cooling
- Thread starter drako
- Start date
Well first of all I personally would not do that. Now I'll proceed to explain myself. You have a great fan, it works on a slip clutch so it doesn't slow down your engine hardly at all. Besides, once you throw your electrics on there, unless it's a much smaller fan, you will DEFINETLY lose HP. When you transfer one energy to the next, even if it's really well built, you'll lose about 20% efficiency. In other words, your fan right now is working directly off the power the engine is creating, there's no converting of energy. If you hooked up and electric fan, the engine's power will be converted into electricty through the alternator and then back into the spinning motion of the fan through a little motor. All this will account for probably 20% efficiency loss. The only upside to an electric fan is if you can control it yourself. When you want power, turn the fan off, you'll gain a couple extra HP, but when you begin to overheat...
The ONLY exception!!!! If you're racing your car, take your fan off completly. You should keep moving quickly enough that the sheer wind power will cool off your radiator with the need of an addition fan. Nearly every BMW I've seen that is used scrictly for track use, does not have a fan.
The ONLY exception!!!! If you're racing your car, take your fan off completly. You should keep moving quickly enough that the sheer wind power will cool off your radiator with the need of an addition fan. Nearly every BMW I've seen that is used scrictly for track use, does not have a fan.
drako, I wouldnt change a thing, I totally disagree with BigEarl about losing horse power
by by transfering energy.. What king of thinking is that? It makes no sence!!! You have whats called an alternator
to handle any voltage needed to run the fans. If BigEarls theory is even close to making sence
what do you think would happen when your driving and you turn on the radio and headlights
will the car lose power? I think not! If so dont bother using the heated seats or the rear defrost.
Bob 1994 325i owner
by by transfering energy.. What king of thinking is that? It makes no sence!!! You have whats called an alternator
to handle any voltage needed to run the fans. If BigEarls theory is even close to making sence
what do you think would happen when your driving and you turn on the radio and headlights
will the car lose power? I think not! If so dont bother using the heated seats or the rear defrost.
Bob 1994 325i owner
I'm sorry bob but in case you didn't know, you do lose power whenever you turn those things on. Ever notice at idle when you flick your headlights on your RPMs drop and then pick back up because the alternator needs to generate more electricty which requires greater force to turn the alternator which requires more work on the engines part to keep spinning at the same rate.
Come on guys back me up here, I know I'm not the only person who understands this concept.
Come on guys back me up here, I know I'm not the only person who understands this concept.
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BigEarl, I just came in from starting the 94 325i (with a warmed up engine)and turned on the heated seats, rear defrost, heater,and the head lights guess what no drop in idle speed. From your thread awhile back about alternators maybe yours is going bad. Now if you were to say when you turn on your air conditioner you drop HP thats understandable because of the cluch on the compresser kicking in. What would make any alternator rob power from the engine? It has to spin free to generate current, if it pulled power from the motor wouldnt that mean it has to somewhat slow down and heat up from friction causing a sudden voltage drop. How long do you think they would last not long. The only guage that moved a little during all of this was the volt meter, but when I increased the engine speed it move back to normal. I am not trying to be a jerk about this but your theory doesnt hold any juice. ![[:D]](/images/smilies/biggrin.png "Big Grin [:D]")
ash442bmw said:
BigEarl, I just came in from starting the 94 325i (with a warmed up engine)and turned on the heated seats, rear defrost, heater,and the head lights guess what no drop in idle speed. From your thread awhile back about alternators maybe yours is going bad. Now if you were to say when you turn on your air conditioner you drop HP thats understandable because of the cluch on the compresser kicking in. What would make any alternator rob power from the engine? It has to spin free to generate current, if it pulled power from the motor wouldnt that mean it has to somewhat slow down and heat up from friction causing a sudden voltage drop. How long do you think they would last not long. The only guage that moved a little during all of this was the volt meter, but when I increased the engine speed it move back to normal. I am not trying to be a jerk about this but your theory doesnt hold any juice.
One other thing. The alternator always spins free, that's obvious. It never slows down and creates more friction. What makes it slow down is the heavier electrical draw which increases the resistance of the magnets - THATs Why you feel the power loss.
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Floyd Give me a break!!!! If you think you can feel a power loss by turning on your headlights and trying to claim that an alternator robs any noticeable horsepower... Maybe you should go down to your local BMW dealership and ask a good tech this question. I have been dyno tuning for 21 years in my shop. Even if you disconnect the power steering pump , ac pump you might gain 1/2 hp. And your trying to tell me that an alternator under a load will steal noticeable HP by adding on an electric fan. Maybe thats why all the guys with high powered stereo units with subwoofers spend money on NOS to gain back the power they are losing from adding stress to there alternators. And yes I sure sound like an asshole but the law of
ratios will win this one. Look at the size of the pully on the alternator then look whats on the motor then ask a grade school teacher to explain ratios to you. The pully on the alternator is spinning about 10-1 over the engine. The pulley on the engine couldnt take a strain even if you really wanted it to. Sounds like PinkFloyd.... Hit Another Brick In The Wall.![[?|]](/images/smilies/icon_smile_banghead.gif "Bang Head [?|]")
ratios will win this one. Look at the size of the pully on the alternator then look whats on the motor then ask a grade school teacher to explain ratios to you. The pully on the alternator is spinning about 10-1 over the engine. The pulley on the engine couldnt take a strain even if you really wanted it to. Sounds like PinkFloyd.... Hit Another Brick In The Wall.
