Convert to electric power steering pump

[paulgato]

Kingsway,

I was doing some reading on the subject last night and I came to the conclusion that removing the power steering from the Golf Mk4 is bad idea, unless you need to replace the steering rack anyway, in which case if you can replace it with a manual steering rack with lower gearing then that would be worth doing. VW don't do a manual steering rack for the Mk4 as far as I know but it MIGHT be possible to use a steering rack from a Mk3, although that may be just a rumour.

(By the way, what I mean by 'removing the power steering' is looping the lines for the P/S rack (to ensure continued lubrication but to reduce resistance) and either removing the P/S pump altogether, or else looping the lines from that as well. This is what some people have been doing on various cars.)

The reason why I think it's a bad idea is twofold:

Firstly, even with the pump, etc. taken out of the 'loop', and with the rack's hydraulic connections connected together, there will still be added resistance from the piston in the rack having to push the fluid around the pipes and through the valve. (I read a post from some one who had done this on a later Golf and he said he was going to put it all back how it was because he didn't like it.)

The second reason is that without the P/S pump assist, there will be considerably more strain on the rack/pinion connection point. Because of the higher gearing - and because of the additional resistance caused by the piston pushing the fluid around - there will be more strain at this point of contact than with a lower geared manual rack, ...UNLESS the strain is being taken up by the P/S pump. This rack/pinion area is a common point of wear and when it does wear it creates play in the steering, which is horrible in any degree whatsoever (causes steering wander) and illegal beyond a certain point. (Will fail MoT test.) Changing a steering rack is not easy or quick or cheap.

So, that's my conclusion. Just 'taking the belt off' is a bad idea and it has been dropped from my list of possible mods.

The only possible scenario in which it might be a good idea is if you have a worn seal in the rack, and you're losing fluid from there. As a temporary measure (might last a long time - who knows?) you could loop the pipes from the rack but connect them to a non-pressuried reservoir, so you can monitor leakage and top up if required. That would cost almost nothing and would probably stop the leak for a while as there would be no significant pressure in the system any more. You'd still have the risk of accelerated wear on the rack/pinion point but if the rack is shot anyway you'd have nothing to lose.

However, fitting an electric P/S pump would have none of these disadvantages and should save some fuel, especially if I get around to 'deleting' my alternator and getting most of my car's electrical power from the grid (storing enough for average daily driving in a deep-discharge battery in the car's spare wheel well.) But I'll leave the P/S mod until I've done the alternator delete mod.

[darcane]

I'm not sure if it is feasible for the OP, but one option for electric power steering is to use an electric assist from a Saturn Vue or similar. There is no pump and hoses, the motor just directly powers the steering shaft and mounts under the dash. Inexpensive controllers for it can be found on eBay and work pretty well from what I've read.

[2000mc]

I know this varies from car to car, but don't assume you have to loop the lines or that the fluid movement causes a significant amount of resistance. On my car, with the front tires in the air and engine off, I can turn the wheel lock to lock almost as fast could if there was zero resistance.

[cRiPpLe_rOoStEr]

Instead of an electro-hydraulic power steering, why not an all-electric power steering such as the one from an Opel Corsa? BTW I would be always quite skeptical about an alternator delete, mostly after a mod which increases the electrical load.

[paulgato]

...but cripple rooster, the more components you remove that use engine power, replacing them with components that only use electrical power, the more potential savings there are to be had from 'deleting' or 'bypassing' the alternator and using an alternative method of providing electrical power such as an auxilliary battery charged up at home.

As for using power steering which uses an electric motor rather than hydraulics, that's a rather difficult and expensive mod which will involve changing the steering rack I believe. Just changing the engine-driven steering pump for an electric steering pump is much easier and cheaper.

[cRiPpLe_rOoStEr]

Altough I can understand it, I'd still be quite afraid of having to rely on an external source of electric power for the vehicle.

