I have a 2017 BRZ wit RCE SS-1's and SPC RLCA/SPC front camber bolts in the lower slot. Camber is -4 up front, -2.2 in the rear with 1/16" toe in. Perrin 19mm front swaybar and endlinks. Tires were 225/45/17 A052's - rather heavily worn with 170+ runs.
Ride height in the front is 13.5" hub to fender and 14" in the rear. I do realize this is a bit higher than most and is only a hair lower than stock (Thanks to my driveway).
Finally got the car out to an autocross test event yesterday and the rear end was terrible. On longer sweepers, trying to put the power down, it felt like the rear end was skipping or hopping around. Almost like the rear diff was doing rear diff things searching for grip. This never happened on the stock suspension at all. Video below, but it felt more violent in the car than the video shows.
My settings were on the recommended street/comfort mode of 14 clicks from full stiff in the front, 16 from stiff in the rear. After about 3-4 runs, I upped the settings to only 2 away from full stuff in the front and 3 away from full stiff in the rear. This noticeably helped the the issue, but didn't fully fix it.
If I can wrap my head around it, I'm thinking on the soft settings the car wasn't staying flat enough and I was actually slightly lifting the rear inside wheel, making the diff kick in on power. Stiffening things up helped keep it more level and it didn't skip around as much. Or possibly the car was just bouncing because there wasn't enough dampening for the springs for those conditions.
So, what exactly is the solution here? I can't really change the rear ride height and feel like it being high is goofing with the suspension travel. I can try putting it to full stiff in the rear and tailoring the front the match, but this feels wrong as the recommended 'track' settings are more or less in the middle of the adjustment range. Extra side note, at 3 clicks away from full stiff in other areas of the course, the rear end was more lively than I wanted.
For what it's worth, I actually felt like the car drove better on the street with the stiffer settings on the way home. I have a fresh set of A052's in 245/40/17 on 9" wheels going on this week for the first official event. My guess is the car is going to drive and react completely differently than on the heavily worn tires.
Any suggestions on settings would be highly appreciated. The suspension rides GREAT on the street even on the much stiffer settings.