I have had a Holden six around the 6500 mark and know plenty of guys going to 7 with no dramas...
Im intending to turn my next holden six to 7+ and the last thing im expecting to play up is the V belt....
I cant see a pump running at .1 of a HP pushing enough water to do anything??? But may be wrong??
Hell the bilge pump in my boat is 20A which is drastically bigger than the ones you mentioned and even it hardly pushes anything worth mentioning.
Cheers.
Water Pumps
Started by
_uctorry_
, Jun 12 2011 10:24 AM
66 replies to this topic
#52
_torbirdie_
_torbirdie_
-
- Guests
Posted 21 June 2011 - 09:48 PM
Not really comparing apples with apples here: 10A/0.18Hp electric pump provides 115L per min http://www.daviescra...25-details.aspx, the performance pump mechanical pump shifts 690L per minute consuming 2.2Hp at 4000rpm. Clearly to get an electric pump to do the same amount of pumping is not going to be possible with even a high output alternator. Some applications obviously need this sort of flow at full noise, others dont.
Obviously people selling the electric units will point to the fact that the mechanical ones will be consuming ~7hp at 6000rpm, the davies craig site throws in 10kW at full power(that would be about 7300rpm for a car fitted with a performance pump ), and you'll see even bigger numbers thrown around with fixed mechanical fans for their push on electric fans.
At the end of the day if the car is used on the road, those numbers are irrelevant- the power used by the mechanical pump will be insignificant, if the car is used on the track where full rpm is a constant affair,then obviously changing the gearing of the pump could reduce those numbers to the same as an electric pump, if it could get by with that sort of flow.
Obviously people selling the electric units will point to the fact that the mechanical ones will be consuming ~7hp at 6000rpm, the davies craig site throws in 10kW at full power(that would be about 7300rpm for a car fitted with a performance pump ), and you'll see even bigger numbers thrown around with fixed mechanical fans for their push on electric fans.
At the end of the day if the car is used on the road, those numbers are irrelevant- the power used by the mechanical pump will be insignificant, if the car is used on the track where full rpm is a constant affair,then obviously changing the gearing of the pump could reduce those numbers to the same as an electric pump, if it could get by with that sort of flow.
#53
ls2lxhatch
-
- Members
-
- 5,335 posts
- Location:Perth
- Car:LX Hatch
- Joined: 29-May 06
Posted 21 June 2011 - 09:55 PM
There must be an upper limit to the amount of power the impeller can draw before it starts cavitating.
I would still like to see independent dyno results of an engine with the mechanical and then with an electric pump.
I would still like to see independent dyno results of an engine with the mechanical and then with an electric pump.
Edited by ls2lxhatch, 21 June 2011 - 09:56 PM.
#54
ls2lxhatch
-
- Members
-
- 5,335 posts
- Location:Perth
- Car:LX Hatch
- Joined: 29-May 06
Posted 21 June 2011 - 10:02 PM
This test looks reasonable at first glance. It compares stock, underdrive and electric on a SBC.
http://www.superchev...ump/index1.html
http://www.superchev...ump/index1.html
Edited by ls2lxhatch, 21 June 2011 - 10:03 PM.
#55
_torbirdie_
_torbirdie_
-
- Guests
Posted 21 June 2011 - 10:03 PM
Your already turning the alternator for a start and i think CVR water pumps draw 6amps? That on a 100 amp alternator is not as much load as a water pump........No point arguin over "Science"
Not sure you understand how alternators work, they present basically only bearing friction if they are not providing an electric current.
Electric water pumps may be great, but your reasons for above are no different to saying its because they run electric wipers and electric lamps, rather than vacuum and oil ones.I think electric water pumps are great, Thats why all car makers are running electric fuel pumps electric thermo fans!!
Id like to add that constant temp is required more then keeping it cold as such
Some think that their car needs to run at a precise 84 degrees(and how have they figured that out?), rather than say 82-88 which is what a regular thermostat will keep it between with a mechanical pump....please tell me show me, that the performance of the car will suffer at 82 compared to 84 or 88 compared to 84
#56
ls2lxhatch
-
- Members
-
- 5,335 posts
- Location:Perth
- Car:LX Hatch
- Joined: 29-May 06
Posted 21 June 2011 - 10:31 PM
This test looks reasonable at first glance. It compares stock, under drive and electric on a SBC.
Super Chevy Water Pump Test
The above test is a little misleading as the first figure is an over driven pump. I don't see an alternator in any of the pictures.
Test 1. Stock pump 27% over drive pulley
Test 2. Stock pump 14% under drive pulley
Test 3. Electric pump.
Heres another test. I still can't see an alternator.
Bang Shift mechanical vs Electric
Edited by ls2lxhatch, 21 June 2011 - 10:37 PM.
