Compact Electric Power Steering Pump?

[M2ki]

Have anyone used Mercedes A class electric pump. It has a third thin wire, probably for adjusting the assist. Any info of what kind of signal it wants?

3. Doesn't the steering rack need some form of lubrication to stay cool and operate smoothly - especially a rack thats designed to be hydraulically operated ?

When going with electric column, use steering rack with no power assitist from factory, should be cheap and available from B3 80, at least here it is.

[_ShurikeN]

When going with electric column, use steering rack with no power assitist from factory, should be cheap and available from B3 80, at least here it is.

On many old cars non-servo racks are very 'long' in terms of turns amount. That states some sort of conflict with expectations of most of us to have more 'sportier' behavior of car.
How many turns from end to end is non-servo audi 80 rack?

[S2central.net]

I read the other threads kindly linked by Aaron - there's other links there to the work Des did on his URQ... fairly involved is putting it mildly.

Despite all of the photos in the other threads I was struggling to visualise how it all comes together for a full electric column - still not found stepwise pictures of RHD B3/B4 installation, but it seems quite a fluke that the splined section of Corsa C column fits onto B2/B3/B4 rack. The crucial bit involves accurate welding of the two column sections together so that the upper part can bolt to OE mounting points and the Audi key-switch location is unchanged and the lower motorised section comes from the Corsa.

I did read in one of the other threads the non PAS racks have something like 4 turns lock to lock - thats a bit pants - if anything I want the rack to be slightly quicker than the OE S2 rack which I think is 2.5 turns from lock to lock. Anything more than that would not be nice in my reckoning especially with a car biased more towards track applications than anything.

I still don't find an explanation for lubrication or cooling of the OE rack in the other threads so maybe need to read those two more times to find it.

In balance I think a fully electric steering system is a really cool idea, but an awful lot of work on mission critical parts... I think I will stick with the electric pump to generate hydraulic pressure for the OE rack and upgrade that steering disc coupling along the way to help with the steering feel... I can take two hoses from the rack into the cabin and find a suitable corner to hide the noisy pump in... then I need to think about cooling and a suitable location for that !

[Error404]

Alex

[S2central.net]

Jees - sorry dude !

[Thuppu]

I just plugged the orginal rack hose outlets with a hose loop and didn't fully drain it, so there is some oil left inside.

[S2central.net]

Staying on the compact electric pump approach - any reason why the Audi family part made by TRW for the A1, Polo, Ibiza, Fabia is not going to work (maybe it needs other controllers talking to it and a frigging CAN Bus before to tell it a hundred things before it just pumps ?

6R0423156B

Expensive enough brand new - https://www.ebay.co.uk/itm/VW-POLO-L...EAAOSwnDZUKqts

Plenty available for a fraction of that 2nd hand though.

What kind of pressure are we talking about here - I vaguely recall something in territory of 100-140bar

[Kiku]

Im using Opel Astra G hydraulic/electric pump. Working like a charm.

[S2central.net]

Its an ugly big thing and takes up hoard of space. The Audi / TRW part appeals to me more personally - nothing against Opels or Astras mind you... My 1st car was an Opel (Kadett) and my 2nd was a Vauxhall (Astra) - my 3rd was the Typ85 GT Coupe and I never looked back since (except for a 3yr dalliance with an SVT Mustang).

Just curious why it seems folk have opted for the GM part vs VAG family - is it purely down to price, availability or does the VAG one need CAN-Bus etc to make it work ?

I do see another advantage of removing the mechanical PAS pump in your photos - one less clearance issue for a left hooked inlet manifold !

[S2central.net]

So now my fears are realised for the VAG item - trust them to over-complicate things with dependency on a steering angle sensor, ABS interaction, blah blah blah - its a ****ing wonder they can make a washer bottle pump without CAN-Bus.

[Kiku]

Opel Astra pump is actualy exctly the same as porch 911 gt3 rs! And if you think about it it has nothing to do Vauxhall/Opel.
I believe in the end its more compact than original pump with all the hoses ect. Mounting inside a passenger wing could be possible.

[S2central.net]

So how is the control side of things for the Opel pump - does it not worry about engine speed, or steering angle acceleration ?

Is there any good source of technical info on the Opel item ?

[S2central.net]

So now my fears are realised for the VAG item - trust them to over-complicate things with dependency on a steering angle sensor, ABS interaction, blah blah blah - its a ****ing wonder they can make a washer bottle pump without CAN-Bus.

A radical idea to use the VAG part could use some kind of micro controller attached to CAN bus which just fakes the signals needed by the pump controller - and a little extra logic and control surface could allow the driver to select higher or lower amounts of assistance. Some smart person with Raspberry PI knowledge could probably knock this out - on a general level of modern car hacks and mods there must be a marketplace for such a gizmo to send or receive CAN messages to and from different components.

Then again - does the OE PAS rack work perfectly happily on basis of consistent pressure from a "dumb" pump like the Opel one - regardless of engine speed ?

[diesel des]

Exactly, the stick mechanical pump just moves oil and can build up pressure if required. The smart bit is in the valving in the rack. A simple electric pump does the same job, no need for control, just a 50 amp supply. It only draws big current when you hold the rack on the stopper.

Sent from my Moto G (5) using Tapatalk

[S2central.net]

OK - fog beginning to clear on this one then - a dumb pump it is !