grt@twitch.UUCP ( G.R.Tomasevich) (05/23/85)
Mike Bavaro owns Bodymotion in Ocean, NJ and has a wheel alignment computer. He gave the PCA a demo on a 911 he is building for racing. With the shocks in but springs out, he supported the body of the car on his hoist with a 4x4 timber down the center. Two people could easily turn the steering wheel and roll the body to a fixed angle that someone measured with an inclinometer. I forget the exact numbers, but they were something like the following, for the front wheel on the outside of the simulated turn: roll, deg 0 2 4 camber, deg -1.5 -0.5 +0.5 Mike wants to limit the roll to 2 deg, which says that he will still have some negative camber to help cornering. BUT, Mike did not consider tire flex. Assume that in hard cornering the outside wheel sinks 0.5 inch and the inside wheel rises 0.5 inch. For a 57-inch track, that is another degree of roll and +1 degree added to the outside wheel camber. Thus, the actual camber at "2" degrees of roll would be positive. Concerning Guido's posting on weight transfer, I suspect the main reason sway bars help (unless the chassis flexes a lot), is that they help preserve negative camber in turns. -- George Tomasevich, ihnp4!twitch!grt AT&T Bell Laboratories, Holmdel, NJ