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hozzziii

Electric water pump routing

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Hello everyone

My first post here, hopefully first of many

I've been doing some research about a project I'm currently planning, and I have noticed that the good people here have a very deep understanding of the engine I'm working on, so I'm asking the question here. 

I have an E30 with the M10 engine, and I'm planning to do turbo upgrade to it in the future, currently I'm reading everything I find, I learned a lot from the megasquirt efi build on the faq here. 

I live in a very hot climate, and currently with the stock radiator and waterpump, my car cannot sustain "spirited driving" in this hot summer, or even long distance casual cruising between cities. Not that it has blown up or anything, just that the temp gauge goes a lot higher than it should. 

So, while planning the turbo build, I have decided to get a turbo with oil AND watercooling, to extend the life of the turbo. With this choice, I have also decided to get a bigger radiator, electric fans, and also electric water pump. 

And we arrive at the question of today: what is the actual route of coolant in this engine?

I'm asking this because I want to erase the mechanical water pump, and get the electric, so it moves more water, and can also keep cooling the engine, while it is off; I've noticed the temp goes high after turning it off, because of the heat soaking effect I'm told. 

So, where do you think I should put the electric pump? 

Also second question, I'm going to control this pump with the ecu, that is going to decide pump load based on engine coolant temp, so if it's cold, it wont run, if it's a hot day, it will keep running even after the engine is off, so I don't think I need the regular thermostat anymore, am I correct?

Also based on what I can see from looking at the engine, I have drawn a very, very, simple diagram as to how it looks, but I haven't figured out the direction of the coolant flow, so, maybe you can help me out. 

Thank you for your help 

IMG_20190709_200033.jpg

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(edited)

Also notice that on the thermostat housing I have drawn a circle where the actual thermostat blocks the coolant if its closed. 

So when it's closed, the coolant just keeps looping around the engine, am I right?

And also, next to the water pump, I pointed an arrow and I wrote, "Behind". That's becuase I have no idea where it goes, due to my lack of knowledge here. 

Edited by hozzziii

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The water flows from the water pump into the block (large rectangular port in the front timing cover behind the water pump).  The water then passes primarily through the block and up into the head at the back of the block (there are some small passages between the head and block the entire length of the block but the major flow comes up at the back)  it then flows through the head and out the top. 

 

You need to run the pump all the time even when it is cold to make sure you don't get hot spots while the entire system comes up to temp,  you should be able to do this without a thermostat and just throttle the pump down very low.  Take your temperature measurements in the stock location at the outlet at the top of the head and throttle the water pump based on that temp.  As such you can just come off the bottom of the radiator and go to the electric water pump then make an adaptor on the front of the engine to feed the water into the block in the stock location.  Come off the top of the engine and go straight into the radiator. 

 

Are you planning on running a heater?  If so you will need to run the stock hose from the back of the cylinder head to the heater control valve then from the other side of the heater core you will need a T fitting just ahead of the electric water pump (radiator side) and feed the water back into the system there (so you will get some flow through the heater).  If you are not going to run the heater just block off the water outlet fitting on the back of the head.   

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(edited)
6 hours ago, Preyupy said:

The water flows from the water pump into the block (large rectangular port in the front timing cover behind the water pump).  The water then passes primarily through the block and up into the head at the back of the block (there are some small passages between the head and block the entire length of the block but the major flow comes up at the back)  it then flows through the head and out the top. 

 

You need to run the pump all the time even when it is cold to make sure you don't get hot spots while the entire system comes up to temp,  you should be able to do this without a thermostat and just throttle the pump down very low.  Take your temperature measurements in the stock location at the outlet at the top of the head and throttle the water pump based on that temp.  As such you can just come off the bottom of the radiator and go to the electric water pump then make an adaptor on the front of the engine to feed the water into the block in the stock location.  Come off the top of the engine and go straight into the radiator. 

 

Are you planning on running a heater?  If so you will need to run the stock hose from the back of the cylinder head to the heater control valve then from the other side of the heater core you will need a T fitting just ahead of the electric water pump (radiator side) and feed the water back into the system there (so you will get some flow through the heater).  If you are not going to run the heater just block off the water outlet fitting on the back of the head.   