#57
greens nice
-
- Members
-
- 1,011 posts
Forum Fixture
- Name:Kevin
- Location:QLD
- Car:EH Holden
- Joined: 01-November 08
Posted 21 June 2011 - 10:42 PM
may i also add harmonic balancers do not work as well when your driving shit off the intertia ring. IE holden 6.
#58
_Bomber Watson_
_Bomber Watson_
-
- Guests
Posted 21 June 2011 - 10:49 PM
Hell the bilge pump in my boat is 20A which is drastically bigger than the ones you mentioned and even it hardly pushes anything worth mentioning.
I lied here.
About 10 minutes ago i was ramdonly thinking about something else and 5 minutes ago randomly looked at the boat, bilge pump is only 6 amp. So the same as the CSA electric pump.
So yeah, i might be a drunken lart who randomly throws numbers around but at least im honest when i prove myself wrong
Still it pushes frOck all water really, more than i expected when i first got it but still frOck all. I can take it out on the river and video tape the bilge pump running after the boat tries to fill up with water if you dont believe me.....
Cheers.
Edited by Bomber Watson, 21 June 2011 - 10:51 PM.
#59
Toranamat69
-
- Members
-
- 2,117 posts
Forum R&D Officer
- Location:Brisbane
- Joined: 07-November 05
Posted 21 June 2011 - 11:00 PM
I have had a Holden six around the 6500 mark and know plenty of guys going to 7 with no dramas...
My 202 used to spin up to 7K fairly regularly - make sure you run 2 slotted bracket for the Alternator or you will be chucking belts left right and centre. Your 202 will probably wear out befor the V belt if you sit it above 7K for very long.
That bangshift comparison ^^^ pretty much confirms the figures I quoted.
7HP is scarcely within the repeatability of successive dyno runs on the same engine. You would be far better off just measuring pump flow separately if you wanted to measure actual pump losses at varying speeds with a measuring device with a more suitable range. Say 0 to 20HP range with precision down to the 0.1 HP or something like that.
This is all the mech pumps are using at 1500rpm.I cant see a pump running at .1 of a HP pushing enough water to do anything
#60
ls2lxhatch
-
- Members
-
- 5,335 posts
- Location:Perth
- Car:LX Hatch
- Joined: 29-May 06
Posted 21 June 2011 - 11:21 PM
I had a look at the Meziere electric pumps.
The 35 GPM pump draws 6-7 amps and the 55 GPM pump draws 11-12 amps, both would take less than 1 hp to drive with an alternator based on a rough estimate of 1 hp per 15 amps with an alternator drive ratio of 2.5.
According to Stewart their mechanical pump produces 180 GPM at 8000 rpm. Using the calculator gives 90 GPM at 4000 rpm, 45 at 2000 rpm and 15.8 GPM at 750 rpm.
It is interesting how low the electric pump flow is compared to the mechanical. I presume that the mechanical pump flow is only higher because of the flow requirements at low rpm.
The 35 GPM pump draws 6-7 amps and the 55 GPM pump draws 11-12 amps, both would take less than 1 hp to drive with an alternator based on a rough estimate of 1 hp per 15 amps with an alternator drive ratio of 2.5.
According to Stewart their mechanical pump produces 180 GPM at 8000 rpm. Using the calculator gives 90 GPM at 4000 rpm, 45 at 2000 rpm and 15.8 GPM at 750 rpm.
It is interesting how low the electric pump flow is compared to the mechanical. I presume that the mechanical pump flow is only higher because of the flow requirements at low rpm.
Edited by ls2lxhatch, 21 June 2011 - 11:24 PM.
#61
Stedz_lc
-
- Members
-
- 1,144 posts
Forum Fixture
- Joined: 10-November 05
Posted 21 June 2011 - 11:45 PM
Stedz_lc, on 21 June 2011 - 09:12 AM, said:
Id like to add that constant temp is required more then keeping it cold as such
Some think that their car needs to run at a precise 84 degrees(and how have they figured that out?), rather than say 82-88 which is what a regular thermostat will keep it between with a mechanical pump....please tell me show me, that the performance of the car will suffer at 82 compared to 84 or 88 compared to 84
^^ That to me is a constant temp, if you read what i said Constant temp is required more then keepin it COLD, Some ppl think the colder it runs the better this is very very in correct.
I would say 82-88 is constant in the world of thermostats and the like.
Id like to add that constant temp is required more then keeping it cold as such
Some think that their car needs to run at a precise 84 degrees(and how have they figured that out?), rather than say 82-88 which is what a regular thermostat will keep it between with a mechanical pump....please tell me show me, that the performance of the car will suffer at 82 compared to 84 or 88 compared to 84
^^ That to me is a constant temp, if you read what i said Constant temp is required more then keepin it COLD, Some ppl think the colder it runs the better this is very very in correct.
I would say 82-88 is constant in the world of thermostats and the like.
