# Hydraulic pump for EV conversion



## HelioArcturus (Oct 14, 2021)

Hey all, back again with another question. Does anyone know of an electric hydraulic pump for an EV conversion? If there are no dedicated EV pumps, what are the alternatives? I would like to make my E46 bimmer direct drive to eliminate any risks with the transmission and/or differential blowing out under the high torque.

Any help would be great!


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## Electric Land Cruiser (Dec 30, 2020)

Yes there are. Tons actually. What sort of hydraulic system are you interested in pumping?


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## HelioArcturus (Oct 14, 2021)

Power steering, mainly.


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## Electric Land Cruiser (Dec 30, 2020)

HelioArcturus said:


> Power steering, mainly.


For my project I got a power steering pump from a 2005 Volvo S40. Runs off 12v and has metric threads. FoMoCo part.


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## HelioArcturus (Oct 14, 2021)

What about brakes?


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## Electric Land Cruiser (Dec 30, 2020)

HelioArcturus said:


> What about brakes?


I'm using a vacuum pump from a Camaro ZL1 and keeping the stock brake master cylinder that came on my vehicle.


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## brian_ (Feb 7, 2017)

HelioArcturus said:


> What about brakes?


For brakes, you can add a vacuum pump (as Electric Land Cruiser did, and some production EVs had such as early Teslas), or you can replace the master cylinder with an electromechanically assisted unit such as a Bosch iBooster or similar units from other manufacturers (mostly used in hybrid and electric vehicles).


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## HelioArcturus (Oct 14, 2021)

Wow, that's awesome! I like that idea, as I am not too good at retrofitting parts (although that is exactly what I am trying to do).


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## brian_ (Feb 7, 2017)

HelioArcturus said:


> Does anyone know of an electric hydraulic pump for an EV conversion? If there are no dedicated EV pumps, what are the alternatives?


What you're building was very common for years, and is probably still found in many production vehicles, called electro-hydraulic power steering (EHPS) or electro-hydraulic power assisted steering (EHPAS). The unit from the Ford C1 chassis (which includes the Volvo S40 and my Mazda 3) is very common; the one from the second-generation Toyota MR2 was an early example and may be desirable because it works with no computer network communication. These were never specific to EVs; they have been used in regular engine-driven cars and hybrids, but most of them - and probably all EVs - have gone to direct electric motor assist on the rack or column instead.


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## HelioArcturus (Oct 14, 2021)

brian_ said:


> What you're building was very common for years, and is probably still found in many production vehicles, called electro-hydraulic power steering (EHPS) or electro-hydraulic power assisted steering (EHPAS). The unit from the Ford C1 chassis (which includes the Volvo S40 and my Mazda 3) is very common; the one from the second-generation Toyota MR2 was an early example and may be desirable because it works with no computer network communication. These were never specific to EVs; they have been used in regular engine-driven cars and hybrids, but most of them - and probably all EVs - have gone to direct electric motor assist on the rack or column instead.


I guess you would find one of those units on eBay or something?


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## brian_ (Feb 7, 2017)

HelioArcturus said:


> I guess you would find one of those units on eBay or something?


... or an auto salvage yard.


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## remy_martian (Feb 4, 2019)

There's no free lunch. 

The PS and AC pumps are major energy hogs if you run them "on" all the time. You can, in order to keep it simple, but simple carries a price of range.


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## HelioArcturus (Oct 14, 2021)

Actually, I was thinking of eliminating the ac altogether.


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## brian_ (Feb 7, 2017)

remy_martian said:


> There's no free lunch.
> 
> The PS and AC pumps are major energy hogs if you run them "on" all the time. You can, in order to keep it simple, but simple carries a price of range.


That's why EHPAS exists: manufacturers introduced it to replace engine-driven power steering pumps, because the electrically driven version only runs as required, saving fuel - it doesn't run at full speed all of the time. Directly driving the rack or column with an electric motor takes even less energy, but the difference is small (which is why EHPAS is still a reasonable choice in production).


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## HelioArcturus (Oct 14, 2021)

brian_ said:


> That's why EHPAS exists: manufacturers introduced it to replace engine-driven power steering pumps, because the electrically driven version only runs as required, saving fuel - it doesn't run at full speed all of the time. Directly driving the rack or column with an electric motor takes even less energy, but the difference is small (which is why EHPAS is still a reasonable choice in production).


