UDP, Electric Waterpump + Alternator
10-12-2006, 02:58 AM
#1
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UDP, Electric Waterpump + Alternator
Ive heard of all the jabbering about the UDP's and how it takes power away and all that jazz, well, i honestly do want my car to lbe as efficient as possible, as long as possible. So after doing some research i thought of getting a UDP and electric waterpump so that the power of my waterpump isnt thrown away into the UDP and the waterpump would work just as efficiently and effectively as it would without a UDP on my car. There is a Steeda UDP and water pump combo that i've been looking at. However i was also wondering to keep increasing efficiency, would a new radiator +/or alternator (reviewed and tested) be worth the extra gains in efficiency and stability for my car? Opinions? Experiences?
-Im still fairly new to this whole engine stuff, but im working on it, just trying to figure things out. thnx
-Im still fairly new to this whole engine stuff, but im working on it, just trying to figure things out. thnx
10-12-2006, 08:43 AM
#2
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Location: North East Texas on the Red River
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RE: UDP, Electric Waterpump + Alternator
High school physics teaches you that as with money, also with energy, you can't get something for nothing.
If you switch to an electric water pump, the energy must come from somewhere. SOooo, you say, it will come from the battery instead of the crankshaft. And that would be correct. Okay, now, where does the energy come from that charges the battery? It comes from the alternator. Okay, now, where does the energy come from that drives the alternator? It comes from the crankshaft.
SOooo... You would now require even MORE energy because of the loss of efficiency of the alternator AND the electric motor on the water pump.
The only way you would gain horsepower this way would be to run the electric water pump off of a battery that is not charged by the alternator, but is charged whenever you can plug a charger into an outlet. For a drag strip only car, this might be reasonable as long as you don't overlook the weight of the battery.
IMHO, UD pulleys are a great mod with little or no downside that I have personally experienced and I have run UD pulleys on my Vette for about 12 years, but leave the electric water pump for the race only vehicles.
If you switch to an electric water pump, the energy must come from somewhere. SOooo, you say, it will come from the battery instead of the crankshaft. And that would be correct. Okay, now, where does the energy come from that charges the battery? It comes from the alternator. Okay, now, where does the energy come from that drives the alternator? It comes from the crankshaft.
SOooo... You would now require even MORE energy because of the loss of efficiency of the alternator AND the electric motor on the water pump.
The only way you would gain horsepower this way would be to run the electric water pump off of a battery that is not charged by the alternator, but is charged whenever you can plug a charger into an outlet. For a drag strip only car, this might be reasonable as long as you don't overlook the weight of the battery.
IMHO, UD pulleys are a great mod with little or no downside that I have personally experienced and I have run UD pulleys on my Vette for about 12 years, but leave the electric water pump for the race only vehicles.
10-12-2006, 11:29 AM
#3
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RE: UDP, Electric Waterpump + Alternator
ORIGINAL: MBDiagMan
High school physics teaches you that as with money, also with energy, you can't get something for nothing.
If you switch to an electric water pump, the energy must come from somewhere. SOooo, you say, it will come from the battery instead of the crankshaft. And that would be correct. Okay, now, where does the energy come from that charges the battery? It comes from the alternator. Okay, now, where does the energy come from that drives the alternator? It comes from the crankshaft.
SOooo... You would now require even MORE energy because of the loss of efficiency of the alternator AND the electric motor on the water pump.
The only way you would gain horsepower this way would be to run the electric water pump off of a battery that is not charged by the alternator, but is charged whenever you can plug a charger into an outlet. For a drag strip only car, this might be reasonable as long as you don't overlook the weight of the battery.
IMHO, UD pulleys are a great mod with little or no downside that I have personally experienced and I have run UD pulleys on my Vette for about 12 years, but leave the electric water pump for the race only vehicles.
High school physics teaches you that as with money, also with energy, you can't get something for nothing.
If you switch to an electric water pump, the energy must come from somewhere. SOooo, you say, it will come from the battery instead of the crankshaft. And that would be correct. Okay, now, where does the energy come from that charges the battery? It comes from the alternator. Okay, now, where does the energy come from that drives the alternator? It comes from the crankshaft.
SOooo... You would now require even MORE energy because of the loss of efficiency of the alternator AND the electric motor on the water pump.
The only way you would gain horsepower this way would be to run the electric water pump off of a battery that is not charged by the alternator, but is charged whenever you can plug a charger into an outlet. For a drag strip only car, this might be reasonable as long as you don't overlook the weight of the battery.
IMHO, UD pulleys are a great mod with little or no downside that I have personally experienced and I have run UD pulleys on my Vette for about 12 years, but leave the electric water pump for the race only vehicles.
10-12-2006, 12:05 PM
#4
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RE: UDP, Electric Waterpump + Alternator
Doc is right. It's conservation of energy--high school physics.
Keep in mind that there is a direct conversion between Watts of electricity and Horsepower. 1 HP = about 750 watts. That means for every 750 watts of electricity you are using in your car, it takes a little more than 1 HP away from the crankshaft. (I say a little more becasue the alternator is not 100% efficient)
Using your radio, lights, and A/C blower DOES drain power from the car and thus it DOES hurt performance. Ask yourself, if not from the alternator (and therefore the crankshaft) where exactly does this power come from? Aliens in outer space? However, this is a relatively small amount of energy so it's generally negligeable.
