Hi guys,
since the Meziere Pump is not available in my country (germany) and after some short research not even in Europe, i found a different product that is very similar to the infamous Meziere pump. :

http://www.daviescraig.com.au/Electr...5-details.aspx

Its called "EWP 80 Electric Water Pump" and apparently invented in Australia.
Flows ~21GPM and can be controlled by a fan controller with specified temperatures to switch on and off, which is a very nice feature if needed anyway.

What do you think?

 

I installed the updated Bosch pump. It flows more than the originals and its a complete bolt in swap. All other pumps you will need to fab up a bracket to hold the pump and splice in the wiring harness.

R.K.

 

Hi,
well the newer Bosch Pump still only flows 6GPM, while both the Meziere and my proposed one at least 20GPM.

I think i will try this pump in the future, since its available in Germany for aroud 200€.

Is it correct that the CL55AMGs ECU activates the Intercooler Pump "on demand" ? So its not constantly running?

 

I believe that is correct regarding the pump running.

I just want to leave you with this thought, if the pump flows 20gpm, it won't have enough time to cool off the water/coolant in the intercooler circuit. A pump that powerful is good if you have a trunk mounted cooler with ice in it.

Just my $0.02

R.K.

 

After lots of readings, there are people that disagree with that statement.
In fact in this Forum and on Pl....Su...C... there are a few which went from the older Bosch over the Johnson CM30, over the later style Bosch and now stick with the meziere.

On the other hand, there are people out there that claim that larger pumps will kill the HE below the SC, producing leaks that gets sucked fluid into the engine.

I am still uncertain.

 

There is no way a larger pump which could be any of the following meziere, cm30, cm90 will produce leaks in the sc inter cooler core at least on the 55k

 

Ok, but i read that even on some companies websites...

http://www.needswings.com/Intercoole...ICthermal.aspx

 

C32 ones are know to leak

 

Obviously greater flow will increase the pressure in the system.

I still stand by my statement unless you provide me with engineered proof that the 20gpm pump will drop the temps significantly more than the Bosch replacement pump.

R.K.

 

not enough pressure to crack welds.

 

Agreed but any rubber hoses that are fatigued may rupture.

R.K.

 

My Meziere is going out.. Im replacing it this week, still contemplating if i should go with the cm30 or stick with the mezier.

 

i have experimented with a potted voltage to the pump and corresponding coolant temperature.

i have found that running at 10v and 12v and 14.4v has zero effect on coolant temps on a chipped v12 tt car equipped with the updated bosch pump. and yes- at 10 and 12 volts the pump does run slower and i assume pumps less.

therefore i am willing to believe that a bigger pump flowing more will have zero effect on most common scenarios- stock or ecu-ed motor.

your mileage might vary.

 

I suspect the benefit of a high flow pump is the reduced delay to START cooling the charge coolers - when the pump is first switched on due to high IAT, that is. There's quite a lot of hot water sitting in that system - especially thinking about the pipes that run past the turbos - and it must take time to get that round a full circuit.

The argument that high flow rates result in higher charge temps doesn't work on many different levels. Its probably best consider a cooling circuit interms of how it carries heat energy around, rather than how it behaves from a temperature perspective.

Firstly, if the water doesn't stay in the HE long enough to cool down, then the converse must also apply - the water won't stay in the charge coolers long enough to heat up.

Although the water will pick up less heat in each pass through the IC when it flows fast, it will complete more circuits in a given time, so it will complete more passes.

So the question is whether the faster flow is more than enough to offset the shorter heat transfer time. Heat exhanger behaviour is complex, there's nothing simple or linear about how they work. Heat transfer is governed by many variables, but the simplest one is that heat flow is proportional to temperature difference. Therefore if the coolant is cold, the heat transfer willbe fast.

If the coolant circulates slowly, so that it has time to absorb a lot of heat, its temperature will tend to approach that of the air its cooling. As it does so, the temp differential falls, and rate of heat flow also falls. Therefore the highest heat transfer happens when the coolant is coldest.

That's another way of saying that heat transfer increases as flow rate increases, which is one of the other guiding principles of heat exhangers. That's not linear though, as heat transfer depends on other factors - like the surfaces of the tubes. Rough sufaces and high flow speeds will encourage turbulent flow, which is more effective at heat transfer. There's more convection transfer when there's turbulence, so you don't just rely on the conduction of the coolant.

Turbulent flow is difficult to predict, and depends on the fluids, the surfaces and the Reynold's number. Although I did study aerodynamics and fluid mechanics when I was at British Aerospace, I don't pretend to fully understand it all. However, if there's one thing that DOES encourage turbulence, its high fluid speed. Maybe the Bosch pump is fast enough to cause turbulence, but a faster pump MAY encourage it more, and it certainly won't make it worse.

