Power steering electrically assited

[Mick]

Ok Pete needed to distract my own attention of feeling my age onto you the closest other old bastard i know.

Just kidding.

 

[Pete McCluskey.]

Your are only as old as the women you feel :thumbsup:

 

[David]

Handy though the rallywiz controller is I'd rather have my PAS working as it should, ie only active during low speed.

As I understand it the Corsa 'B' ECU detects the engine running before it turns on the PAS and then adjusts the assistance based on a speed signal.

I'm pretty sure the engine running is taken off the low side of the coil in which case a pulsed 12v signal should handle that but does anyone know what the ECU is expecting wrt a speed signal?

 

[Mick]

David the RallyWz ECM instructions indicate clean 12v battery power through a 50smp cirtuit breaker direct the motor on the column, there is a inupt plug the ECM connects to on the motor this has a 12v input via the ignition switch from both the ECM & plug on the column motor. There are no other inputs, I assume the ECM compensates for speed & steering angle Via the reostat control.

 

[Roy]

Mick,
Warrick at Ultimate Power Steering on the northside of Brisbane has a kit available. He has this kit fitted to an AC Cobra replica. The great thing about this kit is you can adjust its sensitivity on the fly. Here's the link.

Motor Sport - Electric Power Assisted Steering. (EPAS) | Brisbane Power Steering Specialists

PS. I have no association with Ultimate Power Steering.

 

[David]

Mick,

The rallywiz controller must constantly send an "engine running" signal and then the adjuster essentially varies the speed the EPS ECU 'sees'.

I don't suppose you have an oscilloscope to see what kind of signal the rallywiz controller is sending the ECU?

Roy,

These kits are great if you are happy with exactly the same amount of assistance at all times or are happy to keep playing with it. I'm looking either to buy or make up my own controller that will give it either a correct or adjusted speed depending on what I set it at.
Making one isn't a problem and even having to work out what it needs isn't the end of the world it would just save me time if I knew the signal forms.

Personally I prefer the Honda NSX/Mazda RX-8 EPS type setup with a linear motor built into the rack. Quite apart from the slightly better weight distribution and better packaging, if nothing else because they're from sports cars rather than the shopping trolley that is the Corsa!

The GTs40 is however both designed for the Corsa 'B' EPS *and* comes with a quick rack (making it a moot point anyway) but more importantly despite being not far off the same width track the RX-8 rack is *far* too wide, too slow (in comparison) and I both have no idea about the NSX rack width and they're rather rare and pricey!

 

[David]

Here is a PDF detailing the EPAS system used in the Corsa (and it appears the MGF too).

http://www.tortoiselogic.com/NSK/PDF\epas.pdf

I wonder if the MGF column might not be a better fit? It's certainly cheaper but doesn't look quite so easy to modify if it isn't the right length already (I'm not going to try as I already have a Corsa 'B' one but someone may want to give it a go).

Wiring appears to be:

Thick Red: Main live to battery via 50a fuse
Thick Brown: Main earth
black: switched live via 10a fuse
green: engine revs
Blue/red: speed signal
brown/white: diagnostic
black/green: dash warning light

I believe the speed sensor in the ECU needs 30 pulses per wheel revolution, I'll rig it up some time on an Arduino and try it. I wonder if the 'diagnostic' is K-Line?

 

[Mick]

Hey Roy it looks the same as the system i have installed, it has an adjuster you change to suite the conditions.

 

[Mick]

David I wandering if the Motec ECU can be used to control steering given that there are a number of inputs/sensors that can be added and controlled bu the ECU.

Mick.

 

[David]

An interesting idea, especially as I haven't chosen ECU yet. Unfortunately I suspect the Motec will be out of budget as ISTR they are rather pricey but we'll see.

 

[Pete McCluskey.]

Update, Mick's power steering works fine he is really happy with it, I'll let him tell you how it improves his driving experience. I have Just bought my barina/Opel
Column from the wrecker but it has the plugs from the input side of the steering
Controller missing. Does anyone know where I can source them in the Brisbane area? For once mr. Google is no help.

 

[roaldin]

How did I miss this thread?!

Thanks for posting this info'.
My old shoulder injury isn't getting any better either...

Tim.

 

[Mick]

Ok finished installing power steering, the system works perfectly. I have been incapacited for 2 months due to a ruptured Achilles tendon (21 year old brain 50 year body) can't see that changing much. Been driving a lot more in traffic without that sense of pressure, manual control is quite sensitive most of the time it's just barely dialed on. The system inspires good confidence and makes the car feel more controllable. Probably the single best improvement you could make to the drivability of your 40. Obviously not for everyone but for those that want to maintain the appearance of originality its well hidden and you wouldn't know you had power assit.
Installing the same system into Pete's DRB in the coming weeks.

Mick

 

[Pete McCluskey.]

I would like to personally thank Mick for all the help he gave me fitting my electric power steering. Particularly since I plugged a couple of wrong wires together and cooked the wiring loom:embarassed:
Yes, electrics are one of the many things I am crap at.
I think Mick did a lot of muttering under his breath about dickhead old white guys!
Anyway it seems to be working fine and my dodgy shoulder will appreciate it.
Once again thanks Mick, my shout!

 

[René]

The Mazda RX8 epas rack looks big?

I also came across a Ford item>>

FORD RACING 2012 BOSS 302R ELECTRIC STEERING RACK M-3200-EPAS

http://www.wheeldealnow.com/product/Racing-Electric-Steering-Rack/default.aspx

here some more info about those racks>>

"This steering technology will turn a lot of heads," said Ted Seeger, Nexteer’s global chief engineer for electric steering. "Although it seems counterintuitive that a high-performance sports car includes a green, responsive electric power steering system, muscle-car enthusiasts will appreciate the enhanced steering feel and handling. It won't be long before more sports cars use EPS for these benefits and the increased fuel efficiency it provides."

Nexteer-brand EPS systems achieve up to four per cent fuel saving over traditional hydraulic steering by eliminating the hydraulic pump, hoses and fluids and replacing them with a high-efficiency motor. The motor draws power only when the driver needs power-steering assistance, as opposed to the hydraulic steering which draws power continuously from the engine.

Less fuel burned means fewer emissions. It also means as much as three horsepower at the wheels. Since 1999, officials say Nexteer Automotive (the former steering division of Delphi) has put more than 12 million EPS units on the road globally, saving nearly 800 million gallons of fuel.

2011 Mustang First To Carry Nexteer Electric Power Steering - Ford Mustang News

and oh, Porsche is also into epas which sounds to be ok too

 

[John]

or you could try a steering shaft type system.

Electric Power Assisted Steering (EPAS)

its very compact.

cheers John

 

[James Harvey]

An old thread, but I've just found some info here on controlling the ECU for the Corsa power steering unit.

Might be of interest for anyone wanting to install a 'dynamic' speed controller rather than the manually adjustable knob.

 

[David]

James you little star! Cheers mate.