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Author Topic: Electric Fans and Underdrive Pulleys Back to Topics
fitz47203

Rookie Author
Indiana

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Message Posted: Dec 9, 2012 2:08:02 PM

Ive been looking online on ways to save mpgs. Anyone tried going to an underdrive pulley system and electric fans. Is it worth the change out??
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13Octane
Champion Author Tucson

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Message Posted: Dec 15, 2012 1:58:02 PM

check with your automotive professional
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wrmedic
Champion Author Nebraska

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Message Posted: Dec 12, 2012 7:20:44 PM

You will not see hardly any difference typically the fan clutch will not lock up over 35MPH. Meaning if you are going down the highway if your fan clutch is working it will not be engaged. In town they are controlled by heat already and the load of the electric will generally be about the same as the mechanical fan.
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PhilnTX
All-Star Author Dallas

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Message Posted: Dec 12, 2012 11:55:19 AM

If you spend $175 to buy and install and electric fan (with all of the corresponding HD wiring, relays and wiring harness), you might gain .5 MPG

You'll never recoup the cost to add .5MPG.

If your car currently gets 20 MPG and the tank is 16 gallons, you'll get a maximum of 320 miles out of the tank. If your MPG goes to 20.5, you'll now get 328 miles (potentially) out of that tank.

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JimBlake56
Veteran Author Akron

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Message Posted: Dec 12, 2012 9:42:44 AM

Electric fans are very common but not EVERY vehicle has them. Their advantage is that they run only when really needed. In fact, the efficiency of the alternator/motor combination is lower than that of a good belt-drive. So a belt-driven fan with a clutch (similar to AC compressor clutch) might actually be better.

Under-drive pulleys drive the alternator, PS pump, AC compressor at a slower speed. Simple, right? But not always good.

If the lights dim a bit at idle that's not the end of the world. But some people would not tolerate that.

Certain engines don't get along with underdrive pulleys, & can damage the crankshaft. But that's not about the pulley's drive ratio - it's about the pulley NOT having a well-designed vibration-damper in it's hub.


[Edited by: JimBlake56 at 12/12/2012 9:48:59 AM EST]
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Casey225
Rookie Author Baton Rouge

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Message Posted: Dec 12, 2012 5:55:12 AM

Both these setups will up your mpg, but is it worth the inital cost?
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MertieMan
Champion Author Lexington

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Message Posted: Dec 12, 2012 5:21:33 AM

With your ideas you will probably get less miles per gallon.
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OceanArcher
Champion Author Mississippi

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Message Posted: Dec 10, 2012 11:37:35 AM

All my cars have electric fans .......
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Alien6500
All-Star Author London

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Message Posted: Dec 10, 2012 10:46:45 AM

my older s10 i changed to electric fan and made a noticeable change, but never tried underdrive pulley system
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WEPSMAN
Champion Author South Dakota

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Message Posted: Dec 10, 2012 10:34:55 AM

Most newer vehicles have electric fans already. I am not familiar with an underdrive pulley.
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OilerFan
Champion Author Tulsa

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Message Posted: Dec 10, 2012 7:36:19 AM

I'm not familiar with the pulley system. How does it work?
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DanFMA
Champion Author Massachusetts

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Message Posted: Dec 10, 2012 6:57:32 AM

All mine have this.
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bearscharger
Champion Author Cleveland

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Message Posted: Dec 9, 2012 11:53:31 PM

most new cars have these setups to begin with
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fuelott
Sophomore Author Calgary

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Message Posted: Dec 9, 2012 2:59:10 PM

I thought about changing the belt driven fan to and electric fan in my truck for pulling the trailer. the only real advantage would be the the horsepower drop you get when pulling up a hill when the fan kicks on full to cool the engine down. however you would still get some because the alternator is now pulling a larger draw to supply the electrical to the electric fan. the savings in over all MPG is very minimal and the price is not cheap. at about $1200.00 for a complete conversion self installed and the only savings being the difference in MPG you are likely to sell off the vehicle before ever realizing any savings from it.
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