Home » Public Forums » GMCnet » Re: [GMCnet] GMC specific Electric Fan kit: gauging interest
| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141062] |
Fri, 26 August 2011 10:42  |
sgltrac
Messages: 2797
Registered: April 2011
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Electric fans do pull a lot of current which must load the alternator. I wonder what kind of hp drop a burdened alternator creates compared to an engine driven fan with the clutch engaged?????
Sully
77 royale
------Original Message------
From: Keith V
Sender: gmclist-bounces@temp.gmcnet.org
To: gmclist@temp.gmcnet.org
ReplyTo: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] GMC specific Electric Fan kit: gauging interest
Sent: Aug 26, 2011 8:02 AM
Boy it's REALLY hard to beat a fan powered by a 455 cubic inch engine ....
Thermo clutches have time and time again proven to be the most efficient way to cool a vehicle and no electric fan made pulls as much air.
that said electrics are REALLY nice!
More room, no shroud etc
But also very $$$
--
Keith
69 Vette
29 Dodge
75 Royale GMC
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141075 is a reply to message #141069] |
Fri, 26 August 2011 12:15  |
sgltrac
Messages: 2797
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Thanks matt
Sully
77 royale
Sent from my Verizon Wireless BlackBerry
-----Original Message-----
From: Matt Colie <matt7323tze@gmail.com>
Sender: gmclist-bounces@temp.gmcnet.org
Date: Fri, 26 Aug 2011 12:03:59
To: <gmclist@temp.gmcnet.org>
Reply-To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] GMC specific Electric Fan kit: gauging interest
sgltrac wrote on Fri, 26 August 2011 11:42
> Electric fans do pull a lot of current which must load the alternator. I wonder what kind of hp drop a burdened alternator creates compared to an engine driven fan with the clutch engaged?????
>
> Sully
> 77 royale
Oh Sully,
Now I have to go look for the cooling fan and the power electric hats at the same time. - There they are....
Now, We have some givens here:
746 Watts = 1 Horsepower so 1Hp ~ 50A @ 14.7V
Efficiency of modern electric machines is 95~99%
The fan on anything as old as a GMC (stamped metal) is not a very efficient fan.
Properly (not all) molded fans can be pretty efficient and only have to be so at one shaft speed (makes a difference).
So - The efficiency of an electric drive is about a wash with other methods of controllable fan drives.
Fact - The fan on a 2001 Jeep 4.7 draws about 75Amp.~ 1.5Hp
There are some reasons for each method:
- Thermostatic fan clutches save fuel and they are simple and by and large effective.
- The parasitic load of a fan and thermal clutch never really goes to zero.
- Electric fans can run at full with the engine at idle. Nothing like a TCS is required.
- When an electric an is not powered, there is zero parasitic load.
- Big Thing is packaging, The FEAD (Front Engine Accessory Drive) people do not have to provide something in the right place relative to the radiator to drive a fan.
Matt
--
Matt & Mary Colie
'73 Glacier 23 Chaumiere (say show-me-air) Just about as stock as you will find
SE Michigan - Twixt A2 and Detroit
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141102 is a reply to message #141062] |
Fri, 26 August 2011 15:38 |
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The unit I'm looking at would draw about 50 amps and move 7k+ cfm. I should note that in my experience on an 80 degree day with the aluminum rad temps never go north of 195 at highway speed. Meaning my fans only go on at low speeds like in traffic...
73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
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| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141119 is a reply to message #141062] |
Fri, 26 August 2011 18:14 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
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Unless some basic laws of physics are revoked, the electric will take more power than the directly driven one - assuming equal efficiency and equal airflow. The electrics nay be more efficient, and can be had which move more air.
