Using an EWP as an auxiliary pump to the mechanical

[Joel K]

Hi everyone,

I thought I would throw this question out there and see what other builders think. I am finalizing the rear cooling tube design and wondering if it would be prudent to incorporate an EWP as an auxiliary pump to the mechanical pump.

After speaking with Davies Craig, you can control their 150EWP with a PWM signal so it makes it easy to add as little or much additional circulation to a cooling system. I am planning on using a PDM for electrical and the PWM feature for the brushless radiator fans. So I figure it is easy to incorporate an algorithm for an auxiliary EWP. Also, the mechanical pump can pump through an idle EWP so I guess there is really no downside.

I’ve read many of the EWP and overheating threads and it sounds like an EWP system with the mechanical pump removed works really well. And also, if a mechanical only system is designed well, it should not need an auxiliary EWP although there are a number of threads where an auxiliary was added to help with cooling at low RPM.

At this point, I do not want to disassemble the mechanical pump from The water pump housing. it is a supercharged engine and I need the housing for all the accessory pulleys. It’s a crate engine and also just don’t want to mess with it.

So anyway, looking for some opinions on this.

Thanks as always for the feedback.

 

[Alan P]

I contemplated adding an EWP to mine, ensuring it was located at a low point in the system, to help with priming and getting the air out. I don’t see a downside to having one if you have the space.

 

[Alex]

If you plumbed your mechanical pump properly there's no reason for you to have cooling issues.

 

[Scott]

I removed my water pump which has a lot of advantages for a supercharged engine (i.e., you can run a massive super damper), but it's a lot of work. A simpler option is to remove the impeller on the mechanical pump. I know it's been done on LS pumps, but I'm not sure about LT pumps.

If you're going to go with an electric pump, I'd go with a Pierburg. I looked at Davies Craig, but I could never get comfortable with their specs (less of a concern if it's just auxiliary). Pierburg was the world's first series-production supplier of an electric coolant pump so they've been doing it longer than anyone. The pumps are manufactured in Germany and are OEM equipment for BMW and others. They have a brushless motor and an integrated variable speed controller which can be controlled via a PWM signal. They are the go-to pump for Agile Automotive who has built multiple endurance SL-Cs and I know that they've been used in higher race classes as well. Nothing against Davies Craig, but Pierburg pumps probably do more hours in a day on daily drivers than Davies Craig do in a decade and they've been proven in race applications.

I'm not aware of anyone who used a Pierburg in an auxiliary capacity, but I don't see why it wouldn't work. I'd run your application past Tecomotive.

 

[Joel K]

Thanks guys, appreciate everyone’s feedback.

 

[Paul Hendrickx]

I removed my water pump which has a lot of advantages for a supercharged engine (i.e., you can run a massive super damper), but it's a lot of work. A simpler option is to remove the impeller on the mechanical pump. I know it's been done on LS pumps, but I'm not sure about LT pumps.

If you're going to go with an electric pump, I'd go with a Pierburg. I looked at Davies Craig, but I could never get comfortable with their specs (less of a concern if it's just auxiliary). Pierburg was the world's first series-production supplier of an electric coolant pump so they've been doing it longer than anyone. The pumps are manufactured in Germany and are OEM equipment for BMW and others. They have a brushless motor and an integrated variable speed controller which can be controlled via a PWM signal. They are the go-to pump for Agile Automotive who has built multiple endurance SL-Cs and I know that they've been used in higher race classes as well. Nothing against Davies Craig, but Pierburg pumps probably do more hours in a day on daily drivers than Davies Craig do in a decade and they've been proven in race applications.

I'm not aware of anyone who used a Pierburg in an auxiliary capacity, but I don't see why it wouldn't work. I'd run your application past Tecomotive.

HI,
Try out these guys, the provide the pilot unit with the pump

Tecomotive - tinyCWA

Tecomotive develops and sells unique electronic devices for use in vehicles of all kinds.

www.tecomotive.com

Paul

 

[Dusty]

Id test the car first before adding the pump. if I used an EWP id get rid of the mechanical pump

 

[Julian]

The downside of a mechanical pump is volume is dependent on engine rpm, that can be solved to an extent with pulley ratios, but then many will cavitate at higher rpm. There's a lot of piping and flow resistance in a mid engine application with radiator up front for a mechanical suction pump and I personally believe an electric booster pump can add value for stop start traffic overheat situations. Not all electric pumps can operate as a booster as you want a flow through design that won't impede the mechanical pump when the former (booster) is not called to run via PWM signal. Davies Craig is flow through, however, Meziere is not, I am not familiar with the Pierburg pump design.

