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I had a set of electric fans from GM off my old 2005 Yukon and decided to try them out on the Damx because they flow a ton of air. I had to cut one little mount off, trim and edge, and move the trans computer. Overall it was a very easy swap and clips right in place! The width is the same but the fans leave 1" on top and bottom of the radiator not covered. Not enough to worry about and they work extremely well. Before towing 10K in the summer I could hit 208* before the clutch fan kicked on to cool it, and you could feel the power being taken away. And it was regular to see the trans temp hit 200* in houston stop and go traffic or hard driving.

Since the fans towing 10k at WOT up to 85mph I have not been able to get the temps over 197*. Even trying to lug the motor down and get EGT's up on long hills the temp maxes at 197*. Normal around town driving with the AC on the temp averages 177-181*. Trans temp seems to be averaging about 20* cooler than before also.

Now for the other good info. The stock clutch fan is said to take 15hp to run. The big dual fans pull 46amps on hi at 13.5 volts. For the electrical guys out there, thats 621watts. And since watts converts to HP at 1.34, these fans are taking less than 1hp to turn on hi. My city mileage has jumped nearly 3mpg since the install. Why didnt GM make these come stock?

I did the swap at the end of July and been running since. The real undisputable test will come when I hook the big TT back up and head to Colorado, but I'm sure it'll never excede that 197* mark.

I have pics I will post up when I get time. Been busy getting the drag truck ready for truckfest Oct 29th. :gearjamin
 

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Im Superrrrr!
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How do you have these set to come on? Temp sensor or just a flip on switch?
 

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What is the highest ambient temp you have driven in?
 

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How do you have these set to come on? Temp sensor or just a flip on switch?
temp sensor from hayden and a diode from the AC possitive so the fans are always on when the AC is on. I'm running a big single 80A relay for both fans in parallel. Stinger sells the relays, but I got mine from the grid heaters off my cummins.
 

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What is the highest ambient temp you have driven in?
Well most of August was over 105* and the hottest day I believe was 109*. Sitting at idle in 109* heat with the AC on, coolant temp drops to 177*.
 

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Well most of August was over 105* and the hottest day I believe was 109*. Sitting at idle in 109* heat with the AC on, coolant temp drops to 177*.
Also, GM Parts Direct used to sell these fans for $219. Much better and cheaper than these other aftermarket kits!!!!!:cookoo[1]:
 

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Also, GM Parts Direct used to sell these fans for $219. Much better and cheaper than these other aftermarket kits!!!!!:cookoo[1]:
what was the gm part number of the fans?
 

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x2 on the part number... sounds good to me being that you live/tested in TX
 

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x2 on the part number... sounds good to me being that you live/tested in TX
Trying to find the whole assy PN on their website. I may have to look up some old posts on PT.net to find it.
 

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Usautoparts.com has those fans for about $240.
That'll work. I havent ordered any of these since maybe late 2005, early 2006.

I can only find seperate componants on GM website.
 

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Ok might be a dumb question but I will bite....whats the draw back on these fans MIke? I have seen a handful of trucks with them on there, and some have been on there for a better part of 3 yrs with no problems.
 

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it's a big debate.

the stock fan flows an outrageous amount of air, and it's been said that no electric fan setup can keep up with the demands of the cooling system.

i personally wouldn't run them, the stocker is reliable as can be. until there are more people running them 5 years plus no issues I'm not too sold on the claimed improvements.
 

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I have been wanting to do this for a while on my rig. I have been steered away from it by folks on this site? Stating that the electric fans wouldn't provide enough air flow.
I tow a 32' toy-hauler and the temps run high. Even in the summer time here in Nor-Cal, with no trailer, the temps run @ 200 motor, and 195 trans.
Now I'm confused, what's the real answer? It seems to me that they work according to this post? Any one else running this set-up with good results?
 

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I was talking to a guy and he has Flex Lite fans on his trucks. First he said they don't move as much air as stock. Second he has issues with the VFD emitting a frequency that interfered with his crank position sensor and/or cam position sensor. This led to his truck stuttering when the fans kicked on.

He uses them in both full race and daily driving applications.
 

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I had a set of electric fans from GM off my old 2005 Yukon and decided to try them out on the Damx because they flow a ton of air. I had to cut one little mount off, trim and edge, and move the trans computer. Overall it was a very easy swap and clips right in place! The width is the same but the fans leave 1" on top and bottom of the radiator not covered. Not enough to worry about and they work extremely well. Before towing 10K in the summer I could hit 208* before the clutch fan kicked on to cool it, and you could feel the power being taken away. And it was regular to see the trans temp hit 200* in houston stop and go traffic or hard driving.

Since the fans towing 10k at WOT up to 85mph I have not been able to get the temps over 197*. Even trying to lug the motor down and get EGT's up on long hills the temp maxes at 197*. Normal around town driving with the AC on the temp averages 177-181*. Trans temp seems to be averaging about 20* cooler than before also.

Now for the other good info. The stock clutch fan is said to take 15hp to run. The big dual fans pull 46amps on hi at 13.5 volts. For the electrical guys out there, thats 621watts. And since watts converts to HP at 1.34, these fans are taking less than 1hp to turn on hi. My city mileage has jumped nearly 3mpg since the install. Why didnt GM make these come stock?

I did the swap at the end of July and been running since. The real undisputable test will come when I hook the big TT back up and head to Colorado, but I'm sure it'll never excede that 197* mark.

I have pics I will post up when I get time. Been busy getting the drag truck ready for truckfest Oct 29th. :gearjamin
I was thinking about doing this so I did a search and found this post. After reading through it I found some issues.

To start I'm a certified, licensed electronic technician, have been for over 25 years, professionally.

The first issue is that 13.5 volts, even at idle, is too low. It should be at least 14.5 volts. I checked mine tonight it with all the lights on, AC on and the doors open, I read 14.6 volts. Barring some other electcial problem, the 716 watt load from the fans is overloading it, at least at idle.

At some point, once the revs increase, you should reach 14.5 volts. At that point, that 621 watt load will actually be 716 watt.

Your watt to horsepower is not exactly correct. When referring to motors and generation you most account for efficiency. A DC motor with 2 speed control, 80% will be a good number, so .96x.8=.77 of mechanical horsepower turning the fans. And you would also have a 143 watt heater.

The alternator has to make the 49 amps to power the fans (at 14.5 volts). A automotive alternator is not very efficient at all, around 50% when hot, about 60% cool. That means to create the power for the fans you'll need about 1.92 of mechanical horsepower.

The other problem with this is heat soak. Sitting at a stop light or in traffic without some air movement, will allow heat from the radiator to transfer to the inter-cooler.
 

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You will want dual alternators if you are going to do this.

And even then, it will still effectively devalue the work capacity of the vehicle, there is no way around it, unless someone has finally cornered "something for nothing".

The 15 HP number being discussed is conservative. The stock fan more than doubles the heat rejection capacity of the stack, even at 50 mph.
 
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