Good day all, my apologies if this has been covered before, but I tried searching without success.

I was thinking about EWP's and their flow rates with respect to the cooling efficiency of our (LT1 specifically, but really all) radiators, and I was thinking that the flow rate of 42GPM (Meziere WP118) may not be the optimal flow rate under all conditions.

I'm sure that Meziere did their homework when selecting the motor for their EWP to handle the cooling needs of a modded LT1 stuck in traffic, where the cooling needs would be the greatest, however i don't think that our cars really need to flow 42GPM at startup on a cold winter day for example, or once you get up to speed after being stuck in traffic and the temps drop back down to reasonable levels.

So my question is basically, has anyone done any analysis to see what flow rate is the best to get the optimum radiant cooling effect from the radiator?

And would it be feasible/sensible to create a standalone controller for the EWP and E-fans to say only pump water once the engine is at a certain temp, and only pump the water at a rate to get the most cooling effect from the radiator, and only turn the fans on when the water in the radiator needs to be cooled? ( I know the stock PCM already does this)

With the idea being that this will lessen the load on the vehicle's electrical system, and greatly increase the finite lifespan of the EWP since it's not drawing max amps and pumping at max capacity all the time.

I apologize if this post didn't make sense or isn't Adv. Techy enough. I'm just brainstorming and appreciate all input you can offer, thanks.

 

t-stat is the temp. flow regulator

 

Yes, that's what I'm talking about in a sense, however what I was trying to "fix" is a situation like a cold start where the t-stat is closed and you have a 42GPM pump going all out circulating the heck out of some ambient temp water inside the engine alone, when a much lower flow rate would suffice, say 5 GPM, until the engine started to warm up and open the t-stat, then maybe 15GPM might be necessary, but only provide full power to the pump when you're stuck in traffic with temps near 212 and both fans are on, or something like that. Maybe you don't ever need the full 42GPM because it forces water through the radiator so fast it doesn't exchange as much heat as it could have if pumped at a slower rate. I don't know. Any ideas?

 

This is an interesting idea, and probably feasible with some basic electronics knowledge. I definitely think that it's a waste for the EWP to be running full blast at all times, and does place more wear & tear on the pump.

I'll ask a friend of mine for a basic circuit design.

 

Whether the coolant in the block is circulating or not, you still have to heat the full mass of that coolant up to the thermostat temp before the t'stat starts to open and allow flow through the radiator. The fact that the coolant is circulating in the block shouldn't make that much of a difference in how fast it heats up. And, the circulating coolant would help transfer the heat from the heads down to the oil, so ithe oil will start to flow better/faster.

 

Sure, but the benefit I see would be after you're up to operating temps, where you may be able to drop your pump's power consumption by some substantial amount and still maintain enough flow to cool your engine during normal (part throttle) driving.

 

Yep. That was the main point of my post, I only used the cold startup as one example of the "waste" as i see it, of running a EWP full throttle all the time. I agree that the biggest benefit as I see it, would be at part throttle cruise on the highway and so forth.

An engineer friend of mine suggested that a pulse width modulator would be the simplest way to vary the current going to the pump, but I'm not quite sure yet how exactly it would all go together, or whether it would be worth it, but it sure seems like it could be.

 

IMO your overcomplicating something that works like it is.

I know of a pump that pumps less at part throttle...the stock one


The pump pulls next to nothing in amps.....I just don't see where the concern is to save power

 

6-7 amps, per the Meziere spec sheet. And as was mentioned before, the pump is being loaded unnecessarily at 100% duty cycle. Increased longevity is another possible benefit.

This may not be a huge power saver in the end, but what's it hurt to brainstorm?

 

your wallet?

 

The car's been doing that for years...

 

What you dont want in your LT1 is localized hot spots. Reducing water flow will increase hot spots.

Also what you dont want in an LT1 is hotter aluminum heads than iron block (or vise versa) at any point during the warm up/constant temp process. Reducing water flow should create less heat being circulated.. therefore creating the possibility of the heads heating up faster and/or having hot spots, and when the heads heat up faster than the block they expand more/faster than the block.. this means there could be more head gasket stress during heat up... meaning increasing the chance of head gasket failure.
When heads get hot spots it also leads to detonation/cracking.
Less water flow also means air pockets/gunk may not move/dislodge as easy, adding to the hot spot problem.

I believe this is one of the benefits of the electric water pump.. to give you constant/adequate water flow ALL the time.

