Electric power steering conversion

So, we have a normal power steering system in the challenge car.

I'm really looking to drop weight and complexity. As well as additional reliability and engine bay clearance.

Seems like a chevy equinox column and an eBay controller is a potential solution. But, what about the box? Can I just fill it with fluid and loop the lines?

In short, learn me electric power steering conversion.

Watching. Very interested in this topic.

I believe the electric power steering takes the place of the hydraulic system.

A guy in my car club put electric power steering in his TR7. I think he sourced everything from the junkyard. I don't recall what the donor was for the motor, but I think it was Mopar.

GM are supposed to have extremely swappable electric columns. I want one for the Quantum.

Yup. There's a $60 kit on ebay for the equinox column.

It's just the rest I'm not sure about.

As far as the box goes, I went for many years with a depowered power box.

Don't fill it with fluid, EMPTY it of fluid. Take the lines off and spin the steering back and forth a bunch. If there is fluid in it, it will be very stiff to turn as you will be forcing the fluid through lots of small orifices. Then loop the lines.

I believe I had about 100,000mi on the box in depowered state. Starting with a 150k mile car. When I took it out of its original home and put it in the next car (because the power box is 3 turns and the manual box is much much slower) I did take it apart to observe how things were holding up. Everything was fine, the fluid that remained after ~70-80k still looked like ATF. I cleaned it all apart thoroughly, refilled with ATF, pumped out the excess again, and slapped it into its new home.

Saturn Vue columns also usable.

Watching...

NordicSaab wrote: Watching. Very interested in this topic. I believe the electric power steering takes the place of the hydraulic system.

Did you get a message from me with a link for this?

So, Knurled, how did the depowered box feel? Any extra dead spots or loss of steering return, etc?

Here's how Flyin Miata does it

Pretty sure Jalopwhatever did a write up that included welding some squishy parts.

MrJoshua wrote:

NordicSaab wrote: Watching. Very interested in this topic. I believe the electric power steering takes the place of the hydraulic system.

Did you get a message from me with a link for this?

So, share the link with the whole class?

Edit: you did it while I was typing apparently.

In reply to Dusterbd13:

I sent Nordic one a week or so ago with a link to an using the electric setup like you mentioned with the ebay controller. A few people have had problems getting messages lately so I was wondering if it had gotten through. Hopefully the Flyin Miata link helps. If you could, would you please document your power steering project on this forum. I've read about doing it, but I would like to see how well it works from someone here.

PS- do you have a link for the ebay controller handy?

Dusterbd13 wrote: So, Knurled, how did the depowered box feel? Any extra dead spots or loss of steering return, etc?

Felt just like a manual box but not as slow.

The perverse thing was that, at least on that chassis (FB RX-7) the steering wasn't even any heavier than a manual steering car once the power steering pump and nuclear bunker-grade pump bracket were removed. It's like the car only needed power assist to deal with the added weight of having power steering.

Box was still fine when I took it out for a rack and pinion conversion. The rest of the steering/suspension was shot and it was cheaper to install an FC subframe with new struts than it would have been to replace the bushings and ball joints and idler arm and half the tie rod ends. That one is a power rack that I depowered by plugging the lines and looping the ram lines together. Works just fine ~80k later.

So, the rx7 was box, and you went to rack, correct?

And hell yeah ill document if I do it.

And don't have a link handy. I just searched for electric power steering controller.

In reply to Dusterbd13:

It was box, that I depowered, which was great and the box outlasted the car it came from, and got put into another car. The rack came much later. In both cases, I didn't weld up the spool valve like some people say you have to do or you will die a fiery death crashing into a bus full of pregnant nuns, or something.

Use the electro-hydraulic unit from an MR2 or XT-6. Mount it where you need the weight and plumb the lines to the rack.

You get power steering but no HP robbing pulley/pump on the engine at high RPM. It only really steals power loading up the alternator for current in turns and in the paddock when you don't care and it's not robbing anything but a small load at 7000RPM WOT on the straights. Plus, it feels like power steering is supposed to. And it's variable so you can run it slower for more effort.

I did this on two race cars now, it's the way to go.

An electric rack on a car with a dead battery is eye-opening. The alternator could not keep up with the rack at medium parking lot speeds, so the assist kept on cutting in and out. If you kill the battery in an EPS car, charge it before driving instead of just jumping it!

I don't have any direct experience with the column type EPS units as found in the Chevy Cobalt/Saturn Vue. I work with the EPS racks found in most other cars.

Anyway, the Cobalt/Vue units appear to be fully self contained with built in controller. From what I gather the column units require a high current power leads, an ignition lead and CAN connections. If the column EPS units work like the racks then you can get them working by suppling them with high current power and ground. A low current ignition signal is required to enable the unit. The CAN messages send vehicle speed data to the EPS unit and allow variable boost. Unfortunately without the proper CAN messages the EPS units will default to high boost... Well that's how the racks work on newer GM and Ford products, I'm assuming the older column units work the same way.

I am doing the Vue/Equinox/etc install on my Benz right now. Well not riiiight now, but I am in the middle of it. Here is a preview, I'll post up the full install later.

The hardest part for me was figuring out how to fit that box and my pedals in the same area. I actually took off the computer and will remote mount it and had to rotate the unit a hair so that it will all play nice.

Other than pedals and it wanting to take up the same place at the same time, it is one of the easier things I have done to the car so far. Haha

I used a Vue rack for now. I have heard everything from use no fluid to use a little fluid and make sure there is a small vent on using an ex-power rack with the electric PS stuff. That I can't help you with.

All the stuff to put the steering column in is super easy to pull out. I had to go back once. I ended up cutting off a piece on the column the second time. It is the piece that the steering box slides into on the steering wheel side. The way I did it, I actually still have a collapsible column if I get in that bad if a wreck too.

There are also apparently two different types of boxes. One has a plastic black computer. That one is a no go. The other has a metal computer. That one is good to go.

If you want more info let me know. I will try and throw up more pictures.

Doc Brown wrote: I don't have any direct experience with the column type EPS units as found in the Chevy Cobalt/Saturn Vue. I work with the EPS racks found in most other cars. Anyway, the Cobalt/Vue units appear to be fully self contained with built in controller. From what I gather the column units require a high current power leads, an ignition lead and CAN connections. If the column EPS units work like the racks then you can get them working by suppling them with high current power and ground. A low current ignition signal is required to enable the unit. The CAN messages send vehicle speed data to the EPS unit and allow variable boost. Unfortunately without the proper CAN messages the EPS units will default to high boost... Well that's how the racks work on newer GM and Ford products, I'm assuming the older column units work the same way.

The size of the power leads going into the Miata rack speaks volumes about the amount of current involved. It's hefty.

We powered a Miata EPS rack on the bench to snoop on the CAN system and it didn't provide any boost at all when manipulated by hand. So unless you can speak CAN, I think it defaults to no boost at all.

MrJoshua wrote:

NordicSaab wrote: Watching. Very interested in this topic. I believe the electric power steering takes the place of the hydraulic system.

Did you get a message from me with a link for this?

yup, sorry, been really busy, but yes! thanks for thinking of me :)

NordicSaab wrote:

MrJoshua wrote:

NordicSaab wrote: Watching. Very interested in this topic. I believe the electric power steering takes the place of the hydraulic system.

Did you get a message from me with a link for this?

yup, sorry, been really busy, but yes! thanks for thinking of me :)

No worries.

Following.