discuss the electric water pump
02-14-2011, 02:08 PM
#51
I'll correct a part of what I wrote above: The Gen III Prius engine apparently uses an EWP. (Don't confuse this EWP with another Prius EWP, which has been subject to lots of problems, that runs the cooling system for the battery). One might search for articles about its operation in a street car. I'm guessing it makes more sense for a hybrid since the engine is on and off a lot, at stop lights and so on. Makes one wonder if engine-stop technologies might eventually force a shift to EWP's to keep stopped engine temps under control.
Last edited by HiFlite999; 02-14-2011 at 02:15 PM.
02-14-2011, 02:55 PM
#52
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I agree that hybrids have a particular use for EWPs, but I think the rotary is still in need of such technology. However, for the crazy people looking to implement this on their own, I would recommend doing an electric thermostat first.
The EWP offers the advantage of increased flow at low speeds and flow when the engine is off, both of which are great. However, with the current thermostat in there, as you increase flow with an EWP, the coolant will cool off and thereby close the thermostat, which means you're just pumping coolant around the engine. Not running a thermostat is nice in theory but has too many disadvantages to be practical IMO.
To me, the best starting point is an electric thermostat with a MWP. You won't have control over the rate of coolant flow, but you would be able to control exactly how much goes through the radiator. With more advanced fan control, this offers the possibility of making the cooling system very dynamic and able to adjust to a wide variety of ambient temperatures and operating conditions. With this, the days of blocking your radiator in cold weather would likely be gone.
Also, an electric thermostat is much less invasive. No need to mess with readjusting the belts to account for the MWP being gone and design a motor to be able to fit in the available space. Also, if a diverter valve is implemented, a rotary encoder could be placed on the rotation axis of the valve to ensure the thermostat is operating and provide a substantial amount of failure detection.
Of course, a controller would be needed, but the algorithm implemented could be relatively simple. Start with just coolant temperature and adjust the diverter valve based on that. Then implement an adaptive diverter valve position algorithm to analyze ambient temperature and coolant temperature and predict what the valve position should be, then use direct feedback from the coolant temperature to adjust the prediction based on if the engine is too hot or too cold, thereby providing system feedback if your predictions are wrong as well as data for the adaptive algorithm to adjust its future predictions on actual driving data.
While this sounds complicated, I have implemented such algorithms, specifically in the area of real-time noise cancellation, and can attest that it is very realistic to build such a controller.
The EWP offers the advantage of increased flow at low speeds and flow when the engine is off, both of which are great. However, with the current thermostat in there, as you increase flow with an EWP, the coolant will cool off and thereby close the thermostat, which means you're just pumping coolant around the engine. Not running a thermostat is nice in theory but has too many disadvantages to be practical IMO.
To me, the best starting point is an electric thermostat with a MWP. You won't have control over the rate of coolant flow, but you would be able to control exactly how much goes through the radiator. With more advanced fan control, this offers the possibility of making the cooling system very dynamic and able to adjust to a wide variety of ambient temperatures and operating conditions. With this, the days of blocking your radiator in cold weather would likely be gone.
Also, an electric thermostat is much less invasive. No need to mess with readjusting the belts to account for the MWP being gone and design a motor to be able to fit in the available space. Also, if a diverter valve is implemented, a rotary encoder could be placed on the rotation axis of the valve to ensure the thermostat is operating and provide a substantial amount of failure detection.
Of course, a controller would be needed, but the algorithm implemented could be relatively simple. Start with just coolant temperature and adjust the diverter valve based on that. Then implement an adaptive diverter valve position algorithm to analyze ambient temperature and coolant temperature and predict what the valve position should be, then use direct feedback from the coolant temperature to adjust the prediction based on if the engine is too hot or too cold, thereby providing system feedback if your predictions are wrong as well as data for the adaptive algorithm to adjust its future predictions on actual driving data.
While this sounds complicated, I have implemented such algorithms, specifically in the area of real-time noise cancellation, and can attest that it is very realistic to build such a controller.
02-15-2011, 08:12 AM
#53
rjon----that may be another option? the coolant sensor could drive the fans. Matter of fact some aftermarket gauges have that capability and of course the Cobb unit you can do whatever to the fans. The S2 model has updated and more efficent fan package with 3 speeds.
Hmmmm --for street driving it may be best to change one thing at the time?
1st--thermostat idea with more precise fan control?
2- use ewp as acessory pump for low speed use only?
3- computer controlled ewp?
