I've been contemplating replacing my mechanical water pump and thermostat with an electric pump and electronic controller like this. In theory, it reduces load on the engine (more power and better fuel economy) while also improving cooling performance.

I haven't really looked at what would be involved technically with doing this on a 2IS, so it may not be practical. Does anyone know much about our cooling system? What do you think lobuxracer?

 

Here is something interesting I found on the American Society of Mechanical Engineer's website. It seems particularly interesting that the radiator can be downsized (weight savings).

 

To go back to my LS1 past. Electric water pumps on a 350 rwhp F-body's give you 15 rwhp. You need 10-20 rwhp to make 12's at Ennis. I think you should try one. As for mpg's I've never seen in info on that, it's always just been H.P

 

While reading other articles, it's apparent that the "optimum" coolant temp changes with ambient temperature since the oil temperature is impacted by both. Therefore, when the ambient temperature is low, coolant temps need to be higher, and conversely, when ambient temp is high, coolant temps need to be kept low. Basically, the OEM thermostats are set somewhere in the middle of the range to be "good enough" for all climates. The cool thing about a digitally controlled thermostat is that you can easily change the target coolant temp as the seasons change.

I found a more up to date site for the EWP system. From what I've read, the engine needs about 1/3 of its HP number in Liters per minute, so it looks like the 350 would need the EWP 110 and the 250 could get away with the EWP 80.

 

My LT1 was faster :P

Seriously though, you do pick up some HP, but the typical thinking I saw was that the electric pump was great for a track car, but the mechanical pump was better for a daily driver. The reason?

Mechanical pumps tend to fail gradually, by leaking, and you can still get home.

Electric pumps fail by just stopping working entirely, and tend to let you know they failed when the car overheats.

You can rig up something to warn you when the electric pump fails, but it's just that, rigged up.

 

If the EWP controller didn't have some sort of warning buzzer, that would be a significant oversight.

 

a few things to think about. Heating the cabin air. More GPM (flow ) will decrease heating. The amount of GPM through the motor has already been matched perfectly from factory the trim on the water pump impeller is sized for this. With DI on this car and the Lean burns under light loads; the combustion chamber needs to stay at a certian temp. The only gain would be freeing up load on the motor. You would have to match the GPM for factory flow. As in a smaller cooling cell and changing the thermostat. This works BUT only when in motion. Siting in traffic you would over heat. This is one of those mods that is just not worth the trouble unless you plan on adjusting your flow for seasons and driving conditions

 

I had an electric water pump in my 97 LT1 camaro, it worked awesome. I had it in the car for over 3 years without a single problem. I was going to upgrade the system so that it would only come on when the car was warmed up, but I sold the car before I could ever make the upgrade. Anything to remove drive line loss is a very good upgrade in MOP. If you remove your accessories from the engine and just drove the old fashioned way your gas mileage will go up a little and your going to pick up some power. Granted your battery will die, and the steering would suck with out a power adder, and most people cant live without AC. That was another mod I did to my camaro, the AC compressor craped out one day so I put a "delete" pulley in its place, I know I picked up some HP by doing this and also the added weight reduction helped also.

The only problem I can see with the items your looking into is that they are not specific to our engines. If you remove the stock water pump drive system, your going to have to add a dummy pulley or reroute the stock belt system in some way. One way to do it would be to take out the stock water impeller system and leave the pulley in its stock location, kind of like GM LS engines, or find some way of rerouting the belt with a shorter or longer one. The cool thing about the LT1 water pump system is that its driven off the camshaft not by a belt, http://www.projecttransam.com/projects9.asp , so no modification of the accessory system is required and the LS1 set up just puts a dummy pulley in place of the stocker http://www.ls1howto.com/index.php?article=27

Another thing to think about is the benefit this will have on a smaller engine. A V8 putting out over 400hp and 400ft of torque doesn’t have as hard of a time running the accessory system. But a engine with only 200-300hp/tq will show a lot more improvement because it doesn’t have the extra power to waist. I used to own a MK3 supra turbo and one of the first things I did to that engine was replace the stock clutch fan with and electric one, I didn’t really notice a difference until I went to trade the car in and I put the stock fan back on, it was very noticeable then. The car really felt like something was holding it back.

 

It seems like you kind of jumbled a few separate strands of thought.

What about heating the cabin air? The flow will be whatever it needs to be to maintain a more constant coolant temp. The stock system does the same thing, but by opening and closing the thermostat valve. I don't see how cabin heating wouldn't be improved by delivering a more consistent heat source.