Well, I have two arguments here. 

First, the route you suggested makes perfect sense. I also thought I could just replace the thermostat housing with the electric waterpump and, like you said, feed the water into the block. However I think there is a problem here: the pump has two inputs, if we call the large rectangular hole on the timing cover output, one comes from the thermostat, the other comes from the right side of the engine. I've seen people run a long pipe from there almost to the back of the engine, is that the second input for the pump? Or is that the return path from the heater core? I can't see mine, it's just blocked by all the manifold and carburator and stuff. 

Second, yes I will be running a heater, I am actually. I'm confused, why do I need a T fitting after the heater? Can you elaborate? 

I had the heater blocked off because I was suspecting a leak in it, then changed the o-rings on the valve, and hooked it up. From what I saw, it has an inlet and an outlet that both go from and to the engine, am I mistaken?

Edited by hozzziii

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5 hours ago, hozzziii said:

...is that the second input for the pump? Or is that the return path from the heater core?

 

Well you can call it either since it comes from the heater and goes into pump. The electric pump doesn't have that second inlet like the mechanical pump that you're removing. Therefore you need the T to connect the heater return to pump inlet.

 

While removing the thermostat you also remove the hose that currently goes from top of the engine to thermostat.

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4 minutes ago, Tommy said:

 

Well you can call it either since it comes from the heater and goes into pump. The electric pump doesn't have that second inlet like the mechanical pump that you're removing. Therefore you need the T to connect the heater return to pump inlet.

 

While removing the thermostat you also remove the hose that currently goes from top of the engine to thermostat.

I totally agree with that second part. 

 

About your first statement, I thought that was the case. So I was thinking, maybe I can keep the return hose from the heater in the original location while also keeping the other end the same. But inside the original pump, I remove the blade and the pulley part outside, then weld a half pipe to make the pump housing act like a pipe! Therefore the heater outlet comes to the original location, goes through that half pipe, and inserts into the T at the new pump inlet, and merges with the radiator outlet. 

I know what you're thinking, what about the new pump outlet? Well, we can make a hole, right in front of that rectangular inlet in the block, and we're in!

Just have to make sure the flow of the heater outlet and the block inlet is completely seperated. 

And yes I have to block off the top of the block that went to thermostat housing. 

 

So, what do you think?

 

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I drew another diagram to make things simpler for myself to understand. 

Also to show off my artistic talent

 😆but please ignore my handwriting, I was excited. 

So you can see what I mean by the "Passthrough" arrows, utilising the both ends of the old pump, frankly I really like that idea, very neat location, and goes in front of the engine without making a mess. 

And also where I have to cut into the pump housing, I checked, its a clean area, I can cut through there, and make it the inlet. 

Don't think this will be an issue. 

IMG_20190711_155625.jpg

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I have also thought about using the pump housing as an adapter plate, but haven't actually done the electric pump installation. I was thinking to connect the electric pump between radiator and the inlet of the pump housing and just close the rest of the holes. To me it feels that while your idea would probably work it makes the whole thing a bit more complicated without real benefit.

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4 minutes ago, Tommy said:

I have also thought about using the pump housing as an adapter plate, but haven't actually done the electric pump installation. I was thinking to connect the electric pump between radiator and the inlet of the pump housing and just close the rest of the holes. To me it feels that while your idea would probably work it makes the whole thing a bit more complicated without real benefit.

Well this is the same plan, only I am keeping the heater. 

We have very cold winters where I live, it's not a question of should I keep the heater or not, I have to. I agree it makes it complicated, but you see the benefits of the electric pump too. 

I can't think of anything simpler than that. 

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The idea of removing the impeller and plumbing the electric pump into the old water pump inlet makes a good adaptor.  The problem with running the return from the heater core to the old connection on the mechanical pump is it is no longer a low pressure inlet to the pump (you are pumping water INTO that housing now) and you will not get any flow through the heater core because the pressure will be the same on both sides of the core. The return line must be connected on the inlet side of the electric pump ( the need for the T fitting) 

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The hose that currently runs from the water outlet at the top of the head to the T-stat needs to be blocked off at the head, remove the T-stat, run a hose from the bottom of the radiator to the electric pump and the outlet of the electric pump to the inlet of the old mechanical pump.  The outlet at the top of the engine goes directly to the top of the radiator. 

