tre5
+1y
The accumulator on a cylinder doesn't act like a shock or a coil... it kinda acts like both.
You have to think of the cylinder, line and accumulator as one unit. Think of it like an off road shock with a long reservoir hose... where there is oil in the shock body, the reservoir line and part of the reservoir. Inside the reservoir of the off road shock there is a floating piston that separates the oil from the nitrogen. In the accumulator there is a bladder that separates the oil from the nitrogen. The big difference between the two is that the shock has a valve stack that controls the amount of dampening whereas the cylinder just has the seals that keep the oil inside of the cylinder. With both setups when you hit a bump the shaft moves the oil through the system until it hits the piece that separates the oil from the air. The amount of air pressure helps control the stiffness of the ride, but like I said on the off road setup, there is additional damping with the valve stack. The thing that allows the accumulator to act like both is the fact that you can adjust the amount of oil inside the cylinder. The more oil, the more spring... kind of. The more nitrogen in the accumulator, the stiffer the ride (in most cases).
Accumulators are sometimes tricky to dial in perfectly... reason being... because they hold a small volume of oil and air. If you put too little pressure in the accumulator they will fill up with more oil when you lift the vehicle and then when you hit a bump the amount of oil that can enter the accumulator before the bladder bottoms out is less (because they are already almost full of oil). And the opposite, if you put too much pressure in the accumulator it will not allow oil to enter the accumulator at all (because the amount of air pressure keeps it out). So you have to find the happy medium based on the weight of the vehicle and where the cylinder is positioned on the suspension (because of the leverage applied to the cylinder). A good starting point is around 350-500 psi on the standard size accumulators.
The location of the accumulator doesn't matter because, like I said, you have to think of the cylinder, line, and accumulator as one unit. The line pressure increases when you hit a bump whether the accumulator is at the cylinder, at the pump, or somewhere in between.
Moral of the story... you can run a setup without coils or shocks and you will get a pretty good ride. However, if you add a shock to the suspension you will gain some additional damping control. The ride with accumulators is often described as "floating." Since you have the freedom to design the suspension on most trucks it would be beneficial to add shocks in the suspension to control the amount of floating.