How much energy does it take to turn a power steering pump

[2000mc]

Originally Posted by jamesqf

In a reasonably-sized car like a Civic, why do you need power steering, anyway?

Because some people don't have as much upper body strength and don't think to let the car crawl a bit to ease steering effort.
I drove my car fine without the belt on the p/s pump for a few months with the p/s gear, but swapped in a higher ratio manual steering gear which I thought made it virtually seamless. However, my wife has since decided "I'm the worst" because it's hard for her to turn when completely stopped. She doesn't drive that car much, but it took her over a year to notice.

[Xist]

I removed the power steering from my Civic. It is only a problem when I need to crank the wheel while stopped, but I felt that the steering in my Forester was far too soft.

Doesn't the Prius have electric power steering?

[California98Civic]

Originally Posted by Xist

... Doesn't the Prius have electric power steering?

Yes. There are discussions of it on Priuschat.

[user removed]

Lots of newer cars have EPS. Power steering is about as old as the first commercially viable computers. I owned quite a few cars before I owned one with Power Steering, including a 67 Formula S 383 Barracuda. It didn't have Power Brakes either. No room in the engine compartment, you changed the plugs from the bottom.

regards
mech

[JRMichler]

The 1965 base model Chevrolet Suburban came with a 230 cubic six cylinder engine, manual drum brakes, and manual steering. It had terrible roll steer, a good crosswind required turning the steering wheel 1/3 turn to keep it straight on the highway. The optional automatic transmission was a two speed Powerglide.

The standard tires were two ply bias ply. My father kept them inflated to factory spec, but four of the original five tires blew out before wearing out.

My mother was able to drive that car.

[oldtamiyaphile]

Originally Posted by Xist

Doesn't the Prius have electric power steering?

Four of my cars have EPAS, two are hydraulic, I also have an MR2 electro hydraulic pump that I will one day maybe retrofit to something (originally intended for an older van). There aren't many cars currently sold with hydraulic P/S at least in the case of those coming from Japan or Europe.

[whatmaycome14]

Originally Posted by jamesqf

In a reasonably-sized car like a Civic, why do you need power steering, anyway?

I've had mine removed for nearly 2yrs now. I don't ever have any problems with it...

[oil pan 4]

Originally Posted by MkVer

I wonder if you could put a solenoid controlled bypass line in so at highway speeds the pump pretty much free spins.....

When you are driving straight and not using any power assist they pretty much free spin.
This power requirement that I measured is pretty much what you get with the inefficiencies of the pump just pushing the fluid around.

[oil pan 4]

Originally Posted by California98Civic

Oilpan... the 3 mpg number you speculate fits nicely with the 2 or 3mpg I thought I saw jn my Civic after removing the PS system.



Or an electromagnetic clutch for the pulley like most alternators have now. The ECU could just disengage the pulley under certain conditions, as it does a "smart" alternator. "Smart" pulley driven power steering pump is born. Could put such a pulley on an "on/off" switch too and ckntrol it from the dash. So you would only draw power from the engine at the low RPMs that oilpan is saying draw very little power. But his test was without turning the steering wheel, so wouldn't turning the wheel increase power draw somehow?

I would love to do a power steering clutch but the problem is finding something like an air conditioner clutch that will fit my type of power steering pump.
I believe a 1970s keyed straight shaft pump for a truck or a pump with a tapered keyed shaft form late 1960s and 70s car may fit up to a modern A/C clutch. But no auto parts stores carry these pumps they would have to order one just to find out.
The pump internals are pretty much the same since they are all Saginaw style pumps, just some time by the late 70 or early 80s some one at GM came up with the great idea to make all power steering pumps take a press fit pulley.

We know the power steering hydraulic system uses much more power when the wheel is being turned. Off road guys have to install power steering coolers because they can over heat the system pitching the wheel back and forth. I have seen burned up black power steering fluid come out of an off road vehicle with an OEM power steering setup and a power steering reservoir "boil over" before.

[Xist]

I have read about people installing MR2 pumps in cars, although it sounded expensive.