducted and focused airflow via negative pressure in front of the fan. given that the stock fan was set so far back from the radiator, a method had to be devised to focus the airflow. Don't get me wrong, GM did a great job of getting it done, but I think that almost 40 years later there may be some better options out there. It should be noted that the stock shroud does not cover the total surface area of the radiator. though I have not done any hard number crunching my 2 17.25 fans cover more surface area then the singular 19" fan used in the stock application. my power fans are also mounted just under an inch off the radiator, though I should seal the shrouds for maximum air draw, however what little air seepage around them that there may be seems to be irrelevant...
| tmaki wrote on Sun, 18 July 2010 13:11 |
On 7/18/2010 8:47 AM, Bill Bryant wrote:
>
> There has been considerable discussion here to find an
> electric fan replacement for the original fan/fan clutch.
> Here is where I am aparently missing something.
> replacement of a simple
> well performing system, with a system that requires a
> number of additional parts (which likely means lower
> reliability) in an unproven application for questionable
> gain, brings me back to my question, what am I missing?
I'm kind of with you on this, Bill.
I've been studying the cooling system with respect to some
of the ideas presented, and of course that study includes
understanding the original design and its components.
There have been several ideas for improvement as we know.
But nowhere in any of the discussions of the topic that I've
seen over the last 11 years has there been any discussion of
the fan shroud and what has lovingly been called the"horse
collar" -- except to get rid of it, and then only to make
changing belts, etc. easier.
That "horse collar" is an integral part of the cooling
system, and GM clearly makes a case that the rubber seal
should be intact all around. The more important part of the
assembly is that that several pounds of steel is a venturi
ring and has a designed purpose, which I am convinced was
not to use up surplus steel that GM picked up over in the
foundry yard on Montcalm St.
I'd like to know more about why it has been found beneficial
to remove this part, how removing it might contribute to
degrading cooling system performance, and how aftermarket
fan shroud assemblies have addressed the design function of
the venturi ring.
I understand the venturi principles involved. My study of
this part and its function has taken me to several other
disciplines, and I'm not convinced that removing it
contributes to better cooling system performance.
I have no cooling issues with my GMC at this point and it
has the original radiator, and a replacement AC/Delco fan
clutch with intact fan shroud, venturi ring and surrounding
seal. And it gets driven in the kind of heat that seems to
put others on the side of the road.
I'd like to know more.
Toby Maki
'73 Glacier 230
Riverside, CA
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73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
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| Re: [GMCnet] Radiator Electric Fans [message #92411 is a reply to message #92394] |
Sun, 18 July 2010 13:48 |
jw mills
Messages: 199
Registered: September 2006
Karma: -30
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Senior Member |
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On Sun, 2010-07-18 at 13:10 -0500, Shan Rose wrote:
>
> SNIP
> As for those who seem to poopoo the idea of an Electric fan being a worthy update, because "the stock system is sufficient" to that I say why bother updating the GMC at all, since when it rolled off the assembly line everything on it was functional and "sufficient" with that attitude we would never have had all the snazzy updates that we have now like the reaction arm brakes, 4 bag systems, updated front ends and so on.
The reason is that NO ONE EVER has a problem with their fan clutch.
Just like a hammer any changes are strictly embellishments.
Now be for I get nuked (nest stage beyond flamed) I quote Foghorn
Leghorn " That's a joke, son, a joke"
--
Jim Mills
Greeley, CO
1973 CanyonLands 260 TZE-063V100731(under renovation)
1973 Glacier 230 TZE-033V101993
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| Re: [GMCnet] Radiator Electric Fans [message #92423 is a reply to message #92402] |
Sun, 18 July 2010 14:40 |
tmaki
Messages: 200
Registered: September 2005
Karma: 0
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Senior Member |
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On 7/18/2010 11:26 AM, Shan Rose wrote:
>
>
> I understand the concept of the venturi ring, it was to
> maximize efficiency of the stock fan by creating a ducted
> and focused airflow via negative pressure in front of the
> fan.
Yes, exactly. (Also see the new Dyson fan - different
application, same principle.)
Believe me, I dug your idea and implementation so much that
I went out to the Pick A Part out here on Milliken in
Ontario and found a TB SC with fan intact. If I'd had the
tools, I'd probably already have that thing installed. If it
hadn't been snot-boiling hot the last week, I might have
gone over there again.
Your idea is a complete departure from the original design
and has a high level of merit. It needs to be judged based
on what you intend and how it turns out, and not compared to
the performance of the original components and their
performance. Which gets me back to my original curiosity,
how have changes to the original system that discard the
venturi ring helped or hindered the quest for better system
performance?
I'm not sure an answer can be found, as there are just too
many variables out there. We know the GMC has a GVWR of
either 10500 or 12500. Are folks who have cooling problems
running way over GVWR, pulling 25000 lbs. of trailer, or
doing something else outside the design envelope? Are their
systems maintained to specification?
I'm just curious to know if an alternative to the venturi
ring was installed, did it really help in a way that either
operating within the design envelope of the original or
maintaining all parts of the system to the design
specification wouldn't have? And if the alternative didn't
implement the venturi ring, why didn't it? What was the
reasoning behind abandoning it?
Keep working on those fans. I like it. I don't like the high
current draw, but I didn't used to like lima beans, either.
Toby Maki
'73 Glacier 230
Riverside, CA
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| Re: [GMCnet] Radiator Electric Fans [message #92432 is a reply to message #92370] |
Sun, 18 July 2010 15:41 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
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Senior Member |
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Bill,
All of the new replacement clutch fans come on at 10% lower temps
than the OEM ones they replaced. I hit a wall with clutch fans. I
cannot find one that works. By works I mean that comes on around 210
and shuts of around 195 give or take on both numbers. I tested many
new ones on the bench and in my GMC and they all seem to engage
waaaaay to often and stay disengaged for too short of a period of
time. Quite a few others are having the same problem. Heck, with
the alum radiator, I drove for almost 2 years on a dead clutch fan
(died disengaged) and never saw temps over 205. I have gone through
three replacements and none of them are working like I think they
should. A controllable electric seems a good alternative to me.
