electric vs. clutch fan

[race420]

I was thinkin, if an electric fan is suppost to be so superior to our stock clutch fans, why wouldnt nissan just put electric fans on the engine from the factory. I think they both cost about 250 bucks. There must be some sort of advantage to a clutch fan.

Ive noticed that BMW uses clutch type fans on their vehicles. to an extent it can be said that BMW wouldnt compromise for cost savings on something like that.

on the other hand, the g35 and other infiniti's that use the 3.5 engine use electric fans.

another thing, I am no expert by any means on this. But to power an electric fan, doesnt energy have to be transformed twice. newtons to current, than current to newtons? my units may be wrong, havnt taken physics for a few years.

what do you all think, know, or think you know?

[navysnail]

exactly. conservation of energy, that energy to run either fan comes from the engine. the only diff. with electric fans is that they can turn off at high speed, while a clutch fan mostly disengages. IMO not worth it, but many people do it.

[race420]

This is true, clutch fans still cause some load on the engine even when they are not engauged. But why dont you think nissan would not just use electric fan set up from the factory?

[corn322]

probably because of the price:airflow ratio. I'm sure the clutch fan can flow a lot more air for cheaper than an electric can.

[dfw240_EE]

One advantage to Electric fans is that they are more compact. I saw a guy's 240 with an electric fan, it was so much easier to get at the front belts and pulleys.

I am a BSEE (Electrical Engineering graduate) so this is a biased opinion, but USUALLY electricity is more efficient at transferring energy than mechanical means. In summary, you need to expend less HP to run the fan. Though we are probably talking fractions of HP here.

[SHIFTrl240]

well they arent looking for the most efficient way, more the cheaper way. even if the electric fan was 50 dollars more per car, thats 50 dollars for EVERY car put off the line... that adds up quickly

[dfw240_EE]

I guess I was thinking more along the lines of why someone would swap out a clutch fan for an electric aftermarket.

[bluemax]

here's my experience on a Zenki w/ Koyo alu. rad., and large front mount.

With the the clutch fan, I didn't have problem with city driving at normal ambient temp. On hot days at 3k-4k rpm cruising speed in 5th gear, the engine temp tend to rise quite high but I never had overheating problems.

So I decided to go with dual Altima fans that are activated with a thermal relay. This setup caused the temp to fluctuate too wildly up and down. At highway cruising speed, I still didn't have enough air flow through the rad to keep the temp down and constant. The fans have to kick every so often. Just moving my front license plate to the side helped but not enough.

Now I am running one fan that turns on with the ignition and the 2nd fan only kicks in above a set temp. I have a more stable temp now. The second fan doesn't really kick in unless it's a hot hot day. The engine temp with this setup is similar to my clutch fan setup in city driving and normal ambient temp. At highway cruising speed on hotter days this setup does a much better job of cooling than the clutch fan.

Ever wonder why the engineer design a sidemount IC and clutch fan? I think it is because of poor airflow across the rad and a need for constant airflow.

So if you have a frontmount, you will need a constant airflow across your radiator. In cooler weather, the clutch fan would probably be sufficient. In hotter weather you might want to go with good electric fans that is on constantly. And there goes that idea about saving a few horse by having the efans off.

well that's my experience anyway...good luck people.

[race420]

i did some more searching, i believe a clutch fan is cheaper for the manufacturer. I guess those electric fan motors are pretty expensive. I wonder if nissan installs a heavier duty alternator for the vehicles that use electric fans too. that would also raise the cost difference.

think clutch fans are more reliable?

so far it seems like they only cost less and make the 240 sound like a truck.

[dfw240_EE]

I would think that electric fans are more reliable. There are very few moving parts in an electric motor, so as long as it is protected from excessive current it should be solid.