fan clutch - which type?
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
fan clutch - which type?
I've been searching the forum and net for info on power losses in engines, and came across an interesting quote regarding the flywheel power output with various cooling fan systems....
Car Craft test, May 2000 issue, page 50-51.
No fan = 496 hp
thermal clutch fan 487 hp
HD thermal clutch fan= 476 hp
non-thermal clutch fan= 485 hp
plastic flex fan 460 hp
HiPerf flex fan 476 hp
lo Profile flex fan= 466 hp
6-blade rigid= 449 hp
electric fan= 494 hp
4-blade rigid= 473hp
I'm looking at putting in a fan clutch, as it seems I could pick up at least 10 easy horses going from my current fixed rigid fan to a clutch fan, with no real downside that I can see.
Looked at fan clutches, and they are available in thermal, non-thermal, and heavy-duty series,
I guess the question I have is what is the difference between the types offerred.. regarding effectiveness/reliability/noise ???.
Car Craft test, May 2000 issue, page 50-51.
No fan = 496 hp
thermal clutch fan 487 hp
HD thermal clutch fan= 476 hp
non-thermal clutch fan= 485 hp
plastic flex fan 460 hp
HiPerf flex fan 476 hp
lo Profile flex fan= 466 hp
6-blade rigid= 449 hp
electric fan= 494 hp
4-blade rigid= 473hp
I'm looking at putting in a fan clutch, as it seems I could pick up at least 10 easy horses going from my current fixed rigid fan to a clutch fan, with no real downside that I can see.
Looked at fan clutches, and they are available in thermal, non-thermal, and heavy-duty series,
I guess the question I have is what is the difference between the types offerred.. regarding effectiveness/reliability/noise ???.
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
I don't have any cooling issues with current setup, but for ~$50 to fit a fan clutch and pick up 10 more horses.... seems like a no brainer.
What am I missing?
Drifting
Joined: Jul 2002
Posts: 1,944
Likes: 20
From: The only Corvettes in Highett Victoria
Original????????????????????
Tom,
You've got a right hand drive Corvette and you're looking for "original" under the bonnet????? What about the steering box on the right side of the chassis, brake booster and master cylinder on the right side of the firewall, or the HVAC unit on the left?
Do what clutchdust says and go electric. I have and it's great. I made a custom fibreglass shroud and use a single 16" puller with the sender unit stuck between the fins in the upper left corner of the rad. under the inlet hose. Works fine plus it's quieter, uses less petrol and releases more power to the transmission.
BTW, are you planning on going to America in August? There's a group of us going from Melbourne on two different packages and we're gonna have a ball! Let me know.
Regards from Down Under
aussiejohn
6 months to go
You've got a right hand drive Corvette and you're looking for "original" under the bonnet????? What about the steering box on the right side of the chassis, brake booster and master cylinder on the right side of the firewall, or the HVAC unit on the left?
Do what clutchdust says and go electric. I have and it's great. I made a custom fibreglass shroud and use a single 16" puller with the sender unit stuck between the fins in the upper left corner of the rad. under the inlet hose. Works fine plus it's quieter, uses less petrol and releases more power to the transmission.
BTW, are you planning on going to America in August? There's a group of us going from Melbourne on two different packages and we're gonna have a ball! Let me know.
Regards from Down Under
aussiejohn
6 months to go
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
My 79 L-82 came with a HD thermal clutch fan
Hp = heat So as I hot rodded the motor the **** poor fan clutch showed it's problems. On hot day and you run your motor hard just when you need the most cooling it goes into free wheeling and no fan moving air.
The second thing is the power it takes from off idle to accelerate some big heavy 7 blade fan from low rpm to higher rpm. It's a big clunk of heavy dangerous metal spinning around.
If you are running the rpm up in every gear it just smokes the belts with the stupid clutch engaging and disengaging on gear shifts up and down
POS for anything but a work truck
. I've never figured out why ragazines praise POS all the time. The true test is: If it works - It is on every race car.
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
Tom,
You've got a right hand drive Corvette and you're looking for "original" under the bonnet????? What about the steering box on the right side of the chassis, brake booster and master cylinder on the right side of the firewall, or the HVAC unit on the left?
Do what clutchdust says and go electric. I have and it's great. I made a custom fibreglass shroud and use a single 16" puller with the sender unit stuck between the fins in the upper left corner of the rad. under the inlet hose. Works fine plus it's quieter, uses less petrol and releases more power to the transmission.
BTW, are you planning on going to America in August? There's a group of us going from Melbourne on two different packages and we're gonna have a ball! Let me know.
Regards from Down Under
aussiejohn
6 months to go
You've got a right hand drive Corvette and you're looking for "original" under the bonnet????? What about the steering box on the right side of the chassis, brake booster and master cylinder on the right side of the firewall, or the HVAC unit on the left?
Do what clutchdust says and go electric. I have and it's great. I made a custom fibreglass shroud and use a single 16" puller with the sender unit stuck between the fins in the upper left corner of the rad. under the inlet hose. Works fine plus it's quieter, uses less petrol and releases more power to the transmission.