Regarding the perfectly matched impellar fins ... that's just nonsense. The conventional cooling system is all about compromise. The impellar itself will have a certain RPM where it will be most efficient, then above that, it will start to cavitate. In order for the water pump to flow well enough at the engine's redline, it has to be "geared down", which causes flow at idle to be very insufficient. Since the car would be overcooled when the impellar is moving at it's optimum speed, they stick the thermostat in there to reduce the flow. Basically, they have to guarantee that the cooling system remains equally inefficient throughout its whole operating range!

I'm certain that the engine (even with DI) would run better if the pump could flow enough coolant at high load. Unfortunately, I'm reading lots of reports on other forums that these pumps can't deliver their claimed flow rate when implemented in a real cooling system. It might take multiple pumps to create the required flow for a car that is driven agressively for any period of time.

 

The LT1 is not a direct injection motor also not dual cam. I do agree that the gain will be impressive if you can get the right setup. EWP`s will work on any car, But you are taken a chance. I kinda think its about as risky as nitrous. (blown head gaskets HA)

 

Your right, the pump does cavitate, hell it does it the entire time the T-stat is closed. My point is that the flow rates are important. The less time water sits on a surface area the less heat it will transfer. I'm not tring to talk you out of this. Go for it. Just look at it from every angle. As for heat who really cares about heat. There`s a metering device on the leaving side of the coil for proper flow anyway. You should stop checking engineers web sites and look up PUMP LAWS.

 

I really do appreciate everyone's input. If there was a pump like the Meziere that could be used as a universal pump, then I would jump on it. Unfortunately, I've been reading a bunch of bum reviews of the DC EWP. It seems to be a plastic POS.

BTW, does the Meziere just run at full speed all the time, and the thermostat remains in place, or is there an electronic controller? The controller seems like an important part of the upgrade to me.

 

All the electric pumps will run at full speed the second your ignition is turned on unless you use a speed controler. Something like what was used here http://www.tundrasolutions.com/forum...ed-controller/

 

Stock pumps don't cavitate when the thermostat is closed. They simply circulate the coolant within the cylinder head(s) and block. I'm not sure as to how much you will gain but from experience on the 2JZ engines we have found the Meziere water pumps to gain no more than 4 hp. And I simply recommend guys against that mod.

I do know for a fact that the engine ECU uses the ECT not only for coolant temp compensation but also to inspect thermostat performance. This is purposely programmed into it for emissions monitoring. If the vehicle were to have a low temp thermostat installed it will set a MIL in the engine control system. You may get away with a 5 deg F drop but nothing like a 160 deg unit in place of a 190 deg unit.

IMO, I think there are other areas to look into for gains.

-Joe

 

Cooling systems in cars are all a big compromise. They have to work well under a very wide range of conditions, and they have to meet the designer's goals for the hood line.

Despite what you may see about trucks, it is important to understand that cars are not designed for the same duty cycle trucks are, and therefore, the changes you can make to a truck cooling system are radically different than what you can do with a car. I've seen the radiator needed for an engine running 1000 hp all day long, and it would not fit in any automobile known to man.

Optimizing cooling system design has been in the back of my head for some years now. I have some ideas I haven't patented yet, so I really don't want to discuss them in any detail.

AFA electric pumps, yes, I believe there are some efficiencies to be gained, but those pumps will have to have some kind of feedback control. I'm not certain this can be done efficiently with modulating pump speed.

At the heart of this is the fundamental concept - there is an optimum amount of heat that needs to stay in the engine. Every thermal cycle involves heating every piece that cooled below heat saturation and this heat is completely wasted on reheating the parts that overcooled. The ideal engine would not use the fuel to heat itself to saturation, but would apply the heat directly to moving the piston with every cycle.

The engines we have today are pretty good at managing to keep the heads, pistons, and cylinders near optimum temperature, but as we said before, they're compromised to operate at light load and (briefly) at full load. Don't expect you could floor your ISx50 and stay on the gas for even a two minute stretch without suffering heat related problems. The cooling system just isn't big enough to deal with 306 hp of heat continuously. Typical design standard is 20% duty cycle with heavy duty being 40% in cars, and 75% in trucks.

Know this, you can probably understand why the ideal system would require feedback and control loops to deliver coolant to each cylinder at the right temperature for the current moment in the thermal cycle. The temperature has to be carefully managed to prevent detonation and mechanical damage to the engine components from overheating. At the same time the engine needs to stay as hot as it can to produce high efficiency.

So it's all a big balancing act. The electric pump idea isn't bad, but it's only one small piece of solving the whole puzzle.