ExSRT8Guy
Been There, Done That
I don't know off the top of my head what the "P" rear spring rates are, but I'll bet they're at (or under) 200lb/in. With 3/4" static clearance between the frame rails and the bump-stops, that would allow you less than 150lbs of load transfer to that spring before you're on the bump-stop and go to effectively infinite spring rate (simplified) and that certainly WILL create a "non-linear" handling characteristic. Same will happen if you bottom out the shock on that corner as well...
When you say "the back end started to come around," do you mean that you experienced SOME oversteer, or that you suddenly snapped around? big difference in the diagnostics tree. Also, how much experience do you have on track? If you're timing laps, what is your typical time spread on clean laps? 0.1 seconds? 0.5 seconds? 1 second?
I'm inclined to look at driver input rather than hardware first...
Maybe it's an inch. Didn't measure; just guessed from the visual. But I get your point. That said, there's a measurable amount of compression in the untrimmed bump stop before it goes "solid", right?
Snap oversteer is what we used to get when we lifted throttle mid-corner in a pre-'64 Corvair, or an early 911. Compared to that, this was "some" oversteer. I steered into it, let off, got it straightened out, and kept going. Nothing overly dramatic, but definitely not the quickest way through that corner.
I have no idea what my lap times are. I'm just out there to have fun in a controlled environment, hopefully without thrashing one of my street cars too badly