Hey guys, I was looking at the electric fan kits from LFP and JDM, and was wondering...

How does a fan give you 2 extra MPG and 15-18 horsepower? Is it because of the removal of rotating mass? Or the Extra cooling capabilities?

I really have no clue, and would really love to know, as im thinking about buying one if someone can explain to me how they work?

Thanks guys

 

Less Rotating Mass, Less wieght for the motor to turn. If you think about it, a fan pushing that much air would really put a major drag on the motor and its power.

When eliminating the drag on the motor you free up HP and in doing that you put less strain on the motor and get better gas mileage. It is probably the first mod, everyone should invest in. Just my opinion.

 

The rotating mass removed is around 11 pounds worth. When installed with the aluminum water pump a little more weight loss can be acheived. IMO most of the MPG/HP gain found is in this area versus the cooling factor of the elect fan. I do like mine and i did see a MPG gain. I'm not sure if anyone has done a dyno before/after the fan to see the actual HP gain. 15-18 seems like a lot but.........

 

Removed stock fan to simulate an electric fan. On Danny Swansons dyno we gained 6.3 rwhp and 12.7 pounds of torque. I ordered an electric fan the next day. Skip

 

nice, how exactly do they work? do they use up the battery? Do they do anything weird with the a/c? Im completely in the dark about all this, i really have no clue how any of it works. Also how do the a/c control and on/off swtich (besides the obvious) work?? What are the advantages?
sorry for the 20 questions, but i wanna know EVERYTHING if im gonna pay $450 for it!!

Fill me in!!

thanks

 

I just have a simple question, do the electric fans run continuous, or do they tie into the thermostat, or what?

 

they are controlled by the thermostat/temp probe in the radiator... Flex-a-lite makes a great dual fan setup. pulls 5500 cfm.. R.E.M. carries them i believe....JR

 

Could someone post a link to a vendor that carries the fans, preferably one that they have had a good experience with?
Thanks

 

Skip was this with the fans running or not. Obviously with the fans off you will pick up power, but when they are on the altenator will certainly drag down that power again, Be an interesting dyno though...

Brandon

 

I do not understand this logic. How does the alternator know whether its output is being used or not? The amount of power used to force the armature against the windings should be the same either way, shouldn't it?

 

For the Flex-a-Lite 270: www.summitracing.com

 

How do they work, obviously a fan moves air and thus cools down the device attached to assuming the air being pulled through is of a lesser temperature than teh device. (Well i felt like being a smart a$$ )

They will indeed drain the battery, even 10-20 mins of it running with the truck off will run it down. Alot of guys with the toggle switch run their trucks down quite often at teh tracks cooling between rounds.

They dont do anything to the ac, except you can tie it in so that it turns on when the a/c is on to help keep the condensor cooler and allowing your a/c to work better. Since its controled via the coolant temperature in teh motor and not the condensor, the condensor can get saturated with heat and then your a/c will not work well or at all inside the truck, which is why you need to get the a/c kit on there. If the condensor is getting enough air through it at decent speed obviously it will work properly, only during stop and go, or very low speed travel will the fans need to be on to keep the ac working.

As far as tying into the AC, there is a wire from the climate control that goes to teh a/c amplifer (little doohicky that controls/monitors the pressure/engauges/disengauges teh clutch)that comes on during any selection on your **** that includes A/c..it simply ties into this and triggers the fan relay.


Advantages are that it can move more air than the stock fan can in most cases, you can use it while the truck is off and cool down the truck quicker, and during drag racing you can leave it off during the pass and pick up some power.

Brandon

PS hope that helped

 

No, the alternator does know how much power is being used, by the voltage its outputing. The alternator simply trys to maintain the correct voltage, and will do so assuming the alternator is capable of outputing the amount of current to sustain the voltage. When you put a 'load' on the alternator it draws ALOT more hp off the motor than when it sits idle. Ever notice if you turn your climate control fan on HIGH, turn your lights on full blast, and crank a decent stereo your RPMS fall? Thats because the more current that is being draw, the more magnetic forces that are acting inside, thus the more load you place on your motor...

Brandon

 

The electric fan doesn't add HP, it removes parasitic loss. Thus RWHP and torque are gained.

Tim,
The alternator does in fact know how much to charge. If you turn on your headlights for example, the alternator works harder, etc. If you have somebody turn on your headlights for you, you can actually hear the alternator working harder. If it didn't work this way then the battery could get way overcharged and dry out from it, among other things.

 

Crazyone, beat me too it!