Monday 24 March 2014

Front suspension build

The front suspension is now coming together. I'm taking the MX5 measurements from the Saturn plans, but I don't want the lower adjustments. So I've kept the ball joint where it is, kept the bushes where they are, but brought the wishbone tubes out to between the two. So far so good, although cutting and shaping the fish mouths (is that the correct term?) has been an absolute ballache!!

But before I continued, I want to check what sort of suspension measurements I was going to get. So for camber, I have worked out the following (assuming horizontal suspension at rest);

Upper suspension distance from end of studs to the end of the wishbone (where the balljoint screws in) = 192mm.
Upper wishbone length from end to end = 242mm.
Total upper length (end of wishbone tube to end of studs) = 434mm.

Lower suspension distance from end of studs to balljoint bolt = 130mm.
Lower wishbone length from end to end = 410mm.
Total lower length (end of wishbone tube to end of studs) = 540mm.

On the chassis, the brackets are mounted as follows;

Upper brackets are 335mm from centre.
Lower brackets are 247mm from centre.

By my reckoning, that gives me distance from chassis centre to end of studs at 769mm upper and 787mm lower, a difference of 18mm. A rough calculation suggests this is a 5 degree camber, so I'm going to have to get it down to 4mm for a 1 degree camber (ideal start). I don't expect this to be an issue with plenty of space available in the adjustment.

I'll work out caster tomorrow, aiming for +6 to +10 so fingers crossed for 28mm difference top and bottom!