The Forgotten C112: Testbed for the V-12 and Active Suspension

The Gullwing had an opportunity to return via the C112 program of the early '90s. But this car ultimately served only as a test bed for many technical advances that would be embodied within future Mercedes.

C112 Pioneered Advanced Chassis Technology

The Mercedes-Benz display at the 1991 Frankfurt Motor Show contained a mid-engined Gullwing coupe engineering exercise that contained many systems that would find their way into future models. Designated C112, this sober design represented the next step in Mercedes’ technology development using a mid-engined platform. Its numeric predecessor, the fabled Wankel – and for world record attempts, turbo diesel – engined C111 program teased us with the prospect of a 400hp, four rotor Wankel gullwing Supercar. Begun in the late ’60s the exciting C111 project became essentially a dead end when the factory dropped Wankel engine development. However, technology developed and tested on the C112 proved to be more relevant for future road cars and we rely on many of these technical advances today.

The C112's sober and clean shape eschewed the 'tack-on' styling gimmicks so often found on future - and current - generations of Supercars. Front spoiler was automatically adjustable in concert with rear spoiler depending on the C112's speed. Mirror placement is similar to the Sauber C11 Sports Prototypes of the era.

Active Body Control

In 1991 active suspension had long been a featured technology in the automobile racing world, particularly F1 and was just beginning to enter the production car realm. Infiniti’s 1990 Q45 sedan was an early “active” production car. Each wheel of the C112 is equipped with a combination of spring and hydraulic servo cylinder. Sensors detect all vehicle motions – vertical displacement, roll and pitch and computers evaluate the data and control the active suspension elements accordingly. The result was a high level of stable roadholding. This technology was the basis for what would become Mercedes’ ADS (Adaptive Damping Suspension) initially found on Mercedes’ V-12 cars introduced in 1993.

ADS Racing Heritage

Have a look at the interesting video below for a quick active suspension tutorial by motorsports media maven Chris Economaki. While the system described was on the late Ayrton Senna’s 1987 Lotus 99T F1 car, the basic system concepts are the same for production cars.

A new V-12

Anyone peering under the enormous clamshell rear deck of the C112 in 1991 would have been struck by the prominent cast aluminum intake manifold incorporating 12 intake runners: A V-12. It’s worth noting that Mercedes’ most potent production engine at the time was the 5.0 liter, 4 valve per cylinder V-8 producing a paltry 322hp and 332 ft/lbs of torque. This exotic new 6.0 liter V-12 produced 408hp and massive torque in a silent, linear manner. In a scant 2 years, the Silver Star’s most discriminate and wealthy buyers could purchase this silky smooth powerplant in either an SL or an SEL. The C112 undoubtedly contributed to this range of engines.

Raising the C112’s massive engine cover reveals the 6.0 liter V-12. You’ll have the same view if you raise the hood on a 1993 SL600.

Extendable rear deck predated speed sensitive automatic spoilers by some years. This position was for maximum drag to aid stopping. Mercedes has experimented with his concept with their racing cars, most notably the 300SLRs airbrake at LeMans 1955.

One bit of technology not making the production cars was the active rear steering system. The ESP (Electronic Stability Program) certainly did, however and has helped thousands of over enthusiastic Mercedes drivers avoid slipping their cars off the road and into the bushes: All thanks to the C112′s hard work at the Mercedes-Benz test facilities.

Roy Spencer, editor MercedesHeritage.com

Photography from ign.com and Dirk de Jager

Recommended Reading:

Mercedes-Benz C111: Experimental Cars by Paul Frere, Gunther Moltler and Julius Weitmann (German Text). ISBN-10: 2880010977

The Mercedes-Benz Museum by Max-Gerrit Von Pein, Thomas Wirth, and Markus Bolsinger. (German Text?) ISBN-10: 3797705298

___________________________________

Please post your comments below.