#62
Toranamat69
-
- Members
-
- 2,117 posts
Forum R&D Officer
- Location:Brisbane
- Joined: 07-November 05
Posted 21 June 2011 - 11:58 PM
both would take less than 1 hp to drive with an alternator based on a rough estimate of 1 hp per 15 amps with an alternator drive ratio of 2.5.
You lost me here - Power is Power, the drive ratio is irrelevant. 15A at 12V will always be 180W.
I agree the electric pumps sound to be very low in power.
In my last life with designing pumped cooling systems in power transformers, which are just closed loop cooling systems like an engine - there was a minimum pump size to get the flow rate to eject the heat you required and then a maximum to stay under to prevent cavitation and physical damage to the internals of the transformer but no a very big effect on cooling efficiency in between those 2 figures.
If the coolant flow rate was toward the lower end, the temp gradient from top to bottom of the heat source was larger as was the temp gradient from top to bottom of the coolers but as long as things cooled, it was not usually an issue. Those pumps were huge so the flow rates are not relveant in this case but the rest of the theory is identical.
Those chart on the Davis Craig websites are pretty confusing. As always with these sorts of things. They quote a maximum flow rate for the EWP115 as 115L/min, yet this is at approx 0.2 BAR point of the curve and the open pipe flow is shown as 140 L/min. Then the current draw line stops at the 9.5A/90L/min point.
#63
Toranamat69
-
- Members
-
- 2,117 posts
Forum R&D Officer
- Location:Brisbane
- Joined: 07-November 05
Posted 22 June 2011 - 12:52 AM
I tried to see if I could find some sort of figure for when a pump of this size will start to cavitate. Obviously it is going to be different for each pump and engine depending on flow rates and restrictions but it seems it is not that easy to come up with a figure. My head hurts after reading too much formula stuff this late at night.
#64
_Bomber Watson_
_Bomber Watson_
-
- Guests
Posted 22 June 2011 - 03:02 AM
My head hurts just looking at the screen this late at night.
Smokey Yunicks book has a bit of info on this matter, although its all 1970's and electric water pumps didnt exist.
He did do a fair bit of work though with bits of perspex mounted in holes cut out in blocks and lights mounted inside whilst the engine ran on a dyno....Both oil and water behavior.
I forgot why i started replying or the point of my post....
Cheers.
Smokey Yunicks book has a bit of info on this matter, although its all 1970's and electric water pumps didnt exist.
He did do a fair bit of work though with bits of perspex mounted in holes cut out in blocks and lights mounted inside whilst the engine ran on a dyno....Both oil and water behavior.
I forgot why i started replying or the point of my post....
Cheers.
#65
ls2lxhatch
-
- Members
-
- 5,335 posts
- Location:Perth
- Car:LX Hatch
- Joined: 29-May 06
Posted 22 June 2011 - 03:10 AM
You lost me here - Power is Power, the drive ratio is irrelevant. 15A at 12V will always be 180W.
I was confusing HP with Torque. I was working on 14V for the alternator. What sort of efficiency do you think is reasonable to expect? It seems the typical car alternator is reported as actually producing somewhere between 15 and 30 amps for 1 hp.
Edited by ls2lxhatch, 22 June 2011 - 03:11 AM.
#66
_torbirdie_
_torbirdie_
-
- Guests
Posted 23 June 2011 - 09:04 AM
Unlike electric motors which operate in the 90% efficiency range, the standard auto alternator at partial load operates at 50-60% efficiency, the very best at 70%.
You lost me here - Power is Power, the drive ratio is irrelevant. 15A at 12V will always be 180W.
I was confusing HP with Torque. I was working on 14V for the alternator. What sort of efficiency do you think is reasonable to expect? It seems the typical car alternator is reported as actually producing somewhere between 15 and 30 amps for 1 hp.
Based on the lower figure to produce 10A requires about 0.3Hp, your higher figure of 30amps for 1hp appears to be the more realistic one.
#67
Toranamat69
-
- Members
-
- 2,117 posts
Forum R&D Officer
- Location:Brisbane
- Joined: 07-November 05
Posted 23 June 2011 - 11:33 AM
Unlike electric motors which operate in the 90% efficiency range, the standard auto alternator at partial load operates at 50-60% efficiency, the very best at 70%.
You lost me here - Power is Power, the drive ratio is irrelevant. 15A at 12V will always be 180W.
I was confusing HP with Torque. I was working on 14V for the alternator. What sort of efficiency do you think is reasonable to expect? It seems the typical car alternator is reported as actually producing somewhere between 15 and 30 amps for 1 hp.
Based on the lower figure to produce 10A requires about 0.3Hp, your higher figure of 30amps for 1hp appears to be the more realistic one.
Gee Wizz they are inefficient little buggers arn't they.
Would still not a very marked effect on the power to run and electric water pump though.
It would be good to get a reallistic answer as to the actual power consumption of the mech water pump at varying speeds - in particular where it tops out.
0 user(s) are reading this topic
0 members, 0 guests, 0 anonymous users
