Electric vs. belt driven cooling fan

[redpoint5]

Originally Posted by Frank Lee

I removed the fan from my F150 a few years ago. At first I carried it and a wrench in the cab so I could put it back on if needed. Now the fan is hanging in the garage.

That's what I figured. My Dodge Ram Cummins has a fan that moves a terrible amount of air just after starting, even if it's well below freezing outside. I've wondered what would happen if I just yanked it out. Sadly, I will likely just part ways with the old yellow beast soon.

[busypaws]

I think it's a compromise between the electric fan and the grill block. If you leave the grill in OEM condition then sure you only use the electric fan on the 95 degree day in trafic with the A/C on. If you block 90% of the grill then you run the fan full time after warm up on a 70 degree day. So find the engineering sweet spot. Cover enough grill to decrease you Cd (improve your aero) but not so much that your running the fan all the time and converting all the fuel you saved in aero into electrical energy to run the fan.

I put the LED on the dash to see when fan runs to get a good idea. An 80 degree day at 50 mph with 80% grill coverage causes the fan to run abot 40-50% of the time. Still leaves me a little margin for the 95 degree day and probably really improves my warmup time on my short commutes. Just another thing to trade off in the hunt for mpgs.

[IsaacCarlson]

I've been thinking of pulling the fan out of the truck. Seems like it never engages.

[pletby]

I never have any problem telling if my fan is on. It's electric and wakes the dead! Heads always turn when I drive by from the racket. I'm thinking I have to look at what's going on under the hood. Maybe a aftermarket fan will be quieter. Also, my car overheats on 30C days in traffic with a/c on. Not that I ran the a/c much this year; trying to increase my mileage.

Now with new driving techniques, my fan doesn't engage before I get home from work.

[comptiger5000]

If your fan is that loud and you have overheating problems, the fan may be dying and not pulling enough air. My e-fan is pretty loud, but it moves a ton of air, and I know it's still good, as it was replaced about 1.5 years ago.

[radioranger]

ppoular Hot rodding did a dyno test a long time back where they showed an older style steel fan cost as much as 60 HP on a race motor, tryed running around my old 289 Mustang wihtout the fan and you could defintiely feel the difference so i'm guess it will help . just worried about underhood air temps on the ranger

[bennelson]

60 HP? I'm hoping that's a typo. I've had vehicles with engines smaller than 60 HP, and they seemed to be able to power a radiator fan!

I did some work a while back with a guy who built a drag strip SS. I noticed that car didn't have an alternator on it, and he said it was because the alternator would steal horsepower that could otherwise be used to propel the car! I think he said it was as much as a couple horsepower.

[radioranger]

They were taking a real world race engine and dynoing it, it must be more than a few Hp , I'm talking the old steel type because every car today has either a clutch fan or a electric one, It did seem high , I figure though it was at least 6 hp otherwise the belt would slip . I was quoting the article. I think if you can feel the difference its got to be 5 hp difference , not cruising of course its accellerating the fan, I put a bigger alternator pulley on my truck and you could feel the difference right away, if you are in start and stop traffic it is a big difference, due to the idecrease in momentum of the heavier part, thus a fluid clutch or electric willl be much better in city driving MPG than highway where you are steady state, Think how much power it would take to accelareate a four of five pound steel fan with pulley to 5000 Rpm in a few seconds thats where your power loss is. I forgot the math on doing the calculation but somebody could figure it out I'm sure

[oil pan 4]

Over on dieselplace there is something called "dinosaur fan mod", where you put a radiator fan from a military hummer into a chevy 6.2L or 6.5T diesel truck.
The fan was tested and reportedly to used over 40 horse power at max engine speed.

Now the max speed on those engines is between 3600 and 4400 RPMs. A race motor can turn well over 8,000RPM no problem. To double speed on something like a fan you have to 8x horse power as long as the blades don't stall.
Just driving down the road at normal engine speed a dinosuar fan could be using 5hp or more if the fan is engauged.