Sauber C9

About this model

With the Sauber C8 proving to be a successful jump from the C7, and the Mercedes-Benz M117 turbocharged V8 proving to be a powerful and reliable engine, the C9 was the next car in the partnership between the Swiss race constructor and the Stuttgart giant.

Naturally, the C8 was an evolution from the C8, being lighter, with a strengthened transmission (and Xtrac-supplied differential), uprated Brembo brakes and Speedline wheels. It managed to retain the same amount of downforce, now with 10% less drag.

The 5.0-litre engine remained largely unchanged from its road-going counterpart but came equipped with two off-the-shelf KKK turbochargers and, initially, a Bosch MP1.2 engine management system, allowing the engine to run at high compression with a lean fuel mixture. Power was rated at almost 800 bhp on 2.2 bars of boost and a qualifying tune, but normally reached around 700 bhp in race spec, with a wide power band between 3-6,500 rpm. The MP1.7 EMS came in 1988 for the new C9 switching to a multi-coil ignition system.

Compared to its closest rival, the Jaguar XJR-9, the C9 produced similar torque peak figures but had a broader power band and more torque at low speeds thanks to forced induction. It was more suited to twisty tracks like Jarama and Brno, accelerating faster out of corners, albeit with a larger tendency to oversteer.

Nonetheless, its debut at Jerez was spectacular, with Jean-Louis Schlesser, Jochen Mass and Mauro Baldi bringing home 1st place. During the 1988 World Sportscar Championship and German Supercup the C9s would either win, get on the podium or (rarely) retire, with nothing in between. The only ‘what if?’ was the 1988 24 Hours of Le Mans, where Team Sauber Mercedes withdrew due to tyre concerns following a blowout during Wednesday’s practice. All in all, they finished second behind Team Silk Cut Jaguar in the WSC Drivers’ and Constructors’ titles, winning the Supercup outright.

The Mercedes-Benz C11 was initially planned to debut in 1989 but, as the composite tub was found to be too heavy, it was delayed until 1990 to continue development. The C9 then received the new four-valve 500 SL-derived M119 engine and Bosch Motronic MP2.7 engine management. Minor changes were also made to the gearbox, suspension and bodywork.

The ‘89 season would be an almost complete washout for Mercedes as they would win all WSC bar one, as Jaguar slipped back off the pace.

(In collaboration with @carhistorian)