The electric water pump can be a gain or a loss. It depends at what RPM you're operating at.
The Meziere water pump draws "11 to 12 amps" according to mfg's web site: http://www.meziere.com/index.php?pgName=wp346
Volts * Amps = Watts.
13.8 * 11 = 151 watts.
So that means the pump is using up about 1/5 of a HP to run (plus whatever inefficiency is in the alternator) regardless of conditions.
The stock water pump's "power requirements" will depend heavily on operating RPM. At or near idle, the electric pump will be moving much more water than the mechanical pump and thus it will be costing you HP. However, near redline the mechanical pump will be using more power.
Given that the electric pump is only going to be using about 1/4 HP, I'd say the odds are most likely in favor of the electric pump. However, at idle, this is not true.
Keep in mind that there is a direct conversion between Watts of electricity and Horsepower. 1 HP = about 750 watts. That means for every 750 watts of electricity you are using in your car, it takes a little more than 1 HP away from the crankshaft. (I say a little more becasue the alternator is not 100% efficient)
Using your radio, lights, and A/C blower DOES drain power from the car and thus it DOES hurt performance. Ask yourself, if not from the alternator (and therefore the crankshaft) where exactly does this power come from? Aliens in outer space? However, this is a relatively small amount of energy so it's generally negligeable.
The electric water pump can be a gain or a loss. It depends at what RPM you're operating at.
The Meziere water pump draws "11 to 12 amps" according to mfg's web site: http://www.meziere.com/index.php?pgName=wp346
Volts * Amps = Watts.
13.8 * 11 = 151 watts.
So that means the pump is using up about 1/5 of a HP to run (plus whatever inefficiency is in the alternator) regardless of conditions.
The stock water pump's "power requirements" will depend heavily on operating RPM. At or near idle, the electric pump will be moving much more water than the mechanical pump and thus it will be costing you HP. However, near redline the mechanical pump will be using more power.
Given that the electric pump is only going to be using about 1/4 HP, I'd say the odds are most likely in favor of the electric pump. However, at idle, this is not true.
10-13-2006, 08:40 AM
#5
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Join Date: Aug 2006
Location: North East Texas on the Red River
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RE: UDP, Electric Waterpump + Alternator
ORIGINAL: bascho
Using your thought process.....that means running the radio or heat or lights in the car actually hurts performance and thus should not be used. I completely disagree and think that removing the load of the waterpump would yield a net gain. The problem is that the waterpump is not a very big load on the crank......an electric PS pump would be better.
ORIGINAL: MBDiagMan
High school physics teaches you that as with money, also with energy, you can't get something for nothing.
If you switch to an electric water pump, the energy must come from somewhere. SOooo, you say, it will come from the battery instead of the crankshaft. And that would be correct. Okay, now, where does the energy come from that charges the battery? It comes from the alternator. Okay, now, where does the energy come from that drives the alternator? It comes from the crankshaft.
SOooo... You would now require even MORE energy because of the loss of efficiency of the alternator AND the electric motor on the water pump.
The only way you would gain horsepower this way would be to run the electric water pump off of a battery that is not charged by the alternator, but is charged whenever you can plug a charger into an outlet. For a drag strip only car, this might be reasonable as long as you don't overlook the weight of the battery.
IMHO, UD pulleys are a great mod with little or no downside that I have personally experienced and I have run UD pulleys on my Vette for about 12 years, but leave the electric water pump for the race only vehicles.
High school physics teaches you that as with money, also with energy, you can't get something for nothing.
If you switch to an electric water pump, the energy must come from somewhere. SOooo, you say, it will come from the battery instead of the crankshaft. And that would be correct. Okay, now, where does the energy come from that charges the battery? It comes from the alternator. Okay, now, where does the energy come from that drives the alternator? It comes from the crankshaft.
SOooo... You would now require even MORE energy because of the loss of efficiency of the alternator AND the electric motor on the water pump.
The only way you would gain horsepower this way would be to run the electric water pump off of a battery that is not charged by the alternator, but is charged whenever you can plug a charger into an outlet. For a drag strip only car, this might be reasonable as long as you don't overlook the weight of the battery.
IMHO, UD pulleys are a great mod with little or no downside that I have personally experienced and I have run UD pulleys on my Vette for about 12 years, but leave the electric water pump for the race only vehicles.
Tell me, did you take physics in high school? If so, did you pass the course?
10-13-2006, 12:03 PM
#6
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RE: UDP, Electric Waterpump + Alternator
ORIGINAL: MBDiagMan
I am not AT ALL suggesting that you not play your radio or turn on your lights. Whether you do or whether you don't, the loss is less than 1% and the electrical accessories on your car are as necessary as any other subsystem of the vehicle.
Tell me, did you take physics in high school? If so, did you pass the course?