Water has a high heat capacity, and it could be that the stock pump is fast enough to ensure that the coolant temperature rise through the IC's is low enough during each pass to ensure that the capacity of the coolant itself isn't the bottleneck in the overall cooling system. The limitation may well lie elsewhere, such as with the thermal resistance of the HE to ambient air, or with the IC to the intake air. In that case, the cooing fins may be held at the coolant temperature quite effectively, but there might simply be not enough of them to conduct the heat to what is a fairly insulating medium. But I'm starting to speculate there.

The end result is generally that higher flow rates increase heat transfer, and the END RESULT is that the medium being cooled will be cooler.

Of course it could be that the real benefit is that cooling simply STARTS faster for the first reason I gave. Given that this is effectively a thermostatically-controlled system that only runs on demand, that could be the overriding advantage.

Nick

 

Very nice writeup Nick. I agree to you.
So at the End of the day, in the 5.5L SC and 6.xL TT engines, "flow is king" ???

I really would love to be able to buy a 10-20GPM+ Pump in Europe (or even Germany).
Any suggestions?

For my personal scenario on the CL55 AMG, i'm not a dragracer at all, rather intermediate hard accelerations on the German Autobahn - is the upgraded Bosch Pump enough? I plan on smaller SC pulley, Kleemann Headers, metal catalytic converters and fitting ECU/TCU tune.

 

Thanks, you should be able to pick-up a Meziere or Johnson pump pretty easily from ebay.com or one of the online tuning retailers. Importing from the States is no biggie, I do it all the time. That's what I'm planning to do.

Nick

 

Many of the loss of power complaints due to heat soak seem to come from the E55 crowd that track their cars.

Consider that the stock HEs in the front of the CL55, CL65, and so on are much larger than that on the E55. (The part numbers are not the same as the E55.) I am not saying the CL55 and CL65 have the same size, just they are both significantly larger than the E. The frontal design of the CL series allows this larger HE to be used effectively.

Therefore, with the updated Bosch pump, the CL AMGs in stock form would tend to have less heat soak or the onset of heat soak would be later (more laps) than a comparable E55 with the M113K engine. If there was an upgrade to a higher flow pump in both models, Welwynnick's account of the fluid mechanism would imply the CL SERIES would cool more efficiently than the E. Thus many E55 owners replace their HE with a larger model as they increase their tuning. If the frontal design of the E55 car cannot extract full benefit from this larger HE then increased cooling would have to be made up elsewhere.

Comments?

 

Going back to the original post, that's actually quite an interesting pump - or rather an interesting pump controller.

http://www.daviescraig.com.au/Contro...0-details.aspx

When we talk about Bosch, Johnson and Meziere pumps, we talk in terms of swapping pumps out and using the same electrical interface.

I suspect that one of the biggest issues with the stock pump is the way its controlled - pump turns on at 47oC IAT; pump turns off at 35oC IAT. Maybe it works better than I give it credit for, but it does seem a rather crude algorithm.

Running at full speed all the time is probably too wasteful, but I think it needs better control, that allows the coolant to be kept cooler all the time. Some sort of variable speed control is probably what's needed, and that's what the Davies Craig controller appears to do. There's a variable duty cycle - 25% at low temperature, 50% at medium, and continuous at high temperature.

Since the controller is targetted at engine cooling systems, there isn't the flexibility to support low-temperature cooling systems like ours. The target temperatures can be set to 75, 80, 85, 90 or 95oC, which is too high for us. However, at the lowest setting, the pump would be run at least 10sec on/30sec off all the time, increasing to 10 on/10 off for any temp over 55oC, and continuous over 70oC.

That low duty cycle would probably be ideal to stop the coolant in the pipes heating up during cruising, when there's no boost. But I'm not sure its enough to keep the temp below 55oC when the engine IS on boost.

Perhaps there's a simple way to add a resistor in series with the thermistor, so the controller thinks the coolant temp is higher than it is.

And thinking out loud for a moment, I'm sure there must be a temp sensor somewhere that the stock system already uses. That should make the installation a bit easier. I guess its only an air sensor though.

I expect the Davies Craig controller is intended to be used with their own electric water pumps, but just to prove a theory, it would be interesting to try the controller with the stock Mercedes pump, and see what that does to IAT and subjective performance. I'd like to use one of their pumps as well, but I'd like to understand the individual contributions from the controller, pump, HE, etc.

Nick

 

^^You don't want your pump starting and stopping that frequently. It will burnout faster. The ideal setup would either be a variable speed pump or a pump with constant speed and variable vane to control flow. Both will be expensive if at all possible.

R.K.

 

Quite agree with all of that
Please point me in the appropriate direction

The point is that what we have got are the Bosch, Johnson and Meziere pumps, and those are the options open to us.

