How much HP is an Electric Fan worth?

Kdubslugga

Active Member
Jun 7, 2003
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Akron, OH
Im going crazy this winter not driving my car, and it hasnt even been 2 months yet! Im enjoying adding stuff to my car this winter, lets me spend some time with her. Anyways, ive got about 200 bucks to spend, and i know i want either Lower Control Arms or a Flex A lite Electric Fan. My question is how much HP are these good for, i know they advertise like 15+ but i know thats not true. Also which mod would benifet me more at the strip? If it helps my winter project this year is 4.10s, ET Streets, C/C Plates, Lowering Springs.
 
Kdubslugga said:
Im going crazy this winter not driving my car, and it hasnt even been 2 months yet! Im enjoying adding stuff to my car this winter, lets me spend some time with her. Anyways, ive got about 200 bucks to spend, and i know i want either Lower Control Arms or a Flex A lite Electric Fan. My question is how much HP are these good for, i know they advertise like 15+ but i know thats not true. Also which mod would benifet me more at the strip? If it helps my winter project this year is 4.10s, ET Streets, C/C Plates, Lowering Springs.

yes it is true about 15hp... to the strip probably contol arms: better handling...

btw with an electric fan you'll hve to upgrade to a 3g alternator at least 100-130amps new wiring and some other tsuff to control the fan...

" if it's a fox body, and has the stock 65A alternator - you're gonna need to upgrade the alternator. At least 95A, most folks go with a 130A. "-Michael Yount
 
i run my black magic fan with the stock alternator and no problems,and the idiot that owned the car before me had the previous fan wired on ignition without a temp control so fan was always on as long as ignition was on and i never had a problem.
 
You can't really loose either way. What bothers you the most and/or what do you want more? More power or more controll?

I ran the Black Magic for almost a year with the stock alternator and pullies, no issues but the original alt did go out eventually, probally would have anyways. The 3G is one of those upgrades that should be done anyways. An electric fan would definatly free up a lot of rotational weight and drag, so it would be a good mod. The Controll Arms make a big difference in handling, not just in corners but on takeoff as well. You really should do upper's and lowers at the same time IMO.

I don't see subframe connectors in your sig? If you don't have them, forget the fan and LCA's and get the subframes done first.
 
90mustangGT said:
I don't see subframe connectors in your sig? If you don't have them, forget the fan and LCA's and get the subframes done first.

I second that. Subframes are more important than the control arms at this point; ideally you'd do both the subframes and control arms, but if you only have money for one; get the subframes.
 
saniutza said:
" if it's a fox body, and has the stock 65A alternator - you're gonna need to upgrade the alternator. At least 95A, most folks go with a 130A. "-Michael Yount
i would add, in regard to what Michael said (Michael, if i mess this up, please correct me): with a variable controller like a www.DcControl.com
the stress on the charging system is less. i would venture to say that if one ran one of those units on a 95 amp alt, the system would run like it had a higher output alt (like a 130 amp) due to the lack of 'all or nothing' fan performance.
 
Let's not forget that adding an electric fan puts a bigger draw on the electrical system.

bigger loads on the alt mean the pulley is harder to turn. And that means you suck up a bit of HP to turn the alt pulley.

So say the fan gives you 15HP, but running it costs you 5HP due the alt. You get 10HP from the mod. See where i am going with this?

This is why i have a switch to shut my fan off when i make a run. Electrical draw increases alternator load.

Of course, they you get the ricer who reads this and shuts his headlights off at night when racing because he thinks it gives him 10HP. You laugh, but i met a kid that did that.
 
Let's not forget that adding an electric fan puts a bigger draw on the electrical system.

bigger loads on the alt mean the pulley is harder to turn. And that means you suck up a bit of HP to turn the alt pulley.

So say the fan gives you 15HP, but running it costs you 5HP due the alt. You get 10HP from the mod. See where i am going with this?

This is why i have a switch to shut my fan off when i make a run. Electrical draw increases alternator load.

Of course, they you get the ricer who reads this and shuts his headlights off at night when racing because he thinks it gives him 10HP. You laugh, but i met a kid that did that.
 
Mike, interesting. i do not have the education you do (not in engineering atleast), but i once did some calcs and the additional alt draw was a fraction of one HP. did i screw up the calcs?
 
HISSIN50 said:
Mike, interesting. i do not have the education you do (not in engineering atleast), but i once did some calcs and the additional alt draw was a fraction of one HP. did i screw up the calcs?

I made two passes back to back at the local strip. One with the fan on, and one with it off. Times were so close it wasnt funny. I will go out on a limb and say there is no difference in the real world. The alt takes almost nothing to run. This has been argued many times. The elec. fan frees some noticable HP. What convinced me was taking the stock fan off and driving it. I did this before I installed the elec. fan. Just dont go far. It felt to me like the difference between a/c on and a/c off. They do tax your electrical system though.

I agree 100% with the subframes, they should be a first mod. I will get some real soon.
 
I've dyno tested an electric fan vs. the stock clutch type fan on my '90 coupe. The car has underdrive pullies and showed a 5 HP gain at the tires on a Mustang dyno with the electric fan. This is a little less than 7 HP at the flywheel.

If you don't have subframes, get them. If you do, get the lower control arms, but reinforce your torque boxes in conjunction with the control arm installation.

Good luck.

-Matthew
 
An m8, even if it’s running full speed draws 35A @ 13V, that would be 455W. An alternator , even at full load is 50% efficient, so the worst case hp draw would be (455*2) / 746, which is 1.2 Hp.

The alternator is nearly always running at less than full load and the m8 rarely runs full speed with a decent controller, so I’d say realistically that the drag would be about ½ hp

If you’re generating any real hp, you’re better off forcing the fan to full speed as soon as you come off the line since you’ll be generating more heat than the system will dissipate.

As far as hp draw of the fan, it’s entirely dependant on rpm and is approximately 15* (rpm /5000)^3

7000 : 41 HP
6000 : 26 HP
5000 : 15 HP
4000 : 7.7 HP
3000 : 3.2 HP
2000 : 0.96 HP
 
HISSIN50 said:
Mike, interesting. i do not have the education you do (not in engineering atleast), but i once did some calcs and the additional alt draw was a fraction of one HP. did i screw up the calcs?

Yeah, i did some calcs later on the night i posted that and found it was maybe 0.75HP-1.0HP according to the numbers i used. Nothing to really worry about.

But i was just tossing that fact out there.

Interesting to see it takes less HP to create the electric energy to power a motor to turn the fan than it does to have the engine turn the fan on it's own.
 
It doesn't take less power. If you extrapolate the rpm numbers down to 1700, a mechanical fan uses the same hp that an m8 consumes byway of the alternator but the cfm equates to about 6800 cfm vs 4800 (given that the blade diameter is the same and there is no clutch). The benefit of an e-fan is that the fan rpms are not tied to the engine rpms.
 
They have an article this month in 5.0Mustang&super fords,,A Chicane Sport Tunings Radiator and Fan Assembly.Aluminum radiator and dual fans!!It looks extremely easy to put in.Its the same dimensions as the stock one.The factory clamp downs hold it on.It works on 93 and earlier foxes!! But its a little pricey!!