Electric power steering pumps

[Texas Bob]

A fellow officer who owns like 25 classic cars told me the other day that the new thing was electric power steering pumps. Now whether this is the new thing or not I didn't see to much talk about it, but one wire and eliminating some lines sounds good. I've seen where 4x4s have retrofitted subaru and Toyota MR2 electric power steering pumps on to their rigs so would it be benifitial for a pro tourer?

[Fuelie Fan]

I'm not sure what you mean by eliminating lines...if it is direct electric assist then yes, but an electric pump will still have hydraulic lines.

A true electric assist could cut fuel consumption because it is on-demand. Both electric and electro-hydraulic can be progressive to have more assist at low speeds and less at high speeds to improve feel.

But, if you run an electric pump full time, i don't see a big advantage to be had unless there is also an accumulator to store pressure so that you don't need to run the pump continuously. I'll have to read up on it some more

[David Pozzi]

The latest thing is electric assist steering, no hydraulics at all. Honda uses it in at least one model. Race cars are using it here and there. American LeMans cars need it due to the long distances, and large downforce that makes steering difficult.
David

[BobB66SS]

More OEMs than Honda are using it. It's been in development since the early 90s at least. Saturn used it on the Ion and original Vue models, don't know if the new models have it as well. The last Malibu had it too. The theory is as mentioned - - elimination of the hydraulic lines in the vehicle as well as the equipment to install it at the assembly plants. The reduction in parasitic power loss also helps fuel mileage. It was originally earmarked for use in Europe when their fuel prices were $3-$4/gallon - - guess why it's getting more play here now. Even the ill-fated Quadrasteer system that GM put on its trucks a few years ago was electric. Ford's small SUV triplets use it now, and they plan to have it on nearly all of their vehicles in the near future. The issue with it in general is getting the same driver feel in the system that the hydraulics gives, which initially was difficult to do. New control systems make it much better, kinda like the way the new DoD systems GM has are much better than the old Caddy V8-6-4 system was. Improvements in electronics are the big change.
Another issue is ensuring that in the event of any kind of failure that you don't lose steering ability. The electric motors can all be backdriven in case of power loss, what you have to be careful of is not allowing anything to get into the motor that would lock the rotor to the stator. The electrohydraulic systems, where a separate electric motor drives a pump, give the desired feel but don't eliminate the hydraulic issues. Their other upside is you can place the motor and pump anywhere you want in the car since you don't rely on the crank pulley anymore.

Flaming River sells an aftermarket system today. I saw it on he highboy they had at Autorama which is on display now at the Summit store in OH. Looked like full electric. with a motor mounted on the intermediate shaft. No hyd system at all. I'm sure as the concept grow in OEM use, it'll follow more heavily into A/M use too.

[GetMore]

I know there are systems out there, but what you really need to wait for is the 42 volt electrical systems. The higher voltage will make electric motors work more efficiently, so electric P/S pumps or direct P/S systems, electric A/C compressors and the like will become the norm.
12v systems use too much amperage, lowering the efficiency.

[CarlC]

We have a cut-away of one of the EPS units in our lobby that I was checking out today. Very cool technology but, IMO, in its' infancy and not appropriate yet for our use. If you think a Lee's or DSE steering box is expensive, you will faint after the initial purchase of the rack/motor + control systems and trying to figure out how to integrate it all into a classic chassis.

Want to guess what repair costs would be? Yikes!

[GetMore]

BTW, for something scary: There will be some cars on the road next year that use electric steering systems. There will be no mechanical connection between the steering wheel and the wheels.

[megaladon6]

and full electric brakes too. gives a whole new meaning to "stopping short".

[CarlC]

BTW, for something scary: There will be some cars on the road next year that use electric steering systems. There will be no mechanical connection between the steering wheel and the wheels.

There already are. The one I was looking at is a production version. Hence, I would be very leery of trusting anyone to figure out the integration of the programming, feedback, and modules for these things. They are very highly engineered systems meant to go into one chassis type and not to be retrorfitted by someone without an in-depth knowledge of how they work.