I'm convinced not to do an e-fan conversion. I'm keeping the windmill!

 

^^^+1

 

Yep, another good point. I look at it this way. If my mechanical fan is engaged or if I had a G with all e-fans and they we're all engaged, then that means the engine is scalding hot and heat soaked and the car isn't going to perform well.

Now if someone was to do a dyno (there have been two so far that have dynoed) and it showed even 5whp, I'd do the swap and take back everything I've said about the conversion. DaveO, a previous G guru on this site and developer of the e-fan conversion, swore up and down that the conversion was good for at least 10whp and he said he had dynos to prove it. When I and a couple of others asked for them, he told us to take a hike and if we didn't believe, too bad. He wasn't going to post the data.

 

I think what he means is that most people will think he is just a grill-fanboy and nothing under the hood. Now, a stock grill will be the highest level of sleeper quotient but you get my point..........

 

Wow. Let's see, I have this portable Hampton Bay fan that blows so much air that I use it to dry out basements, etc. It is really uncomfortable to stand in front of at high speed. It draws 2 amps, or 240 watts. I would judge it to move more air, faster, than a car radiator fan.

10 HP is 7460 watts. To gain that at the wheels would take nearly 9000 watts at the crankshaft. That would be enough air to blow over a sumo wrestler!

We know why he would not post the data.

The best reasons to use electric fans in cars are 1) they can continue to cool after the engine is off, 2) you can mount them where you want them without worrying about pulleys and belts, and 3) they are easy to control with thermostats.

 

The alternator is working all the time either way. Yes it powers the electronics when the car is running and the battery picks up slack when it is overloaded but either way it never puts any more or less strain on the car.

When the m-fan is on it has the same strain of the alternator plus all the effort it takes to spin the big fan.

 

I guess we can agree to disagree.

One thing you are wrong on it the e-fans pull air just the same as the m-fan. All fans behind radiators pull air. Otherwise they would push against the natural airflow when the car is moving which would be counter productive.

As for which one can actually push more air, I don't have the data to post so I guess neither of us can prove each other wrong. I have seen data in the past to show the e-fans pull more air because there are two fans with more aggressive blade design which is slightly more effective than the one large m-fan. But, like I said, I don't have the data to post so everyone can choose to believe me or not. As for larger trucks having the fans, yes they do, they are a cheaper design and most trucks are not lacking in low end torque, nor is there as much of a market obsessed with every tenth of a hp/tq like our car. Is that the reason that Nissan changed them? I doubt it, I bet it was more for the sound. Just my guess.

You say two people have dyno'd this with no gains and then you say someone posted that he had gains but did not share his results. Do you have any results to share on the other two or are you going with the rumors too? I could swear I have seen a thread somewhere on here where there were dynos posted and there was ~4-6hp gain. But unfortunately I did not save them and have not taken the time to go looking yet. I will try when I have time. I could be wrong on seeing the thread because I have spent countless hours on here and my mind may be playing tricks on me.

Either way, adding a large fan that the engine has to spin will put an additional strain on it. That is just a fact... Yes, the motor still has the pulley but I have taken that pulley off before, it weighs almost nothing, it quite small and just spins with nothing to drive. Your comparing that the pulley is still there is like saying that removing the a/c compressor would do nothing. With that basic pulley on there and nothing to lag the motor down it is just taking up space. If you removed it, the motor would have a 1/10 to 1/100 of a hp gain as where taking the fan off would help quite a bit more compared to when the fan is engaged.

 

1) true
2) true
3) true

The power example is good but not true for this situation because those use 120V ac as where we use 12V dc. The power equations don't work quite the same.

 

Only difference is power factor, say o.8 for a motor, which would make the wattage 192, if what I remember of engineering maths is right.

As for trucks, if an electric fan would give more power hence better efficiency, the trucking industry would adopt it tomorrow. Over the million plus miles a truck does in its lifetime, a 1 or 2% gain translates to decent money.

 

I don't know if you're aware, but the Gs with mechanical fans are also equipped with a single smaller offset electric fan on the front side of the radiator. It's roughly the same size as one of the dual e-fans on your G. The mechanical fan is much larger than any of the OEM e-fans therefore I think it's safe to assume it will pull a lot more air.


When the mechanical fan is engaged, you know it. It's loud, but the only times it's ever engaged on my car is:

1) On some warm start ups.
2) On really hot days with the A/C on and sitting at an extended stoplight. Once over 15mph or so, it's disengaged.

The mechanical fan doesn't stay engaged for long at all, but I do agree it does suck out some power when it is running. However, the times that it is running, are times or conditions I'd never race in so the power draw is hardly a concern to me. Now when the fan is not engaged, it is simply free-wheeling along. There's no real power draw because the fan and clutch device aren't engaged, much like an a/c compressor free-wheeling when not engaged.

I think we've got a bit off course here but I'll end with this fact. If the Gs with mechanical fans were suppose to be some of slowest, mostly because of the fan, it sure didn't hold true for three of the quickest stock 5AT sedans that did 14.2-14.3@97-98mph of which were all 03s (owners BossSho, AudibleMayhem, and myself).

 

How do I determine which fan I have?

 

Pop open the hood and look in front of the motor. If you see a big fan, it's a mechanical fan.

 

K, my car is backed into the garage and with the hood open I can't see shiit, and I can't find my flashlight . But yes, I did know it was under the hood, and in front of the motor........


So, is the electrical version--2 small fans

I will check tomorrow afternoon.......

 

In the strict sense the power equations differ, as someone else pointed out, because the power factor (cosine of the phase angle) must be included in AC calculations. For purposes of this discussion I could go measure the power factor of my fan, but it would take an hour or so and is really not worth it.

HOWEVER... the power plant still has to generate the rated current, whether it is in phase or not.

In either case, the owner who claimed a gain of 10 whp is deluded by a factor about 40.

Here is a post by a truck owner who actually measured the power consumed by his belt-driven fan -- it varied from 0.2 to 1 hp. I have seen fan-load figures of 20 to 40 hp for industrial diesel engines, and there is no doubt that an alternate arrangement would help there.

 

That sleeper G needs clear corners lol