Converting power steering to electric power steering

[orange4boy]

I'm in the process of installing an electric motor to run my P/S. My Toy. Previa has a an accessory driveshaft that runs alt, P/S, A/C, rad fan, all of which are now disconnected. 4 pulleys, two belts. Initially when I disconnected the Alt.(belt on, my first experiment) and went to deep cycle battery power I got about 17% better FE.

Now the belts are off. I'm excited about my next fill. The throttle response is now so touchy and it revs like a race car. Steering is pretty tough but not as bad as my dads old f150 manual.
A good source of info on this is at the EV discussion lists because the have to deal with this all the time.

By going electric you may actually increase the demand on your engine because now you have to convert hp to elec at 45-50% efficiency then the motor has to change it back into motion at maybe 60-80% efficiency. Unless you go to on demand only or get a new high efficiency P/S unit from a newer car. You have to be careful which method you choose. But that's why we are here.

[steensn]

Whew... making your own electric power steering is much more difficult than you guys realize. There may be kits to throw in your car, but making one from scratch is just too much work. You need to introduce a steeering angle sensor and logic to onlyspin the motor when the driver starts to move the wheel. In our testing for electric power steering we have run across many times where you hit a bump moving the steering wheel and the eps thinks you want to move th esteering wheel creating some "intersting" responces on a test track. It is only interesting on a test track, on the road it is downright crap in your pants scary.

[ATaylorRacing]

Lots of guys that drag race their street driven cars get rid of the power steering by simply looping the hydralic lines into each other and thus bypass the pump. Its make for steering a bit better than having your motor shut off. The bigger your tires and heavier your car the harder it will be to steer. This would also be a way that you could compare with and without FE.

[Hankinator]

Originally Posted by tjts1

A simple solution I'm working on for a heavier FWD Volvo 850 is to replace the PS pump pulley with a clutch pulley from an AC compressor with a switch in the dash. Turn it on when I need it (slow speed city driving and parking) and off the rest of the time. Its just an idea at this point but to me it seems like a cheaper simpler solution.

Great idea! This would be worth trying. You could get real fancy with how you turned it on and off. First I would have it wired to always be on at start up and have to manually turn it off. That way if my wife were to drive my car she has to do nothing for it to work normally.

The next step would be to have the PS atomatically kick in below a certain speed...say 10mph.

Please let us know if you try to tackle this.

[chuckm]

Hankinator has a good idea, but why not make it switchless, programmed to kick in at low speeds? Then add something that senses when the wheel is not at center.

[mopo3]

Why not use a clutched pulley like the AC has?

[Hasbro]

My 04 Civic has EPS, of which I am going to remove. Minus 8 or 10 pounds and it supposedly has better feel although slow speed steering is harder.

[dutchboy]

Originally Posted by mopo3

Why not use a clutched pulley like the AC has?

Where do we get them? I don't think it's an off the shelf item.

Could probably salvage one from junk yard, but will it mate up with your PS pump's drive shaft?

There is probably so much variation it would be very difficult to find a matching AC pulley clutch.

A database of individual results (successful or not) could help the community know what to look for...

[jasonm]

You can use the 2000+ MR2 Spyder pump. It's electric, so with a relay and a switch you could turn it on and off. I picked up one from a junkyard for $50 + shipping.

[fatman57]

there are lots of cars with non-hydraulic power steering.......I am in the UK and I know of a few, in fact the car I currently drive has one (MGF).

it is basically like a starter motor connected to the drive shaft, only comes on when it is needed and should be worth a few MPG, besides being the smoothest steering I have found so far. No more hydraulic fluid & the part is about the size of a starter motor with a little computer to control it.

If you are thinking of making one or retrofitting the problem is the computer - I am planning to do some research on it anyway if I move on and will post some results if anyone is interested.