Electric Power Steering

BBShark

BBShark

Garage Monkey
Staff member
Joined
Mar 5, 2008
Messages
4,864
Location
Right here
A lot of cars have an electric pump that control the hydraulic pump for steering. I think Subaru has been doing it for some time and some other rear engine cars like a MR2 have had this going back to the 80's.

Seems like these conversions are pretty popular with the streetrod crowd. Certainly would be an easy way to control assist but it sure looks like the pump gets a workout!

[ame]http://www.youtube.com/watch?v=PvqNKTVh5L8[/ame]


.
 
Looked like that pump was doing a max of only 100 psi??? that's not enough for a vette, our pumps do 1000 psi....or was something mis interpreted???

:shocking::beer:
 
I can't read the scale on the gauge but these pumps do put out 1500psi. It looks like a regular steering gear in the car and the guy has hydroboost.
 
BBShark said:
I can't read the scale on the gauge but these pumps do put out 1500psi. It looks like a regular steering gear in the car and the guy has hydroboost.
Click to expand...

Thing that gets ME is I thought power steering took like 2-3 hp off a engine....that's a LOT of current at 12 volts....so where does that pressure and flow come from with a little pump???, somehow I don't think it can keep up in a autocross/emergency on the road type shituation....

I have serp drive and so can't ditch the p/s pump anyway.....

hummm....maybe I need look at that again....:stirpot::stirpot::smash:
 
mrvette said:
BBShark said:
I can't read the scale on the gauge but these pumps do put out 1500psi. It looks like a regular steering gear in the car and the guy has hydroboost.
Click to expand...

Thing that gets ME is I thought power steering took like 2-3 hp off a engine....that's a LOT of current at 12 volts....so where does that pressure and flow come from with a little pump???, somehow I don't think it can keep up in a autocross/emergency on the road type shituation....

I have serp drive and so can't ditch the p/s pump anyway.....

hummm....maybe I need look at that again....:stirpot::stirpot::smash:
Click to expand...

That's my curiosity. I do like the idea of a remote pump, buy I'm curious what sort of amperage they take. I've never liked the looks of giant alternators in an engine bay (to power all the electrical loads), so I'd be interested in finding out what the power requirements are for these pumps.
Larry, keep us updated with any information you come up with.
Thanks.
 
I dunno. I always thought the Saginaw pump was one of the most trouble free parts of the car. My 76 Silverado kept it's original pump untill 2001, without ever even a top off.:)
 
69427 said:
mrvette said:
BBShark said:
I can't read the scale on the gauge but these pumps do put out 1500psi. It looks like a regular steering gear in the car and the guy has hydroboost.
Click to expand...

Thing that gets ME is I thought power steering took like 2-3 hp off a engine....that's a LOT of current at 12 volts....so where does that pressure and flow come from with a little pump???, somehow I don't think it can keep up in a autocross/emergency on the road type shituation....

I have serp drive and so can't ditch the p/s pump anyway.....

hummm....maybe I need look at that again....:stirpot::stirpot::smash:
Click to expand...

That's my curiosity. I do like the idea of a remote pump, buy I'm curious what sort of amperage they take. I've never liked the looks of giant alternators in an engine bay (to power all the electrical loads), so I'd be interested in finding out what the power requirements are for these pumps.
Larry, keep us updated with any information you come up with.
Thanks.
Click to expand...


I don't get it either. I have heard estimates for the power required to operate a PS pump at 3-5 HP. At 3 HP you need 2250 watts. 2250watts/12v= 187 Amps! I know with an electric motor you have peak load advantages from rotor inertia but even a sustained 100 amp draw seems excessive. How can these pumps live?

Then there is the all electric colum mounted Delphi ESteer setup. This uses an electric motor right on the column to provide assistance. I've seen these in person and, judging from the size of the motor, I can't beleive it is more than 1/4 HP. You can buy one of these from Flaming River if you have $5000!!!!!!!!!!!

http://www.flamingriver.com/index.cfm/page/ptype=product/product_id=356/prd356.htm
 
big2bird said:
I dunno. I always thought the Saginaw pump was one of the most trouble free parts of the car. My 76 Silverado kept it's original pump untill 2001, without ever even a top off.:)
Click to expand...

