Jeremy Wilkey
Owner, MX-Tech
- Jan 28, 2000
- 1,453
- 0
Hey guys... I've been trying to better articulate some of my ideas, and here is a recent excerpt I wrote up for a friend in the business.
A valve has three interesting variables all related.. Each impacts the other some are more constant some are more dynamic. But each fits into the entire the way a puzzle piece fits into the whole..
A valve (defined as a piston and shim) starts closed or at its least loaded position.. At some point the valve receives enough fluid flow that the input is greater than the existing area, at this point the shims begin to offer resistance to the increase of further port area, and this results in a increase in damping rates, (However not as much (or step on a graph) if the shims did not bend, this would produce exponential or V^2 valving (orifice style))) as the rate in damping increase assuming the fluid flow input increases or remains steady.. However if we where to look at this from another perspective the shims really don't create enough area if the input is greater than the initial value.. So the suspension actually has a tendency to be undersized in the first few microseconds of a input.. Then it is oversized and back again.. If you had a dyno that tracked time and position with enough precision you would notice a very bumpy graph at a constant speed. But dynos read averages..
So Jeremy Wilkeys Theory of suspension. (Theory of perpetual sizing..) 1.)A valve operates not in a steady state but actually responds to input by first being undersized precisely sized followed by over sized in a infinite circle..
A valves job is to place the oil on the shim stack in the most useful way. What is the most useful way? It depends on the speed and the volume of the fluid.. If the piston uses large orifices then it will as a rule produce less deflection than a piston with an equal input but smaller orifices. This relationship never changes. A valve that produces smaller deflections must then effectively regulate the area of valve within the concept of Theory #1. If the fluid flow is so small relative to the orifice then the tendency of the valve will be to under produce area relative to lower speed ranges and over produce area in larger deflections assuming that in the low speed range we have a average shim valve total area that is close to correct. Alternatively, if we have a piston that has smaller orifices and less area it will create larger shim movements to produce sufficient area relative to the input. If the value of the input is beyond ideal then the valve will be soft all the way through and stiff on the higher end of the spectrum, when it goes to v^2 assuming that the valve had correct shim stiffness in the low speed.. In other words it quickly over sizes itself and generally remains that way to v^2 where it rapidly departs from being too soft..
Coming farther form the margins into the comparison of working systems, assuming that both valves concepts are working inside of there given design parameter. The piston with more area will generally strain the shims less as it deflects them less, therefore to maintain sufficient resistance to excessive opening the system will use more shims.. Conversely the system with smaller orifices uses less shims as the material is strained more by greater deflection per unit of area...
When we factor in 2 ports or four ports or 6 ports the material strain is decreased or increased per unit of area. More ports with equal area increases strain on the material so more ports with equal area and similar shim stacks will be stiffer in damping than a 2 port with equal area. Think as the shims bending on more or less plains increases or decreasing the amount of work required to deflect to a value..
Jerey Wilkeys Theory of Suspension. (Theory of ideal configuration) 2.)A piston is not properly designed around a concept of high or low flow but rather configured in such a way that input values are meet with a precisely calibrated shim deflection properties that match the required areas over the widest range as posible.
Finally a valves job is not done alone.. A valve no matter how efficiently it has conformed into theory 1 & 2 will not be able to produce less damping than it did at a speed range below the current one.. (It at best can only produce equal damping) Compromise concept) If we have a need for a certain amount of damping at one speed range and a certain amount of damping at another speed range then the most efficient way to accomplish this goal is to implement the different volumes and how they relate to valve and shim design and exploit the inherent characteristics to optimize the overall design using a series of valves. As they add to the overal damping character..
Jeremy Wilkeys Theory of suspension. (Theory of Damping as the sum of Indudvidual componets.)
3.)In order to produce the lest compromise, it becomes necessary to exploit the given characteristics of divided and proportional volumes. One valve creates larger compromises than multiple valves in a open series..
A valve has three interesting variables all related.. Each impacts the other some are more constant some are more dynamic. But each fits into the entire the way a puzzle piece fits into the whole..
A valve (defined as a piston and shim) starts closed or at its least loaded position.. At some point the valve receives enough fluid flow that the input is greater than the existing area, at this point the shims begin to offer resistance to the increase of further port area, and this results in a increase in damping rates, (However not as much (or step on a graph) if the shims did not bend, this would produce exponential or V^2 valving (orifice style))) as the rate in damping increase assuming the fluid flow input increases or remains steady.. However if we where to look at this from another perspective the shims really don't create enough area if the input is greater than the initial value.. So the suspension actually has a tendency to be undersized in the first few microseconds of a input.. Then it is oversized and back again.. If you had a dyno that tracked time and position with enough precision you would notice a very bumpy graph at a constant speed. But dynos read averages..
So Jeremy Wilkeys Theory of suspension. (Theory of perpetual sizing..) 1.)A valve operates not in a steady state but actually responds to input by first being undersized precisely sized followed by over sized in a infinite circle..
A valves job is to place the oil on the shim stack in the most useful way. What is the most useful way? It depends on the speed and the volume of the fluid.. If the piston uses large orifices then it will as a rule produce less deflection than a piston with an equal input but smaller orifices. This relationship never changes. A valve that produces smaller deflections must then effectively regulate the area of valve within the concept of Theory #1. If the fluid flow is so small relative to the orifice then the tendency of the valve will be to under produce area relative to lower speed ranges and over produce area in larger deflections assuming that in the low speed range we have a average shim valve total area that is close to correct. Alternatively, if we have a piston that has smaller orifices and less area it will create larger shim movements to produce sufficient area relative to the input. If the value of the input is beyond ideal then the valve will be soft all the way through and stiff on the higher end of the spectrum, when it goes to v^2 assuming that the valve had correct shim stiffness in the low speed.. In other words it quickly over sizes itself and generally remains that way to v^2 where it rapidly departs from being too soft..
Coming farther form the margins into the comparison of working systems, assuming that both valves concepts are working inside of there given design parameter. The piston with more area will generally strain the shims less as it deflects them less, therefore to maintain sufficient resistance to excessive opening the system will use more shims.. Conversely the system with smaller orifices uses less shims as the material is strained more by greater deflection per unit of area...
When we factor in 2 ports or four ports or 6 ports the material strain is decreased or increased per unit of area. More ports with equal area increases strain on the material so more ports with equal area and similar shim stacks will be stiffer in damping than a 2 port with equal area. Think as the shims bending on more or less plains increases or decreasing the amount of work required to deflect to a value..
Jerey Wilkeys Theory of Suspension. (Theory of ideal configuration) 2.)A piston is not properly designed around a concept of high or low flow but rather configured in such a way that input values are meet with a precisely calibrated shim deflection properties that match the required areas over the widest range as posible.
Finally a valves job is not done alone.. A valve no matter how efficiently it has conformed into theory 1 & 2 will not be able to produce less damping than it did at a speed range below the current one.. (It at best can only produce equal damping) Compromise concept) If we have a need for a certain amount of damping at one speed range and a certain amount of damping at another speed range then the most efficient way to accomplish this goal is to implement the different volumes and how they relate to valve and shim design and exploit the inherent characteristics to optimize the overall design using a series of valves. As they add to the overal damping character..
Jeremy Wilkeys Theory of suspension. (Theory of Damping as the sum of Indudvidual componets.)
3.)In order to produce the lest compromise, it becomes necessary to exploit the given characteristics of divided and proportional volumes. One valve creates larger compromises than multiple valves in a open series..