School me on hydro steering

call howe, give them a pile of money, enjoy a quiet functional steering system.

It depends on what size cylinder you want to run and what your orbital displacement is. Your cylinder size determines the total volume of fluid you will need to go lock to lock, and your orbital (steering control unit) displacement will determine how many turns of the wheel it will take to go lock to lock. Now the ambiguous part is how fast can you possibly turn the wheel? This is what will determine the flow rate tou need in order to not out run your pump. Based on averaged stopwatch tests I did turning a wheel that had zero resistance and a suicide ball, I would say .375 seconds per turn is about as fast as you can possibly turn the wheel. Probably closer to .5 seconds per turn for a wheel with some resistance and no suicide ball.

So using those numbers, here is an example:

Lets say you have a 2.5" diameter, 8" stroke double ended cylinder with 1.5" shafts. You also chose an orbital (steering control unit) with a 160cc displacement.

The cylinder has an effective volume of 25.1ci (area of the diameter minus the area displaced by the shaft, multiplied by the stroke). Since this is a double ended cylinder the volume is the same regardless of which direction you are steering.

160cc = 9.76ci, so the number of turns lock to lock would be 25.1ci/9.76ci = 2.57.

So lets say you can turn the wheel at a rate of .375s/turn. Therefore it would take you .964s to go lock to lock and move the entire volume of the cylinder. Thus, 25.1ci = .109 gallons, which works out to .113 gallons per second, which then becomes ~6.8 gpm. This would be a high end number that I would consider the upper-end limit of pump you could use. Using the .5s/turn number you would only need ~5.1 gpm which would be much more realistic. Of course if you use a smaller displacement orbital (steering control unit) you will have more turns lock to lock and would be able to use an even smaller pump. Using the same cylinder above, but with a 125cc orbital (steering control unit), which would result in 3.29 turns lock to lock, and assuming .5s/turn, you would only need a ~4 gpm pump.

The Billavista hydraulic steering article is excellent, and I would highly suggest that you read it: http://www.billavista.com/tech/Artic...ble/index.html

'84 Bronco II

edit: hah, too slow

This.

A simple call to Howe is a schooling on hydo steering.

That's some great tech there guys

This is supposed to be a hardcore tech forum and your response to the guy is to whip out his credit card? If he wants to try and build a better understanding of a hydraulic steering systems and perhaps put together his own steering, what's the problem with that? Perhaps Howe has the best steering kit around and you couldn't possibly build your own setup for cheaper (I doubt that), but there are plenty of people who put more time ,money, and effort into building things themselves just for the challenge or enjoyment of doing so.

Let's teach people how to fish instead of telling them to just go buy a fish.

You asked a HUGE question. Ask something specific and you'll get answers.

School you?

Go drive a tractor and look at how it works. Tractors are pretty easy to see all the parts.

You need a pump. orbital valve and a cylinder. Pipe it up and bamm, don't kill anybody.

I simply said that a call to Howe is a schooling in hydro steering. And it is. Every single time I've talked to them it turned into a lesson and I learned a ton. That's knowledge I didn't have and can't be taken away.

One thing with Howe, they don't want to just sell you a ram. They want you to know the exact distance your steering moves first, then they'll add stops in the ram so that the ram and knuckles stop at the exact same time. Less chance of parts breaking and gives a hard point at which the bypass opens. They also mentioned running the lines to the cooler as long a possible. This adds capacity to the system and the longer lines do add a bit of cooling.

Talking to the folks who do this stuff for a living at the highest levels of motorsports is never a bad thing.

I am not the OP there Tiger, and I am well aware of the shortcomings of the OP's post.

Certainly, talking to Howe or any of the other companies is not a bad idea at all. I just got the impression from your post that you were telling him to just go buy a complete system instead of answering his question about pump size.

i was

Thank you for the answers and the link to learn more. Didn't mean to start a shitshow, was just trying to see what people are using and where to get answers and knowledge about a subject that I am new to so I want to do it right the first time.

The gm p pump works, but its crapshoot if you can get a good one from the parts store. Dad has an original from the 80s and works flawless, even after being ran empty and on whatever fluid is slick.
I don't think they like high rpms tho, he runs a sbc so it's done at 3grand.

Depending on what you expect this works very well.

P pump limits out at 7k pump shaft rpm, if you can keep it fed with fluid. It's good for flow but not tolerant of overpressure. But most stockers and reman'd cores are getting old now, and as noted, parts store remans are hit or miss because they can get away with it--a P pump is overkill for most stock vehicles so a half-ass rebuild is still "good enough".

As to OP, yes, you can run hydro on a P pump. Proper way to start is with steering force and stroke needed, then size the cylinder, from there size the valve, then from there, to the pump. Starting with the pump is backwards of how it "should" be done. So... OP... How big are you planning here, weight, tires, axles, usage, etc.?

Its a smaller buggy on toyotas and 39.5's. 4.3 and havn't decided on trans yet, but leaning towards keeping the W56. Dual cases with 2.28 and 4.7 gears. 4.88 gears in the axles right now but probably going to 5.29, I will figure that out after I get it driving. Taking my time on it, not looking to have it ready till spring.