Electric Power Steering

[vinechoy]

"Best $200 Mod Ever - Electric Power Steering" ..that was the tagline stating that it is cheap and easy to install electric power steering in older cars. Well, it cost more than $200 and it took a lot of head scratching, measuring and beer to install electric power steering (EPS) in a 1969 Datsun Roadster.

Cost for a 2002 - 2007 Saturn Vue EPS with metal color control box was $130. The cost for the controller from Bruno on eBay was $100. Add in more money for machining and a support bearing.

Easy? Not for the Roadster. There is no room to mount the EPS under the hood, and barely enough room to mount it under the dash. I feared for my big feet, but the EPS doesn't interfere with driving.

Driving feel is different. There are online discussions about the virility, physical well being and mental well being of those who need EPS. Simply put, for my whole family to enjoy driving my Roadster, my wife benefits from having an easier time turning at low speeds. Its not easy to wrestle the thing steering wheel around a parking lot.
You feel less feedback from the road so purists need not apply. The feedback is damped by the EPS so that it drives much like our Nissan Xtrail which has EPS. WIth maximum assist dialed in, the car feels like my 60 Tbird which I could steer with one finger. I miss the precise feeling but don't miss the wrestling match in parking lots.

How I did it.

Purchase a 2002 - 2007 Saturn Vue EPS with all the wires, upper column and lower shaft with two U joints. Grind off the two mounting ears on the body of the EPS. Grind and separate the collapsible portion of the Saturn upper column.
Trim the Saturn upper inner shaft and reduce in lathe so Roadster upper inner shaft can slide over it. Leave enough length on the Roadster upper inner shaft. There is a C clip that stops the shaft from falling in and we need to weld a washer to the lower end to clear the plastic insert (in the upper outer column) so the inner shaft doesn't pull out when you pull on the steering wheel.
Mate the Saturn upper inner shaft with the Roadster upper inner shaft by pinning with two 3/16 roll pins (see Borgeson website).
I used part of the collapsible portion of the Saturn upper column and welded it to a portion of the Roadster upper outer column, so I could use the Roadster key, turn signal and steering wheel.

Now the Roadster steering wheel can talk to the Saturn EPS.

Mounting the whole assembly involved welding the Roadster column mount to the Saturn upper outer column. Initial tests with the rubber collar and Roadster upper and lower column mounts did not prevent the EPS from rotating in usage. I ended up not using the 3/4 drop spacers, because there was enough clearance. The EPS is securely mounted under the dash of the Roadster.

To connect to the Roadster steering box, I used the Saturn lower shaft with two U joints on it. I trimmed the bottom of the firewall hole by 1/2 inch for clearance from the lower U joint to the rear jet of the rear carb. During choke operation, the U joint could foul the rear jet and leave gasoline spraying through the whole engine compartment. Not recommended.
I cut down the infamous Death Spear ( from the steering box ) and ground a 3/4 in double D shape to fit the lower U joint on the Saturn EPS lower shaft. I tried to phase the U joints as well as possible by grinding the flats parallel to the notch for the bolt on the steering box U joint. If it doesn't phase well, just grind a new notch on the shaft where it fits into the steering box U joint.

With three U joints, its recommended to have a support bearing near the middle U joint. I welded an attachment to the frame of the car near the body mount near the starter.

Bruno on eBay sells a Pulse WIdth Controller that mimics the signal from the Saturn VUe computer. It attaches to one purple and one pink wire on the EPS. The other purple wire is a duplicate and not needed. There are currently no speed sensitive controllers on the market for the Saturn EPS without using the Saturn computer.

WIth the wiring done, it time for test driving....which is nice and balmy in Vancouver at this time of year.

[Alvin]

Neat!
The ingenuity of Datsun owners never ceases to impress me, well done sir!

Forgive if it's been mentioned but do you have speed-sensing assist on or off?
Does the electrical system need to be upgraded to handle the power draw?

[GeoffM]

Wow...way to boldly go.

[Pokerman]

That's a super job , how is the feel on the steering wheel ?

[notoptoy]

Cool, there was a reference in this month's Hemming's Motor news with links to two companies that provide EPS solutions for retrofit to classic cars. I'll find and post those here.
Awesome step by step and detailed instructions. What a neat project.

[vinechoy]

I made no upgrades to the electrical system. I'm still running the stock alternator. I did keep the 80 amp fuse with the original power supply cable, even though the stock alternator doesn't put out 80 amps. The Datsun is so light that the motor probably won't stall in normal usage unless you keep it cranked at full lock.

