[s-cars] active sway bar

Steve Powers sbpowers at gmail.com
Sat Oct 27 08:48:10 PDT 2007

your comment tells me that perhaps BMW haven't gotten it right, e.g.
the control part. I think the idea is sound but the implementation

if it's dynamic that implies that they are pumping variable pressure
to the servo under computer control. the pressure into the servo unit
is what modifies the stiffness of the bar.

what if you replaced all that computer control crap with a hydraulic
screw pump, e.g. like what you have to adjust ride height on
motorcycle shocks. the only moving part is a "screw" into a cylinder -
pressure is increased/decreased by moving the "screw" into/out of the

that would allow one to set the stiffness and adjust it very easily
(within a range) if it needed changing.


On 10/26/07, Theodore Chen <tedebearp at yahoo.com> wrote:
> bmw calls it dynamic roll control.  if you like driving, run away!  it's part of what causes the recent bmws to feel more like video games.
> ----- Original Message ----
> From: Steve Powers <sbpowers at gmail.com>
> To: S-Cars <s-car-list at audifans.com>
> Sent: Friday, October 26, 2007 9:08:27 PM
> Subject: [s-cars] active sway bar
> I was at a high-end body shop yesterday here in Seattle and got a
> chance to eye a BMW 5-series rear subframe up close and personal. The
> unit had been entirely removed from the car with the wheels and struts
> still attached and undamaged.
> I couldn't help but notice the servo lump with hydraulic lines located
> smack dab in the middle of the rear sway bar. It's an active
> suspension (anti-roll) mechanism that is controlled hydraulically.
> Assuming the rates were done properly, would be a pretty
> sweet-adjust-it-from-the-driver's-seat sort of gizmo.
> Otherwise, it would be a large sinkhole for Pentosin.
> I could see some here (hi Hap!) modifying such a beast for use in our cars...
> Steve Powers
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