Volvo S40 Electric Power Steering Swap

[brokencase]

Raspberry Pi for this? Total overkill.

[my8950]

OK,
I would love to do away with the Scorpio power steering pump and switch to the Volvo unit.
From what I can see here thus far is the YouTube guy successfully installs the Volvo pump in his drifting car.
However the problem is that the unit is run in a default power setting which is non-ideal.

I am sure there is more but I have only skimmed through the prior posts. If I have missed something then let me know.

As I understand it, We suspect that through CAN bus the unit is slowed down as vehicle speed increases?

There are CAN bus shields for Arduino. But we would need to sniff the bus on a real Volvo in order to find out what to do.

If someone could tell me what commands to send to the unit I would be more than happy to write code that takes the Vss sensor output on the Scorpio trans and then generate the proper CANbus commands to send to the unit.

Semi-Retired Embedded systems guy, Best I can offer.

If you can provide the S40, I can sniff out the messages for the pump.
Maybe Hertz still has a rental available?

[Nmstec]

OK,
I would love to do away with the Scorpio power steering pump and switch to the Volvo unit.
From what I can see here thus far is the YouTube guy successfully installs the Volvo pump in his drifting car.
However the problem is that the unit is run in a default power setting which is non-ideal.

I am sure there is more but I have only skimmed through the prior posts. If I have missed something then let me know.

As I understand it, We suspect that through CAN bus the unit is slowed down as vehicle speed increases?

There are CAN bus shields for Arduino. But we would need to sniff the bus on a real Volvo in order to find out what to do.

If someone could tell me what commands to send to the unit I would be more than happy to write code that takes the Vss sensor output on the Scorpio trans and then generate the proper CANbus commands to send to the unit.

Semi-Retired Embedded systems guy, Best I can offer.

https://github.com/NMSTEC/Volvo_EPS_FREE
Here ya go my friend!

[Nmstec]

Screw Arduino. Run 22.04 Jammy Jellyfish on a raspberry and your done. No need to run Fortran or some Allen Bradley controller with 32k of memory. Actually this is the steering we are talking about so better off skipping the extraneous electronics (with bugs and delays) and use an adjustable controller. Maybe with a dash mounted knob for fine tuning?

https://www.nmstec.ca/product/psc/

That's my solution!
http://psc-demo.nmstec.ca/
http://psc-demo.nmstec.ca/docs

You can use a knob, another ecu, transmission, whatever to control it. Anything you can think of as input, it can do.

Also yes, this is a shameless plug of my own product. I own the business. if this is not allowed without some form of subscription for business, let me know and I'd be happy to pay it.


Also RPI is a bit of a bad solution for this, due to boot times, terrible power supply, and the delay between ignition and can out.
Arduino also pretty $#!*, but at least its an MCU and is a cheap $#!* way of making it work.

Thanks!

[DPDISXR4Ti]

Also yes, this is a shameless plug of my own product. I own the business. if this is not allowed without some form of subscription for business, let me know and I'd be happy to pay it.

I appreciate the honesty and the information you've shared in this thread. Perhaps one day I'll hit you up for sponsorship here, but not today. Feel free to keep posting away.

[andyofcolumbusmerkur]

That's pretty cool, are there any youtube videos of it installed and working? Seems like it would be well worth the cost of entry.

[Nmstec]

Yes and no lol. Have plenty of people running them but only ONE with a video of it working.
One is running a mazda pump on a boat (schooner).

Heres the one customer who actually posted it working: https://www.youtube.com/shorts/RTiSBri4bBw

[brokencase]

Thanks for posting the code.

Just one question or two,

Looking at the code it appears that the Volvo Pump is expecting a speed value that goes from 6000 down to zero as the vehicle speed increases? What minimum slow speed does 6000 represent?

You are measuring the PWM value from the incoming speed sensor. As far as I am aware the Ford Vss is frequency based, so I will have to make the required ISR changes to measure the period of the Ford sensor then?

I will have to scope the Vss on the Scorpio to figure out the range.

I imagine the speed range of interest for a power steering pump is not very wide, like once you get above 20mph the pump just drops down to a minimal pressure value?

[Nmstec]

Thanks for posting the code.

Just one question or two,

Looking at the code it appears that the Volvo Pump is expecting a speed value that goes from 6000 down to zero as the vehicle speed increases? What minimum slow speed does 6000 represent?