So it only uses energy when you turn the steering wheel? Useful.


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## brian_ (Feb 7, 2017)

HelioArcturus said:


> So it only uses energy when you turn the steering wheel? Useful.


It always uses a bit, but yes, it only uses substantial power when needed.


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## HelioArcturus (Oct 14, 2021)

I see that the 2002 BMW z4 had an electric power steering system. I wonder how compatible it would be with my E46 323i?


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## Electric Land Cruiser (Dec 30, 2020)

There are two types of electric power steering; hydraulic and direct drive on the column. Maybe they are compatible somehow between BMWs. Also you can get shaft assistance kits which are pretty popular these days for muscle cars and the like: https://www.unisteer.com/collections/electric-power-steering


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## HelioArcturus (Oct 14, 2021)

Apparently the Z4 had a full electric system (EPAS) and not the hybrid system (EHPAS). I did see that the Z4 and the Mazda3 were being investigated by the NHTSA for steering assist failure at speed.


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## brian_ (Feb 7, 2017)

Electric Land Cruiser said:


> There are two types of electric power steering; hydraulic and direct drive on the column. Maybe they are compatible somehow between BMWs. Also you can get shaft assistance kits which are pretty popular these days for muscle cars and the like: https://www.unisteer.com/collections/electric-power-steering


There are electro-hydraulic systems that use a normal hydraulic rack plus an electrically driven pump, and there are all-electric power assisted steering systems. The all-electric designs can act on the rack (not hydraulically), or on the column (both OEM and those aftermarket products).



HelioArcturus said:


> I see that the 2002 BMW z4 had an electric power steering system. I wonder how compatible it would be with my E46 323i?





HelioArcturus said:


> Apparently the Z4 had a full electric system (EPAS) and not the hybrid system (EHPAS).


Yes, the E85/E86 Z4 (but not the "M" version) had an all-electric system. The E85/E86 Z4 was mechanically related to the E46 3-Series, so the Z4's steering parts might bolt right into the 323i... it's worth checking out. This appears to be a system with the motor in the column, which makes sense because I know the 2014+ Mazda 3 is arranged that way (and you say that their steering systems were related); that means that you would need to change both the rack and the column, or use just the column (with motor) from the E85/E86 and keep the E46 rack but disable the hydraulic assist in it.


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## remy_martian (Feb 4, 2019)

3. There's also electrically assisted rack & pinion if you don't have the room or inclination to have the assist motor on the column. 

2012 Kia Soul looks interesting, as it reportedly will run in failsafe mode with the CAN bus disconnected. Anyone know of other electric assist racks that will failsafe assist when CAN is not connected?

I'm not sure anyone has deciphered CAN for electric racks. Have been looking.


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## HelioArcturus (Oct 14, 2021)

brian_ said:


> There are electro-hydraulic systems that use a normal hydraulic rack plus an electrically driven pump, and there are all-electric power assisted steering systems. The all-electric designs can act on the rack (not hydraulically), or on the column (both OEM and those aftermarket products).
> 
> 
> 
> Yes, the E85/E86 Z4 (but not the "M" version) had an all-electric system. The E85/E86 Z4 was mechanically related to the E46 3-Series, so the Z4's steering parts might bolt right into the 323i... it's worth checking out. This appears to be a system with the motor in the column, which makes sense because I know the 2014+ Mazda 3 is arranged that way (and you say that their steering systems were related); that means that you would need to change both the rack and the column, or use just the column (with motor) from the E85/E86 and keep the E46 rack but disable the hydraulic assist in it.


That would definitely help keep the complication of the build down. I will absolutely look into it.


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## HelioArcturus (Oct 14, 2021)

remy_martian said:


> 3. There's also electrically assisted rack & pinion if you don't have the room or inclination to have the assist motor on the column.
> 
> 2012 Kia Soul looks interesting, as it reportedly will run in failsafe mode with the CAN bus disconnected. Anyone know of other electric assist racks that will failsafe assist when CAN is not connected?
> 
> I'm not sure anyone has deciphered CAN for electric racks. Have been looking.


Good question. I'm not really familiar with CAN stuff, so that may be a problem.


