First autocross weekend

So, even though we actually broke the car today, I think our first autocross was a success. I drove first and the car really, really bounced around on the rough surface we use and understeered everywhere. I didn't know what was going on until I watched Briget drive, and it looked to me like the car was bouncing off the bump stops. I stiffened the rear suspension a couple of steps and went out for my second run. It was a lot better and started to go through slaloms much easier. For my 3rd run I stiffened the rear another step and also stiffened the front by one step. It was even more controlled but the rear still really bounced in a couple of places. The high speed compression was already at full soft so I adjusted it to full hard but left the low speed compression and rebound at full soft and sent Briget out on her run. Going over the first massive bump on the course, the bracket holding the short arm of the Woblink broke, allowing the rear suspension to move around-our day was done. I got the car back to the shop and took a good look at it. There was enough flex right at the end of the bracket that after Friday's track day and todays autocross, the piece failed from constant flexing. I boxed it so flex has been eliminated and we won't have that problem again. Here's a pic of the broken link:

The data from my 3rd run shows that the car was pulling .6 G at 50 mph (the only time I got on the gas in 2nd gear) and was hitting over 1 G in either direction so it has potential but I certainly was not getting the most out of it. I'm confident that it will be a lot better on a smooth surface without pivot cones. Just check out the video and you will get an idea how violent it was inside the car.  Video of first autocross event

 I was still trying to understand what the rear suspension was doing (other than breaking) so today I put zip ties on the shock shaft to see how much compression they were getting, and I aimed a camera at them. The car was really unstable under braking but was better over the big bumps.

When I got back, the zip ties were shoved up against the bump stops. I changed the high and low speed compression settings from full soft to full stiff and sent Briget out.  When Briget was on course I could see the axle moving back and forth and for a moment thought that the newly fixed bracket broke again, but that was not it. The zip ties were not up against the bump stops this time so that was positive.

 Once in the pits I tried to determine how the axle was moving back and forth and couldn't find anything at first but once I had Briget shake the car back and forth really hard, I found a fracture in a different bracket. Obviously the forces on the Woblink are greater than a typical lateral link like a Panhard or Watts because these brackets were pretty robust and were still snapping 3/16" and 1/4" solid steel plate.

   I know from trying different roll center heights at the lapping session and autocross that the car likes it set above 8" high, so I am going to remove the troublesome Woblink and install an adjustable Panhard around that height. Here is a very interesting video of the rear suspension during a run, once you stop being mesmerized by the shocks moving around, notice how much the diff is moving back and forth due to the broken Woblink.  Video of rear suspension