Donate54- I was lokking at the pics of your truck, nice truck, and saw the pic of the dual electric fans. I was wondering if you could provide me with some info. I went to the Flex-a-lite website and saw that they have two different dual fan set-ups a dual 14", models 250 and 260, and a dual 15" models 270 and 280. They both seem to be to wide though, I think they're both aroud 32" across.
I was wondering what model do you have and how did it work out, (fit, any trimming, where did you get it, how much, did the temp go up at all, did you put in a lower thermostat.) Any info or installation pictures that you have woud be greatly appreciated.

Thanks,
Jetter

 

hello,
i have the flex-a-lite model 210 installed on my truck. sorry i dont have any pics of the actual install, but it was pretty easy. the instructions included with the fan are excellent and very in depth. the kit i bought (summit part # FLX-210) included the mounting brackets and they work perfectly. no trimming of anything was necessary, i just removed the fan shroud. as far as the thermostat, i have the stock one in the truck and i have had no overheating problems. yesterday my truck started to overheat but i found out that it was the thermostat had gone bad. today i replaced it with a new one (of the same temp as the old one) and everything is back to normal. im very happy with the fan. the only thing you gotta be careful of is that flex-a-lite says this model is good for engines making up to 275 hp, so if youre planning on going higher than this, you might want to consider a different model so you dont have any problems. hope this helps!

 

I've always been curious, what exactly are the benefits of an electric fan? Someday I plan on making some serious horsepower, so I'm assuming it would be wise to invest in one (or two). What exactly do they do, and how do they help? Any info. would be greatly appreciated!

 

the benefit doesnt come from adding the electric unit, it comes from removing the stock clutch fan unit. since the clutch fan is attached to the crank pulley, it has to workharder to spin the pulley AND the fan. my reason for the electric unit was not for performance, however. since i have a body lift, my fan was 3" lower from the radiator (since the radiatoris moved up with the lift, but not the engine and fan). by adding the electric ones, they attach to the radiator and cover a much greater area of the radiator which helps the engine stay much cooler. as far as performance gains, its a very small gain.

 

Thanks. I was just checking out the Flex-a-lite site and the 290 series claims a 12 hp and a 16 ft/lb tq gain at the wheels with that fan. Could this be true? If so, I'm gonna have to put that on my mods. list! Probably should have done that when I got the pulleys since the fan had to be removed any ways. Perhaps the 290 series cools the engine slightly better than the 210 series, and a cooler engine performs better. After gaining 11 hp with the pulleys, 12 hp sounds like a lot to me, something I would describe as more than just "a very small gain". To me, a very small gain is something I would describe when installing a K&N drop-in air filter. I guess I'll have to check into this further when I get some more $$$.

 

Donate is correct about the source of the added power. The reason it isn't usually very noticeable is because of the way the stock fan clutch works. The stock fan clutch puts minimal drag on the engine most of the time. It's only at slow speeds when hot that it creates a drag. If the horsepower of an engine was measured on a stationary dyno, with a hot engine, there would be a substantial difference between a stock set-up and an electric fan. However, in most daily driving, the difference is minimal. It works something like this:

The stock fan is connected via a fan clutch. A fan clutch is kinda like a torque convertor, in that the two ends don't ever come into physical contact with each other, but have a liquid between them. This is why you can spin the fan by hand when the engine is not running. The oil inside the clutch "gels" when it reaches a certain, predetermined temperature. It reaches this temperature due to the temp of the air that hits it after passing through the radiator. When the temp rises to a certain point, the oil "gels", and the fan becomes temporarily "solid" with the pulley to which it's attached. This creates a vacuum inside the fan shroud which pulls more air through the radiator, which radiates the heat away from it, allowing the coolant to cool down, thus cooling the engine. In this condition, there is a substantial load placed on the engine in order to turn the fan. When the temp of the air coming through the radiator drops enough, the oil in the clutch becomes more fluid, and the fan just "free-spins" with the engine. In this condition, there is minimal load placed on the engine from turning the fan. Once you are moving more than 10 miles an hour, there should be sufficient air moving through the radiator to keep the temp down so that the oil in the clutch remains a liquid. However, once you come to a stop, or reduce your speed below 10 mph, there is no longer enough air being forced through the radiator, and the oil "gels" and the fan cools. Start moving again, and the clutch oil becomes liquid again. The bottom line is that the only time the fan is in use to the point where it robs power from you is in stop and go traffic, or when sitting still at idle. This isn't a time when peak horsepower is needed, so the loss isn't really noticed.

An electric fan is also thrmostatically controlled by the radiator temp. When it reaches a certain point, the fan kicks on, and sucks air through the radiator. Once the radiator cools, the fan is turned off. Because of this, an electric fan is almost never in use when driving more than 10 mph.

The advantages to an electric fan are many, however. They can have a manual switch added so that you can turn it on at will, although this is rarely necessary. They also can remain on after the engine is shut off, continuing to cool the engine and radiator while you are parked. They also help you when towing, or other times you need top power at very slow vehicle speeds. The down side to electric fans is their lifespan. Most aftermarket electric fans won't last more than 30 or 40k miles, and they often don't give any warning before quitting. Also, if not installed properly, they can drain your battery, or even cause a short in your electrical system. This usually happens when someone installs a manual override switch, and doesn't wire it through a relay. The switch quickly overheats and melts, and you've got a short on your hands.

A stock fan clutch is usually good for 100k miles or more before the oil inside starts to lose it's viscosity, and starts to fail. Also, this will be a gradual failure, so you won't be suddenly stranded somewhere with a fan failure. Most really enthusiastic stories I've heard about an increase in power after installing an electric fan(s) were cases in which the pullies were changed at the same time, and the owner has just decided to give the power increase credit to the fan(s) instead of the pullies. Remember, though, they do offer increased hp, but it's usually at a time when you don't really need it.

Also, however, a good, well installed electric fan system will yeild a noticeable improvement in cooling at idle. When those fans kick on, they work quickly. They also put a heavy load on your charging system at a time when the alternator is generating the least amount of energy, so if your charging system is marginal, forget it.

When my fan clutch starts to lose it's reliability, I will probably replace it with a pair of electric fans. Maybe sooner. I do alot of towing, and the extra power while still cooling well would be nice.

Hope this helps.

Take care,
-Chris

 

PKRWUD,

Thanks for the explanation. I think I'll wait on the fans I'll probably invest in an intake manifold and throttle body next.

 

pkrwud,
wow, thanks for the explination. i never really knew how the stock fan clutch worked.

TF,
i dont know if the 290 model is morepowerful than mine, but they told me taht i would see a gain of about 12 hp/16 ft lbs of tq and there is no way i gained that much. i installed my fans at the same time as the pulleys andi didi feel a big gain, but i disconnected my fans recently (temporarily) and felt no loss of power. so my advice to you, if you dont have any cooling problems, spend your money on some other mods first. good luck!

 

Donate54,

Thanks for the advice. I probably will wait a while until I absolutely do need to upgrade my cooling. Right now, I have no cooling issues