Electric fan difference

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Khoover1988

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1997 1500
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Little engine that can (3.9) lol
I have the 3.9 v6. Ive heard that converting from the mechanical fan to electric can give you 10-15 more hp and save some fuel, improve acceleration. Is this total BS or is it somewhat true? Plus they say its only a 1hp draw on the alternator? Any experience on this? Thanks.
 

crazzywolfie

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it might free up some hp when the electric fans are not running but likely no difference when they are running. i think electric fans might hurt the fuel mileage. i am almost certain my truck got the best fuel mileage with the mechanical fan on the engine. i have run electric fans and currently no fans at all and it don't seem to get any better fuel mileage but i really stopped caring about fuel mileage a while ago. just lived with it as is. personally i found the best part about electric fans is how quick the engine warms up in the winter and how you can adjust the controller to turn the fans on a 200* or 210* so the cab can get very warm very quick. i know my truck can get up to full operating temp in about 10-15 minutes running even on a super cold day.
 

ouch1011

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An electric fan can save some fuel economy, but as long as your fan clutch is working properly, I'd expect to see less than a 1mpg improvement. I've seen dynos that show some larger power gains by going from an engine fan to an electric one, but take into consideration that the gains will only be at higher rpm. You aren't gaining 10-15 hp at 2500 rpm, the only time you might get anywhere close to that would be near redline. Again, if your fan clutch is working well and it isn't one of the ridiculous "heavy duty" ones that basically leave the fan spinning at higher speeds all the time, you might only see like 2000rpm fan speed when the engine is near redline. That takes some power for sure, but not a massive amount.

Biggest issue with an aftermarket electric fan is they are usually too small. Oe applications usually use 2 medium size fans (or one huge one). Aftermarket ones are usually tiny. If all you do is drive on the freeway, that'll probably be fine. But if you do a lot of stop and go or trailer towing (especially if your ac works) most aftermarket fans will be too small and you'll overheat on hot days.
 

dapepper9

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Electric fans have shown dyno proven gains, yes in the 10-15wheel spectrum. As for mileage, in town you MIGHT see a 1mpg gain but it'd be negligible. Highway you won't see anything.

The whole "alternator load negating gain" thing is BS. Even at near max duty cycle, the alternator doesn't drag you down more than 2 or 3 hp.

As ouch1011 mentioned, the most of your gain is at higher rpm if you're looking at numbers. However, I'll explain it like this:
Ever drive your truck before it's warmed up on a cool day and it feels pretty powerful yet later on when it's warmed up a little bit and the engine is up to temp it just doesn't seem to pull quite the same? Electric fan conversion feels more like the first 1 all the time. Negligible yes, but noticeable nonetheless.
 
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Khoover1988

Khoover1988

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Little engine that can (3.9) lol
This is what i thought, my stock mechanical fan works just fine, ive just been relplacing vital mechanical parts that are due and it was annoying to get off lol. So the thought crossed my mind. Thanks again guys!
 
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