Converting power steering to electric power steering

[oil pan 4]

Rack and pinions use closer to 1,100psi and steering boxes use between 1,000psi down to about 850psi.
Flow through the steering boxes is some where around 3 to 4 gmp at that pressure.
Dont know how much flow racks use.

To produce that much flow and pressure we are looking at needed between nearly 2 to 2.5 horse power to maintain it.
The good news is thats only like 5ft.lb of torque, the clutch I want to use can handle many times that.

[wagon]

I'll get around to my conversion eventually. Too many projects! If it works I'll let you all know (the old Falcon uses a steering box). 2.5hp is pretty significant when you think about it!

[oil pan 4]

I was messing with the aero and rolling resistance calculator on here and came up with needing about 35hp to propell the suburban down the road at 65mph.
Which seems correct to me.
It consumes almost 40hp/hr worth of fuel on average, the difference is from maintaining or trying to maintain speed on hills and a few stop and goes that come with highway trips.

2 to 2.5 horsepower isn't much only about 6%, but even on my suburban playing with the aero and hp numbers if I reduce a little under 2hp worth of engine load it should be good for almost 1mpg.
So it looks like I have some numbers to back up the reasoning to do the mod.

[oil pan 4]

I went and found an electric clutch for a V-belt with 3/4'' keyed shaft on ebay. Converting a 3/4'' push fit to a 3/4'' keyed shaft looks a lot easier than making a 1-1/4'' keyed hole fit a 3/4'' push fit pump shaft like I was originally going to do.
So for $200 i bought it. I just cant pick up 1mpg for $200 any more, all those mods have been done for years, or so I thought.
Another thing is that 2hp is 2hp more over the entire RPM range and it will burn less fuel, not many mods will do that.
I have never seen a pump clutch like this one in this size anywhere else.

[dremd]

Not that it will necessarily help anyone, but the mkv VW golf jetta has a electric rack and I'm sure that a Bentley manual would give specifics on electrical connections. And these cars are starting to make their way in to junkyards with moderate collisions.

[wagon]

I'm nearly there with my conversion. We hooked up the pump temporarily and ran it, no troubles. A bracket is being made 'as we speak' and I'll mount the electric pump about where the belt-driven pump is now.

We did some current measurements too. At 'idle' (no steering angle change) the pump draws around 6A. When moving the steering it draws around 30-40A, and at full lock it draws about 66A. The wiring has to be heavy and your alternator beefy. I'll be using a 100A fuse in the 12V supply to the pump. I figure a beefy alternator will chew a lot less juice than another item hanging off the motor.

[oil pan 4]

Thats good to know.

[wagon]

I've had the electric pump installed for nearly two weeks without any problems. It's too early to see if there are any fuel economy improvements, but I expect there will be some. Here is a link to another forum with pictures. The car runs an old-fashioned steering box and the assist now is less than it had with the belt-driven pump : but it's adequate.

[wagon]

Here's a link to another forum with pictures.

http://fordsix.com/forum/viewtopic.php?f=4&t=70149

[dremd]

Originally Posted by wagon

Here's a link to another forum with pictures.

FORDSIX PERFORMANCE • View topic - Electric power steering pump

Way cool!
I've wanted to do this forever. Mad props.