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39 minutes ago, Preyupy said:

The hose that currently runs from the water outlet at the top of the head to the T-stat needs to be blocked off at the head, remove the T-stat, run a hose from the bottom of the radiator to the electric pump and the outlet of the electric pump to the inlet of the old mechanical pump.  The outlet at the top of the engine goes directly to the top of the radiator. 

I will be doing exactly this. 

 

44 minutes ago, Preyupy said:

The idea of removing the impeller and plumbing the electric pump into the old water pump inlet makes a good adaptor.  The problem with running the return from the heater core to the old connection on the mechanical pump is it is no longer a low pressure inlet to the pump (you are pumping water INTO that housing now) and you will not get any flow through the heater core because the pressure will be the same on both sides of the core. The return line must be connected on the inlet side of the electric pump ( the need for the T fitting) 

I think I see where you may have misinterpreted my plan here, maybe I didn't clarify so well. 

I plan to run the two inlets of the old pump as the outlet of the heater, and while I have removed the impeller and pulley, I will weld a half pipe of some sort to the inside of the pump housing! Making the two inlets, just an aluminum pipe. This will make sure the flow goes directly from the heater outlet, all the way through the pump housing, into the new electric pump inlet (I will put a T in there to merge radiator outlet and that incoming hose). 

Also I will cut into the end of the pump housing, maybe weld a fitting in there too, straight into the block inlet and since the two old inlets are completely blocked off, I should be alright. 

Oh and let's not forget, I will also take a small hose off the electric pump outlet and run it to the turbo too, to cool the turbo as well. 

Haven't really decided where to route the turbo water outlet yet, might put it where the old second outlet at the top of the engine was, which we decided to block, could put the outlet there, straight into the rad. 

How does that sound Preyupy?

Think this will work?

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(edited)

On second thought, I don't think this is actually a great route to take 🤔

Because if you think about it, there will be a "stream" of coolant, that can go through the block, into the heater, and into the pump, back into the block. Hmmmph, that's a no-no.

I think maybe in order to make sure all of the coolant circulates the system without skipping the radiator, I should make sure the heater outlet goes to the rad. So I think I should modify the top housing on the engine, and put both turbo and heater outlet there, preferably before the temp sensor, to make sure the changes in temps caused by the heater or turbo are picked up by the sensor.

This feels like a better route to me. 

Any ideas? Thoughts anyone?

Edited by hozzziii

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1 hour ago, hozzziii said:

I will be doing exactly this. 

 

I think I see where you may have misinterpreted my plan here, maybe I didn't clarify so well. 

I plan to run the two inlets of the old pump as the outlet of the heater, and while I have removed the impeller and pulley, I will weld a half pipe of some sort to the inside of the pump housing! Making the two inlets, just an aluminum pipe. This will make sure the flow goes directly from the heater outlet, all the way through the pump housing, into the new electric pump inlet (I will put a T in there to merge radiator outlet and that incoming hose). 

Also I will cut into the end of the pump housing, maybe weld a fitting in there too, straight into the block inlet and since the two old inlets are completely blocked off, I should be alright. 

Oh and let's not forget, I will also take a small hose off the electric pump outlet and run it to the turbo too, to cool the turbo as well. 

Haven't really decided where to route the turbo water outlet yet, might put it where the old second outlet at the top of the engine was, which we decided to block, could put the outlet there, straight into the rad. 

How does that sound Preyupy?

Think this will work?

You need to pump water INTO the old pump housing to get it into the block.  The water flow to the heater core comes FROM the back of the head (this is hot water) through the heater core and then needs to go to a low pressure point in the system so you get some flow, you can't dump it into the top of the radiator because this is still a high pressure point in the system.  The lowest pressure point in the entire system is at the electric water pump inlet.  If you want to dump it back into the top of the radiator you will need a circulation pump for the heater (MB and Audi use them to make sure there is enough hot water flowing at low engine speeds) 

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