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Discussion Starter · #1 ·
I have been reading the latest CCC (December issue, good article on the group B rally cars) and saw the bit about Electric Water Pumps. I have seen them advertised before but wasn't sure of the exact advantages. CCC tested one on a CVH engine and noted a 4bhp gain at 7,000 rpm. The reason being that it works in relation to the engine temperature unlike the standard mechanical item which only works on engine rpm. Given that the cooling on the 4G63 seems to be an issue (hence the overfueling) I wondered if an Electric Water Pump might be a good idea? Has anyone tried one on an Evo? It might be worth investigating as it does seem a relatively cheap upgrade (£300 all in?) although you need to remove the old water pump impellor, blank the spindle hole and use a shorter timing belt to do away with the mechnical water pump (otherwise theres no point).
I just thought someone may want to try it.
By the way, having come back to reading CCC after several years away it does seem.....a bit naff? Anyone else noticed?

Discussion Starter · #2 ·
My old Renault 19 16V used to have an electric water pump in addition to the normal mechanical one.
Its main purpose was to keep the water circulating once you turned the engine off to prevent all the heat soak from causing it to 'Boil Over'.
This could be a useful function on the EVO to stop the coolant overflow dribbling once you stop.

Discussion Starter · #4 ·
I was thinking more of getting rid of the mechanical water pump altogether as its not efficient. The mechanical water pump is designed to push enough water around the system to keep the engine cool at idle revs. At high revs the water pump is going like mad when not really needed to go that fast as cooling is better at speed. An electric pump only operates when needed and at variable speed, they also have a better impellor design to prevent cavitation, unlike the Evo's bent metal blades.
I reckon it could be worth at least 5-6bhp or maybe more. Not high power gains I know but something worth investigating if you are getting to the limits of cost effective tuning (big hint to Blade!).

No one tried one then?

How can I put this?
I have sold my myself ;)

Discussion Starter · #5 ·
I thought is was a brave move selling the evo , there is not much more in my price range that could match it for its looks ! and performance .

athough i have just bought an 1980 series III land rover which is loads of fun i can take it any were and not worry about it being broke in to i can also get it dirty and not bother washing it every other day :)

Discussion Starter · #7 ·
Interesting idea. The electric pump would not be as reliable as the standard, but at least you'd be able to limp home if it failed. Other alternative would be to fit bigger pulley to reduce speed of pump. Are these avialable?

Discussion Starter · #10 ·
Oil goon
i am not 100% but i think alti-cut is alternator cut it does not always turn the alternator which will take a little load off the engine thus giving a slight power increase

Discussion Starter · #11 ·
I am not convinced by the alternator cut off. Racelogic provide AlterPower - and claim 5% power gains by cutting off the alternator at full power.

The thing is, the alternator is mechanically driven from the engine, and Alterpower doesn't physically disconnect it, so how does that reduce the load on the engine???

The engine is turning the alternator to generate electricity, so what exactly are we saving here? My guess is they remove the battery from the alternator, to stop it charging, so that there is no energy transfer from alternator to battery, but you still have the motion being transferred to the alternator - so how can you get the claimed power gain??

Sounds like ###### to me....

The electric water pump, however, seems sensible - provided you take the old pump off, and use a shorter belt (hence less mechanical load). This is a bit like taking air conditioning off, which has quite a gain. Obviously the wate pump drains electricity, so provided the alternator can cope with it, lights and still charge the battery, it should not be any more mechanical load on the engine... and should mean more power... or am I talking ######?

Discussion Starter · #12 ·
You are quite right, an Alt Cut will disconnect the alternator electrically from the charging circuit. You are also right in the fact that the engine will still turn the alternator, however an Alt Cut system will allow engine power gains due to physics ;)
Have you ever seen a demo of a hand turned generator when placing a load on it (I remember it from school)? A generator (or alternator for our purposes) is easy to turn when there is no load on it, as soon as you whack a load on it (say a bulb) then it becomes a lot harder to turn. As with everything in life you don't something for nothing ;)
Cut the output of the alternator (load) and it will have less work to do or in other words it will become easier to spin the rotor. If the alternator is easier to spin then the engine will be able to produce more power for the job it was meant to do, turning those wheels!
I am not sure of the exact amount of gain you will get from an Alt Cut system (it gets a bit complicated to work that out!) but 5% sounds a bit optimistic although I am no expert on the subject.

As for the water pump, spot on ;)
There are also possible extra power gains to be had other than the mechanical pulley removal. Engine power can be influenced by water temperature and you can experiment with an electric water pump on a rolling road to get the best results. Remember the electric pump is controlled by water temperature not by engine speed like the mechanical pump so you can alter the electric pump speed to keep the water temperature at an optimum in the block. You may not get any extra gain this way but it might be possible.

Discussion Starter · #13 ·
Ok i've watched this thread for the last few days.
It has a lot of technical merit.

My question is, to get reasonable cooling, how big a pump is needed, how much power will it draw, and can this be done with a 12v system?


Discussion Starter · #14 ·
Glad you decided to keep the motor, did you ever buy a track-day car or is the Evo it?
The water pump question is interesting I always understood that they gave more accurate temp control because they do away with the thermostat and the pump is of a vairiable speed. ie stoped or v. slow when the engine is cold and pumping like buggery when its hot. I belives some systems have a preheat so you can warm the coolant up before you start the engine and like Nelly mentioned they will stay running after the engine is switched off to reduce the likelyhood of localized vapour locks etc.


Discussion Starter · #15 ·
AndrewN and everyone else,
Have a look here:
This pump is available from Demon Tweaks at £120 with the controller an extra £80.
I have no idea how good it is but there is a very interesting review of it here:

The Davies Craig pump can push around 20 to 80 litres/minute depending on the voltage you supply the pump (via the controller). A typical mechanical water pump pushes 20 to 40 litres at idle (when its needed the most). The Davies Craig pump is a universal kit. It is a 12V pump and will draw a maximum of 7.5A.
The Davies Craig pump is also the one used in the Car and Car Conversions article (pg 102-103, Dec issue have a look in Smiths ;)) and produced a 4bhp gain on a Fiesta CVH at 7,000 rpm. The Ford Muscle article reckoned they gained roughly 30bhp on a 1969 Mustang Mach 1 with the same pump.
(This is getting to sound like an advert!)

I will list the advantages and disadvantages as I see them and you can make up your own minds:

Advantages of fitting an Electric Water Pump
If you remove the mechanical OE pump, thermostat and set the Electric pump up for optimum cooling for power then it is possible to see 5%-15% increase in power.
You can set the water temperature low for high power gains (approx 75C) or slightly higher for improved fuel economy and better emissions (approx 85C).
You can leave the pump running when the ignition is off to prevent heat soak and to cool the turbo.
At idle the engine will not be as likely to overheat.

Disadvantages of fitting an Electric Water Pump
Fitting is a bit of a pain, you have to remove the mechanical pump impellor, pulley, thermostat and blank the spindle hole. You also will need to fit a shorter timing belt.
It only has a probable 3-4 year life span (2000 hours at full power so say approximately 2 hours a day |EQU| 2.75 years). They are guaranteed for 2 years however.

In my opinion due to the hassle of fitting then it is only really for people wanting to squeeze the last drop of power from the car as easier power gains can be had going down other routes.

It took a while before electric fans caught on and now every car has them, perhaps electric water pumps will also eventually end up on every car?

Discussion Starter · #16 ·
Ok HH6, I want one now! A job for xmas. Bugger, I have only just had a shorter timing belt put on when the aircon was taken out!!!
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