ThatGuy1295

Sure theirs some mechanical loss from spinning the cv, but its to small to see any mpg gains. Thats why toyota stopped making manual hubs, not just convenience. All auto manufacturers are being pushed for better fuel economy, you really think they would deliberately cost them selves even .5 mpg if they could avoid it? Having a passenger in the truck is gonna use more fuel then spinning your cv's.

And I don't believe that you are smarter then toyota on this one, even with your "physics grade9" education. Nothing wrong with helpful ideas, my previous post was just this little thing called "feedback". Get used to it.

2big4arunner

Sorry to all others. I don't want to get into a discussion on someone elses thread.

sorry again for going as long as I did. I just hope that people research the options and opinions people propose to see what will work for them.

ThatGuy1295

God your weird.

Dirt Driver

1.) Electric fans help when not being used, the idea being that they use zero energy when unneeded. They only help very slightly over a thermostatic fan clutch....probably not measurably to any of us who gauge fuel economy with odometers and fuel station pumps. ThatGuy is right about the alternator having to power the fan. The fuel still gets burned and powering the fan via crankshaft is hypothetically more efficient that powering the alternator, which has inefficiency, in order to run the fan, which has its own inefficiency.

2.) That paragraph needs a lot of qualifiers.

2big4arunner

K. If your theory is correct go look under the hood of any 2012 hybrid... Truck, car or suv they all run electric fans, electric steering, electric a/c... Did they get it wrong in those vehicles guys. Or did they run it off the battery and have the alternator gradually recharge that for more efficiency.
The only reason I contest these statements is that I do them all the time for better gas mileage and power. I have seen it countless times increase gas mileage. Not just a theory

ThatGuy1295

Hybrids are completely different engines. They use electric fans for many reseons, like theirs no room under the hood for a clutch fan, well gee (the engine is sideways in the cars so you would have to mount the radiator in the fender, or get all crazy and have a driveshaft ran through a gear box to redirect to the clutch fan. But mostly because at low speeds the gas portion of the engine is not running, and the electric motor portion of the engine is [at least the ones i have looked at] direct drive. So how would the electric motor portion of the drive train spin a clutch fan while the vehicle is stopped at a red light? It wouldn't. Thats why the power steering, A/C, fans, and whatever else you can think of has to be powered by its own electric motor. Electric fans just make way more sense in hybrid cars and truck no matter how you look at it.

Electric fans in our trucks, under the perfect circumstances, could be more efficient than a clutch fan. But like mentioned by dirt driver, their not going to be noticable.
It takes the same amount of energy to spin either fan, all your doing is changing which pulley it is takin from.

So in refference to this post, NO electric fans are not a mod to improve gas milage.

gennro

All Tundras still use a clutch fan.......

ThatGuy1295

Is there a tundra hybrid?

ThatGuy1295

Now... the old school directly bolted to the water pump pulley fans are a different story. And in case your wondering, thats were this MISCONCEPTION actually came from. Those fans, WERE inefficient. And by simply replacing them with an electric fan you could see noticeable gains in HP and MPG's. Thats were the clutch fan stepped in and leveled the playing field between mechanical fans, and electric fans. A clutch fan is just as efficient as an electric fan because it shuts off, it mechanically uncouples itself from the engine when not in use. Reducing drag up to 99%. ish. All thats left is a little bit of bearing and hydrostatic friction in the clutch body. And when the air coming through the radiator is moving faster than the fan because your driving, and the fan is being pushed by that air. Theres pretty much no drag.

And for cooling purposes, a clutch fan can displace a lot more air. If it needs to be, its a 100hp fan instead of a 12v fan.
Are little alternators could never power a fan to compete with the clutch fan.
Thats why semi trucks, and anything that can tow something weighing more than 3000lbs has a clutch fan.

TNRabbit

There, fixed it for ya~

ThatGuy1295

hey I'm from warshington.

