Pierburg CWA400 pump

[Paul Proefrock]

Does anyone know the BMW (or other mfg's) models that used the Pierburg CWA400 and if it was controlled by PWM, LIN or some other variant by BMW?

Seems Pierburg has thrown some wrenches into our sandbox.

1) The CWA400 no longer is controllable by PWM, since March, 2024. You can add a control adapter to convert PWM to LIN but that adds a few hundred dollars and more components and complexity to a build.

2) Pierburg is now offering a CWA400PWM but on close inspection, it appears to be based on the older CWA200 product and castings and the outlet is not clockable by modifying a notch. It is the three-bolt retainer version like the 200. To fit our toys, being able to clock the outlet is very desirable.

I can't imagine Pierburg turning away business for the older BMW, Mercedes, LandRover and others. But I don't know which models may have used the Pierburg CWA400 with PWM control. I am hoping by using a vehicle model or part number, I can find one of the older units on the shelf somewhere.

Anyone know the BMW line and which models I should be looking at?

Thanks

Paul

 

[Ken Roberts]

Here is the Pierburg CWA400 Tecomotive was previously selling (pwm). This is the non clockable version.

 

[Paul Hendrickx]

Tecomotive Store

tecomotive.com

 

[Paul Proefrock]

A little more research I learn the BMWs use the LIN bus, even back on the old models. The PMW feature that was deleted has no effect on the replacement market, it only impacts us 'hotrodders'. I'm hoping Pierburg will tell me the model or revision number that I can identify an older pump that still has the PWM circuitry. I want the newer 'clockable' output with the older PWM electronics. It will have to be a pump that has sat in inventory since late 2023 till about Jan/Feb of this year.

 

[Ryan L]

Is this the electric water pump?
I think that first surfaced on the BMW E60 (e6x) 5 series sedan as part of the deployment of the N52 six-cylinder engine (2005 at a guess). It was latter made available across the BMW product range. In everything from X1, X3, X5, 3 series, 1 series ect. Not sure if it made it onto the 4 cylinder version of the engine and was available on things like a mini

you can try searching "realOEM" to locate the part numbers for model specific parts. You might need to find a VIN number of a vehicle that is being advertised for sale to determine what vehicles had what.

I suspect an early E60 530i will be the first iteration of the pump.

 

[Randy Folsom]

A little more research I learn the BMWs use the LIN bus, even back on the old models. The PMW feature that was deleted has no effect on the replacement market, it only impacts us 'hotrodders'. I'm hoping Pierburg will tell me the model or revision number that I can identify an older pump that still has the PWM circuitry. I want the newer 'clockable' output with the older PWM electronics. It will have to be a pump that has sat in inventory since late 2023 till about Jan/Feb of this year.

I can’t find a way to mount the non-clockable Pierburg gracefully. One of the complications with the non-clockable version is that the electrical connector sticks out about 2” and is rotated about 95 degrees from the outlet. If mounted up front, the coolant lines are going to need some pretty sharp bends and the nostril(s) will probably need some modifications.

 

[Kevin B]

Any current update on this topic? I am planning my build and based on other threads, I think I also want to use the CWA400 but I want to make sure I understand the current situation and if there are CWA400 PMW options available. Thank you.

 

[Paul Proefrock]

As I understand it, Pierburg makes two CWA400's. One is the LIN version and the body/outlet is clockable - you can rotate the outlet 360 degrees. The other is a PWM version however it is based on the older, non-clockable outlet design.

There is some research going on to provide a cross-over to allow the LIN to be used but that hasn't been introduced yet. There is also a possibility the older version can be field modified to allow some degree of rotation, but that hasn't been verified yet either.

So no, no changes at this point

 

[Kevin B]

Thank you for the update. I'll keep an eye on this topic and thread.

 

[Randy Folsom]

Adding to Paul’s comments. The older, unclockable version has limited installation options. I couldn’t figure any option to mount it in the frunk. I was able to locate mine on the right side below the alternator with this mount.

https://grabcad.com/library/rcr40-pierburg-cwa400-ps-pump-mount-1

 

[Kevin B]

Thank you Randy. Do you happen to have any pictures of your car for reference? And with the extra mounting brackets - any other issues? It still seem like it may have added extra turs in the system.

 

[Randy Folsom]

Thank you Randy. Do you happen to have any pictures of your car for reference? And with the extra mounting brackets - any other issues? It still seem like it may have added extra turs in the system.

Not a great picture, but you can see the pump is down below where the alternator normally goes. For now, I am using corrugated hose for the return. It loops down behind the pump to the spine tube. The connection between the pump and Davis Craig manifold has a T fitting. Ignore that. The T fitting will be moved to just before the pump’’s inlet.
Because I am using a 12V AC compressor mounted in the frunk, I was able to move the alternator. If the alternator and compressor are in their normal positions, then the manifold outlet needs to be rotated such that the hose goes under the AC compressor and then loops below the harmonic balancer and and then up to the pump. The pump is rotated so the outlet is angled down (assuming it’s clockable).

I designed another mount to place the pump under the AC compressor but have not tried it. If you are interested, I can share the file.

 

[Kevin B]

Thank you again Randy. I would be interested in the mount to place the pump under the AC compressor (as pictured). I'm also going to send you a PM so we don't take over this thread but I'm also interested in your AC compressor set up.

 

[Scott]

I have the PWM version. I removed the cap and welded custom inlet and outlet manifolds to it. I didn't need to clock the cap, but as you can see in one of the pictures there is a simple notch in the cap that indexs. To my recollection it would be trivial to machine a notch in different location to clock it. If you don't have mill, you could file it by hand.

 

[Kevin B]

That look very nice. Thank you for the idea.

 

[Scott]

One more point. It's my understanding that most pumps work best when the inlet is gravity fed (i.e., not pulling the coolant upwards into the impeller). Keep in mind that OEM radiator outlets are typically a lot higher than ours and we have longer runs with more bends. Most of our cooling tubes are on the floor of the monocoque so mounting to the engine means that the pump inlet is above the radiator outlet. For this reason, my pump is mounted as low as possible to the chassis. In this position, the pump inlet is the lowest point of the system which is slightly lower than the radiator outlet. Remote pumps give you a lot of mounting options. IMO it's best to keep it near the engine to maximize pressure in the block, but I've seen multiple cars with them bolted to the floor of the nose.

 

[Kevin B]

Thank you Scott. I had also read that it is important to keep the pump as low as possible. I will keep that in mind.