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## HelioArcturus (Oct 14, 2021)

It looks like the racks are interchangeable: 

Converting Your E85/E86 to Hydraulic Steering - Z4-forum.com


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## remy_martian (Feb 4, 2019)

Some PS pumps operate on CAN only, so beware of them.


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## HelioArcturus (Oct 14, 2021)

remy_martian said:


> Some PS pumps operate on CAN only, so beware of them.


Thanks, I'll check on that.


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## brian_ (Feb 7, 2017)

remy_martian said:


> 3. There's also electrically assisted rack & pinion if you don't have the room or inclination to have the assist motor on the column.


Yes, as I mentioned:


brian_ said:


> There are electro-hydraulic systems that use a normal hydraulic rack plus an electrically driven pump, and there are all-electric power assisted steering systems. *The all-electric designs can act on the rack* (not hydraulically), or on the column (both OEM and those aftermarket products)...


Packaging can affect the choice of system. For example, Mazda uses a powered column in the Mazda 3, but that apparently won't fit in the MX-5 (Miata), so there they use a powered rack.

Although the E85/E86 Z4 uses a powered column, some other BMWs do use a powered rack, and might be a good fit mechanically... but controlling the thing is probably more important.


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## Electric Land Cruiser (Dec 30, 2020)

The Volvo pump works on 12v at a medium speed. It also has CAN input and it has been decoded so you can use it as-is and then later on add CAN control to make it more efficient based on wheel speed or increase the pressure etc.


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## t0astm0nkey (Jun 23, 2020)

Lots of high performance off-road vehicles use Globe Pow-R-Steering electric power steering units from the factory.


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## HelioArcturus (Oct 14, 2021)

I see that it is under the alliedmotion brand:
POW-R STEER EPAS Actuator
Is that the correct one?


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## t0astm0nkey (Jun 23, 2020)

HelioArcturus said:


> I see that it is under the alliedmotion brand:
> POW-R STEER EPAS Actuator
> Is that the correct one?


That's the one - I think it's used in the Wildcat and RZR.


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## HelioArcturus (Oct 14, 2021)

Do you know how it would work on a car?


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## brian_ (Feb 7, 2017)

HelioArcturus said:


> Do you know how it would work on a car?


I didn't register to be able to download documents, but the basic specifications provided by Allied Motion for their Pow-R Steer state 0.88 Nm of assist torque per amp of drive current, and maximum of 50 A... implying that the most torque that it can apply to the steering column is 44 Nm. Is that enough for the car, which pesumably has much more load on the front wheels than the off-road vehicles mentioned?

If your steering wheel is 400 mm across, 44 Nm would be the result of applying 110 N (the weight of 11 kg, or 24 pounds) up on one side and the same force down on the other side of the wheel. That sounds pretty good, but I would want to confirm that it is adequate.

For comparison, I found one supplier that provides torque specs, and all of their models except the "microsteer" are larger units which can produce substantially more assist torque:
_DCE Motorsport_: EPAS
I'm not familiar with this specific supplier or its product - I was just looking for an example of the specifications of units normally used in cars.


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## cejota3 (Aug 15, 2019)

HelioArcturus:
I converted a 2004 E46, 330i convertible, and used one of the Ford MoCo C1 electric PS pumps that someone else mentioned (most widely used in Volvos when Ford still owned them). It has worked surprisingly well. A very close to stock feel. Mounting it was tricky, as well as getting the adapters right to get fittings between it and the stock rack (happy to give you part #s of what I used), but once all put together, it has worked like a charm. I measured current draw at one point, but cannot quite remember off the top of my head, but basically when turning (i.e. when it really needs to put out significant hydraulic pressure) it would momentarily jump between the low teens to mid twenties of amps (so you need to wire and fuse it appropriately, I think that pump is actually rated to something like up to 70A), but when not under load (i.e. the vast majority of time), it was very minimal, I'm not even sure an amp. All a long way of saying it really isn't that much of a draw.
This pump actually has a CAN interface for variable assist, and supposedly some folks have hacked that, but I didn't want to work that hard, so I just "jumped" it so that it would be "always-on" (by providing a switched +12V to a pin on the harness that is easy to track down), and again, it has all worked surprisingly well for almost 2 years now.

