OK. that is what I have done. as we added shims to decrease the grip. but is this the right way? say for instance I want 180Nm. I am well over 250 Nm without shims. so it increases as I shim it out. that is indeed what I noticed so we shimmed it ou further. and I shim it out even more to achieve 180Nm. it adds up to 2.5mm of shims to achieve this.
but now I ask my self if this setup is right? is shimming it out this far common practice or is the group or disc, or both too much for achieving 180Nm?
and one other question. if I find the maximum torque of my engine to be 180Nm, what percentage of safety do I need? if any, as it will more likely grip better when bedded in.
it still feels a bit backwards to lessen the tension, but I think it is to manage the slip and forces better.
yes that is correct, you are actually moving the springs in the cover to the correct place, with no shims you will notice the fingers on the cover are already inwards similar to they would be with the release bearing pushing on them, as you shim it out the fingers move out to nearer where they should be. This is because the parts aren't a good match, you could surface the flywheel or the clutch cover to create the same thing[or use a thinner disc] but thats much more permanent than using shims.
Trial and error is the only way to find exactly what you need for grip as heat will change how it grips as well