--johnny
--- On Fri, 8/26/11, sgltrac@gmail.com <sgltrac@gmail.com> wrote:
From: sgltrac@gmail.com <sgltrac@gmail.com>
Subject: Re: [GMCnet] GMC specific Electric Fan kit: gauging interest
To: gmclist@temp.gmcnet.org
Date: Friday, August 26, 2011, 3:42 PM
Electric fans do pull a lot of current which must load the alternator. I wonder what kind of hp drop a burdened alternator creates compared to an engine driven fan with the clutch engaged?????
Sully
77 royale
------Original Message------
From: Keith V
Sender: gmclist-bounces@temp.gmcnet.org
To: gmclist@temp.gmcnet.org
ReplyTo: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] GMC specific Electric Fan kit: gauging interest
Sent: Aug 26, 2011 8:02 AM
Boy it's REALLY hard to beat a fan powered by a 455 cubic inch engine ....
Thermo clutches have time and time again proven to be the most efficient way to cool a vehicle and no electric fan made pulls as much air.
that said electrics are REALLY nice!
More room, no shroud etc
But also very $$$
--
Keith
69 Vette
29 Dodge
75 Royale GMC
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141123 is a reply to message #141119] |
Fri, 26 August 2011 18:47 |
James Hupy
Messages: 6806
Registered: May 2010
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Johnny, The clutch fans, being belt driven, always have parasitic drag, even
when the clutch is not engaged. The electric fans, while they tax the
alternator quite a bit when they are running, are only required when the
thermodynamic load requires them to run. At the end of the day, the belt
driven fans require more energy to be expended than the electric ones do
over the life of the engine. That is why you see very few belt driven fans
on modern vehicles. We just need to match the cfm with the heat load and
make the system fit into the space available. It isn't an impossible task,
just a difficult one, when costs and availability need to be sorted out for
the relatively short production runs like our GMCs require. If I stopped and
figured out the total costs involved in production of my tools, I probably
get paid $4.00 or $5.00 an hour for the effort. If I didn't feel some sense
of obligation to the GMC community, I probably wouldn't do it. But the
activity keeps my mind sharp and keeps me from dwelling on negative things
like the loss of my wife. I think Chuck A, and Dave Lenzi, and many others
that make stuff for these coaches feel the same as I do. If we didn't do it,
then who will?
Jim Hupy
Salem, OR
78 GMc Royale 403
On Fri, Aug 26, 2011 at 4:14 PM, Johnny Bridges <jhbridges@ymail.com> wrote:
> Unless some basic laws of physics are revoked, the electric will take more
> power than the directly driven one - assuming equal efficiency and equal
> airflow. The electrics nay be more efficient, and can be had which move
> more air.
>
> --johnny
>
>
> --- On Fri, 8/26/11, sgltrac@gmail.com <sgltrac@gmail.com> wrote:
>
>
> From: sgltrac@gmail.com <sgltrac@gmail.com>
> Subject: Re: [GMCnet] GMC specific Electric Fan kit: gauging interest
> To: gmclist@temp.gmcnet.org
> Date: Friday, August 26, 2011, 3:42 PM
>
>
> Electric fans do pull a lot of current which must load the alternator. I
> wonder what kind of hp drop a burdened alternator creates compared to an
> engine driven fan with the clutch engaged?????
>
> Sully
> 77 royale
> ------Original Message------
> From: Keith V
> Sender: gmclist-bounces@temp.gmcnet.org
> To: gmclist@temp.gmcnet.org
> ReplyTo: gmclist@temp.gmcnet.org
> Subject: Re: [GMCnet] GMC specific Electric Fan kit: gauging interest
> Sent: Aug 26, 2011 8:02 AM
>
>
>
> Boy it's REALLY hard to beat a fan powered by a 455 cubic inch engine ....
>
> Thermo clutches have time and time again proven to be the most efficient
> way to cool a vehicle and no electric fan made pulls as much air.
>
> that said electrics are REALLY nice!
