I've heard mixed reviews on E-fans, people tell me they gain up to 15hp and some say they gain 2... I'm not sure if I want to go with one and if someone could provide some evidence, it would be appreciated... Also, good ones to go with and the average price of one. Because if they do add 15hp, I've heard they're pretty cheap so it's something I'll add to my list. Also, how do you control it? Is it something you switch on and off when you think you need it or does it automatically come on when you reach a certain temp? Thanks in advance

 

E-fans dont " add " power they just free up a little, I just put mine on and they are worth it!, the fans come with a controler for each fan with a temp probe that goes in the fins of your rad, they come on at what temp you want them to, and they make your A/C very cold!

 

What kind do you have and how much did you pay? I'm thinking I'm going to get some but I've got some other things higher on my list. If they're not bad in price, I might grab em

 

I got mine from www.jusnesmodified.com its the same kit that Troyer sells I got mine during a group buy for 220 I don't know what the price is now. check my gallery for pics.

 

I've got the Troyer fans, but I would probably check on the Flex-a-lite Fans first. The Flex fans has a shroud that mounts to your radiator unlike the Troyer fans which utilizes brass rods that go thru your rad. fins. The Flex fans are more but worth it IMO. O and it does help with the power factor, especially on the bottom end

 

Think about this for a minute...if it really takes 15hp to drive a stock fan, then wouldn't they need to use a 15hp electric motor to move the same air with an electric fan (the answer is YES)? Then factor in that when your electric fans are on, there is an increased load on your alternator, offsetting some of what you gained by removing the fan. All said, in real life they are worth a few HP, but nowhere near the 15 that the mfgs claim. Are they worth it? I think so.

If you do, go with something with a shroud, like the Flex-a-lite. They will pull air through the entire radiator, whereas the other kits will only pull air through the area of the radiator that is directly in front of the fan. You also don't risk wearing holes in your radiator with the FAL mounts.

 

The answer is no : 1 HP = 746 watts of electrical power. 746 watts @ 13.8 VDC = 54 amps of current flow.

Most e-fan set-ups draw 30 amps or less at full speed, so they would consume a little over 1/2 HP as added draw on the alternator.


I don't know where anyone came up with 15 HP to turn the stock fan - that is crazy !! It takes around that much power to push the truck at a steady 55 MPH on the interstate. A few HP, definitely - 15 ? No way !! Their main benefits are quicker warm up, better cooling at idle and better AC efficiency.

I agree - the FAL-270 is the nicest e-fan kit for our trucks, period. Their controllers have a history of problems, but I think part of that is due to poor connections by the end users / installers. My original controller and fan were in my '01 'Screw and are now in my Lightning.

 

My point was that the claims of 15hp are BS. The answer to original question is still yes - if it takes 15hp to move a certain CFM of air, then you would need a 15HP electric motor to do it. It does not take 15hp to drive the stock fan, it only takes a few. Your calcs work for determining the HP of the fan motors, not the draw on the alternator, but I know what you were trying to say.

As to the claims...from the Troyer site (and we all know that he is right about EVERYTHING ((cough)))..."Power gains from this kit run anywhere from a low of 15 HP to as much as 20 HP at the rear wheels..." Yeah, sure. I'd like to see those dyno runs.

 

Well, if you were going to turn the stock fan with an electric motor, you are right - it would require the same amount of mechanical power to turn, regardless of the source. Good catch - I misunderstood the point you were driving at.

My point was the electric fans move MORE air with less HP required (they are lighter than the factory fan).

Huhhhh ? If you know the draw of the fans, you can most definitely determine the load on the alternator... What am I not understanding in your comment ??

Guaranteed that those dyno sheets do not exist...

 

So if you get 1 or 2 horses out of them, whats the point? more torque or what? Everyone on the forum ive asked said they dont do anything for hp so why does everyone like them so much? Not understanding the hype i guess...

 

They do FREE up some horses. They also help the AC cool better at lower speeds and at idle.
Potential increase in fuel mileage, too.

 

I picked up 2 mpg increase with my FAL #270 kit.

Norm

 

Indeed, there are two points you're missing here. First, yes, it was dyno-tested (by the Troyers) to free up 15 Hp at the rear wheels. It's been years since I saw their dyno graphs, but yes, it is a true 15 RWHp.

Second, that 15Hp is, in fact, due to the reduction in parasitic losses from driving that 11lb mass attached to the water pump. True, if you wanted to drive the factory fan using an electric motor, it would take a 15Hp 12V DC motor (which undoubtedly weighs significantly more than the single nut that attaches it in the stock location) to turn it at the same speed as the water pump at WOT. Yes, there is additional load on the alternator (which, IIRC, the Troyers calculated long ago to be roughly 1 Hp), and that additional 1Hp is used only when the fans are running. On the freeway, mine don't cycle. In fact, at speeds of more than 40 mph, the only time they run is with the AC compressor. With the AC off, they don't run at all at speeds over 40 mph. THAT is where you will see a significant gain in mileage.

Additionally, the engine is, in fact, more responsive. By eliminating the extra 11 lbs of rotating mass, the engine accelerates faster and shifts quicker.

The gains are all around. Electric fans are clearly the way to go. GM is converting all their trucks over. If there wasn't something to be gained in doing so, no OEM would do such a thing.

-Joe

 

Thanks Joe, you have just convinced me to pick one up... one more question though, which one to go with? and the most I should pay for one?

 

As with anything automotive, you get what you pay for.

I personally prefer (and have) the Flex-a-Lite kit. I wasn't a fan of the Troyer kit (no pun intended) due to the mounting of the fans using the through-the-radiator nylin (brass?) ties. I saw too many of those fail on transmission coolers back in the day when I used to sell auto parts 12 years ago. I just wasn't a fan of mounting something directly to the core itself.

The FAL kit mounts to the core using brackets that connect to the original shroud mounting points. It takes some work, but I don't worry about the fan shroud moving or wiggling and chafing through the radiator core. Also, I personally feel that slapping a fan on the core itself is less effective than moving the air evenly over the entire radiator using a shroud. Based on my limited knowledge of heat exchanger design, I feel it's a more effective design, although I'm sure others on the board would beg to differ.

Now, there are other kits out ther. The names escape me, but IIRC, tehre is another system that mounts to the stock shroud, and a third that uses a single fan with a custom shroud. Both manufacturers' names escape me at the moment, but a quick search should turn up a TON of listings here.

-Joe