 

I'm highly doubtful that 42 GPM of flow would be required to make sure the heads, block, and oil all come up to operating temp at their own optimal rates. There should also not be much air or gunk in your cooling system that needs blasting out of place by a large volume of water, localized hot-spots, sure, but again, I doubt you need 42GPM ALL the time.

Would oil temperature be a good predictor of warm-up efficiency? Let's say I record how long the oil takes to get to 200*F with the stock pump compared to an EWP running 42GPM compared to an EWP running 5GPM. Would the shortest time to get the oil up to temp be the best? Or would it have to be more scientific using a cylinder head temp reading, block temp reading, and oil temp reading to ensure the heads aren't getting too hot too fast?

I know this seems like I'm over-complicating a system that already works, but it sure seems like there are thousands of posts on this board pertaining to an LT1 that runs too hot, and they aren't all cars with stock tuning and stock water pumps. There are folks on this board who ask for help with a car that's got an EWP, low-temp t-stat, fans that come on at sane temps, big 'ol aluminum radiators, water wetter, etc that still runs hot and I'm wondering if it's not because the flow rate of the water pump is independent of how much heat is actually being created by the engine and how much is being removed by the radiator/fans.

Not to mention the possibility of less amp draw on the electrical system, and the possibility of turning an expensive, hard to remove and reinstall item, into something rated for 5000 hours instead of 2500.

I totally made up the idea of doubling the lifespan of the pump, that may be a totally unreasonable figure, but I know that with the controller I'm proposing to build, any time I can get away with not running the EWP at 100% duty cycle will extend it's lifespan.

 

I think you are trying to reinvent the wheel here. I understand what you are saying but why mess with something that works. If its not broken dont fix it.

The water pump does not control flow.... period. Mechanical or electric. The flow is controled by a t-stat. End of story. You will not find any measurable gains from slowing down the pump when its cold or at idle/part throttle. The only thing you will see happen is you take a chance at it not working and you spend a lot of time and money to fix something that already works just fine the way it is.

Honestly if the electric motor is not rated for PW service, then what you are proposng will probably do the exact opposite and shorten the life span. You force more amps to turn the motor slower and cause the windings to run hotter. Yeah you might save some friction generated heat on the bearings but I bet you NASA couldnt calculate the difference.

I have an EWP. Its been on my car with 2 different motors for over 6 years now... still works just as good today as it did when I bought it. 99% of the people who have cooling problems or pump failures have install problems or a totally seperate cooling system problem they have not fixed. Sometimes changing things and combining parts not desgined to work with each other just ends up with poorly operating cooling systems.

I have a 550 hp LT4 and the only additions to the cooling system over stock is an EWP and a 160 stat. No problems here.
I just think you are over complicating a simple thing. Why slow the pump down... It will not pump 42 gpm with the t/stat colsed any way. Dont reinvent the wheel.

 

That's not how understood the operation of a thermostat in our cars, or in any cars, I suppose.

The way I understood it was that as the thermostat opens, it allows coolant from the block to flow out into the radiator and coolant from the radiator to flow into the block, and that when it's closed, the pump would just circulate water in the block. And I figured the flow rate of the pump to be constant with respect to engine speed for the stocker, and current for the EWP.

I agree that the t-stat regulates the flow of coolant that gets to pass to the radiator, but that is a passive adjustment based on the temperature of coolant in the block. However, what I'm brainstorming is a flow controller for the EWP that would take into account coolant temps in the block and coolant temps on the inlet and outlet side of the radiator to determine the proper rate at which to move coolant through the system to optimize performance of the cooling system to maintain a desired coolant temp in the block while not overworking the EWP...and maybe eliminate the need for a traditional thermostat.

If in fact dialing back the current to limit the flow of an EWP would damage the motor, it might be a better idea to run it at the rated voltage/amperage, but not 100% of the time, perhaps run it in a pulsing configuration where the flow controller would modulate the frequency and duration of the pulses to achieve the desired cooling effect.

Again, I know it seems like re-inventing the wheel, but there have been a lot of systems in automobiles and ICE's that we thought worked fine until someone took a more critical look at them. Look at nitrous systems for example. AFAIK the first uses of nitrous were a true "fogger" system where racers fogged the whole engine compartment, which I'm sure they thought worked great at the time and didn't want to "fix what wasn't broken" and now we have direct port N20 injection systems.