First, although I consult for SUPLEX and specify Quantum dampers for the 5L and the Williams race car, I am not involved commercially in the M3W suspensions.
I drove quite a few miles (for SUPLEX and for the Morgan Factory)in the M3W with the SUPLEX rear units fitted with their internal rebound spring and the B.A.D. dampers. I do really appreciate that they were indeed very difficult to set up correctly and accurately (and you never really knew they were or not until you drove it), but when they were set they are so good - I took the M3W over licence risking speeds, no concern over ride or stability. Some M3W owners still love them and the Morgan factory choose them over SPAX on their trip to the North Cape with a M3W. But SUPLEX have taken note.
Of course the damping characteristic of a damper is only ever as good as the setting the ride and handling engineer decides on; one can set up a cheap Spax to perform far better than a top of the range Ohlin with a poor setting. The big differences between monotube dampers such as Ohlins, BAD, Quantum etc are that they get rid of heat quickly and also the oil never foams or cavitates with hard use, both of which would degrade the performance just when you need it. The other benefit of a monotube is the instant damper response (no oil foam and greater oil flow rate) that can be made the most of with spherical joints not rubber connections; hence no rubber for the Quantums in the race car but poor ride refinement (Henry does not complain).
Following on from the success with the Williams race car and the work on the 5L, SUPLEX are a long way through a project with Quantum to reinstate a suspension upgrade for the M3W. Fronts will again have a progressive spring rate and internal rebound springs to significantly increase roll stiffness however the rears will no longer have internal rebound springs just ride height adjustment. Dampers are adjustable monotubes.
With respect to the torsional stiffness of a chassis and its effect on the suspension performance as mentioned by a previous writer; it is true on a four wheeler that low torsional stiffness of the chassis can degrade the suspension response particularly with stiff springs and dampers as on std 'traditional' Morgans. Hence once you get the initial spring rate and low speed bump damping down enough the suspension will deflect around 5 to 10x more than the chassis will deform; quite the opposite of some std Morgans. The other resistance to the bump loads though the front suspension is the mass it sees and hence the inertia of that mass. With a three wheeler the torsional stiffness of the chassis is far less important as there is zero roll stiffness at the rear for a single wheel input at the front to react against. Hence on the M3W it is predominantly the mass inertia of the front of the car that resists the bump input on a front corner not the chassis torsional stiffness. With the M3W there is a nice heavy lump (something called an engine I think) pretty well between the front wheels that provides the bulk of the resistance as a front wheel hits a bump or you turn in hard.
Hope this helps more readers than it bores as ever ~ PJB.
