Who is running an electric fan?

This brings up a good point too high of an antifreeze mixture won't allow the engine to dissipate heat well antifreeze does not have a good heat transfer compared to water. Also additives like redline's water wetter helps increase that heat transfer effect. Moral of the story only run the necessary amt. of antifreeze to keep the system from freezing in the winter. All those other suggestions are spot on! Especially a clean rad. and condenser if those have to much crap in the fins air cannot move through them so a thorough cleaning will fix that issue.

 

Really, what is the actual technical justification fur installing an electric fan vs the clutched stock fan? No feelz. What do people think they are actually gaining in real numbers?

 

Here in the buttcrack of hell (Arizona 120 degrees in the summer), some users have reported a consistently lower trans temp by a significant amount especially for towing down here. I think @Torspd ....

Found it: https://www.tacomaworld.com/threads/upgraded-ron-davis-radiator.487191/

and upgraded radiator.

 

It is very subjective as far as feel goes but what I have seen is around 10hp on the avg vehicle. On the dyno the #s we have seen were in the lower and a tiny bit of throttle response. The problem is this is a truck it is harder to feel or see gains of that little compared to a small light weight car. Power to weight ratio comes into effect. On my old 7.3l diesel I gained roughly 15 hp and around the same in tq (yeah I know higher than what I said earlier). I couldn't feel it a bit. I had a 6 position tuner on it and couldn't feel or see any real gains on that truck until I was up near the 100 hp range in gains because the power to weight ratio was so high.

 

I remember that thread. So feelz? What am I missing?

 

So... basically nothing on a Taco?

 

You will get something but would you really be able to tell eh probably not. The biggest thing with computer controlled cars these days is every engine mod you do like intake exhaust etc. the only way to take full advantage of these things is to flash and tune the ECU.

 

Had one in my 5.9 and it kept her under 200°. Any pics of that monster?

 

I have some I can post. But since Photobucket sucks easiest way is to use Google images for jmaack727 on dakdur and dakotart mostly. Shows most of the years from about 2005 to current. M1 swap tko 600 swap pretty much from stock to 100 % every bolt on. Kenne bell removal etc. Tko swap changed due to driveling vibes with a 131 inch wheelbase and such a short trans. Don't want to clutter this thread but I can always post some pics in another.

 

Thats what I thought. Feelz.

 

The before and after dyno testing, would have to be done before basically anything could be proved.

 

Dyno tests aren't useful. No one argues that an engine driven fan takes significant HP to drive and the viscous coupling often isn't working as well as you'd like. What you get with an engine driven fan is simplicity and a ton of air movement.

The stock fan completely locked moves a lot of air. I've seen reference to 10,000 cfm, but I don't know it as a fact (seem reasonable though). If you assume the equivalent of 60 MPH moving across it and sea level air at about 77F it takes about 3.4 H.P. to drive the fan. It's not a small amount of power.

For this to be true that would mean the engine driven fan had to be drawing the equivalent of 11,190 watts, which at 13.8V is 810 amps. That's ridiculous.

Most fans are rated around a couple thousand cfm. The Flex-A-Lite Black Magic Xtreme 180 mentioned earlier is rated for 3,300 cfm. It's got a running draw of 18A (which assuming 13.8V is 248 watts or about 1/3HP). Therefore we can infer it can develop about 0.023 psi across it if it's 100% efficient. That's about 158 pascal or 0.023 p.s.i., which is about the equivalent of driving at 16.3 MPH.

You will have gained about 3 HP doing that. If that's all the cooling you need then that is truly power gained. But it's also only 33% of the original air moved.

Most of the time there's excess capacity in the engine driven fan and so it's truly useful. But sometimes you need the 10,000 cfm, which means two fans or a larger fan.

 

Point is you often don't need the full capacity of the original fan, so an electric fan can save you power and fuel. But when you need the full Monty you don't have it with e-fans. Off road or long pulls up mountain passes are when you do need all the cooling.

To duplicate the full capacity would take 3 x 3,300 cfm fans and about 54 amps. That's roughly 1 HP. In reality the double conversion of engine power to electrical and back to electrical is about 50% efficient so it's really more like 2ish HP taken from the engine to drive the fan. It's a savings still, but in the 1.5HP range (from the original estimate of about 3.4 HP to run the fan).

