I’ve been asked by a couple of people about why I’ve gone for 13” shocks on the front so I thought I might as well give an explanation on my build thread.
I have been working on the issue of the steering contacting wishbones on full droop. I thought I had resolved this by welding in rack limiters as you can see previously in my build thread. This seemed a good solution to prevent the steering on full lock contacting the front of the wishbones but after driving the car in a space large enough to complete a full turning circle it quickly became apparent that the amount of limiting done to resolve the contact issue was too much. I had something like a 19 metre turning circle which I estimated my using google earth lol! I also couldn’t make left turns without going into the opposite lane of traffic, a bit like a bus. So something had to be done.
I know others have used 14” open shocks and rack limiters and have been happy with the results so I maybe just a one off due to my particular Saturn wishbones and the fact I was using Gaz 14” open shocks and not 13” with a 1” top hat. I don’t know, but my turning circle was unacceptable to me.
As I was so far down the line with build and pretty much committed to using MX5 uprights and saturn wishbones (which I actually can’t see how you could improve for clearance without bending) I decided the issue was droop and I needed to limit that droop. Although I didn’t need to change the shocks to limit droop it seemed daft to keep them and not use their full travel. So as a quick test I fitted the 12” rear dampers but they weren’t able to give a correct ride height without a lot of preload and were giving me next to no droop at all and very little actual suspension. So I bought a set of 13” dampers to see were they would put me.
The 13” dampers worked well I could achieve a good ride height without spring preload and also level wishbones, which I’d not been able to achieve with the 14” dampers and 400lb springs (without them being loose on full droop) I also had plenty of droop and active suspension but I was getting contact again at the very end of the steering lock at full droop. So the options were limit the steering lock again but only by a small amount this time or move the shock bracket on the wishbone to again limit droop a small amount and prevent contact.
Limiting the steering was the easy solution but because I’d gone to all this effort I decided I might as well go the whole way and see were I ended up so off came the wishbone brackets and after a lot of careful measuring and estimation of ride height and droop I got them both tacked back on in the right position. It took three attempts to get the 2nd bracket in the correct location to get matching ride height and no wishbone contact.
By moving the brackets outwards slightly I had changed the ride height the cars front frame bottom rail, it was only 85mm off the ground with no spring preload. I could of put preload into the spring but I thought this would be excessive so I ordered some 450lb springs, which seems like a lot but changing the angle of the shock had increased the leverage on the spring.
I fitted the springs last night and with only hand tightening preload the car sits at a static ride height of 105mm. The springs can still be turned by hand when unloaded from the cars weight and the shock length with the cars weight on them is around 12” in length giving 1” of shock droop. Droop at the wheel though is around 1.5-2". The ride is supple yet firm, obviously I haven’t used the car in the real world so I shall keep hold of the 400lb springs for the time being just incase the ride is too firm at the front.
If you can get away with rack limiting with the wishbones you're using and you're happy with it then that’s the solution. As I’ve said mine was just stupid so I had to do something.
