Electric Water Pumps

[hrforever]

I've been thru this forum about the use of electric water pumps and two things that continue to go unanswered are (1) what is the coolant flow rate of the 1UZ and (2) do the electric pumps provide any real benefit over the standard mechanical unit.

I have always been of the opinion that the mechanical unit is terribly inefficient because of its water flow charactistics and that a controllable electrical unit, connected to electric fans, would be a better, more fuel efficient proposition.

I believe the current Davies Craig units are more reliable that the first version, but any comments would be helpfull.

 

[Lextreme II]

I think noise might be an issue. I never install one but I have one for the oil and it was loud.

 

[Peewee]

The only benefit I see from an EWP is that it can continue running after the car is shutdown. The only time you'd want to use this is after a huge burnout.

Other than that the $450AUD outlay is a waste of money and would be better spent elsewhere.

*note - this does not apply to all motors, if you have a chev from the 70's then yes the belt driven pump is probably horrifically inefficient, but this is definitely not the case on a 1UZ.

*also note they may be useful on very high revving motors (>9000rpm) but I think an underdrive pulley on the stock pump would be a better move.

 

[cribbj]

EWP's are growing in popularity on another hipo forum I frequent, and I'm planning to use 1 or 2 of them for my V12 engine.

As pointed out, the good thing about electric pumps and their PWM controllers is their ability to control the flow of coolant according to the needs of the engine, not just solely according to the engine speed.

Regarding the flow of the UZ pumps, there is a way you can calculate the flow, even if you can't measure it directly, by using the formula 500 x GPM x deltaT = BTU/Hr rejected.

If you know the HP your engine is putting out, you can then assume the cooling system has "about" the same HP going into it, and you can measure the difference in coolant temperature going in the engine, and coming out of the engine, you can then calculate the flow of the pump.

I may try to grab this info the next time we put my 1UZ on the engine dyno.

 

[stevechumo]

I think the stock 1UZ OEM pump is good enough, unless you go with crazy hp figure. Just a note if you decide to go with a replacement belt driven pump. The OEM pump has a larger wheel or plate or whatever you call it than most aftermarket pump. Most aftermarket pumps has about 1/2" smaller wheel. However, the outer pulleys are the same to fit the belt. This makes me to believe the OEM will move a lot more coolant volume than the aftermarket pumps, which means more efficient.

 

[hrforever]

As I'm not planning on any great modifications, I know the standard pump will do the job because that's the way they designed it, so prehaps another question; If a motor has approx 120k, would the original pump still be up to the job or will there be benefits in replacing the pump, apart from not having to strip the motor down at a later date. How long do these pumps last or to put it another way, has anyone had a mechanical pump fail under normal conditions.

 

[Peewee]

Toyota pumps normally fail at the seal before they do anything drastic (like seize or have the impeller fall off).
The car will start dripping water but will still be drivable (over smallish distances) as long as you top the water up.

Replace the pump when ever you replace timing belt/bearings/tensioner (or vice versa). Then you only have to pull the front of the motor off once.

Its ~$150 genuine for the pump, and ~$250 non-gen for the timing belt kit.

 

[PEI330Ci]

I'm in the midst of converting a BMW M54B30 engine with a belt driven water pump to a single electric water pump from Stewart. I'm using all AN hardware for the lines, but you can use "normal" hose for a fraction of the cost.













Most of the Speed World Challenge Touring Car paddock is using this pump on their race engines, you might want to look at using 2 of them for a "V" engine.

 

[PEI330Ci]

I'm in the midst of converting a BMW M54B30 engine with a belt driven water pump to a single electric water pump from Stewart. I'm using all AN hardware for the lines, but you can use "normal" hose for a fraction of the cost.













Most of the Speed World Challenge Touring Car paddock is using this pump on their race engines, you might want to look at using 2 of them for a "V" engine.

 

[Zuffen]

If you change the size of the UZ water pump pulley you'll alter the cam timing as the cam belt uses the water pump as an idler pulley.

I can't see that aftermarket belt driven water pumps would/could use a different sized pulley.

I guess you could machine the vanes of the UZ pump then run a EWP but sounds like a lot of work for little gain.

 

[Zuffen]

If you change the size of the UZ water pump pulley you'll alter the cam timing as the cam belt uses the water pump as an idler pulley.

I can't see that aftermarket belt driven water pumps would/could use a different sized pulley.

I guess you could machine the vanes of the UZ pump then run a EWP but sounds like a lot of work for little gain.