Hang on to what you've got if it's working because I dont think you're
going to find a replacement you will be happy with.
On Sun, Jul 18, 2010 at 8:47 AM, Bill Bryant <bryant374@earthlink.net> wrote:
>
>
> There has been considerable discussion here to find an electric fan replacement for the original fan/fan clutch. As I understand it, a good electric fan possibility has been found, although a high current draw requires a new alternator, new wiring, additional brackets, controller, relays, etc.
>
> Here is where I am aparently missing something. I have traveled over 260thousand GMC miles under all weather conditions, without problems in maintaining normal operating conditions, with OEM equipment. Don't get me wrong, I support upgrades & improvements that provide better performance in needed areas. Here is where I am aparently missing something, replacement of a simple well performing system, with a system that requires a number of additional parts (which likely means lower reliability) in an unproven application for questionable gain, brings me back to my question, what am I missing?
>
> I'm sure someone out there will set me right :^)
> Thanks
> --
> Bill Bryant
> 1976~PB
> 1914 Ford
> 1965 Corvette
> GMC MH History CD
> GMC Showroom Films DVD
> http://bdub.net/billbryant/
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
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| Re: Radiator Electric Fans [message #92480 is a reply to message #92370] |
Sun, 18 July 2010 20:27 |
WayneB
Messages: 233
Registered: July 2008
Location: Ontario, Canada
Karma: 0
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I think the electric fan modification Mr.Apocalypse has performed is technically interesting but my personal opinion is that he is taking something of a gamble assuming the electric system will work as well as the OEM setup in preventing overheating and resulting engine damage in all operating and hot weather conditions some of which he may not have yet encountered.
GM developed and tested the original engine driven setup in all weather conditions including the Desert Proving Grounds in Arizona so one would think its a pretty foolproof and somewhat reliable system.
Dont get me wrong, I hope his experiment is a resounding success but it will not be one I am willing to risk on my rig.
My 1997 Buick Roadmaster Wagon came stock with electric fans unless you specified the towing package and then it came with an engine driven fan which mine has.
I guess when traveling at lower speeds with the engine under heavy load forwards airflow through the rad and electric fans couldn't generate enough CFM of air to adequately cool the motor.
1976 23' GMCII By Explorer
[Updated on: Sun, 18 July 2010 20:31] Report message to a moderator |
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| Re: [GMCnet] Radiator Electric Fans [message #92572 is a reply to message #92564] |
Mon, 19 July 2010 11:55 |
Steven Ferguson
Messages: 3447
Registered: May 2006
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thanks Dave.
I'd sure like to play with this stuff. I'm buried in control arm
orders right now and my sandblasting shed hits about 125 deg around
noon time. Just too darn hot for this old fart.
On Mon, Jul 19, 2010 at 9:44 AM, Dave Mumert <dave@mumert.com> wrote:
> Hi Steve
>
> Here are some big fans (3000 cfm), I have no idea what cfm the TB SC fan is
> capable of.
> http://www.thehoffmangroup.com/autoloc/details.lasso?itemid=ZFU14
> http://www.thehoffmangroup.com/zirgo/
>
> Here is a source of fan clutches as well, you have probably checked these
> already.
> http://www.compressorworks.com/default.aspx?page=Fanclutches
>
> Dave
>
>
>> -----Original Message-----
>> Subject: Re: [GMCnet] Radiator Electric Fans
>>
>> Sure would be nice to find an affordable one Paul. I haven't found one
> under
>> $400.
>>
>> On Sun, Jul 18, 2010 at 4:35 PM, Paul Leavitt <leavittpaul@yahoo.com>
>> wrote:
>> >
>> >
>> > I like the idea of the electric fan clutch. The benifits of both.
>> > Power directly off the crank. On and off when you want. Programed off
>> > a controler or an ECM. If it works for a GM diesel with over 600lbs.
>> > of torque it would work for us. But i would't have my timer controled
>> > fan like Arch. I'll try to get some photos and bring to Duquoin.PL
>> > _______________________________________________
>
> _______________________________________________
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--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
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| Re: [GMCnet] Radiator Electric Fans [message #92603 is a reply to message #92581] |
Mon, 19 July 2010 18:05 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
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Senior Member |
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Howard,
95 deg outside, 125 in my shed where the sand blast cabinet is. It's
a blast furnace in there.
On Mon, Jul 19, 2010 at 12:06 PM, Howard and Sue <hnielsen2@cox.net> wrote:
> Steve;
> 125 deg?????????
> You are always telling me how cool it is S V?
> As you say much cooler then Phoenix.
> Howard
>
>
> thanks Dave.
> I'd sure like to play with this stuff. I'm buried in control arm
> orders right now and my sandblasting shed hits about 125 deg around
> noon time. Just too darn hot for this old fart.
>
> On Mon, Jul 19, 2010 at 9:44 AM, Dave Mumert <dave@mumert.com> wrote:
>> Hi Steve
>>
>> Here are some big fans (3000 cfm), I have no idea what cfm the TB SC fan
>> is
>> capable of.
>> http://www.thehoffmangroup.com/autoloc/details.lasso?itemid=ZFU14
>> http://www.thehoffmangroup.com/zirgo/
>>
>> Here is a source of fan clutches as well, you have probably checked these
>> already.
>> http://www.compressorworks.com/default.aspx?page=Fanclutches
>>
>> Dave
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
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--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
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