viability of electric water pumps
04-12-2006, 05:42 AM
#26
Momentum Keeps Me Going
Originally Posted by Marietta 8
A couple ears ago one of our customers tried the Mezier (sp) set up for a special application on his 3rd gen and abandoned it for stock w/underdrive pullies as it proved to be expensive, heavier, and overall didn't gain much on the hp front either. This was on an engine that made 489whp.
Anyhoo, my 2cents.
Anyhoo, my 2cents.
And hondasr4kids, I found the adapter, but no pump w/your link...did I just miss it. That site is pretty bare bones.
04-12-2006, 05:57 AM
#28
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A well respected online performance magazine here in Australia tested a local big name electric water pump. Here is the result of the test.......
"We recently spent a great deal of time and energy extensively testing the newly-released Davies Craig Electric Water Pump. The story in this issue was intended to be Part 1 of a 3-part series on this interesting device. Testing of the pump was carried out on two different cars on both the road and dyno. As a courtesy, we showed Davies Craig the test results that we had found. Unfortunately, because of their responses, we now feel that we cannot bring these stories to you.
Thinly veiled threats of legal action from large companies can do that...
Julian Edgar"
Other than that we can't say too much - aside from the fact that none of the AutoSpeed staff cars are using the aforementioned product.
Thinly veiled threats of legal action from large companies can do that...
Julian Edgar"
Other than that we can't say too much - aside from the fact that none of the AutoSpeed staff cars are using the aforementioned product.
04-12-2006, 07:28 AM
#29
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20 HP is a ridiculous claim.
Their electric water pump draws 0.1kW max which is about 0.14 HP: 7.5A *14V
http://www.hrpworld.com/client_image...pdf_3529_1.pdf
Why would a mechanical water pump require 140 times (!!!) more power?
Their electric water pump draws 0.1kW max which is about 0.14 HP: 7.5A *14V
http://www.hrpworld.com/client_image...pdf_3529_1.pdf
Why would a mechanical water pump require 140 times (!!!) more power?
04-12-2006, 07:52 AM
#30
Momentum Keeps Me Going
Ahh.. that IS the point, isn't it? We DON'T know how much 'wasted' HP is used by the mechanical pump. The mechanical pump has no brain...it HAS to spin at the rate the engine does....from 800RPM to 9000RPM. How much of that at any RPM is wasted spinning?
That IS the point...but I digress...
04-12-2006, 08:21 AM
#31
the giant tastetickles
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You guys should take a look at the tech info in the mazdaspeed website, above 6500 rpm cavitation starts. They also mentioned something about gutting the thermostat.
04-12-2006, 10:37 AM
#32
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Even if there is cavitation. Why would a water pump require about 0.1 HP at 6000 rpm and 1HP, 2HP or even more at 8500 rpm?
Be realistic:
These guys go fishing with 15 HP:
and the RX-8 needs more power to flow some water through its radiator???
Be realistic:
These guys go fishing with 15 HP:
and the RX-8 needs more power to flow some water through its radiator???
04-12-2006, 10:46 AM
#33
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The point of an electric water pump is not power saving, it is control of the cooling flow.
http://www.siemensvdo.com/products_s...water-pump.htm
http://www.siemensvdo.com/products_s...water-pump.htm
04-12-2006, 11:37 AM
#34
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The new BMW 3 series uses an electric water pump. Their design point was that you actually need the most water flow when the car is at idle, since the radiator is a lot less efficent, and you don't want to pump the water at all when the engine is cold. It does increase the efficency of the engine at cruise, but it's not directly there for the peak HP number.
They claim a normal water pump uses "2KW" while their pump uses "200W" - 2KW is about 2.5HP. I'm assuming the 2KW is up near redline.
While everyone here assumes cavitation is bad for HP, I'm not sure that is true. Cavitation reduces efficency dramatically, so that the energy put into the shaft of the water pump doesn't pump as much water as pre-cavitation, but we don't care about that. We care if the shaft of the pump suddenly needs a lot more torque to keep it at the same RPM. I haven't found any evidence that torque/RPM suddenly goes way up when cavitation occurs- just that water flow/energy goes down. If this is true, then when the pump cavitates only matters for water flow, not HP draw.
They claim a normal water pump uses "2KW" while their pump uses "200W" - 2KW is about 2.5HP. I'm assuming the 2KW is up near redline.
While everyone here assumes cavitation is bad for HP, I'm not sure that is true. Cavitation reduces efficency dramatically, so that the energy put into the shaft of the water pump doesn't pump as much water as pre-cavitation, but we don't care about that. We care if the shaft of the pump suddenly needs a lot more torque to keep it at the same RPM. I haven't found any evidence that torque/RPM suddenly goes way up when cavitation occurs- just that water flow/energy goes down. If this is true, then when the pump cavitates only matters for water flow, not HP draw.
04-12-2006, 12:37 PM
#35
Momentum Keeps Me Going
Good info dsmdriver - if the 3 series [Power: 137 kW , 184 HP SAE @ 6,000 rpm] used 2.5Hp (assuming this is at 6000 RPM???) then extrapolating would perhaps give 3.75 at 9000rpm or perhaps more for us? Not sure if it works that way... but it may be close.
wo/FI, we are in a game of accuring small increases in HP, 1-5 HP for each mod. Still if it's say $500 for 4HP that's right in line if not better than intakes, exhausts, and the like.
wo/FI, we are in a game of accuring small increases in HP, 1-5 HP for each mod. Still if it's say $500 for 4HP that's right in line if not better than intakes, exhausts, and the like.
04-12-2006, 03:49 PM
#36
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Originally Posted by Spin9k
And hondasr4kids, I found the adapter, but no pump w/your link...did I just miss it. That site is pretty bare bones.
04-12-2006, 04:01 PM
#37
Prehaps the cavitation is helping with the high coolant temps on the track? From what I understand most 8's are hitting coolant temps of 230F or more on the track. Course our dummy gauge will not give you any warning. Maybe that is one reason mazdaspeed really underdrives their water pumps?
One of my questions is how much flow rate do we need on the track?
Also people are hitting routinly 225F on the street.
Mustang review at 6k gave 3hp gain when swapped to electric water pump.
olddragger
One of my questions is how much flow rate do we need on the track?
Also people are hitting routinly 225F on the street.
Mustang review at 6k gave 3hp gain when swapped to electric water pump.
olddragger
04-12-2006, 04:18 PM
#39
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Since we're on the subject of keeping our cars cool, specifically under high revs - track conditions - who here has overheated their 8 at the track? I don't recall yet reading that anyone has.
04-12-2006, 04:27 PM
#40
Originally Posted by Gomez
A well respected online performance magazine here in Australia tested a local big name electric water pump. Here is the result of the test.......
04-12-2006, 07:33 PM
#42
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Remember that caviation is actually the implosions of gas bubbles on the impeller vanes. This will basically destroy the impeller over time. Underdriving the water pump will definitely help give it more life.
04-12-2006, 08:20 PM
#45
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Originally Posted by rotarenvy
and the same pumps were used by the Prodrive farrari Maranello in lemans events in europe and usa.
Davies Craig promote it's EWP's HP and fuel economy benefits, IMO these are the claims that AutoSpeed challenged. I'm sure the pump does a good job of controlling temperatures.
04-12-2006, 08:25 PM
#47
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Originally Posted by Spin9k
Do you remeber what issue of Autospeed that was talked about in? or is this the one they couldn't talk about for legal reason?
- idiots thinking they are marketing geniuses.