Originally Posted by
Azman Azam
Should I just take the rear roll bars off or both?
Just drop a rate all round, so take the rear off, and go to soft on the front
What difference would it make on handling if we shimed under the balljoints as compared to under the suspension mounts for roll center?
Shimming under the ball joints affects both roll centre, and camber change. The roll centre change is less for the same amount of shims than for under the suspension blocks (on the 415, 0.5mm of shims under the suspension blocks resulted in a 1mm change in RC, 0.5mm under the ball joints changed it by 0.4mm). More shims = lower RC, but also less camber change in the front end (link is flatter). Less shims = higher RC, but also more camber change (link is more angled). In all honesty, I tend to ignore the camber change affect (that can be tuned more effectively by the camber link position on the bulkhead), and just use the shims as a fine tune for roll centre.
What would Kick-up/Antidive setup & also anti-squat gives on car handling?
Anti-dive resists transfering the weight forward, which helps the car corner flatter (this has been covered in more detail.
post #1069 by Apex) It also reduces the castor of the car, improving inital turn-in.
Kick-up is the reverse of anti-dive (in affect, pro-dive if you will). It also helps the car cope better with bumps on a track.
Anti-squat is similar to anti-dive, but it works on the rear, resisting weight transfer backwards, and makes the rear seem to corner flatter.
Changes on the Steering Ackerman would need me to adjust the shims behind the balljoints on the steering rack or the ball joints on the steering knuckle? What would more/less ackerman give?
Shims on the steering rack. If you add shims on the knuckle, then all your chaning is the bump steer characteristics.
Ackerman, for me, is something I'm still trying to fully figure out, but having asked a number of top racers over here regarding the change (and played around with it myself), more shims (link further forward) seems to give the car more steering in general. One thing I have noticed over the last few years, is that the succesful cars indoors on carpet all seem to have very flat steering links, with minimal angle, so less ackerman.
On the 415, I did play with moving the link on the steering hub. Indoors I prefered the feel with the link in the back hole, as it seemed to smooth out the reaction, whereas outdoors I favoured the front hole, as it seemed to make the car more reactive initially to steering inputs.
HiH
Ed