Flow of Stock water pump?

[bolarbag]

What flow is the stock water pump at 6k rpm in l/ph?

 

Any insight to the maximum flow whilst still in its efficiency range and also at which rpm does the range become inefficient?

 

Many Thanks for anyfeedback

[bolarbag]

Bump, anyone?

[JamieP]

Not a clue but why do you want to know?

[bolarbag]

I have an electric one that flows 20gallons p/h, but I'd like to know what the stock one flows at the 6K rpm mark, higher up and the stock one flows out of its efficiency range apparently

 

But the stock pump flows more than 20gallons p/h I'm sure, there is another system I'm looking at replacing it with that removes the thermostat too, but I need to know the stock pumps flow first

[JamieP]

Why bother? genuinely interested as ive not heard of anyone needing to change especially running a small single?

[bolarbag]

Pretty much Preventive maintenance, I either buy a new oem pump or modify the existing design, there is more control over an electronic pump than a mechanical pump, especially for low revs in traffic jams e.t.c

 

Its going to be a track car, so I want to make sure the electronic pump can put up with the abuse and also give me more control, but the car will be driven to track rather than trailored, so will still be a street car

 

My aux belt is not going round the oem water pulley now, or the oem alt position, obviously the V. fan has been removed and so has the oem pump for now, and alt has been moved to the right hand side, all in aid of reducing parasitic drag and removing anything I dont need

[bolarbag]

For my own observation...

 

Suction Cavitation

 

Suction Cavitation occurs when the pump suction is under a low pressure/high vacuum condition where the liquid turns into a vapor at the eye of the pump impeller. This vapor is carried over to the discharge side of the pump where it no longer sees vacuum and is compressed back into a liquid by the discharge pressure. This imploding action occurs violently and attacks the face of the impeller. An impeller that has been operating under a suction cavitation condition has large chunks of material removed from its face causing premature failure of the pump.

 

Cutwater = Cut-water

 

 

Discharge Cavitation

 

Discharge Cavitation occurs when the pump discharge is extremely high. It normally occurs in a pump that is running at less than 10% of its best efficiency point. The high discharge pressure causes the majority of the fluid to circulate inside the pump instead of being allowed to flow out the discharge. As the liquid flows around the impeller it must pass through the small clearance between the impeller and the pump cutwater at extremely high velocity. This velocity causes a vacuum to develop at the cutwater similar to what occurs in a venturi and turns the liquid into a vapor. A pump that has been operating under these conditions shows premature wear of the impeller vane tips and the pump cutwater. In addition due to the high pressure condition premature failure of the pump mechanical seal and bearings can be expected and under extreme conditions will break the impeller shaft.

Edited May 27, 2008 by bolarbag (see edit history)

[Chris Wilson]

Over complication in my opinion, stick with the stock set up!! I have never seen a pump suffer any cavitation damage, ever ever ever.

[bolarbag]

I'm pretty much inclined to stay with the stock fan setup - which would mean some custom work to get the pulley to run that, I agree over complicated,

 

But for our climate, are we in agreement that decent electric fans would be up to the job for a track day?

[Digsy]

Thumbnail calc:

 

 

Assuming the pump was sized for a 320hp (240kW) engine, rejecting a typical 60% of its brake power to coolant, the water flow rate required to keep the temperature rise across the engine to 8degC would be 292litres per minute.

 

 

That's 17500litres per hour, or 3849 UK gallons per hour, so I think your 20gph pump is a tad on the small side.

 

 

It dependes on whether the pump is sized for cooling at max power or at some other condition. Because engine driven pumps are slaves to the engien speed, its not uncommon to find that the pump design point is actually something like a high embient temperature trailer tow, or hill climb test rather than flat out on level ground. The rest of the pump capacity above this speed ends up being an uneccessary overhead. Don't forget that the faster you are going, the better cooling your get from the radiator, so you can drop the pump flow a bit.

 

 

Electric cooling of car engines is a minefield. You will find that brute-force cooling (by attempting to mimic the maximum flow available from the standard pump) drives you down the route of a huge pump. Systems designed from scratch to use electric cooling have clever water jackets with low backpressure (or very fast flow), electrically controlled thermostats, and other gizmos.

 

 

Its very likely that for your specific use you could get away with a much smaller pump, but sizing it will be difficult. For information, to do it properly you want thermocouples in the pump outlet (entry to engine), engine outlet and the radiator bottom hose. The difference between the pump outlet and the engine outlet will tell you the temp rise across the engine (which should stay below 8degC). The engine outlet should also stay below yout chosen max temp - 120degC or so). The difference between the pump inlet and the radiator bottom hose will give you an indication of how open the thermostat is. You may find that by replacing the thermostat with one that opens at a lower temperature, you can decrease the water pump size by increasing the flow through the radiator under fast cruise conditions. If you do this, then a good electric fan will probably also be required for boosting the cooling when the engine load is high but airflow through the rad is slower, or ambient temps are high, etc.

 

 

I know you can buy off the shelf kits to do this that imply a simple fix, but I assure you, once you start looking into the detail it gets very complicated very quickly! Good luck!

[bolarbag]

I was waiting on your reply:)

 

Yes the one I have is actually 35g p/h, the other 55g p/h, way less than the stock pump probably flows, I had bought a TRD thermostat, I think I'm just going to remove it altogether, I may put different inline thermostat in for water retention when I have the pump off under cold conditions

 

I've got quite a bit of space for thermocouples in the motec, and I'm thinking if I have a map saved with various parameters specced for track driving and a different one for daily/norm driving then my cooling and pump should be sufficient after a bit of testing

 

When I get it right the gains will be minimal, but I expect to see better throttle response and more control during cooldown conditions trackside so for a little work should be worth it

[Digsy]

Yes the one I have is actually 35g p/h, the other 55g p/h, way less than the stock pump probably flows, I had bought a TRD thermostat, I think I'm just going to remove it altogether, I may put different inline thermostat in for water retention when I have the pump off under cold conditions

 

Are you sure those pumps aren't 35 and 55 gallons per minute, not hour? Even a relatively small engine will have a water pump sized at around 150 litres per minute (1800 gallons per hour / 30 gallons per minute).

 

The Davies Craig EP80 and EP110 flow 80 and 110 litres per minute repectively.

 

As far as benefits go, you will definately see a faster warm up . Unfortunately I fear that CW is correct in that apart from a load of ball-ache you won't experience much else. Water pumps take virtually naff all power to drive, even at full chat. The main reason that OEMs are looking seriously at them now is to better control the cooling of the engine to keep it warm rather than to keep it cool. The benefits are in keeping the coolant flowing around the cylinder head to control combustion but letting the bottom end run hot to reduce friction. The parasitc loss from the pump itself does play a minor part, however. To fully exploit them you need a much more sophisticated water jacket with different coolng circuits for head and block.

 

Suck it and see, I guess. It would be an interesting excercise to do a write up on.

[bolarbag]

Sorry dont know why I kept quoting g p/h, yes 35g/m, its probably in U.S Gallons so 135litres per minute or 8100litres p/h, life expectancy 3000hours, average current draw 6-7 amps

 

"Never run your engine without the water pump, hot spots can form in the cylinder head before your temp guage begins to register."

 

3000hours would be more than enough for my application, although I may have to look at my battery as the main benefit of this system would be to run this pump when the engine was off, with no alternator my very small battery would discharge very quickly

 

Maybe the Redtop Deep Cycle will come in handy

Edited May 28, 2008 by bolarbag (see edit history)