It is true that the more you electricity you use the harder it will be to trun the alternator. Just like Pink_Floyd said, a more powerfull magnetic field is generated and it becomes harder for the engine to turn over the alternator. I don't know how noticable it will be if you change out the manual fan for an electric fan but I know that when you turn the electric fan on, the alternator rubs some power, it may be very little but it does occur. Those of you who think that it doesn't matter how much electricity you are using, are wrong. Please don't talk about something you have no idea about and act like you know everything.
My two cents!
Go to understeer.com and check out their "fan delete kit". They claim a 3 to 6hp power gain by removing the fan. Racers do this. I did it on my 98 M3 and noticed quicker throttle response. That's fine with me. Could not say anything about a power gain though. The clutch fan weighs about 5 pounds! The kit included a lower temp thermostat and fan switch. I did not install the thermostat switch as the temp guage barely moved past center, but I live in WI! Even this summer with a few 90 degree days, the guage didn't move much past center. The electric fan did start a few times, but now I know that it works!
Good luck!
Go to understeer.com and check out their "fan delete kit". They claim a 3 to 6hp power gain by removing the fan. Racers do this. I did it on my 98 M3 and noticed quicker throttle response. That's fine with me. Could not say anything about a power gain though. The clutch fan weighs about 5 pounds! The kit included a lower temp thermostat and fan switch. I did not install the thermostat switch as the temp guage barely moved past center, but I live in WI! Even this summer with a few 90 degree days, the guage didn't move much past center. The electric fan did start a few times, but now I know that it works!
Good luck!
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I am studying motors and stuff , alternators or generators convert mechanical power to electrical power. Every time you turn a light, a fan, AC, Sound, etc you apply a load to the generator or alternator. This load is like if you were pushing the brakes to these 2 devices. As a result in order to keep on running at the same speed, the alternator or generator demands more rotational power, that is a few more rpms
You do lose power, maybe just a little, not much to see a big difference.
That power can me mechanical power lost from the motor or electrical power from the battery.
I am studying motors and stuff , alternators or generators convert mechanical power to electrical power. Every time you turn a light, a fan, AC, Sound, etc you apply a load to the generator or alternator. This load is like if you were pushing the brakes to these 2 devices. As a result in order to keep on running at the same speed, the alternator or generator demands more rotational power, that is a few more rpms
You do lose power, maybe just a little, not much to see a big difference.
That power can me mechanical power lost from the motor or electrical power from the battery.
Putting a load onto the alternator does in fact make it harder to turn. How much harder, i dunno.
I noticed none of you have actually said why it is that way, youve just reworded what the first guys said:
Think of it as moving two magnets past each other, they have resistance getting closer and give a push on the way out (positive and negative attractions). If you have no load on the alternator, its like moving metal past metal. You put a load on, the electric charge needed to fill that closed circuit creates the attractions on the poles creating resistance (basicly, you apply the load, and that effect locks the alternator in its place magneticly).
What a coincidence, i just saw proof a minute ago. A girl friend of mine left her truck at my place last night and her bat died, i jumped her off. I disconnected and a few seconds it shut off - she put the blower on to get heat..... dumbass. Just like PinkFloyd said, a good bat wont show such fatigue.
But thank you Bob, for sticking with your guns on that one. Made for a nice discussion.
So dont they make high performance alternators? And im not talking about the bearings and pulley crap.
I noticed none of you have actually said why it is that way, youve just reworded what the first guys said:
Think of it as moving two magnets past each other, they have resistance getting closer and give a push on the way out (positive and negative attractions). If you have no load on the alternator, its like moving metal past metal. You put a load on, the electric charge needed to fill that closed circuit creates the attractions on the poles creating resistance (basicly, you apply the load, and that effect locks the alternator in its place magneticly).
What a coincidence, i just saw proof a minute ago. A girl friend of mine left her truck at my place last night and her bat died, i jumped her off. I disconnected and a few seconds it shut off - she put the blower on to get heat..... dumbass. Just like PinkFloyd said, a good bat wont show such fatigue.
But thank you Bob, for sticking with your guns on that one. Made for a nice discussion.
So dont they make high performance alternators? And im not talking about the bearings and pulley crap.
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you'll only lose power if the altenator is not up to the task.get a 140amp (if you don't already have an oem one)and you should be fine.there are certain places that will rebuild your existing one to put out more amperage.and a good battery won't hurt like an optima red or yellow top-in an e36's case,an orange top.
Thank you for backing me up guys. But the idea of losing efficiency when you convert one energy to another (like eyedoll325is said) is real. A friend of mine's father works for a company out here in Jersey called "New Jersey Transit" They operate trains and buses and what not. On the trains, instead of powering them directly on a diveshaft (like a car) they power electric motors to get the train to move. But to provide the electricty to those motors they have diesel engines (that's what he works on) those deisel engines act purely as generators (and heat sources, occasionally) Everhett (that's his name) mentioned that they lose about 20% efficiency doing this but it's safer doing it that way. That's where I learned the idea of losing efficiency.
I don't know how old the batterry is but when I turn the wheel completely to the left or right, the rpms drop for a brief moment and then rise again. I know this has almost nothing to do with losing power when converting turning motion into electricity but I wanted to know if any of you experience this. Thanks.
Yeah andreyiv, your powering steering isn't controlled by electricity as you probably know, it's controlled by a pump. And yes, when you turn your wheel it takes energy from the engine to help you move the wheel. however, I HIGHLY RECOMMEND NOT TURNING YOUR WHEEL WHILE STANDING!!! I know it sounds like I'm freaking out about this and some people may say I'm over emphasising this but your power steering pump would love to gorge your eyes out when you make him turn the wheel while standing still. It hurts him like a mother giving birth. Also, your tire treads will want to be pulled apart and will want to seperate. Maybe I am over emphasising but please, don't hurt your baby!