I'm planning a major re-work of my whole engine bay and one of the items on the list is adding in an EWP setup similar to the ones in this photo.




I'm most interested in doing an AN water manifold similar to the ones in this photo. I've seen a few options from various sellers, but that's the easy part. I'm trying to wrap my head around the routing of the lines. I want to run a Meziere remote pump setup, likely the 55GPM unit or similar with AN lines throughout the whole system. There are a few thing's I'm not sure about when it comes to the routing.

I attached 3 photos here for the 3 ideas I thought it maybe. (Yes, I'm an artist)

Picture 1 is no thermostat.



Picture 2 is an in line thermostat with no bypass.




Picture 3 is a thermostat with a built in bypass.


Are any of these the correct setup. Obviously, you'd be deleting the thermostat, or at least the stock setup. Meziere offers a pump with a built in thermostat, but it's extremely expensive. On a track car or similar situation, obviously this isn't really an issue but on a street car, how do you go about warm up? I've read that even running these pumps with minimum PWM settings can lead to over-cooling in cooler climates (I'm in Colorado), and you obviously can't turn it off completely, otherwise you'd be dealing with hot spots, etc.

Any input or guidance would be appreciated!

 

two suggestions: First is to put the pump down low. part of why the stock setup is so finnicky is the the pump is on top, so if there is any air in there, the pump doesn't work very well
Second, the stock setup, in fact every belt driven water pump has a bypass because the pump always runs, so its always pumping water, its just not always going through the radiator.
so bypass or not depends on if you run the pump with the thermostat closed or not, i guess.

and third, Fiat/Lancia used a remote thermostat, its got 38mm hoses, which is the same as the Rx7's, not sure if its the best way to go, but it exists. and price is right

 

You will get over cooling on a street car without a thermostat! PWM does help but it still will over cool when it is cool out. Also lowering the PWM to the point the pump turns off is simply not a good solution. Getting good flow through the block with a controlled floor temperature is certainly the best solution. PWM should still be used. Picture 3 looks correct to me for using a thermostat with bypass.

Here is my thread on the subject. https://www.rx7club.com/3rd-generati...ostat-1160552/

A few things I played with that I did not update in the thread above was using thermostat restrictor plates. I experimented with all 3 sizes with PWM. The smallest size did help a bit but in colder weather it just is not going to work. I can see the restrictor plates helping a ton on a track car! I also experimented with different thermostats that do not "officially" fit the Meziere remote pump. Living in AZ, the summers are very hot and the North Star thermostat that is meant to fit the Meziere pump is a little too warm in the AZ summer. I was able to modify a LS3 160 thermostat to fit perfectly in the Meziere pump which works great for me year-round.


Also, I will say having a high fill point is not going to be a bad thing. The setup you posted is super clean but bleeding the coolant system without burping the car is simply not going to happen. 100% fake news on bleeding the car without heat cycling it! You can get a lot of the air out by running the pump with the car off but there is no way it will completely get all the air out of the system. I still have to burp my car through 2 heat cycles to get all the air out.

Last thing to note, supposedly sakebomb garage is developing an EWP kit with a thermostat. If this is true that would for sure save you a ton of fab work, which is not at all straight forward.

 

I got my hands on one of these. It retains the function of the oem thermostat and just replaces the pump and cover to the oem assembly. Looks like a good way to prevent over-cooling while having a simplified hose routing method to the EWP itself. No external thermostat to mount and such.

Sakebomb Garage EWP adapter

 

Thanks for the input! I thought that option 3 was probably my best bet, if I could get ahold of one of the water manifolds that includes a filler neck.

 

I'm keen to see how this is meant to be plumb up and retain factory thermostat and bypass functionality. It is not immediately obvious how this would work. Wouldn't it also require side mount alternator because the inlet/outlet hoses are now in the way of the belt path?

It is not simply a matter of having an inline thermostat. You need a way to bypass the coolant back though the block when the thermostat is closed. The OEM system was designed that way for a reason.

When you move the position of the water pump to outside of the water pump housing, the bypass becomes a challenge with plumbing, because the bypass return has to be immediately upstream of the EWP in order to form a circuit so coolant flows through the bypass effectively.

I explain the issues and the challenges an EWP creates when trying to ensure consistent cooling through the block in this thread: https://www.rx7club.com/3rd-generati...-flow-1110563/

 

This plate just interrupts the path that the pump occupies. so all of the other parts (oem filler neck with inlet and outlet and the section the pump plate bolts onto) remain in place, so the internal suction side/inlet to the pump now goes to the inlet of the EWP, and then the internal outlet from the oem pump is now a hose input from the EWP outlet. The hoses to and from the radiator remain in place. I'll have to get mine installed before I can comment on belt routing. I absolutely agree that some flow at all times is ideal to avoid hot spots.

 

Ah yes, got it now and it makes sense! That could a very nice simple way to solve this problem.

 

I spent a bunch of time battling this solution, to include a custom machined remote thermostat housing that resembled a larger version of the inline improved racing thermostat. I am definitely happy to try this SBG solution for sure. Just for the simplified scenario.

 

Keen to see how it goes! Is there some kind of baffling behind to keep the flow path going entirely through the EWP from the inlet/outlet pipes?

I assume you will you be side-mounting the alternator, or is there scope to get the hoses fitting behind or around the alternator belt?