> More room, no shroud etc
>
> But also very $$$
> --
> Keith
> 69 Vette
> 29 Dodge
> 75 Royale GMC
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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>
> Sent from my Verizon Wireless BlackBerry
> _______________________________________________
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| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141127 is a reply to message #141123] |
Fri, 26 August 2011 19:09 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
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| James Hupy wrote on Fri, 26 August 2011 18:47 |
At the end of the day, the belt driven fans require more energy to be expended than the electric ones do over the life of the engine.
|
That sounds like an off the cuff statement.
Show me something that adds up all the loses in both systems.
( or tell me you actually know this fact to be true)
Most cars BTW, have their engines mounted transversely so a mechanical fan ( without going the Corvair route ) cant use a mechanical fan
There is also the noise issue. Modern cars do a lot of little things to get quieter. I'd bet this is a biggie.
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141134 is a reply to message #141127] |
Fri, 26 August 2011 19:47 |
 |
ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
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I don't doubt that in a vehicle like our motorhomes the electric fan will draw substantially less horsepower than the OEM fan over time. The parasitic losses on the freeway would be eliminated, and much of our driving is on the freeway. Also, in stop and go traffic, where you need the maximum cooling from the fan, the engine is at low RPM's. An electric fan is not tied to engine speed and can therefore pull whatever it's programed to do.
Furthermore - if the Onan were running on a hot day for the roof AC and the radiator fan could be powered off of it, then the horsepower loss to the coach would be zero. Not that 3 or 4 horsepower from the alternator would be missed. I see promise in the electric fan.
Larry Davick
Fremont, California
The Mystery Machine
'76 (ish) Palm Beach
----- Original Message -----
From: "Keith V" <my427v8@hotmail.com>
To: gmclist@temp.gmcnet.org
Sent: Friday, August 26, 2011 5:09:49 PM
Subject: Re: [GMCnet] GMC specific Electric Fan kit: gauging interest
James Hupy wrote on Fri, 26 August 2011 18:47
> At the end of the day, the belt driven fans require more energy to be expended than the electric ones do over the life of the engine.
That sounds like an off the cuff statement.
Show me something that adds up all the loses in both systems.
( or tell me you actually know this fact to be true)
Most cars BTW, have their engines mounted transversely so a mechanical fan ( without going the Corvair route ) cant use a mechanical fan
There is also the noise issue. Modern cars do a lot of little things to get quieter. I'd bet this is a biggie.
--
Keith
69 Vette
29 Dodge
75 Royale GMC
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Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141141 is a reply to message #141127] |
Fri, 26 August 2011 20:29 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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In all this efficiency figurin' somebody should consider the drag of an
un-powered fan. Take it from a multi-engine prop driven airplane driver:
An un-powered windmill creates a LOT of drag. And the airflow behind what
becomes essentially a solid disc is very restricted. Unless the proposed
fan can somehow be feathered (blades streamlined into the wind), it will
probably be advisable to keep it powered all the time -- preferably at a
rate varying with vehicle speed.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com
On Fri, Aug 26, 2011 at 8:09 PM, Keith V <my427v8@hotmail.com> wrote:
>
>
> James Hupy wrote on Fri, 26 August 2011 18:47
> > At the end of the day, the belt driven fans require more energy to be
> expended than the electric ones do over the life of the engine.
> ...
>
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Ken Henderson
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141208 is a reply to message #141123] |
Sat, 27 August 2011 11:35 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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Wasn't knocking it - which is why I mentioned system efficiancy. By your analysis the electric system is more efficient. In modern cars, according to my GM eigineer friend, the cost and complexity of a reliable right angle drive for east-west engines (the majority of production) is saved by going to an electric fan. The benefit of no drag when it isn't needed is the icing on the cake.
