If 4Hp is the real number, it's still not a bad mod for the dollars depending on the cost and the reliability of the system. If the actual number is double that, it's that much better. I relate it to the intake example I gave. I don't think even a dyno will show true numbers. You could set the fan up to show gains or lose HP, depending on temperature, air blowing through the radiator with the dyno fan, etc.

It's one of those mods that you have to believe the science/theories behind it. If you don't believe it, don't get it. If you do, go for it. I think no reasonabe person would argue there is absolutely no gain. The question is if it is worth the dollars to you as an individual.

Add abilities like turning it off going through mud- which saves a lot of cleaning later- the benefits become larger. Forget to turn it off and possibly break a blade in water- the benefits become less. It all has to be weighed.

 

Uggg..

OK, The mechanical fan has a gel / fluid in it that reacts to heat. When heat in the surrounding air propigates through the aluminum clutch case and into the gel/fluid, it gets thicker. There-for the fan does'nt slip as much as it does the other 90%-95% of the time. (it never fully locks.. unless it's broken)

This measurement I took is accurate for the MAJORITY of us.. the MAJORITY of the time.

An analogy would be... like comparing drag racing ETs with an extra 200lbs in the back. Is it going to run slower? Well yes of coarse it would.

What *most* people want to know is how much quicker will it go by reducing weight. Not adding it.

In this post I reported how much power I'm gaining by *removing* a torque consuming item.. not adding one.

Rich

 

^^^^That is what I was getting at. If functioning properly, the clutch fan is as effecient and the e-fan when you factor in the e-fan's draw on the alternator compared to the little drag experienced by the mech fan. It would be nice to know actually how locked up the clutch fan is and what amount of time, but that would be hard to test. Like you said, most of the time it is pretty much freewheeling and so long as you keep a check on the condition of the clutch every few thousand miles (just spin it by hand with the engine off. It should free wheel and not be too stiff) then it is foolproof. Now for low speed cooling an e-fan can be better becuase of its constant cfm output, but only if sized properly. From the sound of it the e-fans sold on here are sized properly and that is good. Where an e-fan would really show a lot of gain in hp is during really hot conditions where the mech fan is as locked as much as it can be. But again how much that really is in real life is debatable, but I bet it is not a whole lot.

In reality both types of fans have their pluses and minuses. When sized properly and are in good operation condition, both work well and save hp and mpg over a non-clutch/non-flex mechanical fan. For a truck I like the idea of the mech fan for reliability, but I am not above trying one if engineered and sized properly. And if the price is right. Mainly because they are smoother, and offer less underhood clutter.

 

That is exactly why Ford has mechanical fans on all vehicle with a tow rating of more than approx 1000lbs. Under those conditions it's actually more efficient than powering a e-fan. It also keeps the radiator cooler in slow -to- no speed driving.

This next summer I'll do some temp testing towing my boat. It's about 4000lbs and it'll be interesting to see what it's doing with the underdrive and e-fan.

Rich

 

this is very interesting, different engine and set up by i have been pondering running electric fan on my 93 F150 with a 300 I6. i know its working properly, but how much would i gain power wise? probaly not enough to warrent the time to install.

let me ask this question, since we know in most real world driving scenerios they dont help in the power dept...what about from a mpg stand point? seems more people used e-fans for the mpg gain than power. any idea how/why this would have a positive/negative effect? i have some theories but id like to see what Mr. B has to say.

also, some people could give the arguement that the e-fan has less strain on the waterpump bearings since it is not being loaded down.

me thinks its like looking at the glass half fool and half empty...wasnt the real reason e-fans were used was space limitations and grill surface area on smaller cars?

also, how would an e-fan have on effect on something...lets say a 1966 Fairlane GT with a stock style fan. just to give some more varibles. im on the fence about this particular mod still.

nudder thing i forgot to add...i bet this test would prove better on a truck with a metal fingerswatter verus the plastic one on the newer trucks. so maybe thats why y'all OHV guys are seeing more of a gain.

 

i would guess the primary reason some stock cars started with fans was - sideways engines. Radiators would have to mounted to a fender, lol, to have a mechanical fan. A would think rear and mid engine cars needed one also.

 

I appreciate the test that was done, but it is only part of what needs to be done. You can't make a conclusion on the e-fan's effectiveness or lack there of based on this one test. Period. I look forward to the summertime tests.