fan clutch or solid drive extension

[cudabob496]

Bet your 13 amp 2100 cfm will not come close to 2100 when measured pulling thru the head pressure created by a big radiator.  If it did, you would be pulling a lot more than 13 amps 

Advertised amperage and cfm are subject to a lot of interpretation in the ad wars.

Unless they quote the number of inches of water for the numbers they advertise, it means very little.

I'm sure it could be less than the advertised 2100 cfm. I only care about that is cools the engine,
and it seems to do that. Another testament to aluminum radiators, that my cheapy fan can cool
a 600 horse motor.

[Strawdawg]

You can easily calculate the hp from the amps x the volts and then referring to the number of watts in one hp...then compare  that hp to your statement that it can take 40 hp to turn a solid driven fan at 6000 rpm...

13 amps is not going to come close that number.  The problem with advertised fan flows is that there is no standard used between manufacturers.  If you put your fan in the middle of a room  with nothing behind it, then it may well flow 2100 cfm.  But, and it is a very big but, put it two inches from a wall, and the flow will drop considerably because the head pressure jumped way up.  Unless one is up to paying a lot of money for a Spal or similar, one tends to forget the advertised numbers and go with what works.

The numbers are out there for the big Lincoln/Sho fans and I think the start up draw is over 50 amps, but, I did not go look to be 100% sure and then they fall back by about half when they are up to speed. 

For normal driving, it does not matter if one is driving a six cylinder or a 600 hp, the heat generated is basically dependant upon the power required to move the car which is a very low number so we really need to understand the context of the problem and what we are trying to achieve.

Many of the aftermarket electric fans come with very small wiring and they won't hold up to the fans effort to pull a large amount of current without making smoke.

In the original statement, I think we have all agreed that a fixed drive fan is not the way to go. 

Thanks for posting that link with the various fan designs that were tested

[cudabob496]

You can easily calculate the hp from the amps x the volts and then referring to the number of watts in one hp...then compare  that hp to your statement that it can take 40 hp to turn a solid driven fan at 6000 rpm...

13 amps is not going to come close that number.  The problem with advertised fan flows is that there is no standard used between manufacturers.  If you put your fan in the middle of a room  with nothing behind it, then it may well flow 2100 cfm.  But, and it is a very big but, put it two inches from a wall, and the flow will drop considerably because the head pressure jumped way up.  Unless one is up to paying a lot of money for a Spal or similar, one tends to forget the advertised numbers and go with what works.

The numbers are out there for the big Lincoln/Sho fans and I think the start up draw is over 50 amps, but, I did not go look to be 100% sure and then they fall back by about half when they are up to speed. 

For normal driving, it does not matter if one is driving a six cylinder or a 600 hp, the heat generated is basically dependant upon the power required to move the car which is a very low number so we really need to understand the context of the problem and what we are trying to achieve.

Many of the aftermarket electric fans come with very small wiring and they won't hold up to the fans effort to pull a large amount of current without making smoke.

In the original statement, I think we have all agreed that a fixed drive fan is not the way to go. 

Thanks for posting that link with the various fan designs that were tested

I have an ammeter on the direct output of my alternator. When I flip on my fan, the ammeter shows its drawing an additional 13 amps. Normal
running amps without my fan on is about 5 to 10. I know the MSD draws about 1 amp for every 1000 rpm.

Just took the Cuda out. Its 85 degrees out. We have a highway with stop lights every half mile. Its perfect! I drive it pretty hard between the lights.
At a stop, I flip on the fan, and it keeps the engine between 200 and 210.  Once I start moving, I flip off the fan, and temp will drift down to about 190.
Could not do this with a copper-brass radiator, unless I had the mechanical fan I suspect.  But in the past the copper brass radiator would not cut it for me.
The vented hood helps a lot. I would imagine chucking the mechanical fan is good for 20+ hp savings, and 20+ pounds savings.

[high perf mopar]

after running it today i noticed that after shutdown,warmed up the fan did not seem to turn harder than before i started it..

the fan clutch is a new replacement unit,should it turn alot harder after warmed up when off..or just while running.fan clutch is appx 1 1/2" away from radiator.

[Strawdawg]

is about 2/3's of the blade into the shroud opening?

[Strawdawg]

I have an ammeter on the direct output of my alternator. When I flip on my fan, the ammeter shows its drawing an additional 13 amps. Normal
running amps without my fan on is about 5 to 10. I know the MSD draws about 1 amp for every 1000 rpm.

Just took the Cuda out. Its 85 degrees out. We have a highway with stop lights every half mile. Its perfect! I drive it pretty hard between the lights.
At a stop, I flip on the fan, and it keeps the engine between 200 and 210.  Once I start moving, I flip off the fan, and temp will drift down to about 190.
Could not do this with a copper-brass radiator, unless I had the mechanical fan I suspect.  But in the past the copper brass radiator would not cut it for me.
The vented hood helps a lot. I would imagine chucking the mechanical fan is good for 20+ hp savings, and 20+ pounds savings.

So the fan is not pulling enuf air to cool it on down.  On an 85 deg day it should not take much air flow to  drop it down to the level that speed induced air flow does.  A fan that draws 25 amps or so will do the trick, I suspect.

So you were running a fixed mechanical fan if you believe you saved 20+ hp?

Let's see, I think you said you gained 30 hp from going to synthetic oil, 20 from the fan, and I would guess you picked up 50 when you played with the carb jets so you may need to apply for a missile license to drive that beast on the street 

[high perf mopar]

is about 2/3's of the blade into the shroud opening?

yes,,more like 3/4's of the way in,,while running with my hand in front of the radiator it was drawing alot of cool air and blowing pretty good on the other side,,,warm air.

just curious about the nature of the clutch,,seems to be working fine...i trimmed the factory shroud some so it would fit a little tighter against the radiator when installed,,as tight as it could anyway..

[cudabob496]

So the fan is not pulling enuf air to cool it on down.  On an 85 deg day it should not take much air flow to  drop it down to the level that speed induced air flow does.  A fan that draws 25 amps or so will do the trick, I suspect.

So you were running a fixed mechanical fan if you believe you saved 20+ hp?

Let's see, I think you said you gained 30 hp from going to synthetic oil, 20 from the fan, and I would guess you picked up 50 when you played with the carb jets so you may need to apply for a missile license to drive that beast on the street 

No missile license, but I do wear my Jedi Knight uniform and helmet!!

[Strawdawg]

yes,,more like 3/4's of the way in,,while running with my hand in front of the radiator it was drawing alot of cool air and blowing pretty good on the other side,,,warm air.

just curious about the nature of the clutch,,seems to be working fine...i trimmed the factory shroud some so it would fit a little tighter against the radiator when installed,,as tight as it could anyway..

Google will find you a number of links on clutch fan troubleshooting...here is one   http://www.haydenauto.com/upload/HaydenAuto/Documents/Cat_Imperial/2007-imperial-fan-clutches.pdf