BritishV8 Forum

HIWD on a V8 RX7.

http://www.driftworks.com/forum/chassis-suspension-steering/176479-electric-powered-steering-coumn-my-guide.html

So a pot and a chip, but we don't know what the chip outputs to the controller. Could be a complex waveform, could be a reference voltage. Or anything in between.

Jim

Well, if it's running algorithms, it's kinda hard to build it unless you can copy & burn PROMs.

Too bad somebody hasn't been able to put a scope on the output yet. There are just two wires going to the controller. Two wires from the pot to the Bruno, a hot wire and a ground. The Bruno was described as, "having a small chip" (which these days might not mean much).

I have a bit more than an academic interest. On my bench is sitting an electric power steering pump which I thought could be a good portable source of hydraulic power, like maybe for a tubing bender or something. But it also has inputs for control. Interestingly enough the built-in controller takes DC and creates a 3-phase current to power the motor so just wiring it direct would not work. Probably a waste of time and money to mess with it and I may end up throwing it away but I was curious enough to pick it up at the junkyard, and to take it apart.

Jim

Lots of great info on EPS/EPAS. Backs up Fred Key on not needing the Bruno module.

http://www.forabodiesonly.com/mopar/threads/35-electric-power-steering-with-fail-safe-no-ebay-module-and-no-caster-issues.363066/

Sh!t, I'm running out of excuses for putting this off!

Great info Carl! Are you considering it?

Great info Carl!! Thanks for finding and sharing. Looks like no more excuses not to transform your driving experience! It'll make you faster through the Mountains!

They were discussing it over on the main MG Experience. Someone linked that page. I was amazed at all the info there. Figured it need to be here, as well.  

That could work out really good. I've been driving the RM with the Bruno dial set in various positions and have just about settled on 3/8 as being the best setting. 1/2 is also good. So if those other units in limp mode run at about 1/2 it should be a good set up. Although you CAN vary the setting for different driving conditions, in a very practical sense it is best to find one setting that will work acceptably well for all conditions and just leave it there, and that is exactly what most drivers will do.

I had not noticed the lack of centering but next time I drive the car I will check it out. Considering the light weight of the car, one of the two smaller units should work well, hard to say yet which might be the better choice. But few new cars are in the 2100-2500 lb weight range, or even sub 2700 lb. That should be a consideration when selecting a unit, as should steering rack ratio or turns lock-to-lock. Perhaps the turns should be a divisor of the weight in making a comparison. That would give us some real numbers that we could use.

Jim

Since this is THE main thread on EPS/EPAS, I am cross-posting this from the Triumph section thread.

QuotePick your donor car EPS very carefully. Why buy a Bruno box if it's a set it & forget it situation. Fail Safe mode may be all we need for our LBC.

The Bruno controller is needed for the Saturn Vue, Chevrolet Equinox, etc. do NOT have a factory Fail Safe mode built-in in case it is disconnected from the original vehicle's CAN bus system. Fred Key put an oscilloscope on a Bruno & found out that is about all it does, give the Saturn Vue a fail safe mode (with a potentiometer).

According to this tutorial linked below, a Japanese EPS can be used in Fail Safe mode without the need of a Bruno Box & its variable assist.

The Saturn Vue steering does not self-center well (Mike Moor has discovered this, as well). The author suggests that a Toyota Prius electric steering ECU could be used on the Vue to correct this, as they have the same torque sensor.

[www.forabodiesonly.com]

Dan and I looked up the weights of the Corolla and Prius. About 2500 and 2800 lbs.

Jim

Ok, so what would be the EPS of choice, for a heavier car, say 3,600 lbs ?  Thanks, art.

Maybe the Equinox?

The earlier MGB (CB) steering rack has 2.9 turns L-L so for a 2200lb car that'd give us a steering force factor of about 755 which would vary depending on the tires and any suspension mods. The  RB MGB with a 3.5 ratio and about 200 lbs more weight comes to 685. The MG-RM at 2700 lbs would be 931. Wider tires will increase this number.

The '05 Corolla at 2500 lbs has 3.4 turns and works out to a factor of 735, a pretty good match for the 2200 lb (CB) MGB. Possibly a good choice for almost any MGB.

Specs for the Prius are all over the place, anywhere from 2.28 to 4 turns depending on the source, and apparently the tire size. You'll just have to check the individual car. If it is 2.28 (15" wheels) the number is 1,228. If 3.02 (16" wheels) the number is 927. Both those specs are from a Toyota publication. Whether they both use the same EPS unit is an unknown, but my guess would be that they do not.

Since we are looking for best match in Limp mode, the Corolla looks like a good bet for most MGBs, and the 16" Prius for most more extreme MGBs. The 15" Prius would likely give very light steering, but might be good for a car of about 2700 lbs with unusually wide tires.

