You'll have to expand on that.
[QUOTEtake the time to find out why right from the oem. post the results of that.[/QUOTE
Wish I could, maybe you can post the OEM engineering data?
Can you provide anything other than "opinion" for this? I'm open.
are you near the detroit area...or near enough to make a trip? this will make it easy to provide evidence. and we will use YOUR truck.
taking a week to track down someone to deal with on the subject will prove frustrating yet entertaining for you for sure. probably be able to run for congress after that if your successful. i have had a impossible time trying to get anyone to go on the record here at this site, but i still pursue it. it is a goal.
some data that should be easy to find will be for otr applications. theres plenty of drivers here and i am sure some of them have electric cooling on thier big rigs. people scoff at that thought
the 10000 cfm fans i have seen on otr's draw like 1.5 hp and 80 amps or something. reported to weigh 75-80 pounds and they need some space as its pretty huge.. but it takes up similar space compared to the original offering. i am guessing the radiator is 3 feet wide and nearly 4 feet tall on the ones i have seen, so the fan has to be 33 inches or so, not sure of the specific measurements, i looked it up once to see if they had small enough units for my planned diesel swap and it wasnt even close...small ones are like a foot thick with the motor.
without going into fin count, actual radiator density, static load ect etc...( i am not discounting those factors, its just for times sake), i readily understand the mechanical fan is usually more efficient at moving huge amounts of air. no way i argue that. but it is usually horribly inefficient at moving the necessary amount of air at the best times.
theres the actual supply companies that will give you data if your prepared with specifics. theres plenty of information on the internet. the rx7 thing is a joke, just totally bunk due to the mass issues, blatantly ignored in thais write up. its typical too, like everyone smart seems to like to ignore it. but i also agree with the prejudices about improper installations etc that the page is filled with...
You'll have to expand on that.
Of course, you're not necessarily after better cooling. You've seen those TV commercials or catalogue ads that promise "Up to 17 free HP!" by converting to an electric fan. Well, that's simply not true. There will be a horsepower gain for sure, on the order of 0.5 - 1HP. But remember that the electric power to run the fan must come from somewhere, and that somewhere is the alternator. Electric fans draw quite a lot of current. Most pull surges of 35A or more to start up, then run at 8A-10A. This puts extra load on the alternator. Ever pedaled a bicycle with a generator powered light? If so, then you will know that as the electrical load on a generator/alternator increases, the generator/alternator becomes harder to turn. Suddenly, all that "free" HP you just freed up is once again being used. This time, though, it is being used to turn the alternator. There is also an inefficiency in the whole system. We are converting mechanical energy, to electrical energy, to mechanical again to run the fan. This very inefficient, much less then just driving the fan directly via the mechanical energy of the rotating shaft.
Let's examine the "17 HP!" claim a little further to drive the point home. A little basic math is all that's needed.
One horsepower is 745.69 watts.
Therefore, 17HP = 12,676.89W.
Since W = Voltage * Current, 12,676.89W is 1056 Amps
So in order to do the same work as that stock "17HP" fan, an electric fan would have to continuously draw over 1000 A from the electrical system of the car. Clearly this does not happen. Now I'm sure that somewhere out there is a car or truck with a ridiculously inefficient and so poorly designed stock fan that it actually does rob 17HP from the engine as it turns. But since the RX-7 comes with a well designed freewheeling clutch fan as already explained, the RX-7 is certainly not that car.
There is a dyno chart floating around the RX-7 forums which supposedly show a car gain 10 HP across the board with no other change besides switching to an electric fan. I seriously question the validity of this claim as the 10 HP gain was shown throughout the entire RPM range, all the way to redline. As we all know, the fan clutch should have been disengaged after about 3000 RPM, so it appears that this car was dyno'ed with a stuck fan clutch.
We can do the same thing with regards to an electric fan and factor in the inefficiency of the alternator and the fan motor. Assuming it takes 1HP to turn the electric fan:
745W = 62A at 12V. This is obviously already incorrect since it's ridiculous to assume that an electric fan is drawing 62A continuously. But we'll continue anyway.
Assuming that the alternator and fan motor are both 70% efficient (an over estimate for sure considering the quality of automotive electrical parts...see Alternators) we need to take those losses into account.
So 62A + 30% = 62 + 18.6 = 80.6A
Then add another 30% for the inefficiency of the fan motor: 80.6A + 18.6A = 99.2A
If our e-fan really saved 1HP from the shaft of the engine, it would be drawing almost 100A from the electrical system of the car to do the same work! We can see that this is not the case, especially in a car with a 70A/90A alternator.
so...proof?
simple. well working loosely within the data of the mazda fan myth anyway..
we can say the fan on the mechanical side of the mazda genius mythbuster is able to do work that can possibly, and skeptically "according to the dyno sheets" consume 10 hp. soooo, maybe have that for the goal here instead of the 17 hp?? it is a tiny little wormy fawker fan for a tiny little wormy engine after all in the case of its oem life, agreed?
it is a fixed aggressive pitch fan..and it has (x) for mass due to its operational conditions. for the time its as efficient and cost effective as possible for the manufacturer no doubt.?.?.?...??
for an electric motor to turn
that fan to its
best cooling ability all of those million watt conversion bullshit numbers are likely very close.
totally believe it.
but.... that is not,
NOT what the average 2000 cfm application little electric motor is turning. it does not turn a 4-6 pound object.... its turning the silly little plastic blade it was born with. generally its a carefully matched rpm specific range deal. and likely to be drawing 1/2 of a horsepower with all the conversion loss bullshit.
and that is measurable and calculable with an ammeter using the stated formulas here. so what is so hard to understand?
a clutch fan generally has a range of 15-20% unlocked to 80% full lock.
if the dyno result posted in the quote of 10 hp was because of some odd failure that was indeed 100 percent locked, just on mass...not including the resistance of the blade working.....i cant see where the unit can ever pull less the 1/2 hp unless it is unbolted from the engine
best part of that artical, is that the rx7 factory power only ramped up from there and they went to electric fans in the following generation....and the reason was for them then in 1993 for the rx7,is the same as it was for ford in 2010 with the f150.
maximum efficiency
whats maximum efficiency mean?
maximum available hp to the wheel
max ac cooling at any speed
maximum potential fuel economy
maximum belt and pump life
minumum n.v.h. to get it all done
would i put a e fan on a mass produced 400 hp truck that any tom, dick, or mary will have a chance to operate like an idiot?
FAWK NO!
not clearer at all now? then i cant help ya.
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the electric fan won, i lost.
