Questions on Hydro Steer

[Hydra]

So yesterday im at the u-pull when I notice an oddly hacked and trail beaten samurai, so I figure ill go look and see if its got anything worth taking.

Well it turns out it did, I know have a pump and orbital set up for a sammi that I got for $50.

My question is, how do I go about purchasing a double ended ram and measuring for my needs. If anyone knows a good site or link please post up. I never planned to put hydro on my sammi project but hey for 50 clams I can't go wrong.

Any help or ideas would be swell, im not looking to build this all instantly, but ilike to know what to keep my eyes open for.

[Ruepart Hoaxley]

That's one hell of a pick-and-pull find. Which JY were you at?

[Hydra]

At chuckles and edwards

[Zullock Holmes]

i would never run full hydro on a vehicle that sees any street/highway driving. period.

other than that, PSC double ended rams are cheap, poly performance has em in all shapes and sizes for less $200.

basically to determine the legnth of the stroke you need to decide how much turning you want.

I don't know the exact way to calculate it, i just bought a 10" stroke one pretty much cause someone told me to.

But obviously for 50 degrees of steering you would need a ram with a longer stroke than say 35 degrees of steering.

might want to look into running a single ended ram with a tie rod, those setups are known for having a dead spot in them, which is less than ideal for racing but alot of the rockcrawlers use them because they are alittle more simpler to fit into a tight space. who cares if you need to turn the wheel one extra time turning left

[Hydra]

I've read that a 6" stroke ram would be enough for a yota axle, and I don't plan on having over 50* of steerings.

As for double/single ram, really cost would be the limiting factor. What's usually more $$, the single with an entire tie rod or double with the 2 little rods?

[OWEN]

Nice find.

I thing the reason people are turned off to full hydro on street vehicles is the mis-conception that the steering doesn't return to center. If your orbital is load-reactive and you set your caster correctly, the wheels will return to center.

As for cylinder sizing, you will need to do some research to find out the displacement of the steering valve that you aquired to size your cylinder. Quoted from PSC "The displacement of the valve divided into the steering cylinder volume will determine the required turns of the steering wheel to turn the steering axle full lock to lock." I have seen a chart of valve displacement vs. cylinder bore with the number of turns to steer lock to lock, but I can't seem to find it

Most people seem to run run double ended cylinders, at least for front steering. They are more money, but the advantage is equal steering "feel". A single ended ram requires a different volume of fluid to extend versus retract the cylinder (less volume on the retract side because of the cylinder rod).

As for suppliers, I chose PSC for my build, but Surplus Center might be a good place to look for individual components. http://www.surpluscenter.com

Good luck

[OWEN]

Oh and probably the most in-depth write-up on hydro steering

http://www.pirate4x4.com/tech/billav...ng/index2.html

[Hydra]

That writeup was pretty helpful, yet also utterly bewildering.

So what I got from it is that your pump and orbital have an effect on what ram you should use, but only in so much as it effects the number of wheel turns it takes to go from lock to lock.

I don't really plan on streeting this vehicle other than maybe to the gas station, so road feel and highspeed responsoveness aren't huge priorites.

While I know ill need to check the specs on my pump and orbital, isn't it true that just my axle width andsteering angle/throw should be the real determiner in my ram length? What I mean to say is that I probably could never use a 10" ram because it would literally rip the knuckles right off the axle?

[customcreationsllc]

If you're just going to use the steering arms on your knuckles you have now just measure how much the tie rod travels as your steer lock to lock.

Then the closer further out the ram compared to the arms will change your ackermann a little.

The longer the arms the less force in the ram and links required to move your tires (torque) so longer travel rams allow you to run longer arms, also when you get up and over 45º you need the longer travel so you can steer the wheels enough without a little tinny arm.

then your diameter is all about how much force you want.

Basically there is 6" for the stock toyota guys then 8" large and small OD for normal guys. 10" large and small for the 45º plus steering or extreme rock racer guys.

Then you have like 3 speed orbitals so if you have a slow orbital and a 10" large ram it will take a few turns to steer. But the steering speed is mostly whatever the driver wants.


I would run full hydro, a cut line is just as bad as a link falling off both can happen just the same.
People race at 100+mph and don't think twice about it.
With full hydro you can still steer even if the engine stalls.

Just don't let it over heat then you can loose your steering.

If your going with PSC give me a call first.

[Hydra]

So I have an Eaton 211-1183-002 orbital, sourced from a forklift.

Goods news is it is open center, but I don't believe its load-reactive. From what I've read though this fact only worries people looking to drive their rig on road and maintain the feel of normal steering.

The pump I haven't figured out yet. Its a standard alone pump without atteched reservoir, most likely sourced from the same forklift.

I need to find out if its gonna be a constant output pump like a normal ps pump, or if it's variable.

Part number on the back says N 7810.

[Hydra]

Here's the unit

[customcreationsllc]

Pump shouldn't matter so much as long as the pump can keep up with the volume requirement and just put a reservoir above as direct as possible to the pump PSC reservoirs have baffles and stuff in them.

Then just unrestricted return with a huge cooler. If it over heats boils you will loose your steering.

There is a lot of good info on Pirate.

As for the orbital just blow air into one of the outs if it turns the wheel it is force feed back.

You need open center because p/s pumps are continuously flowing when the engine is running so you want the fluid to just flow right through the ram when your not turning.
A closed center would dead head the fluid, this would be used on large equipment when you have a lot of hydraulic stuff. Or if you had an electric pump that only ran when you steer.

Think of an Orbital as big pump that you turn by hand to put fluid in the ram but you have a lot of pressure by the p/s pump so it is easy to put push the fluid into the ram. force feed back has nothing to stop the fluid from pushing back against the pump, so if you push fluid from the ram back into the orbital it will try to turn the wheel.

Non force feed back is like a one way check valve you can put fluid in the cylinder then it locks it out cannot force the pump back so you wouldn't need to hold the steering wheel to force the tires up against something.

Basically you probably have the right orbital I think only large equipment use the stuff we don't want.

PSC and Howe might modify them a little to get them to work better I know they open up the orifices in the steering gear boxes to flow more fluid for the ram assist to work better.

Worst thing it is not the correct orbital you run with it for a little while and the right one will be a direct bolt in. For a crawler just about anything will work. Street/go fast you want everything to match up.

If you're not going to use if for a while stop by one night I would like to make a CAD model of an orbital.
If you want any PSC parts give me a call first.

~Justin

[Hydra]

Will do boss, how's friday night for you? Ill stop by with the orbital and have a beer or something.

[customcreationsllc]

Friday is good.