BTW, are you planning on going to America in August? There's a group of us going from Melbourne on two different packages and we're gonna have a ball! Let me know.
Regards from Down Under
aussiejohn
6 months to go
G'day John,
What brand / model fan and where did you source the 16" electric fan from? Where are you located? You say it works OK...
It gets bloody hot here in Adelaide... I did fit a Dewitts aluminium rad with the new motor, and the current cooling system works good.
But releasing a few more neddies is always on the agenda.
yes, vette is RHD, but it does maintain a reasonable period appearance
..... 
I'm not concerned about NCRS.
But I do like the nostalgic look of an engine bay with a carb and spinning fan at the front, and one which makes all those mechanical noises associated with muscle cars of the 60's.
I am an ol' fart, after all.
timing of the trip to US in August this year doesn't fit into plans for me....
but I am looking at going over to US/Canada in 2010. Have some rellies in Toronto and Syracuse to catch up with. Certainly are some very good international travel fares on offer at present.
cheers
tom
Last edited by OzzyTom; Feb 19, 2009 at 05:01 PM.
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
On hot day and you run your motor hard just when you need the most cooling it goes into free wheeling and no fan moving air.
The second thing is the power it takes from off idle to accelerate some big heavy 7 blade fan from low rpm to higher rpm. It's a big clunk of heavy dangerous metal spinning around.
If you are running the rpm up in every gear it just smokes the belts with the stupid clutch engaging and disengaging on gear shifts up and down
The second thing is the power it takes from off idle to accelerate some big heavy 7 blade fan from low rpm to higher rpm. It's a big clunk of heavy dangerous metal spinning around.
If you are running the rpm up in every gear it just smokes the belts with the stupid clutch engaging and disengaging on gear shifts up and down
A thermal clutch will not act anything like what you described.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
It had the thermal wound spring thing on the front. It was GM junk. Lot's of things were very dissapointing to me about my new L-82 Vette with nearly all the options. It was not a performance car or have drive train that was made to last.
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Race Director
Joined: May 2006
Posts: 18,736
Likes: 2,582
I purchased a fan clutch from "thepartsladi" last spring for my SB. Drove it about 5 miles, heard something go boom under the hood, felt myself driving over parts of my car. Pulled over, opened hood, fan schroud was toast, hood had crack, front cover of fan clutch had separated from main body and launched itself. Not really sure if these fan clutches are new or rebuilt. Ended up buying a new fan clutch from another source.
Intermediate
Joined: Jul 2008
Posts: 40
Likes: 0
I was thinking about going electric fans too with a Painless thermostat setup.
I saw this item fan clutch eliminator unit from Ecklershttp://www.ecklers.com/product.asp?p...ept%5Fid=1252#
It says it cools more, but doesn't mention anything on HP loss.
I saw this item fan clutch eliminator unit from Ecklershttp://www.ecklers.com/product.asp?p...ept%5Fid=1252#
It says it cools more, but doesn't mention anything on HP loss.
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
An article I was reading on thermal fan clutches pointed out that the original designs back in the 60's were specified to lock at temperature around 170~180*F, whereas fan clutches made today are set for about 190~200*F. This is due to higher operating temps of cars for cutting down emissions.
Maybe those cases where overheating is occuring is due to mis-match of thermal spec of fan clutch to thermostat?
So question is, can one source a thermal fan clutch rated to operate at 170*? I haven't seen any advertised with an actual temp rating.
Maybe those cases where overheating is occuring is due to mis-match of thermal spec of fan clutch to thermostat?
So question is, can one source a thermal fan clutch rated to operate at 170*? I haven't seen any advertised with an actual temp rating.
Burning Brakes
Joined: Feb 2001
Posts: 929
Likes: 5
From: Marietta GA
MelWff, sorry to hear about your bad experience. The one I bought was new in the box and manufactured by Eaton. Anyway, there are individuals that can rebuild these fan clutches and they may have an inventory of correct fan clutches. Search the NCRS baord.
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
I was thinking about going electric fans too with a Painless thermostat setup.
I saw this item fan clutch eliminator unit from Ecklershttp://www.ecklers.com/product.asp?p...ept%5Fid=1252#
It says it cools more, but doesn't mention anything on HP loss.
I saw this item fan clutch eliminator unit from Ecklershttp://www.ecklers.com/product.asp?p...ept%5Fid=1252#
It says it cools more, but doesn't mention anything on HP loss.
I can certainly vouch for the statement...
"NOTE: Due to being a direct drive, you may experience more fan noise."
On the dyno at 5500 it sounded like a 747 taking off...
......... fan noise, not exhaust noise.!
Drifting
Joined: Apr 2007
Posts: 1,970
Likes: 45
From: Cameron Park CA
I was thinking about going electric fans too with a Painless thermostat setup.
I saw this item fan clutch eliminator unit from Ecklershttp://www.ecklers.com/product.asp?p...ept%5Fid=1252#
It says it cools more, but doesn't mention anything on HP loss.
I saw this item fan clutch eliminator unit from Ecklershttp://www.ecklers.com/product.asp?p...ept%5Fid=1252#
It says it cools more, but doesn't mention anything on HP loss.
