Are there any advantages or disadvantages with your proposed system (other than cost) compared to eg considering replacing leaf springs with modern coil-over systems, like the popular SSL 5-Link,
Not really John, the reason I'm taking my own path is because I enjoy improving Monty, a considerable percentage of the pleasure I take from owning the car comes from developing it. Monty is largely used on the road, but must also perform well on the track and at hill climbs where I can properly test my cost effective changes, simple ideas that make engineering sense to me.
The SSL 5-Link is very expensive, I'm also not convinced the same or even better results can be achieved for a lot less outlay. As I see it, the two key challengs a suspention engineer is up against when designing solutions to improve the performance of the rear suspension on a Morgan are:
1. The lack of available suspension travel - Morgan's decission to place the axle over the chassis rather than the common practice of placing it under arched chassis rails will always limit available travel, and having such short stroke supension considerably limits the time available for the dampers to tame that big heavy axle
2. The far from ideal relationship between sprung and unsprung mass - A very light body suspended over a very heavy axle is always going to present challenges
An effective suspension tune that balances traction, handling performance and ride comfort requires a holistic approach that considers the total vehicle mass, its distribution across the front and rear axles, and most importantly the relationship between sprung and unsprung mass. On our cars the sprung mass is exceptionally low compared with the unsprung mass, in simple terms a super light body suspended over a big heavy cast iron solid rear axle will always present challenges when choosing spring and damper rates.
The two primary objectives for a suspension system are to isolate the passengers from road imperfections, and to keep the car's tyres in contact with the road at all times. The uncomfortable truth we must all accept is, with the percentage split between sprung and unsprung mass being far from ideal on our cars there will always be a limit to what can be achieved. The SSL five link is extremely expensive, especially for a setup that actually does nothing to address this fundimental design challenge.
Because the far from ideal relationship between sprung and unsprung mass remains, I'd be very suprised if a SSL five link would deliver any better results than the simple cost effective ideas I'm implementing on Monty, ideas that not only involve turning my Bilstens by 90 degrees, but will also include the installation of a pair of lightly sprung coil overs.