OEM GM pump on my '85 dodge van, 300k miles I don't recall EVER replacing a P/S pump, any vehicle....
 
The whole drive by wire thing rattles me. I do not like the idea of no physical connection between the steering wheel and the front wheels in case of failure. What do you do if the alternator or PS pump quits? Bend over, stick yer head between yer knees and kiss yer nutz goodbye? What kind of a back-up do these things have?
 
To my (limited) knowledge, there are no drive-by-wire steering systems on a production car. The concept has been demonstrated but I think the manufacturers are not going to accept the potential liability.
 
BBShark said:
To my (limited) knowledge, there are no drive-by-wire steering systems on a production car. The concept has been demonstrated but I think the manufacturers are not going to accept the potential liability.
Click to expand...

I agree with Larry here. Most electronic systems have a "soft fail" system built into them if there is an electrical failure. The "throttle by wire" systems, during a failure mode, will cause the engine to drop to a fast idle so that the vehicle can still move itself out of the way of faster traffic. At worst, the engine stops, rather than the throttle going to WOT, which is a definite no no. Electrical assist steering, at worst, will just resort to manual steering mode (high effort). Drive by wire, and stop by wire, are two items that the manufacturers are reluctant to persue. These features, in the automotive world, are commonly called "Lawyer bait".
 
does the fact that the pump is electric rather than what were used to make's it "drive by wire" ?

I thought that "drive by wire" was a system where the steering is not directly connected to the steering wheel.

I agree that car mfgr wont touch this with a 10 ft pole.

ok 69427 just answered my question
 
Last edited:
Pacha said:
If you want to convert to OEM electric power steering pump, follow the link:

http://www.driveev.com/jeepev/convpgs/psteer.php
Click to expand...

80 amps is a hell of a load, especially at idle in a parking lot....

jeez...need a GREAT alternator to keep up with that...CS145? would do it, I think, but if the dual spals are on and the a/c, and and and.....

maybe NOT at that, Leece Neville, where are you???

:devil:
 
Leece-Neville? Just another name for Lucas, "The Prince of Darkness":harhar:

The 4 stroke Detroit Diesel 60 Series would auto shutdown for a few different things- low oil, hi temp, etc., but there was/is an override switch on the dash so you can get off the road. Get one of those dead in the road and the lawyers circle.:twitch:
 
mrvette said:
Pacha said:
If you want to convert to OEM electric power steering pump, follow the link:

http://www.driveev.com/jeepev/convpgs/psteer.php
Click to expand...

80 amps is a hell of a load, especially at idle in a parking lot....

jeez...need a GREAT alternator to keep up with that...CS145? would do it, I think, but if the dual spals are on and the a/c, and and and.....

maybe NOT at that, Leece Neville, where are you???

:devil:
Click to expand...

Sounds like an opportunity for DUAL ALTERNATORS!:evil::evil:
 
What pump are you using? 2nd or third gen mr2? (third gen is the spyder model), the 3r gen ones are unreliable, not sure about the 2nd gen. They crap out and a new one here was 1500 bucks from the dealer, however a blow with the hammer will sometimes get it working again.
 
My cooper has a electric power steering pump. has its own cooling fan also. has two speeds controlled by the speed of the car. Runs faster at slower speeds and slows down as your speed is increased. Gives you more feel at higher speeds. It has a loud whine I'm not fond of. Guess I would pick a belt driven over the electric pump.

The wire that goes to it looks like a battery cable.
 
Twin_Turbo said:
What pump are you using? 2nd or third gen mr2? (third gen is the spyder model), the 3r gen ones are unreliable, not sure about the 2nd gen. They crap out and a new one here was 1500 bucks from the dealer, however a blow with the hammer will sometimes get it working again.
Click to expand...

:3rd::bump: Pardon me, but that's funny as shit.....
 
You must log in or register to reply here.
Top