 

In the LS community there have been a lot of failures of the meziere pumps and I personally feel that they’re garbage as I’ve had one fail after 6 months of light daily driving and the replacement lasted about the same amount of time. I changed over to the CWA 400 with a tecomotive controller and have had it for 3 years without issues. BMW uses it as an oem water pump and it’s an absolute beast if you turn it up.




https://tecomotive.com/en/products/CWA400_PWM.html

 

I would also take a hard look at WHY you want to do this. On a street car, this is crazy overkill - it adds complexity and failure points and the stock thermostat/water pump setup works VERY well and is VERY reliable.

Dale

 

I agree the stock setup is fine, but here are 7 reasons why you would want to do this on a street car:

1. Mechanical pumps run at a speed fixed to rpm and not at the actual demand required at that moment. They therefore run too fast under some conditions, ie high rpm, and cavitate. When it cavitates, it is not pumping any coolant through the system. At low rpm, they may not run as fast as the system need at that particular moment. Electric pumps run at the optimum speed required at that point in time under all conditions.
2. The mechanical pumps sap a noticeable amount of torque, which increases as engine speed increases. When I first did one of these conversions of my old 12A, I picked up 10rwhp from the conversion at 7500rpm. That may not sound like much, but consider this: you are picking up that power under ALL load conditions/throttle positions. The mechanical water pump drag is fixed by rpm and doesn't care what your throttle position is. So, under low throttle conditions, you are still getting back 100% of the power consumed by the mechanical pump by switching to electric as you would at wide open throttle. This will definitely save on fuel and makes everyday driving noticeably better. You can experience in real time what the difference is. Cruise on the freeway with AC on vs AC off. Also do the same going uphill. In the latter scenario in particular, the low torque rotary engine needs every advantage it can get. I wager the water pump requires more power to drive than the AC just based on the task it has to perform and unlike the AC which switches off automatically at 3,000rpm, the power consumed by the mechanical water pump increases the higher you rev. According to Davies Craig, power requirements on the mechanical pump increase as a cube of the increase in engine speed. On a 13B peaking over 8,000rpm, that is going to be significant enough to make the exercise worthwhile. Yes, there will be an additional load on the alternator to drive the electric pump, but at max load the Davies Craig EWP only uses 10A. It is rarely going to be running at full speed and even then 10A is nothing in a modified EFI car. 10A is the exact current draw from two 55W bulbs at 12V.
3. While early electric pumps were limited, modern electric pumps have a higher flow rate than the factory mechanical pump (especially at lower rpms where you actually need it most, ie low vehicle speed / high load conditions).
4. When set up properly with the thermostat and bypass, warm ups times are significantly reduced on the electric setup. I didn't do back to back measurements, but I would reach operating temp very quickly after startup with the electric setup compared with factory. This is because the algorithm for the electric pump during the warmup phase uses quick intermittent bursts just to very slowly circulate coolant rather than constantly circulating at full speed like you have with a mechanical pump. Of course if you don't use a proper bypass setup, the reverse is true and warmup times increase significantly over the factory setup. This is why I recommend using a thermostat with bypass with the EWP.
5. You can run an electric pump with the engine off allowing you to avoid heat soak after shutdown. This is a significant advantage on its own, particularly on an FD as anyone who has heard the coolant girgling with the car off can attest to.
6. An EWP setup can be significantly lighter. The EWP itself is about 1/5th the weight of a water pump for the Davies Craig one, but you do have the ability to ditch the whole water pump housing. There is about 5kg (11lb) to save with the right setup.
7. The belt configuration on the FD is complex. There is minimum belt contact and a high tendency to slip by running the mechanical pump in reverse and the back of the belt against the pulley. This is further complicated if you delete the air pump. Air pump delete plus water pump delete means you have a straight belt run from crank to alternator and zero slippage. Then you also have the flexibility to side mount the alternator (for example sitting it where the AC compressor would go) cleaning up the whole front of the engine greatly. So, yes, the EWP setup does add complexity in plumbing and electronics, but it also simplifies things in other ways.

 

Thank you for the great reply.

I agree with Dale that for most people using street cars, an electric pump IS overkill... but there are a lot of things that we do overkill on these cars. In my opinion cooling (one of the biggest weaknesses of our cars) is one of the things that has the best rational for doing the overkill approach. Id rather have an underpowered car that goes overkill on cooling, than an overpowered car that runs too hot.

 

I will be doing an ewp on my car because it will look cool to delete the water pump housing and side mount the alternator. Sometimes this is the only thing that matters. A heavily modded street FD cannot be justified financially or practically so why use logic when making decisions with what to do with it?

 

Could someone explain/show how this works on the car? It looks like bolts to the water pump housing in place of a water pump, but with the two large hose outlets, presumably that's where the two large radiator hoses route to, so what do you do with the old lower hose outlet on the water pump housing? Plug it? And how does this impact the thermostat housing (which has one of those outlets).

 

Talked w Heath @SakeBomb Garage. He explained that the two ports on their adapter are simply for inlet & exit to the remotely installed EWP. Think of it as OEM+, where the stock thermostat continues to do its thing. And the SBG adapter, connected to the EWP, simply replaces the hydraulic function of the mechanical water pump; all other housings & hoses remain intact, functioning as-is.

The plus factor is the ability to regulate water flow according to temperature instead of engine rpm speed. And obviously, the other big plus of circulating water throughout the engine internals after shutdown.

 

So it's literally an in and out to the EWP, and the standard pathways from water pump housing to radiator and back remain in tact?