[paulgato]

Cripple rooster, you would still have the alternator, and you can switch it back on with one press of a button, so you're not relying on an external source of power exclusively. The way I plan to 'bypass' my alternator would be by using a second battery which keeps the starter battery charged in the same way that the alternator normally would, so the starter battery would remain 100% fully charged all the time...

http://ecomodder.com/forum/showthrea...mod-27179.html

...but then each of us has their limits. I, for example, would not want to do anything to my car which makes it look odd in any way. No fish tails or boat tails for me!

[jasantal]

You connect the big black wire to plus, big colored wired to negative and from the 9pin connector 5 and 9 to positive to get it going. Tried it on mine (building an electric Citroen Xsara at kWsara dot com) and it works. I got the info from here: hr-ev dot blogspot dot com. Can't post proper URLs yet.

[paulgato]

Aha! Thanks jasantal!

This is what we need.

My goal is to do away with the accessory belt entirely on my Golf TDi.

The belt drives the air conditioning, the alternator and the power steering pump.

The air conditioning system can be binned in its entirety, and that's the first thing I'll do as I never use it, and removing the system might free up some space for fitting an electric power steering pump later on. It will also save some significant weight. I'll leave the actual compressor in place temporarily as it's not in the way, but all other parts of the a/c system can be binned now.

An electric power steering pump can then be fitted (thanks again jasantal for the info on wiring!) and plumbed up to the existing power steering hoses. When that is all working satisfactorily, then both the original power steering pump and the aircon compressor can be removed, and a shorter accessory belt fitted to drive the alternator.

The alternator can remain in place for the time being as a back-up, but the belt can be removed for daily local driving, as I'll be charging the battery up at night from the mains, and for short drives I should never need the alternator. I can carry the belt and a spanner in the car in case I need the alternator, and maybe re-fit it before long journies away from mains power. (It is very easy to fit the belt - just pull the spring tensioner away from the belt with the spanner and slip the belt onto the pulleys. Release the spanner and all is done.)

As for the power steering using more electrical power than the engine-driven pump, well it will, and that is kind of the point as it it precisely there that the fuel savings can be made if electrical power is generated off the vehicle. So the electric power steering will eat into the useful battery life, but for short local journies that won't matter so much, as I'll have enough power in the battery for short journies, and for longer journies which involve a lot of motorway cruising, I won't need power steering, and can switch it off to save amps. A simple ON/OFF switch on the dash should do it.

I've also looked into solar power to top up the battery, and it does seem to be feasible these days. In theory I can fit about 225w of cells on the roof. (I may need to custom build them from bare cells and embed them in resin permanently on the bodywork to accomodate the curvature of the roof, as ready-made 'semi-flexible' panels won't bend in two planes at once.)

As far as I can determine, a nominal 225w of cells should produce something like 80w (or 6A) even on grey winter days, and that happens to be the minimum my car needs to run the engine and nothing else (6.4A). Over the 5 hours of daylight one can expect in winter around here I'll be putting 30Ah back into the battery, which represents approximately the amount of power I'll use in daily local driving over an hour and a half or so. In theory this 6A should be enough to keep the car going indefinitely if I restrict long journies to the hours of daylight. And building solar arrays oneself is actually quite cheap, if time-consuming. Even 400w worth of cells is cheaper than a new alternator for example. Now I MAY have got the calculations wrong here but it does seem that solar power for recharging a car battery is entirely feasible. Of course in summer the electrical load is lighter and solar power production much higher but I want to design around the worst case winter scenario. (This is really a summer project because it will involve lots of bodywork. Summer is finished here now so maybe next summer I'll tackle the solar assist side of things.)

But one thing at a time. Well, two or three at most! I'm going ahead with the electrical alternator disablement plan and nightly battery re-charge off the mains. Also with the engine pre-heater. These two things both involve plugging the car in to the mains at night, so they kind of go together and I'll concentrate on those for now. But all this power steering pump info is getting filed away for the medium future. Really useful.