Steering... Quicker

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zayne2427

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Running rockwells and a PSC TC pump, my current Orbital is a 5.6 and is approximately 4.5 turns lock to lock on double ended ram (will measure size tonight).
How much quicker can i go and not strain my pump and make it hard to turn in slow stuff? I like being in the 2-3 turn range but dont want to make it tough to turn at low rpms or strain my pump.
Thanks
 

d_daffron

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435
From what I understand of hydraulics, how hard it is to turn the wheels is mostly determined by the pressure of your pump and the displacement of your ram. The volume of your orbital will make it take less turns lock to lock but not really affect the overall system power much. It does affect the amount of leverage the steering wheel has over the tires but thats such a small amount of force (a few ft/lbs vs 1,000+ psi) that it really doesnt matter. The only negative going to the larger orbital could cause is the higher volume orbital may be able to move the fluid faster than the pump can supply the fluid. The actual time to turn he wheels lock to lock would not change but it could feel slower because the steering wheel gets hard to turn when you turn faster than the pump can supply fliud.

My new setup is a fairly large orbital (200ml) with a stock CB pump and a 2.75" PSC double ended ram and low speed steering is amazing. The high speed steering Is decent but not great due to the stock pump not being able to keep up with the volume demand of the 2.75" ram. It sounds like your PSC pump wouldnt have that problem though.
 

TBItoy

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With the good pump, you should be able to put a 10-12 cu in orbital on it and still steer ok. You’ll know if you are “outrunning the pump”
 

paradisepwoffrd

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Based on those numbers it take 25.2 cubic inches of fluid to fill your cylinder in one direction.

If you wanted 2-3 turns lock to lock, you'll need a valve with 8.4-12.6 in3/rev.

Let's say you can turn lock to lock in a second. You should be displacing 25.2 in3 every second and the pump needs to flow that. That's 0.11 gal/sec or 6.6 gal/min.
 

RustyC

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Fluid pressure = power output. Low pressure can be felt in the steering input.
Fluid flow is the speed of the system.
Pressure is a result of restriction, add more restriction pressure goes up even is flow stays the same. Keep the restriction the same and add more flow, pressure will rise too.

Your orbital has lower flow that you like. 7.3 with a stock pump or 9.7 if it is a crawler. If racing go 9.7 and a upgraded pump. IMHO
 

zayne2427

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The place I was looking at ordering from has a 9.7 or 12.2. would the 9.7 be quick enough? Or would the 12.2 been too much?
 

paradisepwoffrd

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Re: Re: Steering... Quicker

zayne2427 said:
My Double ended ram is 8" stroke 3" diameter with 1.5" shaft
That cylinder takes 42.4 in3 of fluid to fill lock to lock. With a 5.6 you are 7 turns, with a 9.6 you are 4.5 turns, with a 12.2 you are 3.5 turns.

How big of a pump you need depends on how fast you want to be able to turn the wheel.
 

b.boyd

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The orbital you have is certain very small particularly to be powering such a large ram. Speaking of the ram,part of your problem is a 3 inch diameter ram. That size ram is excessive. A 2.5 inch ram combined with an orbital in the 9.7 c.i. or 11.6 c.i .displacement would put you very close to spot on what you are looking for . If you run a p pump ,your pump will be up to the job no problem. Even running rockwells you don't need bigger than a 2.5 inch ram..
 

zayne2427

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Gotcha. It was on it when I got it. I had ordered a 12.2 before starting this thread and tried to change it to the 9.7 but it had already shipped. I came in this morning and I got it put on today. I'm right at 2 1/4 turns lock to lock. I'm fine with as long as my PSC TC pump will move it quick enough. If I would be better of swapping Rams and smaller orbital I can sell what I have and do that as well. I just want it to be right. Beigh rockwells do I need a 2.5x8 or 2.5 x10 ram? Thank goodness for rear steer. The front steer angle sux.
This is my first set of rockwells.
 

b.boyd

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158
zayne2427 said:
Gotcha. It was on it when I got it. I had ordered a 12.2 before starting this thread and tried to change it to the 9.7 but it had already shipped. I came in this morning and I got it put on today. I'm right at 2 1/4 turns lock to lock. I'm fine with as long as my PSC TC pump will move it quick enough. If I would be better of swapping Rams and smaller orbital I can sell what I have and do that as well. I just want it to be right. Beigh rockwells do I need a 2.5x8 or 2.5 x10 ram? Thank goodness for rear steer. The front steer angle sux.
On the ram "throw" , aka length, the rockwells actually take a 9 inch. However, 8 works fine with rear steering . A 10 inch typically requires a limiting spacer either internally or externally to limit the travel of the ram.
Being that you have rear steer, an 8 inch throw vs 10 inch really seems to be an academic point unless you are trying to compete in the racing series. SO, a 8 inch would be fine. I have been using rear steering for 18 years. Thus, with that said,I can't think of one time I thought I was I had half an inch more turn to the right or left.Rear steering is your friend. thumb.gif
 

paradisepwoffrd

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1,068
Re: Re: Steering... Quicker

zayne2427 said:
Gotcha. It was on it when I got it. I had ordered a 12.2 before starting this thread and tried to change it to the 9.7 but it had already shipped. I came in this morning and I got it put on today. I'm right at 2 1/4 turns lock to lock. I'm fine with as long as my PSC TC pump will move it quick enough. If I would be better of swapping Rams and smaller orbital I can sell what I have and do that as well. I just want it to be right. Beigh rockwells do I need a 2.5x8 or 2.5 x10 ram? Thank goodness for rear steer. The front steer angle sux.
This is my first set of rockwells.
I believe that rockwells technically can do 9", but many run 10s.

Is your steering in front of the axle or behind?
 

zayne2427

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b.boyd said:
On the ram "throw" , aka length, the rockwells actually take a 9 inch. However, 8 works fine with rear steering . A 10 inch typically requires a limiting spacer either internally or externally to limit the travel of the ram.
Being that you have rear steer, an 8 inch throw vs 10 inch really seems to be an academic point unless you are trying to compete in the racing series. SO, a 8 inch would be fine. I have been using rear steering for 18 years. Thus, with that said,I can't think of one time I thought I was I had half an inch more turn to the right or left.Rear steering is your friend. thumb.gif
No racing here just trail riding so the 8 will be fine. I've had rear steer for the last 8;years or so and can't get used to driving without it. Swapping from the 3" ram to 2.5 will it make it quicker or easier to turn? Or did I mess up all together going with the 12.2 orbital
Steering is behind axle.
 

b.boyd

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158
zayne2427 said:
No racing here just trail riding so the 8 will be fine. I've had rear steer for the last 8;years or so and can't get used to driving without it. Swapping from the 3" ram to 2.5 will it make it quicker or easier to turn? Or did I mess up all together going with the 12.2 orbital
Steering is behind axle.
Using a 2.5 inch ram will result in "quicker" turning or less turns lock to lock. As for being easier to turn, if you have a pump up for the job a 3 inch ram has more power than a 2 .5 inch. However, the headaches of getting a 3 inch ram to turn quickly and keeping the steering pump happy is quite a challenge.
 

zayne2427

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2,427
b.boyd said:
Using a 2.5 inch ram will result in "quicker" turning or less turns lock to lock. As for being easier to turn, if you have a pump up for the job a 3 inch ram has more power than a 2 .5 inch. However, the headaches of getting a 3 inch ram to turn quickly and keeping the steering pump happy is quite a challenge.
Yeah I may be better off swapping out the Rams now instead of burning up a pump
 

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