--johnny
--- On Fri, 8/26/11, James Hupy <jamesh1296@gmail.com> wrote:
From: James Hupy <jamesh1296@gmail.com>
Subject: Re: [GMCnet] GMC specific Electric Fan kit: gauging interest
To: gmclist@temp.gmcnet.org
Date: Friday, August 26, 2011, 11:47 PM
Johnny, The clutch fans, being belt driven, always have parasitic drag, even
when the clutch is not engaged. The electric fans, while they tax the
alternator quite a bit when they are running, are only required when the
thermodynamic load requires them to run. At the end of the day, the belt
driven fans require more energy to be expended than the electric ones do
over the life of the engine. That is why you see very few belt driven fans
on modern vehicles. We just need to match the cfm with the heat load and
make the system fit into the space available. It isn't an impossible task,
just a difficult one, when costs and availability need to be sorted out for
the relatively short production runs like our GMCs require. If I stopped and
figured out the total costs involved in production of my tools, I probably
get paid $4.00 or $5.00 an hour for the effort. If I didn't feel some sense
of obligation to the GMC community, I probably wouldn't do it. But the
activity keeps my mind sharp and keeps me from dwelling on negative things
like the loss of my wife. I think Chuck A, and Dave Lenzi, and many others
that make stuff for these coaches feel the same as I do. If we didn't do it,
then who will?
Jim Hupy
Salem, OR
78 GMc Royale 403
On Fri, Aug 26, 2011 at 4:14 PM, Johnny Bridges <jhbridges@ymail.com> wrote:
> Unless some basic laws of physics are revoked, the electric will take more
> power than the directly driven one - assuming equal efficiency and equal
> airflow. The electrics nay be more efficient, and can be had which move
> more air.
>
> --johnny
>
>
> --- On Fri, 8/26/11, sgltrac@gmail.com <sgltrac@gmail.com> wrote:
>
>
> From: sgltrac@gmail.com <sgltrac@gmail.com>
> Subject: Re: [GMCnet] GMC specific Electric Fan kit: gauging interest
> To: gmclist@temp.gmcnet.org
> Date: Friday, August 26, 2011, 3:42 PM
>
>
> Electric fans do pull a lot of current which must load the alternator. I
> wonder what kind of hp drop a burdened alternator creates compared to an
> engine driven fan with the clutch engaged?????
>
> Sully
> 77 royale
> ------Original Message------
> From: Keith V
> Sender: gmclist-bounces@temp.gmcnet.org
> To: gmclist@temp.gmcnet.org
> ReplyTo: gmclist@temp.gmcnet.org
> Subject: Re: [GMCnet] GMC specific Electric Fan kit: gauging interest
> Sent: Aug 26, 2011 8:02 AM
>
>
>
> Boy it's REALLY hard to beat a fan powered by a 455 cubic inch engine ....
>
> Thermo clutches have time and time again proven to be the most efficient
> way to cool a vehicle and no electric fan made pulls as much air.
>
> that said electrics are REALLY nice!
> More room, no shroud etc
>
> But also very $$$
> --
> Keith
> 69 Vette
> 29 Dodge
> 75 Royale GMC
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
>
> Sent from my Verizon Wireless BlackBerry
> _______________________________________________
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> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141222 is a reply to message #141062] |
Sat, 27 August 2011 12:48 |
 |
WD0AFQ
Messages: 7111
Registered: November 2004
Location: Dexter, Mo.
Karma: 207
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Senior Member |
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Someone mentioned, in another thread, we need to fix the problem, not throw money at it with new stuff. I do agree but I have no cooling issues, never have. We installed the aluminum radiator before we took off on our long journies so we would have no heat/cool problems. I appreciate all of the discussion on this topic and it has been discussed here before. Nothing new happens without discussion and this group is great to batter things around. The fan clutches must be coming from China. So, since there are so many problems with them, lets build an electric system for those who would rather have one. My fan clutch seems to work fine, now. I just want an electric fan, if it can happen. Same thing on my Mustang.
Thanks to everyone that has expressed opinions on this topic.
