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I have been working on the in's and out's of my mini buggy's cantilever air suspension. I am shooting for 12" of travel and I always go for the do it different method. I was looking at these air cylinders used on Honda cars to slam them, 4" bore and 4.5" of travel. I can run in a 2.5-2.75:1 ratio that will give me 12-3/8 at the wheels, they produce 1250lbs of force at 100psi which translates to 450 per corner which is more then enough. I will run them with a .5 gallon tank connected to each cylinder with a 1/2" line to increase air volume and smooth the ride out a bit. Of course 4 pressure valves to control each cylinder independently.

I think my sprung weight without passengers will be no more than 1000 lbs so I should be able to run the cylinders and WAAAAY less then their 200 psi working psi, more like around 70. What do you think will it work?
 

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Discussion Starter #3
They are designed to work with air systems, I would rather just use air to keep it simple.. i wonder what the downfalls of that would be..
 

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Discussion Starter #7
I have sourced a cylinder with a 3" bore 12" stroke, this will make this much easier to do. I do not have a Pneumatic or Hydraulic background at all. I have been told by Pirate member Air Ride that he runs a 5 way closed center valve for his air cylinder setup. Well I for the life of me cannot find a 5 way valve, I can find a 4 way which will allow positive control of the cylinders both up and down.

I cannot figure what the function of the 5 way would be and the interweb is not giving up its secrets easily. I still feel like I will have to run a small tank on the extend side of the cylinder to allow for more damping and I am concerned about pressure and vac in the other side of the cylinder when the suspension cycles. I am soooooo confused right now can someone shed some light on this, I feel so close to a solution but can't get there.
 

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Discussion Starter #8
Okay here is my thinking here and I am sure its off the wall as hell.... In the picture below we have the pump, main tank plumbed to the control valve.. 4 way closed center 5 ports. The exhaust ports open when air is supplied to the opposing side of the cylinder. I have an accumulator tank on the top side of the cylinder to increase air volume to allow a little more spring action to the ram.

Here is the weird side there will be a control valve on the bottom end of the cylinder and will have to positions drive and cycle. In cycle it will connect the bottom of the ram directly to the cylinder. In drive mode it will allow the air from the bottom side of the cylinder to breathe thru a bleeder valve to give the cylinder a damping effect.

Unless the function of the mystery 5 way valve is revealed this may be the only way to get the type of suspension response I want.
 

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Here is an idea. Why couldn't you just use a standard 2 way hydraulic valve, like for rear steer. Plumb the main tank to pressure inlet on the valve, then run one outlet to the accumulator tank, then to the top port on the cylinder. Just plug the bottom port. When you want to let air out of the cylinder just hit the opposite direction on the valve and it will become the exhaust. Would that do what you want? It seems to me that it would. Just like the lift mast on a fork truck, it just powers up and exhausts down. I'll draw a picture, be back in a second.
 

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Here is an idea. Why couldn't you just use a standard 2 way hydraulic valve, like for rear steer. Plumb the main tank to pressure inlet on the valve, then run one outlet to the accumulator tank, then to the top port on the cylinder. Just plug the bottom port. When you want to let air out of the cylinder just hit the opposite direction on the valve and it will become the exhaust. Would that do what you want? It seems to me that it would. Just like the lift mast on a fork truck, it just powers up and exhausts down. I'll draw a picture, be back in a second.
Whoops, don't plug it, that won't work but I know what will.
 

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Discussion Starter #11
I thought about doing just that until realized the advantages of being able to LIFT a wheel if need be. That is where the thinking began...
 

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If you think about it will only be air at one atmosphere in the bottom of the cylinder, air is easily compressed so there is no need to route the bottom of the cylinder to a relieve pressure like a single acting ram. You simply compress the air in the bottom with the air in the top.

So when you activate the p port you pressurize the top with no need to relieve volume off the bottom. The return line for the valve becomes unnecessary. Then when you hit the return the air just goes back the way it came and exits through the t port like the fluid would to return to the tank. I think it would work, and it would be one component and cheap. You could have 4 valves and control each wheel independently
 

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it will, but if controlled he can set lower chamber pressure to do that or actually lift the wheel, maybe, but, due to the unsprung weight and pressure required it might not be practical, however, being able to adjust the pressure differential (like an ori) would add tuning, might also consider adjustable orifices between the strut and aux. tank to add "valving" to the setup..
 

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Discussion Starter #16
I am following you, seems like the extra circuit is not needed, I can use the 4 way valve to control movement and just let the the air compress against the valve.
 

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Discussion Starter #18
I can find no information on the 5/3 flow patterns that make sense to me... The 4/3 way directs air into one side of the cylinder while at the same time exhausting it out the other. Does the 5 way allow you to preload each side of the cyllinder? I have been at this for hours and getting no where fast, I may need some sleep...
 

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Discussion Starter #20
I think we are talking about the same valve here using different terms.... flow pattern looks the same as the one I found from Mcmaster Carr.
 
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