Originally Posted by swamp2
You mean active roll stabilization for essentially variable rate roll bars or electronic damper control for variable shock damping. I think if I had to pick one I would go for EDC ala M5.
Yes, active roll stabilization. The way BMW implemented it is not by varying the rate of the sway bars. Thats actually constant. What they do is apply a variable pre-load to counteract the tendancy of the car to roll when turning. Its basically a small motor that twists the bar in the center. It can also effectivly disconnect the bars if the motor is allowed to move freely.
The reason I think the technology is the best improvement BMW has had since the move away from semi-trailing arms in follows. BMW refuses to use a front suspension with a better dynamic camber curve. So therefore to minimize camber losses and to keep the tires flat they also have to keep the car flat. Now the traditional way to do this is to run massive spring rates. Thats not acceptable in a street car. By varying the pre-load on the sway bars BMW can do the same thing without any loss of comfort or compliance when the car is not turning. Also interesting the effective spring rates do not change even when the car is turning, all the effect of keeping the car flat is from dynamic pre-load.
Basically its a way to keep the car from leaning without having to run stiff springs.
m3ichael: You are right I am not a mechanical guy. I hate to work on cars. However, I have done some vehical simulation software in the past (err, video games) and have a general engineering background (not comp sci).