WHat do yall think--other than I am completly crazy and need to get laid more often?
Hmmmm --for street driving it may be best to change one thing at the time?
1st--thermostat idea with more precise fan control?
2- use ewp as acessory pump for low speed use only?
3- computer controlled ewp?
WHat do yall think--other than I am completly crazy and need to get laid more often?
02-15-2011, 09:41 AM
#54
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Getting laid more often cannot hurt 
As for the EWP, I think for the RX8 it adds unneeded complexity and another unnecessary failure point. I like the idea of an electric thermostat but i will have to research that bit. I can say that changing the fan controls VIA the Cobb seems to have worked for me but we will see once the hot weather comes.
As for the EWP, I think for the RX8 it adds unneeded complexity and another unnecessary failure point. I like the idea of an electric thermostat but i will have to research that bit. I can say that changing the fan controls VIA the Cobb seems to have worked for me but we will see once the hot weather comes.
02-16-2011, 10:04 AM
#55
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Though it's generally more expensive than modding cars. 
02-17-2011, 10:03 AM
#57
The EWP offers the advantage of increased flow at low speeds and flow when the engine is off, both of which are great. However, with the current thermostat in there, as you increase flow with an EWP, the coolant will cool off and thereby close the thermostat, which means you're just pumping coolant around the engine. Not running a thermostat is nice in theory but has too many disadvantages to be practical IMO.
Additionally, on cold winter days, even if the coolant is only 170F I want coolant flowing so my heater works!
On the other hand, having noticed heating issues last Summer when I was stuck in stop and go traffic after hours of highway travel, and again last Autumn when I was in a funeral procession that hopped on the highway, forcing me to pretty much stay in third gear or lower the whole way from Brooklyn to the Long Island, keeping the car in front of me in the procession close by to keep some jerk from cutting me off despite the Funeral stickers in our windows and our lights and hazard lights being on.
In the Summer situation, my engine temperature reached 245F according to my ScanGuage II. I had already converted to Evans coolant, which I think is the reason my engine didn't die right then and there. Coolant temperatures had been fine while I was on the highway.
Please note that I have the original OEM pump, and I think it is perilously vulnerable to cavitation, which is another advantage of a constant speed electric coolant pump.
I will either convert to a REmedy coolant pump or an EWP when the weather warms up, to try to keep those troubles at bay.
Last edited by longpath; 02-17-2011 at 10:06 AM.
02-18-2011, 07:42 AM
#58
One thing I realized as I was researching Evans coolant was that in an ideal situation one of the tasks of coolant is to even out temperatures in the engine, not merely shed temperature from where it's hottest. This is one reason I wish that our engines flowed coolant from the bottom to the top (kind of like what you have in a reverse coolant flow piston engine). That being said, I would want coolant flowing full time, whether the thermostat was open or not.
02-18-2011, 08:22 AM
#59
Uh ----no. That burp hole doesnt allow any flow. How do I know this?
Mount a coolant sensor in your top radiator hose using the oem thermostat. You will be surprised how long it takes for that sensor to start recording any warm temps. Now the oem sensor is in the thermostat housing and records the by pass temps also so it reacts much faster at warm up.
Remedy ---- drill two 3/16 holes in the thermostat lid. I discovered this a couple years back when I was figuring out the best way for me to use the second radiator set up.
Point made earier about the fans. That was a good thought and I highly recommend the 09 fan upgrade to the S1 cars.
Wow Evans allowed you to survive with coolant temp of 245F!!
OD
Mount a coolant sensor in your top radiator hose using the oem thermostat. You will be surprised how long it takes for that sensor to start recording any warm temps. Now the oem sensor is in the thermostat housing and records the by pass temps also so it reacts much faster at warm up.
Remedy ---- drill two 3/16 holes in the thermostat lid. I discovered this a couple years back when I was figuring out the best way for me to use the second radiator set up.
Point made earier about the fans. That was a good thought and I highly recommend the 09 fan upgrade to the S1 cars.
Wow Evans allowed you to survive with coolant temp of 245F!!
OD
02-18-2011, 12:21 PM
#61
Uh ----no. That burp hole doesnt allow any flow. How do I know this?
Mount a coolant sensor in your top radiator hose using the oem thermostat. You will be surprised how long it takes for that sensor to start recording any warm temps. Now the oem sensor is in the thermostat housing and records the by pass temps also so it reacts much faster at warm up.
