By Jeremy Martien
Active Suspension is the type of automotive suspension that controls the vertical movement of the
wheel and suspension relative to the chassis of the vehicle using an onboard system unlike passive
suspension where the vertical movement is determined by the road surface. The basis of Active
Suspension can be defined by the “skyhook” theory stating an object can maintain stable posture if it is
traveling suspended by an imaginary line. To further define the history of Active Suspension and its
technological advances, we will develop a timeline on milestones for the industry successes/advances.
History brings us back to over half a century ago in the early 50’s when the first production car of its
type, the Citroen DS, was introduced to the auto industry with the premiere of fully active self-leveling
hydro pneumatic suspension system named Hydractive. It wasn’t long after that GM adapted to the
technology and the 1957 Cadillac Eldorado Brougham premiered with its own active self-leveling air
suspension. This was just the beginning for the revolution of active suspension technology.
It started to become more prominent during the “Golden” era in the 80’s with the Lotus and Williams
Formula One teams adapting active suspension technology to the fastest road course cars in the world.
There were major hurtles and shortcomings’ (strides to overcome) that almost indefinitely ended the
revolution of active suspension. From the lack of experience with the new system, to Lotus having
trouble establishing a relative cost to benefit, and finally in 1992 when the FIA banned active suspension
due to Williams success in the FW14B and FW15C chassis that almost drove the technology away.
During this era, production vehicles were introduced to the enhanced suspension technologies with
Mercedes-Benz, BMW, and Toyota hopping on board each bringing a new suspension system to their
higher class cars. The Mercedes Benz SL of the R 129 model premiered with a multi-stage electronic
damper adjustment as an option while its German competitor BMW offered the BOGE adjustable
damping system as an option for the late 80’s BMW E30 M3. Toyota did an incredible strive during the
era starting in 1983 with the Toyota Soarer premiering semi-active Toyota Electronic Modulated
Suspension (TEMS). By 1986, the Toyota Soarer had the world’s first electronically controlled full air
suspension system featuring spring constant and variable attenuation force.
In 1988, GM invested over $27 million into designing the most advanced suspension system ever built
on a production car. So by 1990, based off Lotus’s original architecture, GM developed a program for a
Delco computer to hydraulically control all four struts to actively level the body through corners and
undulating road conditions. This new development would be adapted to 25 pre-production 1990
Corvette ZR1s. Similar to technology today, the Delco computer sees speed, tire load, steering, throttle,
and other inputs into a complex algorithm to dictate which hydraulic pump would deliver its fluid to
which strut. Unfortunately, the system didn’t make it into production till ten years later and had many
faults including electrical interference and the unknowns of friction and corrosion that caused reliability
issues. Ten years later, GM developed the Magnetorheological active suspension using their previous
experience from the ZR1 to develop on the 2003 C5 Corvette.
From 1989 to 1994, Toyota/Lexus developed various suspensions that were deemed new technology
eventually earning them an award from the Japan Society of Mechanical Engineers for New technology.

These suspensions included the TACS(Toyota active control suspension) for the Celica in 1989 as well as
an updated version of TEMS(Toyota electronic modulated suspension) from the Toyota Soarer back in
’83 for the Celsior. Skyhook adaptive computerized suspension was implemented after much success
from Toyotas suspension program and design which ended up in the second generation Lexus LS 400 in
1994.

Mercedes-Benz CL500/CL600 Coupe set the new standard for automotive engineering excellence in
1999 with the world’s first active suspension system in a production car. ABC, active body control was
the milestone in dynamic handling control and ride comfort. This system like previously designed
systems was hydraulically controlled servos in the spring struts to work in unison with the passive shock
absorbers. The ABC active control only reduced oscillation boy vibrations up to 5hz (low frequency)
while the gas pressure hock and springs were responsible or handling high frequency wheel vibration
from 6hz-20hz. The downfalls to this system was described by the damping effect was less pronounced
than conventional suspension systems at the time.
In 2005, Mercedes and Porsche developed the active suspension to system respond the quickest it ever
has before. Mercedes had the W 221 S–class with an enhanced airmatic air suspension system in
combination with ADS, adaptive damping system. This new system continuously optimized strength of
shock absorber response in line with the condition of the road, driving style, and load within
50milliseconds. PASM, Porsche active suspension management was introduced in 2005 to production
997 911 vehicles with the option of PASM suspension over the standard suspension. PASM would later
become standard on 997.2 911’s till present day 991’s using the same algorithm process with two
accelerometers receiving input to the PASM controller on steering input, body roll, and suspension
bump.
In 2007, Nissan revealed the R35 GTR at the Tokyo Auto Show that had Bilstein B4 damptronic dampers
and a controller unit similar to the PASM on Porsche. This brought another manufacturer giant into the
active suspension mix establishing that active suspension was the new wave of technology for the
automobile industry.
In 2011, Mike Levitas founded DSC Sport which offers an open-interface suspension control module
offering unlimited tuning capabilities for your active suspension whether its OEM or aftermarket
suspension. DSC Sport also offers to vehicles with passive suspension a Stand Alone Harness kit to adapt
active suspension technology to these vehicles, even Restomods. The future of active vehicle suspension
can only get better and more compatible with more vehicles.
Ford adapted active suspension with the magnerheotoric dampers starting in 2016 for the Focus RS and
Mustang GT350 and GT350r.
Today, active suspension has made great leaps in technical advances and compatibility with many
vehicles. By now, most mainstream manufacturers have active suspension standard for their higher class
vehicles such as GM(Corvette C7, Camaro Gen 6), Chrysler(Force 1 V10, Dodge Viper), Porsche(991, 981,
Macan, Panomera), Nissan R35 GTR, Ford (Focus RS, Mustang GT350), and BMW(M3, M4, M5). There

are several aftermarket options for electric and magnetorheological dampers to this day from Bilstein,
KW, Tractive, and more.