smart1275gt
|
| posted on 13/11/07 at 08:43 PM |
|
|
Electric Water Pump?
I'm mounting a 1275cc MG Metro engine in the back of my Smart car and wondered if the existing water pump will cope with the distance to the
front mounted radiator? Do you think I need to install an electric booster pump or a full stand alone pump?
Cheers.
|
|
|
|
|
RazMan
|
| posted on 13/11/07 at 11:05 PM |
|
|
I don't think it will have a problem with the extra length of pipes but why not fit an EWP anyway and release a few more horses too?
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
|
|
|
kb58
|
| posted on 14/11/07 at 01:25 AM |
|
|
I"ve always been a little skeptical about an electric water pump consuming less power than a mechanical one.
Looking at it from a systems point of view, the mechanical one has a loss in the the belt and another in the impeller. The electric solution has a
loss in the belt, the alternator, the wires, the electric motor in the pump, and in the impeller. I think that the marketing gets skewed by only
discussing efficiencies at really high engine rpm.
Mid-engine Locost - http://www.midlana.com
And the book - http://www.lulu.com/shop/kurt-bilinski/midlana/paperback/product-21330662.html
Kimini - a tube-frame, carbon shell, Honda Prelude VTEC mid-engine Mini: http://www.kimini.com
And its book -
http://www.lulu.com/shop/kurt-bilinski/kimini-how-to-design-and-build-a-mid-engine-sports-car-from-scratch/paperback/product-4858803.html
|
|
|
RazMan
|
| posted on 14/11/07 at 08:08 AM |
|
|
The main point about EWPs is that if they are used with a proper controller, they are not running all the time - only when the engine needs cooling.
Consequently the pump will not run until the engine is hot enough to warrant it, and even then the dedicated controller will start
'pulsing' the motor until everything is up to full operating temperature and then it will vary the speed of the pump according to
temperature.
The result is that the pump consumes NO POWER until it is required, then only just enough to maintain cooling - a mechanical pump consumes the same
amount of power ALL the time, hot or cold.
I estimate that my EWP saves about 5 bhp overall........ which I will gladly use elsewhere 
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
|
|
|
minitici
|
| posted on 14/11/07 at 09:04 AM |
|
|
My experience of A-Series water pumps in rear engined front radiator installations in GTMs tells me that an electric pump is a better idea.
I found that the standard pump just does not move water below 3000 rpm, due to the long and convoluted path to the radiator. Then of course there is
cavitation of the pump over about 6500rpm.......
|
|
|
designer
|
| posted on 14/11/07 at 09:06 AM |
|
|
Why do we keep getting involved with everything new?
We are building cars for the road, not racing!! Why do we have to chase everything new and fancy.
Water pumps consume very little. Let's not all get caught in the hype!
High, and correct, performance requires an engine to be at working temperature, when the water pump will be working.
|
|
|
bimbleuk
|
| posted on 14/11/07 at 09:25 AM |
|
|
I have used a EWP pump in an MR2 mk1 a few years a go. I did see about a 5HP power gain on the supercharged engine. The pump could cool the engine no
problem and having a manual switch to run the pump full speed was useful on the rolling road (it was on there a lot!)
However the only issue I had was the heater never seemed to have enough flow to work properly. I probably could have investigated a bit more and
fitted a booster pump up front but the car was never driven that much to bother.
|
|
|
02GF74
|
| posted on 14/11/07 at 10:02 AM |
|
|
the other advantage of EWP is that it can run, and indeed should be wired so that it runs, after the engine has stopped to avoid local heating up of
water in the block after a hard workout, thus alleviating possible head warppage problems.
re: controller - these cost about as much as the pump itself - why can't a electric fan switch with relay be used instead? crude but should
work just as well or??
|
|
|
zilspeed
|
| posted on 14/11/07 at 10:23 AM |
|
|
quote:
Originally posted by designer
Why do we keep getting involved with everything new?
We are building cars for the road, not racing!! Why do we have to chase everything new and fancy.
That's not really true though. A large number of the people on here are involved in track activity.
|
|
|
andygtt
|
| posted on 14/11/07 at 05:11 PM |
|
|
quote:
Originally posted by zilspeed
quote:
Originally posted by designer
Why do we keep getting involved with everything new?
We are building cars for the road, not racing!! Why do we have to chase everything new and fancy.
That's not really true though. A large number of the people on here are involved in track activity.
and a mid engined layout means the pump has to push the water a lot further hence seeking a reliable solution.
Andy
please redefine your limits.
|
|
|
RazMan
|
| posted on 14/11/07 at 11:13 PM |
|
|
quote:
Originally posted by designer
Why do we keep getting involved with everything new?
So you prefer sidevalve, pushrod engines, leaf spring suspension and solid rubber tyres?
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
|
|
|
John Bonnett
|
| posted on 20/11/07 at 05:29 PM |
|
|
Raz posted: The main point about EWPs is that if they are used with a proper controller
Raz, do you have any recommendations for an ewp and controller.
atb
John
|
|
|
RazMan
|
| posted on 20/11/07 at 07:02 PM |
|
|
I think the choice is a little bit limited but I went for the Davies Craig model
which is excellent.
You will hear a lot of horror stories with earlier pumps but they have now sorted the gremlins out and I have found my one to be totally reliable.
Coupled to the controller it cools my V6 with only a Polo rad - a little too efficiently in the colder weather but at least you can vary the operating
temp with a simple adjustment.
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
|
|
|
John Bonnett
|
| posted on 20/11/07 at 07:09 PM |
|
|
Thanks Raz, that was the one I'd thought of. I didn't realise they did a controller for it so that's good to know.
Best wishes
John
|
|
|