Jim

From Tony Gentile's thread: List of EPS Units

QuoteBelow is the list of cars that have Fail-Safe Electric Power Steering columns, this means that Only 3 wire connection. Ignition On, Power and Ground to the Steering ECU. That's it ! These units will run in limp mode, which is a power assist that is more than enough to supply power steering to the light weight of our little hot rods, and if there is a full failure revert back to your original manual steering

2004-2009 Toyota Prius
2009-2013 Toyota Corolla
2006-2011 Toyota Yaris - (With ABS)
2007-2009 Nissan Versa
2009-2012 Nissan Cube
2012-2014 Kia Soul

ECU Part Numbers:

2004-2009 Toyota Prius 89650-47102
2009-2013 Toyota Corolla 89650-02300
2006-2011 Toyota Yaris - (With ABS) 89650-52120 / 52050
2007-2009 Nissan Versa 28500-EM30A / 991-30303
2009-2012 Nissan Cube 28500-1FC0B / JL501-000932
2012-2014 Kia Soul B2563-99500 / 4PSG1312 / FPSG1312

I pulled this list off of the forum "For A Bodies Only" and a post by waid302, Below is a direct link to this post

[www.forabodiesonly.com]

Hi everyone.  Very interesting information.

Has anyone compared the Nissan Versa EPS physically to the Saturn Vue EPS ?
It looks like it uses a similar three bolt flange to mount the upper column to the motor.
That might make it an easy swap for any of us who have modified the MGB mount to bolt to the Vue EPS motor.

Mike

I just picked up a unit today from an 08 Nissan Versa. Laying it next to my 74.5 BGT column looks like it won't be too difficult to make work. I did power it up using the red and black wires with it mounted in a vise, it would turn easily to the right but didn't seem to work turning left. There is a small electrical box integral to it with 4 small wires coming from it, any of those needed?

Has anyone considered the Yaris for the EPS?   The Yaris is about the same weight as the MGB and the ECM can control the motor in either fail safe (three wires) or with a square wave speed signal.  The speed signal could be generated from the drive shaft with the appropriate hall effect sensor.  Comments??  
Any final feedback on the comments about the Saturn units lack of self centering?

I picked up one out of a '09 Corolla yesterday. Haven't had a chance yet to do anything more than look at it, but the housing diameter is about 1/2" smaller than the one in the Roadmaster and the motor is 1/8" smaller in diameter. Otherwise very similar I think.

Jim

I've kind of lost track of the options...  Have we come up with one that can take a VSS signal or similar to have variable assist?  Without an extra external controller?  I'm thinking longevity - don't want to rely on a part made by someone who might not be making them any more 5-10 yrs down the road.

I found from driving the Roadmaster that there is really very little need to change the setting. It's a preference thing of course but I've pretty much left it center scale. If that is the default with no input I think it'll be fine that way.

Jim

Had a chance to bench test the EPS unit the other day and it works just fine. Battery positive is on the heavy blue lead, found that by testing. It is the closest one to the red motor lead.

The control unit has four plugs, power, motor, feedback, and control. The motor and feedback plugs go back in the same way they came out so nothing to change there. The power plug has 2 heavy leads. The control plug has 3 wires, a twisted pair and a single lead which in this case I think was also blue. It appears the twisted pair is for variable output control because when I had the battery hooked up to the power leads with blue to + and connected the blue control lead to + I heard a relay click in the control unit after a second or so and knew I was on to something. Afterwards, twisting the input shaft with a small pair of visegrips caused a clear boost in power to the output. Now I'm not certain, there may be a bit more delay or there might be some feedback going on there before full power is applied or whatever. Maybe it needs the resistance of being installed. But at one point it did spin the motor around the shaft while I was playing with it so I know it is working.

So far that is my test result with no Bruno box. If, as reported elsewhere the unit gives midrange power under these conditions I believe that will be quite fine with me. But it'll be some time before I have a modified unit ready to install.

For any of you not intimately familiar with fabbing and prototyping though, I very much recommend getting a unit from Mikey. He's got all this worked out and can sell you a unit ready to bolt in at a reasonable cost. Easy R&R in half a day, Bruno or no Bruno. (I put the potentiometer on the Roadmaster through the top of the left cowl half and it's quite a good place for it.)

For those of you who want to source your own unit, I found the pick-n-pull I go to doesn't know what this is yet. I was able to buy the gearbox as a "steering column" for $50 minus steering wheel and switches (sourced from a car with blown airbags so I didn't feel bad about destroying the parts to remove them), the control box they want another $15 for. But that may not last. Once they figure it out I could see the cost doubling. I just got lucky.

Now about removal: I recommend you not cut the wires to the motor. There is no good reason to do so. You will have to tear the top off the dashboard to get the module out in any case, might as well do that first and just unplug the motor. The module is attached with a sheet metal bracket, that is easily broken loose from the box by flexing the spot welds until they break, after you have it out. You can get about a foot of wire with the power connector and about 6" with the control plug without stripping out the wiring harness. When you wire it in the heavy leads go directly to the battery (or starter) and the small control wire goes to the ignition switch.

Jim

QuoteFor any of you not intimately familiar with fabbing and prototyping though, I very much recommend getting a unit from Mikey. He's got all this worked out and can sell you a unit ready to bolt in at a reasonable cost.

FYI: The "Mikey" that Jim B. is referring to is Mike Moor (Capt'n Moorgone).

Another reason...
I finally had time to look at the EPS unit out of the Toyota Corolla and make some closer comparisons. It turns out to be unsuitable for the MGB. The reason is that the motor is positioned on the wrong side. We have room for it to be on the left of the column which is where the ones Mike builds are positioned. The Corolla has the motor on the right side. There just isn't enough room for it to go there. Too bad, the smaller size could have been an advantage.

Jim

I'll take a look at the TR7 and see if there is room there.  I'll also look at the TR4A.

Hey Guys, Page 5 and 6 on this thread, Robert has his on the right side. Chris Gill is doing his now with the Corolla unit.