rustysuor

Has anyone deleted their Clutch Fan and put an electric fan in its place. If so, with what results. I'm told that it can be done and that the Clutch/Fan combo rob roughly 25-30HP.

Waynerd

No way they rob that much power. I have a 98 that did not have a clutch fan when I got it. I installed one and there's no noticeable difference. That leads me to my other reply. Never use one of thos electric fans that mount to the radiator with the plastic pins that go through the fins of the radiator. Those things will put a hole in the radiator one way or another.

What I was thinking of doing is using an E fan from a right hand drive Cherokee. Pretty sure they were on the opposite sides. Not sure if they will work on a left hand drive radiator though. I know the left side electric fan shrouds won't fit properly on the right side. It doesn't line up with the bottom slots right.

I was also thinking of using the mechanical fan shroud and rigging an electric fan that's pre mounted to a small shroud.

extrashaky

LOL, no. The mechanical fan only pulls power from the engine when it's needed, and it's not 25 hp. The rest of the time, the fan clutch allows it to freewheel. And it adjusts itself along a range, so that it only pulls as much power as it needs when it needs it.

To move the same amount of air with an electric fan, you need enough electricity to do the same amount of work. That electricity doesn't just appear from nowhere. It comes from the alternator, which is turned by the engine. So the load on the engine will end up being similar, just from a different place. The big difference will be that when the electric fan is on, it's pulling a full load from the engine rather than only pulling what is needed, whereas the mechanical fan clutch achieves much better efficiency by only taxing the engine as needed.

Cane

i looked into it for the tauraus fan upgrade. depending on the fan you're using, maybe you can get away with only removing the studs on the pulley assembly. since the taurus is so big you need to remove the bearing from the bracket and cut a part of the bracket in order for the fan to fit. then I think the new belt should be between 82 and 83 inches in length.

i'd also give it 5hp max, nowhere near 20 lol

bad_idea

I'd agree with Cane (once again) that it MIGHT rob 5hp. You building a race car? If not, don't worry about it. It will take a SERIOUS electric fan to push the same air as the mechanical fan. From what I understand, the Taurus fan fits the bill, but takes a bit of work to fit in there.

4BangerDanger

I've looked into this for my 4 banger, to try and squeeze as many ponies out as possible. The numbers I've always seen thrown around are 5-10 hp. It's supposed to be a ton of work, as the others have said. However, a lot of the guys that have done it claim it's worth it and that they can feel a difference.

Cane

great minds think alike ! haha

let's say you do the manifold upgrade, bore the throttle body, swap injectors, replace manifold for a header, then maybe you'll reach a 20hp gain. it's definitely possible but not with the fan delete alone.

extrashaky

I would need to see dyno numbers before I would believe it actually pulls even 5 hp from the motor.

ETA: After a bit of Googling, it looks like a 1/2 HP motor in an industrial fan will move around 2500 CFM. IIRC, our mechanical fan also pulls about 2500 CFM. So I SERIOUSLY doubt our fan pulls more than one HP when fully locked up. It's probably not even measurable most of the time.

EEVEE

extrashaky

I'd like to see that repeated by other people on other motors, but I guess I can accept that there was a bigger HP penalty than I thought there would be.

However, they said something kind of stupid, that they didn't include a test with an electric fan because the alternator is always running anyway. That seems to imply that they believe the load on the alternator doesn't change the load on the engine. That's just not true. Physics still says you don't get work for free, so it's not possible for an electric fan to push as much air as the mechanical fan while using less energy unless the design of the fan itself is somehow much more efficient. Given the fairly simple and mature design of fans in general, that seems unlikely.

If you see an increase in HP when going to an electric fan, it's most likely because the fan you selected is really weak and isn't pulling as much air.

TimV

Just to throw another .02 in the pot.....

It's been shown on other dyno tests that 1 or 2 hp is used up just for belt drag or whatever ya wanna call it. If so, deleting the mechanical fan AND it's associated pulley could provide a small advantage. Also consider, any fan is probably not needed at highway speeds. One has to evaluate their needs and expectations carefully.

Also noteworthy, if any of the numbers being thrown about are correct, a 2hp draw on an I6 is about 1% of available power, whooopdee, whereas on an I4 it's closer to 2%!! Wow, double the gain!!

fb97xj1

Swapping a mechanical fan for electric increases the load on the electrical system. The alternator has to spin that much faster to keep up with demand, which will probably kill any hp gains with an electric fan because the engine has to spin that much faster just to run the alternator. If hp is the goal, an electric fan isnt the answer.

BrawnyDog

I haven't heard much about a direct drive flex fan. That probably not what it's called but it bolts right up to the pully and at low rpms the blades pull more air. At high rpms the blades give to pull less air.
I'm old so that very well could be ancient technology that is no longer used.

s346k

electric fans eat more power than clutch fans? somebody needs to alert EVERY RACING TEAM ON THE PLANET. they're all doing it wrong.

it is more than noticeable when the fan is locked up. id guess a 15-20hp loss at full lock. i did not watch the video, bc data.

to the op: my only reservation about removing the clutch fan would be lack of cooling ability. most any other application i'd say go for it, but the tiny xj radiator needs help and the clutch fan moves air.

tinytrax78

i ran twin stock electric fans the hp gain was minimal and it did not cool enuff either so im back to the stock set up of fans ,i did upgrade the water pump to a flowcooler and bought a cheap all aluminum radiator off fleabay all is good now after a good flush and new stuff installed