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As part of my ongoing project (Maserati twin-turbo into a Dino), I'm trying to model the original chassis in Vsusp before making any alterations so that I can sanity test anything I do in advance.

The problem I'm having is that there are almost no definitions of the values you need to enter. So, for instance, it asks for 'Hub to upper ball joint X' - the little diagram helpfully shows you which axis it considers to be X, but it doesn't explain which part of the hub to measure from.

When I do it from either the disc-mounting face or the hub-mounting face, I get nonsensical results - around 10 degrees instead of the 5 or 6 which I would expect. The only way to get 'sensible' numbers is to more or less double the measurements, placing the measurement point well away from what the diagram shows. I've entered everything else (control arm lengths, etc.) reasonably accurately, so I'm clearly doing something wrong - what am I missing?

x is right to left, y is up and down.

It is the mounting surface for the wheel at the axle center point


10deg for the angle of a line through the ball joints to contact patch is exactly what it is on a 308.

Brilliant - thank you - I hadn't realised that Ferrari ran such a high KPI, so thought I'd got my numbers wrong!

After all that I finally found the factory specs for the Dino - the KPI should be 9 deg. 30', so I was clearly on the right lines!

Great news finding a drawing, it makes things way easier.

Yeah, old suspension is not new suspension. It's laid out to make manual steering and small diameter wheels work. I'm not sure how much it really matters performance wise though.....spreading out loads let you have less flex with less weight and it you are fighting for techs of a second it does matter, but I'm not sure it matters for a good street build and is why I decided to mostly keep the stock stuff on my car.

My intention is to get everything as close to stock as I can, but with the enormous Maserati wheels and brakes. Quite how these will affect the geometry I have yet to determine - but at least I now know that the sums I've done thus far compare well with those on vsusp.

One thing is certain - with the quick rack (a performance upgrade I got from from Superformance many years ago) and the super-wide front tyres, steering it at low speeds would have been a nightmare - which is why I'm in the process of converting it to electric power-assist!