fkrieger

I wanted to see if anyone had thoughts on BMW's active roll stabilization versus MB's Active Body Control (as found on the CL and higher end MBs). I have an e60 545 and really like to take loooooooong turns at high speeds to feel the car flatten out. A family member has a 2006 CL500 with ABC and he swears that it is unlike anything on the market. From the research I have done it looks like both technologies are trying to address the same problem: eliminate body roll (with the ABC's added advantage of being able to raise the car a few cm's to get above the driveway lip).

The difference from what I can tell is that (taken from a few sources on the internet) the BMW system addresses lean only (lateral to the car):
The BMW Active roll stabilization winds up the stabilizer bars in the front and rear suspension to resist body lean while cornering. It uses a hydraulic coupling in the middle of the stabilizer bars. This unit decouples when the car is going straight, allowing the suspension to be more compliant and the ride to be softer. When you make a turn, the stabilizer bars reconnect and keep body lean in check. Because cars use active control only as needed, the technology reduces vehicle spring rates and stabilizer bar stiffness, resulting in a smoother ride.

The MB, on the other hand, addresses the problem at the struts themselves and uses computers to "sense"road conditions and adjust accordingly for both lateral and "vertical" (front to back) adjustment. Again, taken from somewhere on the internet:
Four spring struts are equipped with microprocessor-controlled plunger cylinders which almost completely compensate yawing, pitching and rolling movements of the vehicle body. The computer receives information about the relevant driving situation from the various acceleration sensors, then compares this with the data from the pressure sensors in the spring struts and the level sensors in the steering control arms. The ABC system translates this information into control signals, which are implemented as precisely metered oil flows by hydraulic servo-valves on the front and rear axles. When oil flows into the plunger cylinders, these adjust the tracing point of the steel springs integrated into the spring struts, generating the forces necessary to counteract movements of the vehicle body.

swajames

They're different means to the same end, and as far as I can tell both systems do a very good job is eliminating or reducing body roll. I've had a lot more experience with ARS, and it works exactly as advertised, but the ABC system available from Mercedes is essentially the same thing.

gmethod

Being a former late model SL500 owner (currently own 07' 550i sport), I could tell you the systems feel vastly different. I agree they ultimately achieve a similar result (body roll reduction), Mercedes ABC system is pretty sophisticated in functionality. While BMW hydraulic swaybars mostly affect body roll, ABC controls every aspect of suspension travel. Nose diving during hard braking is eliminated....squadding during hard acceleration gone....body roll greatly controlled...suspension firmness adjustments witht the press of a button...and so on. Also, as you mentioned, being able to raise the car to avoid steep driveways like mine is a major plus...specially after I lowered the car. Another cool thing about the ABC system is that it lowers the car close to 1" during high speed cruising for better aerodynamics.

As I said before...pretty sophisticated system. That being said, handling it's not mercedes best attribute. Although they can carve the twisties with confidence..the SL felt more like a cruiser than anything else. Even with the sport setting on..moving the 4000+lb SL around turns was a bit daring. Dont get me wrong...it did fine but not as well as the 550i. Before the SL500 and I had an SL600...and before that I had a C5 Corvette (heavily modified) and a C6 Z06. I've driven a few AMGs and they are fantastic!! But still...very heavy and the feel heavy. The only reason why I sold the SL was because I wanted a fun car with 4 seats. Even though my SL and Corvettes were not my daily drivers (have another car for that duty).

BMWs hydraulic sway bars are great...pretty simple solution in my opinion. Specially since we get to keep proper springs and struts! And those can always be upgrade! Now that I have a great daily driver...the 550...I'll look into getting a nice convertible...4 seats of course...a few years from now.