Electric water pump question?

[montanna]

Hello! Does anybody know if it is ok / a good idea to run an electric coolant pump with a mechanical pump still in the system? I'm installing a Kawasaki ZX10 in the rear of a reliant kitten.
Thread in readers rides:-

retrorides.proboards.com/index.cgi?board=readersrides&action=display&thread=53797

I want to have the rad at the front of the car and the engine in the rear. Because of the lengths of the runs to and from the rad (2m - 2.5m either way) I'd like to help the mechanical pump by adding an electric one, is this needed or not and is it a bad idea, as I'd have no idea of the flow rates and pressures of each pump?

If it is a good idea what cars could I pull one out of in a breakers? So far I've come up with a golf VR6 and a V6 vauxhall omega.

One like this:



Any ideas?

ant

[dave21478]

The Vauxhall V6 one - Also fitted to cavaliers and calibras - is an aux unit that keeps the coolant flowing after the engine is stopped to prevent heatsoak. Its only meant to keep a trickle flowing, and I believe isnt up to shifting much volume while the engine is running.

[suterman]

I looked into converting my old volvo to run using two of these pumps parallel to each other. They pump about 20 litres a minute (tried it into a bucket)

I don't think you need to worry about the pressure too much as there wont be much of a difference in height between the engine and rad.

I took my pumps apart and cleaned the impeller and casing out (its a magnetic drive) as one of them was clogged with gungey stuff (poor/no servicing on the doner car) but they are meant to last 15000 hours so you should be ok.

[popuptoaster]

I was warned off using electric pumps alone in a road car unless you can run them at variable speeds to suit engine revs, you need more water flow at high revs and less at low revs or the engine wont cool properly.

[montanna]

Cheers for your responses guys,
Dave - I'll look into that and make sure I don't end up with one like that! Cheers!

Suterman - I was hoping to get away with using only one of these things along with the mecahnical pump but I'm just not sure if the pressure from the more powerful one will damage the slower flowing one?!?

popup - As above I was planning on running it WITH the mechanical pump just to sort of give it a hand with the resistance of the long runs of piping!

Any more comments ideas with this would be great help, I just want to know if I can run a low powered electric pump with the existing machanical one or if that will brake one / both??!?!

Cheers Ant

[justanotherhigh]

My grandfather used to run a Morris 'special' kit-car-roadster-self-build thing, and he pumped the water around the system using the pump from a large garden water feature!
If he can happily chug around in that for several years, I can't see you having any problems ;D

[Mystery Machine]

Celica GT4 - the charge coolers on these cars have pretty heavy duty water pumps.

Mine (in my Mk1 MR2) runs all the time, isn't to noisy and does a damn good job of keeping the charge water cooled. It certainly seems to shift a fair volume of water around. Might be worth considering?

[froggy]

you don't need one if you use the micra k10 rad you will triple your water capacity and the stat will regulate the temp perfectly well. my pipe runs are fairly long but the top of the rad is higher than the top of the water in the engines so bleeds up easly and will not go over 85c even on a summer trackday

[bazzateer]

I've got one of those pumps assisting the main pump in my Imp. Main pump pumps water from bottom rad hose into engine and on to the front of the car where the heater and a small aux rad are located. The secondary pump is fitted after the aux rad to help push the water back to the rear to the main rad. all works fine for me, both pumps run at full speed.

[<Type desired username here>]

I wouldn't think you would need one either.
I'd build it all up and try it. no point in fitting one if you don't need it. Nissan Serenas and Mitsubishi shoguns run rear heaters and all sorts with only one water pump, I think it will work ok providing you get a decent size radiator as froggy suggested.
When you buy a fancy pants electric water pump kit you can map the ecu to run the pump only when needed. But those are intended as replacements to conventional pumps rather than add ons.

[montanna]

Hello, sorry only just seen all the latest replies, thanks for all the input! Seems to me that the general idea is that I wouldn't need one but if there was one in the system it wouldn't damage anything

Froggy: Interesting to know that your's dosn't need one but as I'm going down te turbo route I reckon it couldn't hurt if I could get one cheep!

Thanks aain for all the info, Ant

[ruishy1]

The omega pumps are 700 litres per hour static flow, so are certainly capable of helping coolant flow