 

[Dusty]

That reasoning makes sense and car builds like these are a kind of big kid science projects where Ideas are tested. …But this EWP idea smells potentially like over engineering. I would hope that the combo of a proper radiator and a proper pair of fans would keep these cars cool even on hot days in traffic. I don’t have any windows in my car and I live in the San Joaquin valley so this topic is important to me.
I personally would rather not spend time developing radiator ducting and long time consuming thermal management experiments. If this EWP idea is a way to make the radiator work much more effectively then I’m all In

 

[Howard Jones]

Dusty, It will make absolutely no difference what pump you run if you can't efficiently produce sufficient airflow and coolant volume through an adequately sized radiator. This is where all the "big kid" "science projects" and "over-engineering" have come in.

However. Here is a video from Stewart Componites racing water pump website that I think can be interesting, Note: it is a flow-through design like the Davis Craig.

I am considering using one of these up at the radiator inlet in series with my Davis Craig EPW150 (located back at the engine inlet) and the DC controller. I intend to run the Stewart pump continuously on with a relay and temp sensor that is actuated by the power on switch for the Davies Craig pump. This will allow the DC controller to fine-tune water flow/coolant temp with the EPW150 while the Stewart pump provides baseline flow.

The on temp for the Stewart pump would be set at a very low temp like 125F, then the coolant temp target for the DC controller can be selected to be 185F. This way the Stewart pump will run all the time and the added flow from the DC pump can fine-tune overall coolant temp to the 185F target.

I believe that the EWP150 is running near full-on when the car is tracked on very hot days as the coolant temp can creep above target at the end of a session. Since I believe I have optimized the rest of the system it appears a little more total flow is needed at the limits of the current system. I see approx 200F at the extreme with a target coolant temp set to 185F. This is not really bad but it leaves very little margin at the limit of the system performance envelope.

Early on I was struggling with coolant temp approaching 245F on hot but not extreme ambient temp summer days. That was before all the science projects.

https://www.stewartcomponents.com/

 

[Neil]

Remember that increased coolant flow won't help unless you also have enough air flow through the radiator to carry away the heat.

 

[Alan P]

Increasing the flow rate will increase the Reynolds number, therefore making the heat transfer more efficient and allowing the same amount of air to carry away more heat. Obviously more air is better than a higher Reynolds number, but the flow rate does help.

 

[Neil]

Air flow through the radiator is where the heat from the coolant is transferred to. Reynolds number of the coolant flow is effective to transfer the coolant heat to the radiator fins; without sufficient air flow over the fins to dissipate the heat, the radiator and coolant temperature simply increases.

 

[Joel K]

Guys, thanks for all the input. At this point I think I’ll stick with the mechanical only solution and see how it does once I get to go cart and put the body on and let it idle. I have upgraded fans, a full shroud and planning on a heat extractor in the hood so hopefully that works. Also planning to do Howard’s mod to the front clam which directs air into the radiator.

The Gen V LT4 engines are known to run on the hot side so that is where my concern is.

 

[Dusty]

In the world of rockcrawlers/rock racing (only world i know) overheating is a constant thorn. Ultra 4 race cars (rock racers) have powerful v8s (mine is underpowered by current standards at 500hp) that find themselves working really hard in a car that is often moving really slow. Motors and trannies (torque converters) are making tons of heat and there is no wind to take it away. there is rarely much of a fan shroud as the engine bay is open. in my case the motor is in back and the radiator is behind my head-no shrouding at all.

The problem is solved by using big radiators with big fans. the radiator on my racer is twice the size of the ones in the superlight. right behind both of the seats is a tranny radiator with an electric fan. I have a 210 amp alternator. As long as the fans are running the heat is directed away from the seats. if the tranny fans die the seats will fry.

I really cant see how the little radiator in the superlight cools these cars

 

[Frank Clark]

Just saw this post. I use the Davies EWP150 *and* an a Davies EBP23 pump. I am currently running a Toyota 1UZ, turbo charged with water cooled turbo and waste gates. For a while I was running a Water to Oil Oil cooler as well. Mine is currently setup as:

Booster pump runs with ignition and pulls from engine then pushes through turbo/wastegates/oil cooler(when installed) then through a small side mounted radiator.

