Electric Power Steering w/o hydraulics
 

I'm about to take a deep plunge into the ecomodding arena, but I'm not quite ready to reveal my big surprise :)
You'll have to wait a week for that.

What I am ready to do is brain storm a bit! I was considering a bunch of mods, and wanted to leave myself open to going EV within 2 years so I'm considering mods that I dont have to "undo" if I go EV. I've heard about how much a typical hydraulic PS system steals from a car, I've heard everything from 5.5hp to 8 - 10 hp. One big problem I keep seeing is people using electric motors to power traditional hydraulic setups. Well one step in the right direction, but why not something like a servo or stepper motor hooked up to the lower half of the steering system and a position sensor (uhmm potentiometer seems perfect)? I've been doing a lot of googleing and ebay searches trying to see if that's something that's done in other cars and the only thing I can find are some pictures of what might be what I'm talking about.

ELECTRIC POWER STEERING COLUMN GM HOT RAT STREET ROD:eBay Motors (item 160364539271 end time Sep-29-09 19:24:35 PDT)

or

2008 Pontiac G6 Electric Power Steering Assy:eBay Motors (item 230376727997 end time Oct-11-09 10:00:08 PDT)


I work at a driveshaft shop and we do make steering linkages (that's the right term correct?) for firetrucks and ambulances. I'm sure as long as it's close I could have the guys in the shop weld up my current system with something like that.

Anyone have any knowledge to share on a direct electric (drive by wire) systems and/or knowledge about what I'm looking at in those pics?

Thanks in advance, and I promise you'll all be excited in a week!

I don't think any power steering is actually needed for midsize and smaller cars.

even at low speeds? my friends power steering went out in his POS kia, not sure what model exactly it was like a tiny tiny suv, and well he grew some muscles just trying to get out of his driveway everyday.


At any rate these parts seem to be going for 50 - 75 bucks which is a drop in the bucket. Just don't know if they are what I think they are. ya know? ;)

Erm, plenty of cars use electric only power steering. Its essentially a motor mounted to the steering column/rack.
eg: Opel/Vaxhall Corsa
Fiat: Punto MK2 / 500
Some version of the MR2
etc..

So, maybe just use an existing one and adapt it to your car?

That's what I'm hoping to do. wondering what a good one to use would be that would be a nice starting point.

thanks for letting me know that this is something other cars do. Whenever I tried to look it up I kept finding electric hydraulic conversions and that's not what I want.

Rube Goldberg syndrome? Be a man and throw a manual box in it, I was but a sprig when I drove farm trucks and tractors around with manual steering. Less weight, less cost, less complexity, little cars aren't that hard to steer.

Right. A small car with a failed power steering system is hard to steer because the rack is geared differently, plus there's hydraulic fluid that you have to pump out of the way with your arms. Get a manual rack.

The Honda Insight has electric power steering (EPS), which is presumably lightweight like everything on the car, but you need the rack, steering column, and EPS computer. Then you have to figure out how to attach your tie rods to it.

Looking forward to the big reveal.

Maybe you should try to mount an A/C clutch on the power steering pump. Seems like that's the easiest way to get what you're after.

Using electric power steering in conjunction with a traditional rack, like what Chevy does with the Cobalt is quite effective. The Cobalt which is no lightweight is rated 37 highway.

However, going to a purely steer by wire system is a big no-no. Think what would happen if the motor burned out or you blew a fuse on the highway. I don't see mechanical racks disappearing any time soon.

sirus20X6,
As vinny1989 mentioned there are a few available already.

One well worth a closer look is the Honda NSX set up.
Link below:
Electric Power Steering

My approach would be estimated the weight and forces on the steering wheels and find a standard production unit as close to where your calculations tell you yours should be. Then look around to get it all fitted.

Pete.

I can't even remember all the cars I drove without power steering, but one example is a 1967 383 Formula S Barracuda. No power steering or brakes with discs up front. That sucker would put callouses on your vertebrae stopping it.

Another was a 1959 Corvette but the brakes in that car were a crude joke.

Mt Echo has power steering and if I get the chance it will be replaced with the manual
steering that was available.

regards
Mech

ok so as i understand that system:
"The NSX system consists of a rack-and-pinion steering gear with an electric motor installed concentrically around the rack. The motor transmits its power through a recirculating ball drive mechanism to push the rack right or left."

it's an electric motor built into/around a manual steering linkage? seems like the ultimate in power savings / survivability in a catastrophic failure.