Dan
3 In Stainless Exhaust Headers
One Ton All Discs/Reaction Arm
355 FD/Quad Bag/Alum Radiator Manny Tran/New eng.
Holley EFI/10 Tire Air Monitoring System
Solarized Coach/Upgraded Windows
Satelite TV/On Demand Hot Water/3Way Refer
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| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141563 is a reply to message #141123] |
Mon, 29 August 2011 16:00 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Senior Member |
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On Aug 26, 2011, at 7:47 PM, James Hupy wrote:
> Johnny, The clutch fans, being belt driven, always have parasitic drag, even
> when the clutch is not engaged. The electric fans, while they tax the
> alternator quite a bit when they are running, are only required when the
> thermodynamic load requires them to run. At the end of the day, the belt
> driven fans require more energy to be expended than the electric ones do
> over the life of the engine. That is why you see very few belt driven fans
> on modern vehicles. We just need to match the cfm with the heat load and
> make the system fit into the space available. It isn't an impossible task,
> just a difficult one, when costs and availability need to be sorted out for
> the relatively short production runs like our GMCs require. If I stopped and
> figured out the total costs involved in production of my tools, I probably
> get paid $4.00 or $5.00 an hour for the effort. If I didn't feel some sense
> of obligation to the GMC community, I probably wouldn't do it. But the
> activity keeps my mind sharp and keeps me from dwelling on negative things
> like the loss of my wife. I think Chuck A, and Dave Lenzi, and many others
> that make stuff for these coaches feel the same as I do. If we didn't do it,
> then who will?
> Jim Hupy
> Salem, OR
> 78 GMc Royale 403
Jim, what you say may hold true for small engines in small vehicles but I doubt that the parisitic load of a non running fan clutch will be more that the very large load of electric fans to cool a 455 engine in a motorhome. You also have not mentioned the drag caused by non-running electric fan blades but that is also significant and would have to be included into your analysis.
If electric fans were that good in very large vehicles why don't large trucks use them?
Emery Stora
>
> On Fri, Aug 26, 2011 at 4:14 PM, Johnny Bridges <jhbridges@ymail.com> wrote:
>
>> Unless some basic laws of physics are revoked, the electric will take more
>> power than the directly driven one - assuming equal efficiency and equal
>> airflow. The electrics nay be more efficient, and can be had which move
>> more air.
>>
>> --johnny
>>
>>
>> --- On Fri, 8/26/11, sgltrac@gmail.com <sgltrac@gmail.com> wrote:
>>
>>
>> From: sgltrac@gmail.com <sgltrac@gmail.com>
>> Subject: Re: [GMCnet] GMC specific Electric Fan kit: gauging interest
>> To: gmclist@temp.gmcnet.org
>> Date: Friday, August 26, 2011, 3:42 PM
>>
>>
>> Electric fans do pull a lot of current which must load the alternator. I
>> wonder what kind of hp drop a burdened alternator creates compared to an
>> engine driven fan with the clutch engaged?????
>>
>> Sully
>> 77 royale
>> ------Original Message------
>> From: Keith V
>> Sender: gmclist-bounces@temp.gmcnet.org
>> To: gmclist@temp.gmcnet.org
>> ReplyTo: gmclist@temp.gmcnet.org
>> Subject: Re: [GMCnet] GMC specific Electric Fan kit: gauging interest
>> Sent: Aug 26, 2011 8:02 AM
>>
>>
>>
>> Boy it's REALLY hard to beat a fan powered by a 455 cubic inch engine ....
>>
>> Thermo clutches have time and time again proven to be the most efficient
>> way to cool a vehicle and no electric fan made pulls as much air.
>>
>> that said electrics are REALLY nice!
>> More room, no shroud etc
>>
>> But also very $$$
>> --
>> Keith
>> 69 Vette
>> 29 Dodge
>> 75 Royale GMC
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>>
>> Sent from my Verizon Wireless BlackBerry
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
> _______________________________________________
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Emery Stora
77 Kingsley
Santa Fe, NM
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| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141678 is a reply to message #141563] |
Tue, 30 August 2011 10:23 |
hertfordnc
Messages: 1164
Registered: September 2009
Location: East NC
Karma: 0
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| emerystora wrote on Mon, 29 August 2011 16:00 |
Jim, what you say may hold true for small engines in small vehicles but I doubt that the parisitic load of a non running fan clutch will be more that the very large load of electric fans to cool a 455 engine in a motorhome. You also have not mentioned the drag caused by non-running electric fan blades but that is also significant and would have to be included into your analysis.
