This is all great information. I have a somewhat related question. In ur opinion what is the ideal motion ratio and why? I like to hear what different manufacturers and tunners theories are. Most I have talked to like to shoot for a 1(shock) to 1.75 (suspension) motion ratio. Also would like to know what ur stance on digressive shock geometry? I have heard that if you are within 10 degrees (10* being extraleam) of 90 the effect on the shocks is not noticeable. That being said I fell like that would mainly apply to big shocks and not smaller diameter stuff.
There is no ideal motion ratio because all vehicles are different, generally from our experience more than 2:1 and your really working the limits of component strength, and asking the damper to do a-lot of work creating more heat and wear. We did work on a product for a industrial SxS that had a little over a 2:1 ratio on it it turned out working great but took quite a bit of tuning to make perform to their needs, and it was really pushing the limits of the arm design. to summarize, if your shocks are of old design and you are struggling with flow issues and cant get the shaft speed out of them it is the shocks fault not the ratio, more ratio could help the issue by slowing down the shaft but its not the fix. ALL of our bypasses have high flow reservoir ports to prevent the shaft displacement from being a fluid restriction. and we match tube flow to shock size for each application.
Ratio is help full for packaging realistic lengths into trucks, it would be really hard to get a 16" coil over under the hood of a Tacoma, and a 30" travel axle mounted bypass sticking out the back end of a truck would be silly. If your specific shock can flow enough fluid to keep up with the shaft speeds you are developing, then you would be in the operating window of your hardware. the closer you are to 1:1 or even less ratio the shocks would run a little cooler in theory since it wouldn't be working as hard to control the forces, think less valving to do the same work. (see the back of Kyle Leduc's pro 4 truck.)
We compensate for these scenarios by going to larger shocks with greater fluid capacity and flow that can generate greater damping forces.
choosing the right tool for the job is a better way to look at it, if your running a 1500lb dune buggy im not going to recommend a 4.0 shock its would be the wrong tool for the job would i recommend a 2.5 shock for the back of your trailing arm race truck also no its not the right tool.
I don't want to start the argument on "my buddy has digressive shock geometry and it works fine", "fine or good" is all relative, if your asking what we design and work with, you always want your suspension to be progressive or linear in design. don't go past 90 degrees the forces are nearly impossible to control, you start fighting flow issues because you have to nearly go solid with valving which feels like trash, most of these guys that say it works are HEAVILY relying on the hydro bump to catch all the slack.
We have recommended to many, that they make changes from digressive to progressive and they have been extremely thankful after making the changes, you might loose a little travel depending on your design but you will be able to effectively control your suspension which is the whole point of what an high end shock is for.
You guys can debate all you want but that's all we will contribute to it hahaha