You are measuring the PWM value from the incoming speed sensor. As far as I am aware the Ford Vss is frequency based, so I will have to make the required ISR changes to measure the period of the Ford sensor then?

I will have to scope the Vss on the Scorpio to figure out the range.

I imagine the speed range of interest for a power steering pump is not very wide, like once you get above 20mph the pump just drops down to a minimal pressure value?

Hey! So the code you're looking at is made for an arduino, not the PSC controller.
The arduino code was also designed specifically to read PWM from an ECU, not a VSS.

0-6000 is actually flipped due to Rob using a pot backwards, but it signifies a VSS signal from ABS. Never bothered figuring out the encoding, but my guess is 0-245kph. At 6000 it just stopped going any slower.

If using the Arduino code, yes, its actually easier to measure frequency than duty cycle, just measure from peak to peak, average it with 5 samples, and theres a good VSS input.

If you're asking about the PSC controller, whole different story. PSC controller has a pwm/frequency pin, that you can adjust the pulse vs tire size yourself, and map it out. https://psc-demo.nmstec.ca/ is the demo of the UI, you can play with it!

Here is a demo with an older version of the PSC: https://www.youtube.com/watch?v=Xr3lT_tCxW4

And here is a walkthrough of the older UI as well. https://www.youtube.com/watch?v=ns88mwG ... e=youtu.be



The speed range is actually pretty linear on OEM volvos, as opposed to ford and mazda (same pump basically). starts at 100% around 0-20kph, then drops to about 80% linearly to 60kph, and then continues down to 0% (which is like 5%).

[brokencase]

The speed range is actually pretty linear on OEM volvos, as opposed to ford and mazda (same pump basically). starts at 100% around 0-20kph, then drops to about 80% linearly to 60kph, and then continues down to 0% (which is like 5%).

I thought it would have dropped off faster than that. You don't really need much assist once the car is moving. Naturally if we have a micro running things we can map it to behave as we desire. I imagine every rack and vehicle is a bit different.

Looking on your site I see there is also a potentiometer input to adjust the duty cycle of the pump.
Seems like it would be simpler to forgo the CANBUS interface and just use PWM output of the micro to something like a clm6000 to adjust the resistance divider input to the pump.

Unless the pin 3 input "PWM form ECM" works. Which is even simpler.

[Nmstec]

The speed range is actually pretty linear on OEM volvos, as opposed to ford and mazda (same pump basically). starts at 100% around 0-20kph, then drops to about 80% linearly to 60kph, and then continues down to 0% (which is like 5%).

I thought it would have dropped off faster than that. You don't really need much assist once the car is moving. Naturally if we have a micro running things we can map it to behave as we desire. I imagine every rack and vehicle is a bit different.

Looking on your site I see there is also a potentiometer input to adjust the duty cycle of the pump.
Seems like it would be simpler to forgo the CANBUS interface and just use PWM output of the micro to something like a clm6000 to adjust the resistance divider input to the pump.

Unless the pin 3 input "PWM form ECM" works. Which is even simpler.

It doesn't drop off too fast, because if we try the pump out, anything below 50% is not even considerable as assist. I can record video showing that today.

I mean, if you want to do PWM, feel free, if you want to do VR VSS in, that would be pin 4. However you can already map it out inside the PSC controller itself. No need for external control.

Just realized I can't upload screenshots...
If you go to: https://psc-demo.nmstec.ca/
Mode: VSS MAP
Map Mode: VR VSS

And there ya go, you can set whatever OEM style map you like.


If you want PWM, then Pin 3
Mode: PWM
Map Mode: PWM 0-100

For reliability sake keep it under 4khz. Nothing really should be running at 4khz anyway, but fair warning.

[brokencase]

Thanks for your input. I realize you are selling a product and the price is very reasonable.

Can you please expand a little more about the benefits of your product? I think it offers a lot more than what I might, upon some amount of effort, would accomplish on my own.

I want to be clear, I do not intend to pursue or market anything similar. Just very curious.

Am I correct in that I can download the profile I desire into your PSC?

What about the pressure sensor and temperature inputs to the unit? Do you do anything with those?

Keep in mind, I'm not a drifter or anything. I just want to get away from what I feel is a primitive setup on the Merkur Scorpio.
I've replaced the original pump with remanufactured, but it is still noisy. Happy to get rid of it and replace with something modern.