If electric fans were that good in very large vehicles why don't large trucks use them?
Emery Stora
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Emory,
I am unencumbered by knowledge, or experience but I have been looking into this for some time and I have some thoughts.
From the manufacturers point of view the clutch fan is better- simple, reliable, proven.
Electric fans showed up on transverse mounted FWD cars for reasons, that probably had nothing to do with fuel economy. But mileage did improve.
In recent years they started showing up on bigger RWD vehicles, presumably for fuel economy.
Meanwhile, people in other vehicle cults like hard core off-road and racing added electric fans for performance.
So it seems likely that there is a performance/MPG gain even for big blocks, if you can get enough air moving.
i think the reason bigger trucks don't go that route has to do with relibility versus cost versus fuel savings.
From a fleet managers point of view, an electric fan system can fail in several places versus a single component with a clutch fan.
But for some of us, there might be a valuable increase in fuel economy, and we are comfortable maintaining fairly comnplex things ourselves, this might be a good idea.
Dave & Ellen Silva
Hertford, NC
76 Birchaven, 1-ton and other stuff
Currently planning the Great american Road Trip Summer 2021
It's gonna take a lot of Adderall to get this thing right.
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| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141807 is a reply to message #141123] |
Wed, 31 August 2011 07:50 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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| James Hupy wrote on Fri, 26 August 2011 16:47 |
... That is why you see very few belt driven fans on modern vehicles. ...
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Granted I am not in the business and do not see THAT many "modern vehicles."
Most "modern vehicles" have transverse engines. With that lay-out it is MUCH easier and cheaper to use electric fans.
The few "modern vehicles" that have longitudinal engines have belt driven fans with some type of clutch. It is very likely they also have electric fans -- in addition to the belted fan.
For example, all of the Audis I have looked at have a belt driven fan on the right side of the radiator and a electric fan on the left. The electric is a pusher fan and is mounted in front of the radiator and AC condenser.
Now our GMC's already have a belted fan mounted slightly to the right.... hmmm....
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: [GMCnet] GMC specific Electric Fan kit: gauging interest [message #141837 is a reply to message #141690] |
Wed, 31 August 2011 10:51 |
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ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
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Senior Member |
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I was walking by a big rig parked on my street, engine idling while loading up, when its fan activated. Holly BeGEEZ was that thing loud! When those fans kick in they must pull a bunch of horsepower!
For me the whole argument about the fan blade blocking air flow at speed is moot if something like Ken's flaps can be included with the electric shroud. If I were to block all the places that air can go other than the radiator then it would either go around the coach or through the radiator and push the fan and the flaps out of the way.
I'm kind of stuck on the benefits of stop-and-go traffic and the cool down when the engine shuts off. Also, that fan and shroud are archaic relics from the jurassic age.
Larry Davick
No Dinosaur, Me.
On Aug 30, 2011, at 9:43 AM, Mark Grueninger wrote:
>
>
> Another reason electric fans are not used in large trucks is that the efficiency gain is not significant compared to the clutch system they use. Large trucks do not use a viscious fluid clutch. The clutch is activated with air pressure and when released you can hold the fan with one finger while the engine is running. Very little energy wasted. Yes I know good way to loose a finger if the AC comes on and the fan kicks in. The clutches are heavy and very expensive though and probably not practical for small engines. They are not mounted on the water pump either. When the fan comes on though you will see about a 1 to 2 mpg decrease on a vehicle that is only getting 6 to 7 mpg to begin with. They move a lot of air and are very noisy.
>
> Mark
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Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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