I am not AT ALL suggesting that you not play your radio or turn on your lights. Whether you do or whether you don't, the loss is less than 1% and the electrical accessories on your car are as necessary as any other subsystem of the vehicle.
Tell me, did you take physics in high school? If so, did you pass the course?
Yes I did and yes I did. I never said that you actually suggested running the radio or heat would reduce horsepower.....just simply that your theory about the increased electrical demand on the alternator would create a net loss of power. That is why I said there should be a net gain with an electric water pump. CrazyAl agrees with this yet he does give the disclaimer about a possible loss at idle.
But who gives a crap about power at idle if by 2000rpm you have a gain?
We could argue all day about this....but we can't really be certain of a net gain or loss without knowing exactly what power is needed to spin the water pump vs the alternator under additional electrical load.
We would have to have a engine dyno where we could take base-line #'s of the engine with no parasitic accessories. Then we would have to add-on each accessory (water pump, PS pump, alternator, etc) to determine the total horsepower loss with each accessory.
I think there would be a net gain......you think there would be a net loss. Unless either of us have access to an engine dyno we'll never know for sure.
10-13-2006, 12:42 PM
#7
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RE: UDP, Electric Waterpump + Alternator
ORIGINAL: bascho
We would have to have a engine dyno where we could take base-line #'s of the engine with no parasitic accessories. Then we would have to add-on each accessory (water pump, PS pump, alternator, etc) to determine the total horsepower loss with each accessory.
I think there would be a net gain......you think there would be a net loss. Unless either of us have access to an engine dyno we'll never know for sure.
We would have to have a engine dyno where we could take base-line #'s of the engine with no parasitic accessories. Then we would have to add-on each accessory (water pump, PS pump, alternator, etc) to determine the total horsepower loss with each accessory.
I think there would be a net gain......you think there would be a net loss. Unless either of us have access to an engine dyno we'll never know for sure.
The problem that I keep seeing with this debate is that everyone is comparing apples to twinkies...
dyno's do not actually (or at least accurately) measure power of an engine in a form that one could use to write a closed equation such that one could get the right answer...
dyno's are measuring power under acceleration as they are typically used... So, you are going to see the effects of inertia and impulse response which will make working out the math more difficult.
This works just dandy for getting a good idea of how the car is tuned....
Turning an electric water pump can only give a NET increase in power if the mechanical pump it replaces is extraordinarily inefficient...
If not, then the energy conversion (twice) means lots of power loss... (on a true NET basis)...
Now, the "observed" effect would very likely be better acceleration as for a short time under acceleration of the inertial benifits of not accelerating the mechanical water pump will couple with the fact that you are drawing stored electricity from the battery (at least for a moment)...
So, it is all about WHAT you measure and WHEN you measure it...
On a NET basis - electric water pumps:
1. convert energy twice - that means loss
2. spin faster than mechanical pumps at idle - that means better cooling but more loss
BUT - they provide a boost during acceleration in the form of reduced inertial load...
Electricity is not free - converting too and from it is a lossy process...
10-13-2006, 01:05 PM
#8
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RE: UDP, Electric Waterpump + Alternator
Great post Cekim.
As you said, the real issue here is that we don't know how much energy the mechanical pump is using. If we knew, then we could say once and for all exactly how the electric pump compares.
We know for a fact that an electric pump is less efficient than an equivalent mechanical pump, simply becasue you have to convert mechanical energy into electricty and then back into mechanical energy again--this wastes power. But the problem is that the electrical pump is a constant load whereas the mechanical pump's load depends on RPM.
That means there is some particular break-even point, below which the mechanical pump is better, and above which the electric pump is better (at least from a parasitic-loss point of view).
Based on Mezire's published specs of 11-12 amps draw for their pump, I'd venture to guess that the electric pump probably has a pretty good advantage--at least in the parasitic loss department.
As you said, the real issue here is that we don't know how much energy the mechanical pump is using. If we knew, then we could say once and for all exactly how the electric pump compares.
We know for a fact that an electric pump is less efficient than an equivalent mechanical pump, simply becasue you have to convert mechanical energy into electricty and then back into mechanical energy again--this wastes power. But the problem is that the electrical pump is a constant load whereas the mechanical pump's load depends on RPM.
That means there is some particular break-even point, below which the mechanical pump is better, and above which the electric pump is better (at least from a parasitic-loss point of view).
Based on Mezire's published specs of 11-12 amps draw for their pump, I'd venture to guess that the electric pump probably has a pretty good advantage--at least in the parasitic loss department.
10-13-2006, 01:54 PM
#9
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RE: UDP, Electric Waterpump + Alternator
Electricity could be free if the electrical generator was driven by air. Has anyone proposed using an exhaust-driven turbine to drive accessories like the alternator, PS pump, waterpump, etc? I am just brainstorming here....so forgive the rough thinking behind this.
10-13-2006, 02:04 PM
#10
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RE: UDP, Electric Waterpump + Alternator
ORIGINAL: bascho
Electricity could be free if the electrical generator was driven by air.
Electricity could be free if the electrical generator was driven by air.
P.S. heat is an issue here... gas turbines are HOT - water/ps/alternator would rather not be (to put it mildly)...