Main pump is in the front foot box right by the radiator inlet. Uses one of the Davies rubber mounts. It is run PWM from the ECU. Factory WP blades are removed and system has no thermostat. ECU runs the pump as needed to maintain desired water temp.

Oil cooler is now oil/air with a fan to move the air.

All the above was with discussions with Davies Craig and I reviewed the setup and results with them at PRI this year.

So the booster pump insures there is always circulation in the engine and I could after run it if desired (I don't). You could do the same by putting the booster pump on the heating circuit. This engine has custom water fittings front to back so no heater circuit/manifold heat/etc.

Prior to this, I have always had overheating issues. Car could not sit at idle for an extended period of time and temp was border line when at speed for an extended period of time (150+ for minutes on end). Now the main pump never hits 100% and I can easily hold the temp at 180 if desired.

Car has RCR provided radiator and fans. Simple aluminum fan shroud and footbox is sealed to the body (so all air coming in goes through the radiator. The side radiator is off a 1000cc ATV. I have blocked off the side radiator with carboard some times to help get heat in the car quicker - it still controls the temperature well with the side one blocked.

I do recommend the electric pumps, especially if you can control it with your ECU (deleting thermostat).

I am not sure how much the electric pumps fixed my cooling issues and how much additional coolers fixed it. If you are having cooling issues, I'd probably suggest an oil cooler as the first step.

 

[Rob]

Back to the original discussion about running a mechanical pump and an ewp as a booster, would the mechanical pump not inhibit flow from the ewp under low rpm situations? if so you just end up with pressure build?

 

[Julian]

Back to the original discussion about running a mechanical pump and an ewp as a booster, would the mechanical pump not inhibit flow from the ewp under low rpm situations? if so you just end up with pressure build?

I think the video Howard linked in post #10 should answer the question, but remember 1. for pumps operating in series the head (differential pressure) is cumulative. 2. the typical automotive mechanical water pump is not a sealed impeller so some flow by can occur.

 

[Russell]

Hi everyone,

I thought I would throw this question out there and see what other builders think. I am finalizing the rear cooling tube design and wondering if it would be prudent to incorporate an EWP as an auxiliary pump to the mechanical pump.

After speaking with Davies Craig, you can control their 150EWP with a PWM signal so it makes it easy to add as little or much additional circulation to a cooling system. I am planning on using a PDM for electrical and the PWM feature for the brushless radiator fans. So I figure it is easy to incorporate an algorithm for an auxiliary EWP. Also, the mechanical pump can pump through an idle EWP so I guess there is really no downside.

I’ve read many of the EWP and overheating threads and it sounds like an EWP system with the mechanical pump removed works really well. And also, if a mechanical only system is designed well, it should not need an auxiliary EWP although there are a number of threads where an auxiliary was added to help with cooling at low RPM.

At this point, I do not want to disassemble the mechanical pump from The water pump housing. it is a supercharged engine and I need the housing for all the accessory pulleys. It’s a crate engine and also just don’t want to mess with it.

So anyway, looking for some opinions on this.

Thanks as always for the feedback.

 

[Russell]

Re original + an EWP 150 pump. Just joined and am having trouble keeping my RF GT40 cool in 30 deg C days. Long story but I have blocked the sides bottom and top of the rad. Have added a shroud to the dual 1560cfm Maradyne fans. 347W with a Edelbrock pump and just added a EWP150 pump. New high flow 71 deg C thermostat. Now, it still creeps over 100 deg C standing still with the AC on. It has standard nostril outlets that only go half way down to the center of the rad fan motors. So it all sounds good but here's the kicker!! The rad core that was specially made by the previous owner while a very reputable brand is 81mm thick! It may as well be a block of wood in my opinion. Then there is a 25mm AC condenser covering 3/4 of the rad as well!! So I'm going to cut the side and bottom flanges off the nostril outlets and try to add some aluminum extenders to deepen the nostrils and add a central v shaped deflector. Trying to do this without modifying the nostril floors for now. I think the issue is getting the air out, and through the wheel wells doesn't work. Am I on the right track? Cheers