[Nmstec]

Thanks for your input. I realize you are selling a product and the price is very reasonable.

Can you please expand a little more about the benefits of your product? I think it offers a lot more than what I might, upon some amount of effort, would accomplish on my own.

I want to be clear, I do not intend to pursue or market anything similar. Just very curious.

Am I correct in that I can download the profile I desire into your PSC?

What about the pressure sensor and temperature inputs to the unit? Do you do anything with those?

Keep in mind, I'm not a drifter or anything. I just want to get away from what I feel is a primitive setup on the Merkur Scorpio.
I've replaced the original pump with remanufactured, but it is still noisy. Happy to get rid of it and replace with something modern.

Oo boy, this is a long one! That's correct, I am selling the PSC module for profit. I do release bits and pieces of code which I know don't financially impact me, for example Volvo pump. That being said I usually do it for Arduinos as thats what most people looking to save money use.

For feature set, i'd recommend looking at the youtube video guided tour, but in a short form answer:

1. Fully control many types of steering assist systems. That includes steering racks, columns and EHPAS.
2. Ability to have different types of control. You can just set a constant assist with no changes in soft, you can attach a potentiometer, you can wire in a PWM pin from your ECU if you want the ECU to control the pump speed (Rob Dahm style), you can also use canbus, where same thing, your ECU can control the PSC but via canbus. You can also attach a VR/HALL sensor, and it act as an OEM style assist, where you can map your assist levels by speed. It can also sniff the canbus and read a VSS signal if one already exists.
3. Can act as a VR conditioner. Many aftermarket ECUs lack VR inputs, and you can feed one into my controller, and it can either output a physical frequency output that any ECU can read, or it can broadcast it on the canbus as well.
4. Has temp/pressure compensation as well as output data. So if your hydraulic temps start rising, and you lose assist, it can bump up the speed and bring it up. Same with pressure. Mostly used however for data logging other stuff on EV conversions and all.
5. Has 2x 0-5v push/pull outputs. Can be used to emulate a speed sensors, turn warning lights on, or provide feedback at what dutycycle youre on.
6. Wifi connection. We went specifically for wifi for many reasons. Major one was, every laptop/phone has wifi. Not every has bluetooth. USB, and bluetooth would require platform specific software. With wifi we host the UI in the controller, and any chrome based browser can read it.

What sets apart my product, is basically all the above features, as far as I know, I'm the first in line with this kind of design. Mostly i'd say it would be the dual can, to allow ECU control, mappable assist by vehicle speed, and being a generic controller that can run any assist system. I also have constant FW updates for more vehicle support and features. This also presents a good option for specific customer needs, if they for example need a feature added or changed.


For some specific customers I also add other features, for example we have a guy running a honda engine in his gt86. So in his case he wants the airbag light off and EPS warning light (Track car), so on the second vehicle canbus I added a few more addresses that emulate the oem equipment, eliminating his lights.

Another customer stuck this controller on a Schooner (some fancy boat), because his volvo pumps run constant 75% and burn out. So in his case we used pressure sensor on low side, to see if any torque being applied, and if so, raise assist level.

If you were to go this route, I would highly recommend 10-12 Mazda pumps. They are essentially the same as Volvo pumps, since Ford contracted TRW for them. The difference is because no one could run Mazda pumps in limp mode, no one used them. They are cheap at junkyards, can pick one up for $50. Another good addition to it, is the remote reservoir we discussed before, some volvos do have it, but all Mazdas have them.

All of them have 1300psi internal bypass. Pressure is dependent on the rack, load, and tire size, but I have not seen someone reach the limits yet.

[my8950]

If you were to go this route, I would highly recommend 10-12 Mazda pumps. They are essentially the same as Volvo pumps, since Ford contracted TRW for them.

2010-2012 Mazda what?

[Nmstec]

If you were to go this route, I would highly recommend 10-12 Mazda pumps. They are essentially the same as Volvo pumps, since Ford contracted TRW for them.

2010-2012 Mazda what?

Well I mean conversation is regarding Power steering pumps. Mazda EHPAS between the years of 2010-2012.
https://www.ebay.ca/itm/134349461399?ha ... SwUUBjiWpd

2010-2012 Has two connectors
2004-2009 Has three connectors

Both have same parameters, but the older one has slightly slower response to assist request. Not a deal breaker, but still.