[dbrick]

Awesome mod, between that and a remote brake booster if needed you can make the car drivable by someone who otherwise couldn't.

[Linda]

Stupid question, what if you have a power failure, what happens with the steering?

Linda

[vinechoy]

When the electric power is lost, the steering reverts back to manual steering. The linkage is all mechanical, but electric assisted.

[vinechoy]

Update to electric power steering.

While surfing Youtube, I came across a video which expands on the electric power steering assist choices. DIY Electric Power Steering 1 - EPS with Fail Safe by Waid. Advantages over the Saturn Vue are 1) no $80 ebay controller module 2) wide choice of assist units 3) self centering in some cases.
If you are a stickler for authenticity, then you can choose a Nissan Versa motor as I did. My assist motor is from a 2012-2014 Nissan Versa
With fail safe mode, you only need to hook up constant power to the unit and a switched +12 V to one other wire.
I had difficulty finding Saturn Vue assist motors because Saturns didn't sell so well and a lot of the motors have been pulled already for other projects. There are tons of Nissans and Toyotas being sold and crashed which allows for trips to the wrecking yards to pull parts.

Viney

[Gregs672000]

Wow, amazing work!

[GoldHawg]

Update to electric power steering.

While surfing Youtube, I came across a video which expands on the electric power steering assist choices. DIY Electric Power Steering 1 - EPS with Fail Safe by Waid. Advantages over the Saturn Vue are 1) no $80 ebay controller module 2) wide choice of assist units 3) self centering in some cases.
If you are a stickler for authenticity, then you can choose a Nissan Versa motor as I did. My assist motor is from a 2012-2014 Nissan Versa
With fail safe mode, you only need to hook up constant power to the unit and a switched +12 V to one other wire.
I had difficulty finding Saturn Vue assist motors because Saturns didn't sell so well and a lot of the motors have been pulled already for other projects. There are tons of Nissans and Toyotas being sold and crashed which allows for trips to the wrecking yards to pull parts.

Viney

I saw a 2011 versa in the pick and pull today; any reason why it wouldn't be as good as the 2012-2014? Also, can you give a report on the steering feel? Any special tricks to getting out of the donor car for when I go back next week to get it?

[vinechoy]

NIssan Versa from years 2008 to 2014 work for sure. 2011 is fine. Steering feel is probably on par with honda civic and lighter than Nissan Xtrail. Cannot steer with one finger, probably two or three. WIth power steering, power brakes, and catalytic converter, the Roadster is updated for the twenty first century and is a pleasant daily driver.

Special tricks.....need a trained monkey or two.
Get a tetanus shot, bring gloves and flashlight or headlight
Bring a metric socket set (all 3/8" are fine), large wrench to remove the 22-25 mm steering wheel nut, maybe a gear puller or steering wheel puller. There is a special way to remove the air bag/horn button by pushing in tabs behind the steering wheel with a long screwdriver ( see Youtube ). The unit is heavy and will want to drop onto your head. Undo as many wires at their plugs as possible that don't relate to the eps. You will need to cut part of the wiring harness and keep the plug that provides electricity to the eps, so leave some extra wire attached to that. You may need to separate the wires on the wiring harness that runs between the computer unit and the sensor unit. You can leave the wire and plug connected between the eps motor and the computer box. Disconnect and keep the U joints and shaft below the steering unit to use for your car. This may need persuasion under the hood to loosen the U joint there. Try to keep the Rubber seal over the U joint shaft to use in your car also. Wire cutters for the 1/4 " cable between the ignition key release and the shifter(?). Keep the ignition key if possible to easily turn the shaft, otherwise you have to bust off the ignition key early to spin the unit.
Applying electricity and just turning the shaft next to the steering wheel won't give any assist. I thought I had a bum eps, until I watched Waid's video again. He has clamped both ends and when he applies torque to the steering wheel, the eps unit rotates against the fixed end.

Viney

[Bigtaku]

I was looking into making my wide wheels and tires work easier and found ZPowersteering.com
I wonder if anyone has contacted them about our little cars. They make kits for the Z and the 510.
http://zpowersteering.com/

ZPS_1.jpg

ZPS_2.jpg

ZPS_3.jpg

[Bigtaku]

“ Hi Michael!

We've actually already done several for autocross and track cars.

We just don't stock them, we build them on a per-customer basis.”

This is what they just told me!