Remedy ---- drill two 3/16 holes in the thermostat lid. I discovered this a couple years back when I was figuring out the best way for me to use the second radiator set up.
Mount a coolant sensor in your top radiator hose using the oem thermostat. You will be surprised how long it takes for that sensor to start recording any warm temps. Now the oem sensor is in the thermostat housing and records the by pass temps also so it reacts much faster at warm up.
Remedy ---- drill two 3/16 holes in the thermostat lid. I discovered this a couple years back when I was figuring out the best way for me to use the second radiator set up.
02-18-2011, 07:18 PM
#67
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02-18-2011, 09:26 PM
#69
Oh that not even the worst of it. Stack 2 boxes on top of the fans--then you have a good picture.
Better fans are great but you have to clear the stuff out from the back of them for them to work well.
Do that and then the hot air is not redirected under the car---its shot right into the engine bay. At low speed/normal city stop light driving--thats a LOT of heat. To help with that low speed problem you will need a properly vented hood.
So instead of all that --just add the secondary radiator up front in a position to get good air flow.
It works and i think with the mentioned additions it just may be the best coolant temp control we can get.
Better fans are great but you have to clear the stuff out from the back of them for them to work well.
Do that and then the hot air is not redirected under the car---its shot right into the engine bay. At low speed/normal city stop light driving--thats a LOT of heat. To help with that low speed problem you will need a properly vented hood.
So instead of all that --just add the secondary radiator up front in a position to get good air flow.
It works and i think with the mentioned additions it just may be the best coolant temp control we can get.
02-18-2011, 09:37 PM
#70
I do run a vented hood which helps (even though a lot of people say it doesn't). But I have been able to keep the engine temps down one mod at a time to much more reasonable temps. With one radiator, improved fan, and by opening up the back of the oil coolers.
02-19-2011, 03:34 AM
#73
Super Moderator
Wonder if you put a 7 blade fan on (same as the other 7 blader, so you have two 7 blade fans), would help..
AS far as EWP, no experience there for me..
AS far as EWP, no experience there for me..
02-20-2011, 07:35 AM
#74
If one did that, don't expect 2x the airflow. First, you're blocking air with the front fan mechanism. Second, from the aviation world anyway, the corkscrew rotation started by the first fan tends to make the second less efficient. Here too, that twist will cause the airflow to be misaligned with the straight radiator fins which will increase flow resistance. Overall, it might help some, but there are better solutions IMHO.
02-20-2011, 08:46 AM
#75
you know after pondering on this for a little while (he) the best set up may be:
1- a more sensitive electronic thermostat with multistage fan control
2- axillary electric pump
3- stay with antifreeze water as the coolant.
Here are my thoughts.
let me preach on it!!!!!! Can I hear an "Amen!!"
I hear something but it is not that
Ok--- the weakness in our oem cooling system seems to be at the low speed, stop and go situations for most of us, or for those unlucky bastards living in the desert states the extreme temps. I choose not to speak about the demands of tracking the car as that is a different world.
AIR FLOW is king when it comes to cooling. Right? So number 1-- better control over high output fans will certainly be of help.
To take advantage of the increased air flow available with the fans, the idle and low speed coolant flow could stand to be increased---so the small ancillary exp that operates only during those times.
Stay with water antifreeze for the simplicity and familiarity. Evans is great stuff but on the street i dont think it will have that much advantage once a better cooling system is in place.
From looking at the options that I am aware of, it looks like the cost would be around $500-$600?
Worth it--for some yes, for all---dont know.
OD
1- a more sensitive electronic thermostat with multistage fan control
2- axillary electric pump
3- stay with antifreeze water as the coolant.
Here are my thoughts.
let me preach on it!!!!!! Can I hear an "Amen!!"
I hear something but it is not that
Ok--- the weakness in our oem cooling system seems to be at the low speed, stop and go situations for most of us, or for those unlucky bastards living in the desert states the extreme temps. I choose not to speak about the demands of tracking the car as that is a different world.
AIR FLOW is king when it comes to cooling. Right? So number 1-- better control over high output fans will certainly be of help.
To take advantage of the increased air flow available with the fans, the idle and low speed coolant flow could stand to be increased---so the small ancillary exp that operates only during those times.
Stay with water antifreeze for the simplicity and familiarity. Evans is great stuff but on the street i dont think it will have that much advantage once a better cooling system is in place.
From looking at the options that I am aware of, it looks like the cost would be around $500-$600?
Worth it--for some yes, for all---dont know.
OD