This doesn't factor in the load on the electrical system. What happens with the headlights on and if you're running the fan for A/C and heat? Another thing to consider is you only get full alternator rating at high RPM. At idle an alternator will be down to half it's rating. There's nothing for free here.

 

Have you seen the engine driven fans on a 7.3l diesel IIRC it is an 8 blade but it is almost 2 ft in diameter. The fans in the 3/4 ton and up diesel trucks move a ton of air and are a large parasitic drain on the engine. You are not factoring in the power required to turn a large diameter "weight." Back in the days of early hot rodding one thing they would do to gain power is reduce the diameter of the fans thus less power to turn a weight hanging further out also less cfm. Today's factory fans almost eliminate the weight thing due to them being made of plastics yet there is still some weight hanging out there.

I can tell you from real world experience that those calculations are a good base but do not tell the whole truth in HP gain and the benefits of an electric fan. I do agree that under heavy load when the engine is really working you need a lot of capacity to cool the engine. Also manufacturers set up the crank and alt pulleys to have max output at cruising RPM so lets say 65 mph 1500 RPM or around that. I can agree that max alt output is not made at low or idle RPM but once you get to the RPM that is set for that specific vehicle to have max output then you're good. One thing would be to run a smaller pulley on the alt thus driving it at a higher RPM at idle speeds getting more output. And yes when you have the full monty electrical load unless you have a large amt of amps to supply that you will rob hp but that is because you are loosing power to those components that create power like ignition, fuel, etc.

 

I thought we are talking about the 15" ones on our Tacomas. I'm sure the 7.3L has a lot of cooling capacity. I gave the formulas, you can figure it out yourself. I seriously doubt there's 4x the capacity, though, to get to 15HP. You'd be talking 44,000 cfm. I'd bet the stock 7.3L fan is more like 5 to 6 HP.

 

I gave the example of my old 7.3 diesel. I have not switched my tacoma yet. Again I go back to my points of the formulas are great to get a baseline but until you actually put it to real world tests they only give you that a baseline. There are a lot of factors that the formula is leaving out the gear reduction of the pulleys the weight of the fan and distance from center line that weight is, etc. The calculations are much more complex than that simple baseline one.

 

None of that is important, it's inclusive in the power coming from the crank. You may change the efficiency, I assumed 80% mechanical efficiency in the 3.4 HP number to account for the coupling slip.

I gave the e-fan the benefit of 100% efficiency, assuming no loses for mechanical-to-electrical conversion nor did I assume any motor inefficiency on the fan. If you want to start adding up system loses we can, but it's only going to increase the power necessary to drive an electric fan.

 

The one piece of missing data in all of this is the CFM of the OEM fan. That data never gets published, but I'm guessing it is way over the output of these E-fans. I'm pretty sure the engineers would not over design that aspect, since it would impact fuel economy ratings. These trucks were designed to function across their performance envelope, in virtually any environment, from the Arctic to Death Valley. If that capability is to be preserved, then the electric fans would have to produce the same CFM. To trade cooling capacity for power is fine if your expected environment does not tax the system. The only way to see whether E-fans are working more efficiently is to compare apples to apples.

 

So, here's an example alternator efficiency curve. You can see right off the bat that at most it's 55% efficient at converting mechanical input to electrical power. So if you need 1 HP, 746W, or 54A at 13.8V you need to take 1.82 HP from the engine.

 

Here’s my 2 cents. I’ve had 5 Toyota trucks all bought new. Both Tacoma and Tundra. (4 Tacoma’s , 1 Tundra) All have had stock oem cooling systems. I live in the Sacramento valley in California where summer temps hit 110+. I tow my 3500+ lbs boat often in 100 temps. I’ve off roaded and taken them in the mountains in hot weather. Never, not one time have I had a over heating problem. I’ve never had the temp gauge go much over half way. If you are having a overheating problem I don’t think an electric fan is the solution. I think you need to check the entire cooling system and make sure all is good with it. Taco’s shouldn’t be over heating.