And now perhaps we can add the Davies Craig pump (and controller), so the options just got a bit more interesting. Not exactly what we want, but maybe a step forwards.

Nick

 

Another possible senerio is to have the pump controller some how wired so the IAT signal goes into it and it then varies the current or voltage to the pump which basically turns the pump into a variable speed pump. You can pick any pump to do this with. As the IAT go up, so does the speed of the pump. When they go down, the pump will slow down but will constantly be flowing until it reaches the minimum temp (that way the car/coolant warms up properly on cold startups).

R.K.

 

Looks like the inlet and outlet`s are far larger than the 3/4" lines we use on our system.

Pumps are about head pressure and the cm30 and cm90 are magnetic drives and from our test on the cm30, can not outflow the stock bosch not even close to the meziere. Even the rated 20gpm Meziere, can only flow about 6 gpm on our system and that is still the best pump I have tested on our cars by far.

 

Correct me if I'm wrong, but in fluid hydraulics flow and pressure are two different things, increasing flow does not necessarily increase pressure and vice-versa. You can have low-pressure high-flow and vice-versa.

 

People are always drawing comparisons with water circuits when they try to explain elementary electronics, so a backwards comparison might work as well. The hydraulic pump is like the dynamo or battery, the pipes are the wires, and the IC & HE are the resistors. The pump generates a certain pressure, and this is analogous to voltage.

The whole circuit has an overall resistance to flow, which restricts the current, so to speak. If there was just one IC, the resistance would be higher, as all the flow has to go through one resistor, rather than being split between two parallel units, and so on.

Unless we make changes to the IC or HE, that resistance is fixed, so we can only change the pump. The pump will only achieve its maximum voltage/pressure when it’s delivering no current. That's like putting a voltmeter across a battery - you get the max voltage, but there's no load. As soon as current starts to flow, the voltage drops, and when you take it to the extreme with nothing connected to the pump, you will achieve the maximum flow, but there will no pressure. Similarly, when you crank an engine, the battery voltage plummets. These extreme conditions are just like open circuit and short circuit on a battery - you either get maximum pressure or maximum current, but not both at the same time.

I believe pumps typically operate in a middling condition, where both the pressure and flow are somewhere near half the respective max values. So if a pump can achieve 6 psi open circuit and 10 gpm open circuit, I'd expect it to achieve something 3 psi at 10 gpm in a typical installation; perhaps a little more than that. That's what all those pressure/flow charts are all about - they show how much pressure loss you get when coolant starts to flow - or alternatively how much the flow drops when you add resistance to the circuit – it’s the same thing. Pressure times flow is power, and pumps deliver most power to the fluid when they work in the middle region. If the flow or the pressure is close to the maximum value, the pump is working against too little or too much resistance respectively, and the pump won't be doing as much useful work as it could.

The faster you push the coolant round, the more pressure you need (but its not linear, it’s more like a square function). So, if we fit a bigger pump with a higher flow rate, that MAY increase the flow around the system, but ONLY if the pump can generate a higher pressure at that higher flow rate. What we're looking for is not just a pump with a high max pressure, or with more max flow, but one where the pressure/flow curve moves up and to the right, in the area where the system actually works.

Alternatively, we could fit a larger HE, hopefully one with more pipes, and hence less flow restriction. That in itself will increase the overall flow rate slightly, because the total resistance of the cooling system is reduced. The resistance will reduce, the flow rate will increase, and the pressure will reduce. The operating condition of the pump will find a new equilibrium point, and will move to the right slightly. That's a good thing, because we gain from the reduced thermal resistance of the larger HE, plus the higher flow rate round the cooling circuit.

So we do need to consider both pressure and flow rate, but they are related.

Many electric pumps are designed for engine cooling, so they often have 1.25" outlets. The Meziere and Davies Craig pumps have the option of various diameter outlets, including 19mm, which should be ideal for our cars.

Nick

 

So can i use the EWP80 Pump or not?
Will it have enough "power" behind it, so it can flow enough?
I wonder because comapring the pictures of a Bosch and this EWP80 pump, the front looks very similar in Design, however the Bosch aswell as Meziere, etc have a large cylindrical unit attached to it (motor) which the EWP80 is missing.
Also current-draw is of my concern. Can the ECU/Small-cables deliver 7.5AMPs ?

Compare:
http://www.daviescraig.com.au/Images...cs%20Sheet.jpg

www.benzworld.org/forums/attachments/w215-cl-class/217682d1233047360-charge-cooler-bosch-pump-possible-replacement-bosch-0392022010-1-.pdf

EDIT: They also have a 25GPM Pump... lol!
Check out the vids:
http://www.daviescraig.com.au/ewp_demo-content.aspx