Converting power steering to electric power steering

[paulgato]

Interesting thread. I have a 2002 VW golf Tdi and the serpentine belt runs the alternator, the P/S pump and the A/C compressor. I have no use for the A/C and want to junk that whole system anyway. It occured to me I could drive the alternator off the crank pulley using the existing tensioner and drive the P/S pump via a short belt with an electric motor put in the place of - or in the guts of - the old A/C compressor.

An A/C-style magnetic clutch to go on the P/S pump would be great though. A very elegant solution. The trouble is, that would take a fair amount of hunting around and measuring up and tinkering, and all with the P/S pump off the vehicle. And meanwhile, I'd have no vehicle.

I think for myself, it would make more sense to first install an electric P/S pump out of an old car, get that working, and THEN remove the old P/S pump to tinker around with it. I'm planning on running almost alternator-less anyway so running without the serpentine belt would be fine for a few weeks probably.

Another possibility is to somehow (??) fit an electric motor in the guts of the A/C compressor, but again, there is the problem of how to use the vehicle in the meantime. I think (but I don't know) that the Mk4 Golf would have been produced without A/C in some models, in which case there should be a shorter belt available. If this is the case then I could try getting a suitable electric motor to fit into the body of the compressor.

I admire the elegance of fitting a clutch pulley to the P/S pump but I can't see how I can do it realistically, so I think I'll be going down the route of fitting an electric P/S pump/motor from a Citroen C4 or Peugeot 307. This also give me the advantage that I can remove the serpentine belt entirely and save a little more fuel if I don't need the alternator. (On my daily, local routes I probably won't need the alternator, and if I get stuck, it is but the work of a moment to put the belt back on. Just need to carry the belt and a spanner in the boot.)

I'm surprised at the (maximum) current draw of electric power steering pumps though. 50A? 80A? ...people were quoting here? That's huge. It's only momentary, and I don't believe a larger alternator would be necessary. After all, you don't need a large alternator to run a powerful starter motor. But it does show how much potential saving there is to be had from going electric if you DON'T use the alternator to produce your electricity, but use the grid or solar cells instead.

If my alternative charging system becomes so good that I can ditch the alternator entirely then I can convert the alternator into a motor and use that to drive the existing P/S pump on demand via a shorter belt.

Hmmm... I still think the most realistic idea is that of fitting an electric P/S pump from another vehicle. For me at least. A simple ON/OFF switch on the dash so I can switch it off for motorway cruising and switch it back on for city driving.

[dremd]

As an FYI: the MKV golf/ jetta has an electric rack, I have no Idea if it is a bolt on affair, but would love to know.
I'm on my second ALH.
The MR2 pump has always appealed to me, and I wish I had tried to install one during my swap, but that was a massive project to begin with (1.8t auto -> ALH 6 speed manual+ lots o bits).

[teoman]

Originally Posted by oil pan 4

Rack and pinions use closer to 1,100psi and steering boxes use between 1,000psi down to about 850psi.
Flow through the steering boxes is some where around 3 to 4 gmp at that pressure.
Dont know how much flow racks use.

To produce that much flow and pressure we are looking at needed between nearly 2 to 2.5 horse power to maintain it.
The good news is thats only like 5ft.lb of torque, the clutch I want to use can handle many times that.

What would a 160 psi electric water pump do (similar to the one on your water injection kit). Would it provide any noticeable improvement?

Also, does the system keep pressure or does it constantly flow back to the reservoir?

[teoman]

These guys have a kit. You cut the steering column and insert an electric motor in between.

vw columns

(No affiliation)

[oil pan 4]

I don't think a low pressure pump would do anything.
When there is no steering wheel input the flow just runs around the loop building only a little pressure.