These pumps are pretty easy to find, and not that expensive. Here's one example:








2004-2013 Volvo C70 C30 S40 Power Steering Pump Assembly with Reservoir OEM | eBay


2008 - 2013 C70 VOLVO 70 SERIES. 2004 - 2004 VOLVO 40 SERIES 5 CYLINDER (VIN MS, 4TH AND 5TH DIGIT). 2007 - 2013 VOLVO 30 SERIES. 2005 - 2011 VOLVO 40 SERIES (5 CYLINDER). 2006 - 2007 VOLVO 70 SERIES CONV.



www.ebay.com





Here's even someone selling a harness to go with it (albeit for a silly expensive price IMHO, but still, if you want one that is just done):








Electric power steering (EPS) pump wire harness for Volvo/Ford Type 2 pump | eBay


This harness uses factory-style connectors sourced from the factory supplier. The wire is automotive-grade GXL insulated wire rated for under hood use. All wire connections are crimped.All our products are assembled by hand in the United States.



www.ebay.com


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## dpkahmke (Mar 3, 2013)

cejota3 said:


> HelioArcturus:
> I converted a 2004 E46, 330i convertible, and used one of the Ford MoCo C1 electric PS pumps that someone else mentioned (most widely used in Volvos when Ford still owned them). It has worked surprisingly well. A very close to stock feel. Mounting it was tricky, as well as getting the adapters right to get fittings between it and the stock rack (happy to give you part #s of what I used), but once all put together, it has worked like a charm. I measured current draw at one point, but cannot quite remember off the top of my head, but basically when turning (i.e. when it really needs to put out significant hydraulic pressure) it would momentarily jump between the low teens to mid twenties of amps (so you need to wire and fuse it appropriately, I think that pump is actually rated to something like up to 70A), but when not under load (i.e. the vast majority of time), it was very minimal, I'm not even sure an amp. All a long way of saying it really isn't that much of a draw.
> This pump actually has a CAN interface for variable assist, and supposedly some folks have hacked that, but I didn't want to work that hard, so I just "jumped" it so that it would be "always-on" (by providing a switched +12V to a pin on the harness that is easy to track down), and again, it has all worked surprisingly well for almost 2 years now.
> 
> ...


Hello, I wanted ask you since what you discribed is very similar to what I am looking to do, can you say what pins you provided the 12 volts to? I have a Volvo/ford PS pump that I want to just turn on, I've got main power and 3 control wires. 2 I suspect are CAN and one power. I've tried 12v to the one I believe is not the CAN. But I'm kinda stuck since the pump does not react. Thanks

Daniel


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## cejota3 (Aug 15, 2019)

dpkahmke said:


> Hello, I wanted ask you since what you discribed is very similar to what I am looking to do, can you say what pins you provided the 12 volts to? I have a Volvo/ford PS pump that I want to just turn on, I've got main power and 3 control wires. 2 I suspect are CAN and one power. I've tried 12v to the one I believe is not the CAN. But I'm kinda stuck since the pump does not react. Thanks
> 
> Daniel


Here are the notes I made when I last worked it:


=========================================
1. The large guage red and black leads, as likely suspected, are +12V and GND. These should be continuously powered "live".
2. The "control" would normally be a "CAN" connection via the three wires on the other plug, however, in nearly all cases, trying to reproduce CAN is unlikely, so instead just provide a "switched" +12V to the "grey with blue stripe" wire, which will put the pump in a continually on mode.
3. High pressure output fitting size: metric M16x1.5 o-ring sealed fitting.

Volvo part number for the "power harness": 30775461
one example: https://www.autopartsway.com/part.c...minpb8o4ni5aivczszch26oa58eaqybcabegkb9pd-bwe
Volvo part numbers for harnesses: 30728420 and 30658215. (just the housings with no terminals or isolators)
Max pressure of pump: 120 bar = 1,750 psi
Fitting adapter that should work on the high pressure side: Edelbrock/Russell 648060

Return hose barb fitting: 0.395" = 10mm;


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## Dillzilla (Aug 6, 2021)

have you considered using a EPS? Electric power steering


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## remy_martian (Feb 4, 2019)

A lot of butchery, baling wire and duct tape involved with the EPS installs I've seen where mechanical integrity comes into question vs dealing with a plumbing problem and not futzing with the stock steering rack/box and column. 

Everybody has their own constraints, abilities, sensibilities, and standards, so one size does not fit all.


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