I found this interesting info on "smart shocks". After reading this, I think it is likely that the Sachs shocks on the Genesis are tuned wrong:
http://www.advanceautoparts.com/english/youcan/asp/ccr/ccr20001101vv.asp#Monroe%20Reflex%20&%20Rancho%20RSX
Shock absorbers improve ride quality by cushioning suspension movement. Even on smooth roads, shocks stroke approximately 1,750 times per mile, which is why many OE absorbers won't last beyond 10,000-12,000 miles.
Traditionally, shocks are prioritized to deliver a ride biased toward one end of the ride-control spectrum: either comfort/softness or handling/stiffness. The shock's valving has the biggest impact on firmness. Standard shocks are commonly valved so that about 30% of their available damping goes to compression and 70% to rebound. This bias cushions bump impacts, then cushions the spring's rebound force while the tire maintains road contact.
Smart Valving | Back To Top
For years, motorcycle front forks have moved either faster or slower based upon road conditions. Early automotive adaptations of this philosophy were electronically controlled "active" suspension systems in Formula 1 cars and exotic sports cars such as the Lotus Esprit. A more mass-marketable mutation was driver-controlled adjustable valving, such as the Rancho RS9000 off-road shock (see Photo 2). A dial allows five different levels of firmness to be selected.
Recent technological advancements now allow automotive shocks to automatically alter their valving to match road conditions. The two prominent ways of accomplishing this are through position-sensitivity or impact/inertia-activation. The Monroe and Rancho divisions of Tenneco Automotive are pioneers in these areas, and the Edelbrock IAS shock is another popular example of an impact- or inertia-sensitive shock.
Monroe Sensa-Trac | Back To Top
The Sensa-Trac shock and strut are position-sensitive, using piston travel to change their valving. Under smooth conditions, tapered grooves in the cylinder allow the hydraulic fluid to flow freely for soft damping up to mid-stroke. When the piston travels beyond the tapered grooves, fluid is routed through the piston only, which stiffens the ride.
Monroe Reflex & Rancho RSX | Back To Top
Tenneco Automotive calls the adjustable valve system in its Monroe Reflex and Rancho RSX shocks Impact Sensor Technology. When a bump is encountered, the valve cushions the impact in 12 milliseconds by letting more fluid through. The harder the bump, the more fluid is allowed to pass, so the damping becomes progressively softer. The shock returns to its firm/control damping in 15 milliseconds. This is particularly advantageous in taller vehicles such as SUVs—the shocks are firm for flat cornering but soften to absorb road irregularities. In evasive maneuvers, the Reflex reduces body roll by as much as 12% compared to new OE shocks. In ABS braking, the Monroe Reflex reduces pitch rate up to 18%. The RSX has heavy-duty seals and includes shock boots to help withstand off-road abuse.
Edelbrock IAS | Back To Top
As with most self-adjusting shocks, Edelbrock designs each of its IAS (Inertia Active System) units for the specific application. Furthermore, a standard shock has two circuits (compression and rebound), whereas the IAS has a third "compliance" circuit. Edelbrock says that this circuit can sense the difference between side loads (pitch and roll during braking and cornering) and vertical forces (such as potholes) and adjust itself accordingly. For example, during cornering or nose-dive braking, the IAS switches to a higher damping force to keep the chassis stable. Over bumps or potholes, the damping force softens to allow the
wheel to follow the surface irregularities without transmitting the jolts to the chassis. Furthermore, Edelbrock claims that the Inertia Active valving has a wider damping range than conventional shocks: stiffer on-road than non-adjusting shocks that are valved for "performance" and softer than those biased toward comfort.
Conclusion | Back To Top
Naturally, these "smart" shocks are more expensive than garden-variety replacements. However, they increase safety as well as comfort. Improved tire-to-road contact translates into better handling and shorter stopping distances.
Resources | Back To Top
Edelbrock, (800) 416-8628,
www.edelbrock.com
Monroe/Rancho, (888) SAFER-RIDE, (888) 467-2624,
www.monroe.com,
www.gorancho.com
Toyota/Lexus, (800) GO-Toyota,
www.toyota.com
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) that our "Canadian" Genesis suspension is identical to the rest of North America. My car certainly has the same ride issues, as I have posted before, and I know other Canadian owners have also written about their concerns as well.
