Electric Fan Gains

[rogue38]

For those of you who have converted to an electric main cooling fan instead of a belt drive fan, what kind of mpg gain did you experience.

On my old V8 Pontiacs when I removed the belt drive fan I normally would gain a good 3 mpg.

[nando]

Zero. Clutch fans freewheel unless they are hot, then the clutch locks. This doesn't happen at speed.

[bmwm42]

An mpg at most you do free a tiny wincy bit of power if doing lots of stop and go. Thats a few less lbs dragging the engine down.

[rogue38]

Didn't think much since the fans were so small and had a clutch. My old birds had clutch type fans too but fan diameter was huge.

Thanks

[Morrison]

The "clutch" fan on my car spins all the time whether hot or not. The "clutch" of course allows some slip to occur so the fan is not spinning at a 1 to 1 ratio, until heated. My inclination therefore is that there is some amount of gain to be had by replacing with electric.

Think of it this way. If its moving air, then work is being done. Work per unit time equals power.

[KenC]

It's negligible. Though there's a guy on here that claims 5whp (dyno proven, or so he says) on the m42 with the fan removed.

I converted to a high flow electric because it cools better and I don't have to deal with the clutch nut ever again. It gives a lot more room in the bay too.

[nando]

sure, .1hp :p

and a lot of people don't bother to think about wiring and just have it turned on with a switch/running all the time, so they're actually losing HP.

I'll probably go back to just an electric fan, but not until I can control it with PWM. the on/off nature of the stock wiring drove me nuts.

[Jaxx_]

sure, .1hp :p

and a lot of people don't bother to think about wiring and just have it turned on with a switch/running all the time, so they're actually losing HP.

I'll probably go back to just an electric fan, but not until I can control it with PWM. the on/off nature of the stock wiring drove me nuts.

PWM isn't on off? :P You still have Hi/Lo with the factory wiring. I only use high.

To me it's about efficiency -- you might not gain much but there's absolutely no reason for a fan to be turned on if you're going 50MPH and only slightly warm.

Be smart about your electric setup and it's worth the gains. Not to mention you don't have to deal with fan clutch failures, or fans destroying radiators.

[Ryann]

I have gained zero mpgs post e-fan conversion.

[KenC]

My electric radiator puller fan is tied into the radiator thermoswitch just as the front aux/condenser fan is.
The biggest improvement from my electric puller is the increased performance of my A/C system at idle.