I like


ok maybe i should point out a little more info. 94 honda civic ....

thanks for the input I was wondering if this was feasible too. What is your opinion on cutting out the hydraulic system and using a barbed fitting to connect the steering systems input and output, bypassing the pump and such?


how much easier to steer would a manual system be for something like a 94 honda civic than the bypassed system be?

Also 50 - 75 bucks doesn't seem that bad to get a little bit of electric assist for steering what do you think about integrating that?

sorry for all the questions I've just had a ton of wild turkey 101 and just brain storming about what I can do :)

Thanx

Congratulations! We have a winner!

No, not a winning recommendation; I mean this may be the 100th time I've seen "put an a/c clutch on _______" and yet I've never seen any evidence that anyone anywhere on the globe has ever done it (besides Mad Max and his switchable supercharger).

************************************************** ********

I personally haven't bypassed a hydraulic rack by looping the lines although I understand it's been done plenty of times. I've run GM power steering without a belt for several years with no ill effect and the steering effort was only an issue at stops, and even then I quickly got used to it and it was no big deal.

A 94 Civic needs no power steering of any kind. This would be especially true if you run higher tire pressures. One thing you learn with manual steering is to make sure the car is moving (even if very slowly) when you turn the wheel. Sometimes this may not be possible but that is rare.

regards
Mech

Not sure if the Civic p/s was an option or not. If it was then it was most likely aimed at the market segment wanting "power everything" and was oblivious to the cost in MPG to pay for it all.
If there was a manual option then I would fit the manual rack and delete the whole p/s ass'y to save weight.

Pete.

VX model had no power steering, probably others as well. You could get a rebuilt manual rack or used.

regards
Mech

Some honda's have electric power steering. I know the Fit does.

To the original OP. I would not even dream of trying to convert a 94 Civic to electric PS assist. It could turn out to be a real engineering nightmare.

Just drop in a manual rack and you will have a perfectly working system without all the added complexity. That's from the perspective of 60,000 hours of auto repair experience.

I have driven cars that weigh 1000 pounds more than that Honda with manual steering. If you just get the car barely moving the steering effort for the manual is nothing.

regards
Mech

Power Steering Belt Deleat.
 

Hi folks...I'm dk and new here so forgive me if I repeat anything already covered, although most of the posts I have read about dropping the belt off the P/S pump are a few hundred years old ;) .

FWIW..I would like address the P/S system as a whole as I have read some thought about the systems that are misunderstood..

Reason P/S gets heavy when there is no power assist is primarily due to the fluid YOU have to now push through the system with the steering wheel.

If you drain ALL the fluid from the system, including the rack or box, the steering will be much lighter.

Without the pump being driven there is no fear you will damage anything in the steering train with the fluid drained..

To really drain the system you need to blow all the fluid out with air pressure down the pressure line.

If you increase tyre pressure to the side wall indicated max' this helps to.
( Changing back to cross ply will help too! :D)

( Off thread slightly...) Don't over inflate as this breaks cords in the tyre. All tyres used in the USA have a MAX pressure recommendation on the side wall. I use a 8ply tyre rated at 65psi on my Westy..........

If you are needing power assist even then, you could use a 12 vdc motor like they use on truck cab rams or similar where the pump is a starter motor body.

I know...starter motors are not continuous duty motors. So...the cure?

If you have a few engineering skills it is possible to build a P/S system to give you full time P/S and yet have the motor to pressurize the system come on intermittently.

Having a system that kicks in at idle or when the throttle is closed is not a good idea. This can produce some unwanted input to the system that will one day catch you by surprise.....and due to Sod's Law...it WILL .

My idea is as follows...although I have not built one yet.....that's for the future.................

As I said..some fire and semi truck cabs have an electric hydraulic pump run from the 12 volt system to lift the cab..these should be more than enough for a P/S system with a usual max' pressure demand of 400psi.

Other motors come from snow plows and tail lifts.

These pumps are built from 12vdc Starter Motors ...about 1/2 hp and up.

You will need a pressure reservoir and a Hobbs switch or similar to limit the pressure and cut the motor.

My only problem at present is coming up with a pressure reserve tank or accumulator with sufficient volume to not kick the pump in every few seconds.

Perhaps one of those Engine Oil Pre Lubers maybe....?....or perhaps one of these...draft beer/co2 tanks good to 1,800 psi.

No doubt someone here has a source for those. Gotta be cheap though:).

Any ideas ?

regards

dk

You really don’t need power steering on a 94 Civic. And you shouldn't be steering unless you're moving anyway... it's bad for tires and the road surface.

Some EMer DID do this after I made this post!

Who/Where?