Electric water Pump

[robertcosta]

While I was re-doing the head gasket on my elise and about to fit a remote thermostat, I realised that the Elise uses an electric water pump to assist the mechanically driven one.

Sounded to me like a good idea for the Esprit! It would sure help when stuck in traffic and hot. Where in the cooling system would be the best place?

The attachment shows its position in the Elise. Is it a good idea or mad or a waste of time.......

[iainskea]

I like this idea, but I think you will need to have the electric pump switch on via the otter switch as my understanding is that the cooling system via the radiator is closed when the thermostat is closed (no loop).

I would fit it below the otter switch.

Iain

[robertcosta]

Hi Iain,

In fairness the electric water pump in the Elise is to stop heat soak when shutting done a hot engine to protect the head, not so much to circulate the entire cooling system, but I thought that this idea of an electric pump aiding the existing mech one was interesting.

[iainskea]

I think it is a great idea Robert because it combats the hot-idle situation, providing circulation and thermal transfer.

Back to the mechanics of it - if the electric pump was inline, what would happen if it were off, does it block the flow from the main pump? This could be a problem, so it would have to be on when the thermostat was open and you would therefore need a digital sensor controller to switch on the pump.

hmmmmm...thinking...

Iain

[matk]

I don't really see how it would combat hot idle. It's the airflow through the radiator that is cooling the water. At idle, then it doesn't matter how fast you flow the water, if there's no airflow, makes no difference? Seems like an extra weight and complication to me, just fit a fan overide switch?

[robertcosta]

Mat,

I would have thought that as well but at idle the mechanical pump is running as slow as it does. In both in the Esprit and Elise,at idle with the fans running, if I bring the revs up to 1500 or 2000 I do get a visible drop in the water temp. Would not fitting an electric pump that is in parallel with the mechanical pump not improve the flow?

Edited September 4, 2008 by rlc

[Loose Cannon]

I think this would be great mod, and had been mulling it over myself not so much because of the heat-soak idea, although that's an excellent reason, more that modern electric pumps are so efficient compared to mechanical these days (like the electric chargecooler idea).

Bit of a dunce here, would the pump and fans have to be wired in permanent live to run until the car cooled to a set temp, or just run on a timer like those turbo cooling kits?

[andydclements]

Do all Elise variants use both pumps, or just the K-series ones? Just curious as the K-series had heat issues causing head issues in the Rover group cars.

[robertcosta]

Hi Andy,

HGF is well known in Elise circles!

Rover improved the head gasket over time but had a bad time of it particularly with the Freelander using the same engine as the Elise/MGF etc.

The last mods before Rover went under was to use a MLS head gasket in the Freelander but it never made its way into Lotuses. They added the electric pump in 2001 (I think!) to Elises which runs briefly after engine shutdown to take some heat out of the head coolant.

My Elise made it to 47000klm before she went! It is well published that by the time a Rover K-series 1.8 has clocked up 130000klm 100% fail !

[Esprit Aviation]

All,

My car relies SOLELY on an electric pump controlled by a variable speed controller, via a thermocouple that drives the pump faster as the heat increases. Go to my garage, I think there is a pic of it and a brief explanation. It is a Davies Craig EP80(not sure about model #). It has been in the car for four years now w/ no problems. Please ask if you are seriously interested in doing this conversion, I can help you avoid all the problems!!!!!!! It is very easy, just needs to be in the correct place for proper circulation. Huge benefits from reduction of rotational mass!!!

Cheers, Lee

Edited September 9, 2008 by Esprit Aviation

[mchlrodrigues]

"While I was re-doing the head gasket on my elise and about to fit a remote thermostat, I realised that the Elise uses an electric water pump to assist the mechanically driven one."

The electric pump in the Elise is to improve circulation to the heater core, not to improve cooling.

[robertcosta]

Not quite, its as per my post 3.

Check out the implementation on MGF's here : http://www.mgf.ultimatemg.com/group2/coolant/ewp.htm

[mchlrodrigues]

Excuse me, but I should have specified. My comment applied only to the US Federal Elise with the Toyota motor, as per posts on Elise talk forum. I'm not familiar enough with the ROW K motor cars.