Dirt Driver

Hybrids don't run everything off of the alternator. Hybrids get a large chunk of their efficiency from regenerative braking; the car's kinetic energy is converted into electrical energy and stored in batteries until needed. That stored energy is then used instead of burning gas, whether it's assisting vehicle takeoff or running the fan or A/C. That's why their highway economy figures are usually worse than the city figures; not much braking going on so the engine does a lot more of the work. It all goes back to that conservation of energy thing I mentioned.

Many, many, many hybrids also have front transversely-mounted engines, so a mechanical fan presents serious packaging hurdles for the cooling system. Packaging is also a factor in power-assisted steering and braking.

2big4arunner

K... The only hybrid you want to look at is a small car? Forget it. Do what you want. I get good gas mileage in a modified 3.0 auto. For me to share my information that I know 100% is correct from the 10+ different makes that I have converted over using junkyard parts and common sense seemed like a good thing to do.
If you don't think I am right. Convert it over and reset your ecu. Drive and prove me wrong.

ThatGuy1295

I have proved you wrong. I stuck an electric fan from a ford tauras in my 89 a few years ago because the clutch fan exploded while water crossing. And it didn't do a ----ing thing for gas milage. I even got the fancy temp sensor kit to run it. The good one that cost's over $100. Then I eventually put a clutch fan back in there. Again no change in mpgs's.

Your the one trying to prove something, and you don't have any facts or arguments except ''hybrids have electric fans''. So with my amazing deductive logic and awesome "grade9" physics education, Ill get hybrid mpgs if I stick an electric fan in my truck.

So you prove it.

BMcEL

Can someone please explain why we're comparing hybrids to 20 year old trucks?

Why on earth would you need to reset the ECM after installing an electric fan?

ThatGuy1295

I wish i knew

KBJ

My thoughts on the fan idea are that when driving around town, stop and go traffic, quick on/offs the highway, is when you're getting the most inefficient mileage, it's also likely that the engine is heating up considerably more than it would during extended highway driving. When that fan is engaged to maintain a good operating temp around town it is certainly drawing energy from the engine output. It's at this time when it would seem most advantageous to eliminate that draw on the engine, when the fan is most likely going to be engaged.

As far as the electric fans also drawing down on engine power because it has to spin the alternator, I'm not so sure about that, I would have to see how many amps those fan(s) are using, I suspect it's not going to be very much. Not only that, that alternator is usually always running generating electricity for many other systems in the vehicle so the additional draw from a fan seems likely to negligible.

I don't really know the answers to the above speculation, but it's certainly something I'll be asking about next week when I take the vehicle in to be checked.

ThatGuy1295

Alternators become harder to spin as more electrical load is applied.
Take a look at 5HP generator. They usually produce around 2500watts. Anough to power a coffee pot and a microwave at the same time. But it takes 5 horse power to do so. And 0 HP when not powering anything. DC electric fans draw a lot of amps. Enough to more then double the resistance of the alternator pulley. When your driving around with the head lights and radio on that same alternator is not working very hard at all. Probably 10% of its capability. And no an alternator doesn't magically produce power without resistance. Its just an mechanical energy transfer through wires. Same effort it takes to rotate the fan = same added effort to rotate the alternator. There is no energy savings when running the fan. Unless you put in a weaker fan than you should, in that case your only hurting yourself.

Dirt Driver

You're just being a troll at this point and further undermining your own credibility. Anyone can state opinions as fact. It's not my job or anyone else's to prove you wrong, it's your job to prove yourself correct.

For the curious, try this: measure the force required to turn a thermostatic fan clutch when cold, calculate the torque(force in pounds x distance n feet from center of fan), and then how much power( [torque x RPM] ÷ 5252) it absorbs at operating speed. That will give you an idea of how little savings an electric fan will provide. It's still a savings, but done right, a very high investment-to-return savings dependent on vehicle usage and not high on the hypermiler's list of things to do IMO.

Exactly, power out has to equal power in minus losses to inefficiency/friction.

Ignoring losses, good electric fan might draw 40A in operation, so around 3/4hp (40A x 13.8v = 552W, 552W ÷ 746W/hp = 0.74hp) that the alternator has to get from the engine.

ThatGuy1295

Couldn't have said better my self.