Hi all,
Been struggling with rear axle hop under hard braking on track in my '12 Boss. Anything over ~0.8g's, especially if the pavement has some ripples. Getting some pretty violent vertical movements from the rear axle which of course de-stabilizes the whole car, needing release and re-apply of the brakes to get back under control. This is during straight line braking. The approach to turn 7 at Sonoma is pretty much guaranteed to happen once i start pushing the braking zone. Has also happened to me braking for turn 5 at Laguna and a few other places I can't recall. Otherwise the car handles and performs great on track. Rear end feels planted and stable on power.
I have the Maximum Motorsports road & track package, which includes MM springs (progressive rate, avg. 340 lb/in F, 300 lb/in R I believe), koni yellows, shortened bump stops, rear LCA's + relocation brackets, and UCA. Shock rebound setting on all corners is nearly full soft. 275/40/18 Nitto NT01 tires square. Stock brake calipers and rotors, pads are Raybestos ST-47 F, ST-43 R. This front/rear split was recommended to me by David Ray from his experience with Spec Iron.
I track it with traction & stability control fully off (hold button for 10 sec while on the brake). I'd expect that increasing the shock rebound setting in the rear would make the problem worse, so have not messed with that.
Anyone dealt with this issue before? Could it be caused by the stock ABS not being calibrated properly for the setup I have?
Thanks!
Been struggling with rear axle hop under hard braking on track in my '12 Boss. Anything over ~0.8g's, especially if the pavement has some ripples. Getting some pretty violent vertical movements from the rear axle which of course de-stabilizes the whole car, needing release and re-apply of the brakes to get back under control. This is during straight line braking. The approach to turn 7 at Sonoma is pretty much guaranteed to happen once i start pushing the braking zone. Has also happened to me braking for turn 5 at Laguna and a few other places I can't recall. Otherwise the car handles and performs great on track. Rear end feels planted and stable on power.
I have the Maximum Motorsports road & track package, which includes MM springs (progressive rate, avg. 340 lb/in F, 300 lb/in R I believe), koni yellows, shortened bump stops, rear LCA's + relocation brackets, and UCA. Shock rebound setting on all corners is nearly full soft. 275/40/18 Nitto NT01 tires square. Stock brake calipers and rotors, pads are Raybestos ST-47 F, ST-43 R. This front/rear split was recommended to me by David Ray from his experience with Spec Iron.
I track it with traction & stability control fully off (hold button for 10 sec while on the brake). I'd expect that increasing the shock rebound setting in the rear would make the problem worse, so have not messed with that.
Anyone dealt with this issue before? Could it be caused by the stock ABS not being calibrated properly for the setup I have?
Thanks!