electric power steering

I think most cars with 'electric' steering just have a hydraulic pump that's electrically driven rather than off the engine

Try this link -

Ohh that's possible... thanks. :)

Unfortunately you "think" completely wrong.

How do you think, with sensors. The same way everything else on your car that requires interaction is triggered.

It helps turn the steering for you ffs :)

Electric motors /are/ generally high torque...

Actually electric power steering uses less power than conventional hydraulic steering, with a slightly beneficial result on fuel consumption as a result.

Cars with *any* serious current drawing gadgets generally have a more powerful alternator...

The problem is not getting an electric motor to turn the steering, that's the easiest bit of the equation. The real problem is getting it done in a fashion that provides realistic feedback. And that's something that, as yet, has not really been fully cracked. A lot of systems still have a tiny delay as well before assistance is triggered.

Electric assistance sucks ass, but unfortunately it offers so many benefits over conventional hydraulic PAS (economy, simplicity, maintenance, reliability, etc) that it's here to stay.

Ok, it's been done, but it's not a very efficient method...

Mk2 MR2, some Vauxhalls, Puntos? use electro-hydraulic systems.

Does he?

I would say that the majority of electric power steering systems out there are those fitted to Astras / Zafiras / Corsas, and that's exactly how they work.

First one I remember seeing was the Seicento.

Wrong. The Corsa B and C have epas columns which have a starter motor sized motor sticking out at 90 deg under the dash. They can draw in excess of 40A, but this is only at low speeds and particularly when you hit the limits of the rack. There are multiple levels of assistance but it's all switched off above a certain speed. I think it's around 50. There is quite a bit of inertia in the column when it's sat on the bench. You can certainly feel the effect of the motor mass when turning the steering shaft. There is a speed/direction sender mounted on the column, but I'm not sure how it decides how much torque to supply.

It was pointed out to me once that the losses involved in turning engine power into electricity to turn an electric pump to power the steering, are more than the losses involved in using the engine power to turn the pump to power the steering.

So does the electric pump stop and start, and is that how it saves on energy? In that case doesn't it affect the feel of the steering? I'm just interested, that's all.

There's no continual drag on the belts by having an extra pulley, that helps I suppose. But I can beleive that the losses incurred generating the power to turn it mean that when working, it's less efficient. Of course, it's not going to be working all the time, at least not for the average drive, so it works out better overall.

Personally, power steering is another one of those gadgets I just don't see the need for unless you're not physically able enough to drive without it. I've had cars with both.

I much prefer driving cars with PAS. The Golf doesn't have it, resulting in stupidly heavy steering at low speed.

It saves on energy by not being used when the steering is straight ahead or at high speeds - unlike a belt driven pump that is using power all the time.

Also bear in mind there is no need to keep a reservoir of PSF pumped up to pressure. It just adds torque as required, powered via the battery.

Power steering is nice, but I certainly only notice it when parking and could happily live without it. It's definitely possible to have excellent steering without power assistance, after a thread on this I tested the TR and can say that it manages to lurch violently from side to side with no more than the force of one finger pressed (gently enough) on the top of the wheel at 15 mph.

Course, at parking speeds you need both hands on the wheel, but that's fair enough and who cares about that?

Lovely steering on the TR. It's a slightly strange thing to note that modern cars don't have lovely steering. Dunno why. I'd have thought technology meant it got better with time. They just turn or lurch, little or no feel unless you have to use lots of force. C'est la vie.

Fine if you go back to the days of skinny crossply tyres, low geared steering and RWD cars. Oh - and traffic conditions where you don't have to park in tight slots.

I'm on 155/13s, fwd at the moment, and low geared steering, and every parking space around here is tight. I manage :) Was on same tyres, rwd, similar steering set up, not much difference.

But I'm not thinking about the current cars I've got, I'm thinking Maestros, Cavaliers, etc that I have driven. The mk2 Cav is a right bastard, especially on the wider rubber, but I coped fine with parking it. Yes it was more effort when I wanted to park, but it didn't have something running all the time that I use for very little of the time (the argument for electric power steering, if you need power steering at all, IMO).

I can't see any reason why a car today needs power steering when the equivalent car of ten/ fifteen years ago managed without it. And I do see the point of power steering for people who haven't got much upper body strength, I just also see it as a gadget for many others.

I would say as you drive old cars you should know, but you've got a lazy bugger Rover, haven't you?

Wish I had! :)

That's why you don't see the need. Skinny high-profile tyres, see.

But a more modern car weighs a good few hundred kilos more for an equivalent sized car to those mentioned above, plus they run on larger wheels with wider, lower profile tyres.

See above - weight, wheel size and tyre width.

Plus, modern cars with PAS run different suspension geometry which trades light steering for grip and handling - older cars without PAS were set up with a bias towards lighter steering.

Having said that - have you driven an 80s hatch with 185/60R14s that doesn't have PAS - it's absolutely horrible, especially at low speeds.

Well my current car has a fairly hefty diesel lump above the front wheels, with 185/60/14 rubber and a fairly short rack (for a non PAS rack) and i cope fine, although my g/f moans whenever she has to drive it. TBH i've driven some cars that have over assisted PAS and feel horrible, equally i've had non-PAS that feel horrible and vice versa. It all depends how the manufacturer sets it up IMO.

I had a Bedford HA van for ages - much the same as the Viva, and that unassisted steering was as light as many powered setups, so it can be done. (They were very popular as learner cars - probably due to this and the great gearchange. Pity about the clutch and brakes)

I had a Montego Estate without power, and that was a pain to park. Not as bad as my old Landcrab, though, which really was heavy and low geared. Especially with the aftermarket steering wheel.

My record would go to a Riley 2 1/2 litre RM my brother had - so heavy as to be dangerous.

You'd have to design the car from scratch without for it to be decently light. And the suspension settings needed for the maximum speeds modern cars are capable of isn't really compatible.

I've driven a (rare) SD1 without power steering. Misery. Most of the standard ones are far too light, though. Later ones used a different rack.